VideoTestimony: bipolar disorder, ADHD and a hurt ankle

Carla Colon’s testimony with essential oils for bipolar disorder, ADHD and a hurt ankle

VideoTestimony: bipolar disorder, ADHD and a hurt ankle

Evidence that Omega-3 Fatty Acids Support Brain Health

A study published in the February 28 issue of the journal Neurology provides more evidence that high dietary consumption of omega-3 fatty acids, found in fish such as salmon and tuna, may protect the brain against cognitive impairment.

The research team, led by Dr. Zaldy S. Tan, found that healthy older adults 58-76 (m = 67) with the lowest  red blood cell (RBC) levels of the omega-3 fatty acids docosahexaenoic acid (DHA) and eicosapentaenoic acid (EPA) had “older” brains than their peers as well as a vascular pattern of cognitive impairment.  Researchers examined the relationship of RBC fatty acid levels in 1,575 Framingham Heart Study participants who were dementia-free to MRI brain volumetrics and neuropsychological measures of verbal memory, visuospatial memory, abstract reasoning, attention and executive functioning.

Previous research has relied on measures of omega-3 fatty acids in blood plasma, a “snapshot” indicator of how much of the essential nutrients have been consumed in the past few days.  In comparison, this study examined RBC fatty acid composition, which reflects average dietary intake across the RBC lifespan of up to 120 days.

Participants with the lowest DHA and EPA levels had significantly lower total brain volumes, equivalent to about 2 years of structural brain aging, and greater white matter hyperintensity volumes, which have been associated with vascular disease.  Additionally, these participants performed poorer on tests of visual memory, executive function, and abstract thinking, all suggestive of vascular changes.

Findings support previous research suggesting that fish consumption is associated with lower risk of cognitive decline and dementia.  Omega-3 fatty acids may benefit the vasculature and the brain in multiple ways, such as lowering blood pressure, reducing the risk of thrombosis, reducing inflammation, and lowering serum triglyceride levels.

 

Evidence that Omega-3 Fatty Acids Support Brain Health

Aromatherapy/Essential Oils for Attention Deficit Hyperactivity Disorder (ADHD)

ADHD is an acronym for attention deficit hyperactivity disorder, a condition that some experts believe affects between three and five percent of all children in the United States. The condition was previously known (and still sometimes referred to as) attention deficit disorder (ADD). ADHD is characterized by a child’s inattention (inability to concentrate his or her attention on a task for any length of time), hyperactivity (tendency to be significantly more active than what is considered normal for his or her peers), and impulsivity (tendency to produce abrupt and often inappropriate responses or comments). ADHD has long been the subject of considerable controversy among professionals and laypersons, some of whom point out that these behaviors may be within the normal range of behaviors for young children, especially as they reach adolescence. Nonetheless, the treatment of ADHD has become an important challenge for psychiatrists, medical doctors, psychologists, and other healing professionals. Practitioners of aromatherapy are also interested in the problems of ADHD and have a number of recommended treatments with essential oils for the condition.

How is Aromatherapy Used to Treat ADHD?

The principle behind aromatherapy is that certain naturally occurring chemicals contained within essential oils can be used to treat a wide variety of physical, mental, and emotional disorders. The success of these essential oils arises from the fact that they stimulate parts of the body that are not functioning properly, restoring the body to its natural state. Over thousands of years, aromatherapists have experimented with more than 100 different essential oils and found the specific effect (or effects) each has on the body. Recent scientific studies have confirmed the presence of certain key chemicals in essential oils that may react with the nervous or muscular system—or some other part of the body—to encourage healing.

Aromatherapy treatments tend to differ for each individual. The correct essential oil—or combination of essential oils—is often determined by a consultation between an aromatherapist and a patient. However, some essential oils appear to be especially effective in treating ADHD because of their well-known properties.

Some oils that are often recommended include:

• Lavender (Lavendula officinalis): One of the most widely used of all essential oils, it is often effective in producing a sedative effect, causing a person to calm down and relax. The value of this treatment for a hyperactive ADHD child is obvious.

• Cedarwood (Cedrus atlantica): This oil is often recommended because it is thought to stimulate the central nervous system and help correct hereditary problems, which ADHD may be.

• Frankincense (Boswellia carterii): Known for its ability to lower anxiety and depression, frankincense oil may produce a calming influence on the hyperactive ADHD patient.

• Vetiver (Vetivera zizanoides): A somewhat less familiar essential oil, vetiver has been used in scientific studies for the treatment of ADHD because it has a calming influence on patients.

Essential oils can be used with patients in a variety of ways. They are often added to a warm bath or a basin of warm water, allowing a person to inhale the vaporized fumes of the oil. Oils can also be applied directly to the body by rubbing them on the soles of one’s feet, the back of the neck, the shoulders, or the forehead. An important caution concerning the use of essential oils in the treatment of ADHD is that young children are more sensitive to these oils than are adults, and they should be used for therapeutic purposes only under the supervision of a qualified adult.

As is often the case in aromatherapy, combinations of essential oils may be used to treat ADHD because their synergistic effects (effects resulting from their being used together), which can sometimes be quite impressive. One commonly used mixture is called Peace & Calming, a name that reflects the effects it has on users. The mixture is a combination of blue tansy (Tanacetum annuum), orange (Citrus sinensis), patchouly (Pogostemon cablin), tangerine (Citrus nobilis), and ylang ylang (Cananga odorata).

What is Aromatherapy?

Aromatherapy is a system for treating medical disorders with essential oils. Essential oils are organic compounds (compounds containing carbon) that occur naturally in plants. More than 100 essential oils are known to have curative properties, such as the ability to arouse or calm the senses, sharpen mental acuity, and prevent or treat diseases caused by viruses, bacteria, fungi, and other microorganisms. Aromatherapists apply essential oils most commonly to the skin or through the nose (by inhalation). Inside the body, essential oils are thought to affect the muscular and nervous systems and other organs that affect the way the human body functions.

What Causes ADHD?

Scientists still know relatively little about the causes of attention deficit hyperactivity disorder (ADHD). They believe that a number of factors may be involved in the disorder, such as:

• Genetics: ADHD tends to run in a family. Approximately a quarter of all children who develop the disorder have at least one other relative with the condition.

• Exposure to environmental toxins: Children who are exposed to toxins (poisons) in the environment such as lead or polychlorobiphenyls (PCBs) are more likely to develop ADHD than are those who do not have that exposure. Studies have also shown a greater risk of children developing ADHD when born to women who smoked, used drugs, or were themselves exposed to environmental toxins while they were pregnant.

• Altered brain function: Researchers have discovered significant differences in the activity of certain areas of the brain and the usage of neurotransmitters in the brains of children with ADHD compared to those who do not have the disorder.

Aromatherapy/Essential Oils for Attention Deficit Hyperactivity Disorder (ADHD)

Citrus oils produces sedative effects on EEG

Modification of Electrical Brain Wave by Citrus sp. Essential Oil

Inhalation

Jackapun Kwaingjai, Siriphun Hiranyachattada, Chatchai Wattanapiromsakul, Ekkasit Kumarnsit

Abstract

The essential oil of orange (Citrus sp.) has been widely used in aromatherapy according to its anxiolytic effect. Electroencephalography (EEG) is one of the reliable neurological techniques used to study the brain and behavioral functions. This method has been used to record brain waves for frequency analysis. The present study examined the effect of citrus essential oil (EO) on EEG pattern in adult male Wistar rats. Animals were anesthetized with Zoletil (60 mg/kg i.m.). Stereotaxic apparatus was used to fix rat skull for the implantation of 4 stainless steel screw electrodes over the frontal and parietal cortices using bregma as the landmark. Ampicillin (145 mg/kg i.m.) was daily injected for 4 days after the surgery and the animals were allowed to recover for 10 days. On the day of the experiment, individual rat EEG was recorded using PowerLab/4s system. The EEG signals were displayed on LabChart software and processed on a personal computer. The inhalation of EO (20 and 200 μl) and distilled water as control were performed in the EEG recording chamber. Frontal EEG analysis showed that EO (20 μl) increased the percent baseline powers in low frequency bands ranging from theta (4.7-6.6 Hz), alpha1 (7-9.4 Hz), alpha2 (9.8-12.5 Hz) to beta1 (12.9- 18.4 Hz) waves. However, in the parietal cortex, only alpha2 and beta1 powers were significantly increased. In addition, EO 200 μl increased the percentage of the baseline powers only in the theta and the alpha2 bands in the frontal cortex. In conclusion, this study demonstrates EEG pattern in response to inhalation of citrus EO. The data may represent EEG biomarker of the EO in the central nervous system (CNS). However, it remains unknown in terms of its CNS mechanism.

J Physiol Biomed Sci. 2013; 26(1): 5-8

P lants in Citrus genus have been widely investigated for their anxiolytic effects both in human and animal models. In human, ambient odor of orange (Citrus sinesis) was applied in a dental office to1reduce anxiety and improve mood in female patients. Sweet orange aroma also produced an acute anxiolytic activity in healthy volunteers.2 Animal models were often used for confirmation of essential oil effect on behavioral tests such as elevated plus maze task (EPM), light-dark box task and open field task (OFT). The effects of C. sinensis (sweet orange) essential oil on male Wistar rats and mice were evaluated in the elevated plus-maze and followed by the light/dark paradigm. The sweet orange essential oil was found to increase exploration on the open arms of the elevated plus-maze and time spent in the lit chamber of the light/dark paradigm, respectively.3 Lemon oil had the strongest anti-stress effect in all three behavioral tasks which include EPM task, a forced swimming task (FST), and OFT in mice.4 In terms of mechanism, the essential oils of plants in Citrus genus have been demonstrated to stimulate multiple receptor types. For example, lemon oil produced anti-stress via dopamine (DA) receptors and serotonin type 1A receptors (5-HT1A).4

Previously, EEG technique has been used only for making inferences about overall states of sleep and wakefulness.5 Up to date, the EEG technique has been used to record the brain activity following drug treatment of neurological diseases both in humans and rodents.6,7 For example, diazepam is a well- known drug for the treatment of anxiety disorder. In rat model, it was found to increase beta and gamma oscillation.6 However, long term use of diazepam has been found to develop many side effects such as sedation and memory impairments.8,9 These aversive effects also lead to the development of tolerance, dependence, withdrawal symptoms and addiction.10 Some other alternative treatments with safer effects have been searched. This study hypothesized that essential oil of orange has CNS action and produces specific pattern of electrical brain wave. The main purpose of this study was to investigate the effect of essential oil of orange (Citrus sp.) inhalation on EEG pattern in rats.

Materials and Methods

Animals

Adult male Wistar rats, weighing approximately 300- 350 g, were used. Animals were housed in a room maintained at 24 ± 1 °C with12 hr light/dark cycle (light on at 7:00 a.m.). The animals were housed in stainless steel home-cages with the dimension of 30 cm × 30 cm × 30 cm (length x width x high) and a single rat per cage with ad libitum access to food pellets and water. The experimental protocols for care and use of the experimental animals in the present study were approved and guided by the Animals Ethical Committee of Prince of Songkla University.

Citrus sp. essential oil (EO)

The EO was purchased from The Royal Project Foundation of Thailand (Kasetsart University, Bangkok, Thailand). The chemical analysis confirmed that the EO contains 95.88% Limonene. This ingredient was previously found to produce anxiolytic action in mice.11 It was hypothesized to work through benzodiazepine-type receptors.12

Surgical procedure

For the surgical process, the animals were anesthetized with intramuscular injection of 60 mg/kg Zoletil® 100 (Virbac, Thailand). Stainless steel screw electrodes were stereotaxically implanted over the frontal cortex (AP; +3 mm, ML; 3 mm) and the parietal cortex (AP; -4 mm, ML; 4 mm) on the left side of the skull (Figure 1 A – C) by using bregma as the landmark. Electrode fixed at the midline over the

cerebellum (AP, -12 mm; ML, 0 mm) was used as a reference and ground electrode. All electrodes were secured in place with acrylic resin (Unifasttrad, Japan) (Figure1 D).

After full recovery from surgery, the rats were acclimated to connection with cables for 2 hours in the inhalation apparatus consisting of a Plexiglas cylinder with 45 and 30 cm in height and diameter, respectively.

EEG recording

On the experimental day, baseline EEG was recorded for half an hour and 1-hour period following the inhalation of orange oil (20 and 200 μl) or distilled water. EEG signals were amplified with a low-pass 100 Hz, high-pass 0.1 Hz by a PowerLab/4SP system (AD Instruments) with 12-bit A/D converter, and stored in a personal computer through the Chart program software. The EEG signals were processed through 0.78 – 45 Hz band-pass filter: Delta band (0.8- 4.30 Hz), theta band (4.7-6.6 Hz), alpha1 band (7-9.4 Hz), alpha2 band (9.8-12.5 Hz), beta1 band (12.9-18.4 Hz), beta2 band (18.8-35.2 Hz) and gamma band (35.5-45 Hz). The digitized EEG data were segmented into 1024-point (50% overlap) and the signals were converted to power spectra by the fast Fourier transform algorithm (Hanning window cosine transform). Then the power spectra of 2.56-sec sweeps in each 60-min length of selected period of artifact-free signals were averaged to give the power spectra of the period.

Data analysis

Data from the frontal and parietal cortices were expressed in percentage of baseline power. Percentage baseline power of EEG was calculated from pre- and post-treatment. The pre-treatment was set to 100% and the post-treatment was computed to compare with 100% pre-treatment. EEG data was shown in mean ± SEM. Statistical difference between groups was tested using one-way analysis of variance (ANOV A) followed by Tukey test for multiple comparison. The differences were considered statistically significant at P < 0.05.

Results

Results from inhaled EO or distilled water were presented in Figure 2. After a single treatment, EO at 20 μl (EO20) and 200 μl (EO200) were found to change percentage power in the frontal and parietal cortices. In one-way analysis of the frontal EEG, significant increases in power were seen in theta (F(2, 27) = 4.808; P = 0.017), alpha1 (F(2, 27) = 3.516; P = 0.045), alpha2 (F(2, 27) = 4.396; P = 0.023), and beta1 (F(2, 27) = 4.266; P = 0.025). No significant change was observed in the higher frequency ranges.

Multiple comparisons also indicated significant effects of EO20 in the frequency range from theta to beta1 activities whereas EO200 had significant effects on theta and alpha2 only.

In the parietal EEG analysis, significant increases were specific only on alpha2 (F(2, 27) = 3.908; P = 0.033) and beta1 (F(2, 27) = 4.076; P = 0.029) bands. In particular, changes in EEG power were produced by EO20.

Discussion

This study aimed to screen the effect of essential oil on electrical brain activity. The electroencephalo- graphy (EEG) is the most popular technique used to detect the real-time activity of the brain. Basically, it is used to study the brain function. One of the principal advantages of EEG was that continuous brain function can be monitored with repetition of recording by using the same set of animals. It is also practical for longitudinal studies. The present studies examined electrical brain waves in rats inhaled with EO (20 and 200 μl). The results obtained in these studies demonstrated the quantitative effects of the EO inhalation on cortical neuronal activities measured by EEG. The increase in percentage of baseline power produced by EO 20 μl were seen in theta, alpha1, alpha2 and beta1 activities in the frontal cortex. In addition, the EO also increased percentage of baseline power on the alpha2 and beta in the parietal cortex.

It was noted that all changes induced by EO were found mainly in the low frequency range. The increase in slow wave activities might suggest anxiolytic or sedative effects. Previously, diazepam effect on the electrical activity of the brain has been consistently examined in rats and found to increase the beta activity through benzodiazepine site on the GABAA receptors.13,14 The present results also showed similar findings. However, whether or not the EO produced these EEG pattern via GABAA receptors remains to be clarified. Moreover, the CNS action of the citrus EO might be evaluated from brain states of the animals following the EO inhalation. In general, anxiolytic agents promote slow wave activity and sleep.15 Thus, sleep-wake analysis might be needed in order to classify CNS effect of the citrus EO.

Conclusion

Inhalation of citrus EO in rats increased brain wave activity mainly in the slow frequency range. The pattern induced by the inhalation was found, in part, to resemble the effect of those standard anxiolytics. The frontal cortex exhibited relatively more sensitive to the inhalation than the parietal cortex.

Acknowledgement

This work was financially supported by grants from the Natural Products Research Center of Excellence (NPRCoE) and the Department of Physiology, Faculty of Science, Prince of Songkla University, Thailand.

Conflict of Interest

None to declare.

References

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2. Goes TC, Antunes FD, Alves PB, Teixeira-Silva F. Effect of sweet orange aroma on experimental

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3. Faturi CB, Leite JR, Alves PB, Canton AC, Teixeira-
   

   Silva F. Anxiolytic-like effect of sweet orange aroma in Wistar rats. Prog Neuropsychopharmacol Biol Psychiatry. 2010; 34(4):605-9.



4. Komiya M, Takeuchi T, Harada E. Lemon oil vapor causes an anti-stress effect via modulating the 5-HT and DA activities in mice. Behav Brain Res. 2006; 172(2):240-9.


5. Duffy E. Activation and behavior. New York: Wiley; 1962.


6. van Lier H, Drinkenburg WHIM, van Eeten YJW, Coenen AML. Effects of diazepam and zolpidem on EEG beta frequencies are behavior-specific in rats. Neuropharmacol. 2004; 47(2):163-74.


7. Romano-Torres M, Borja-Lascurain E, Chao- Rebolledo C, del-Rı́ o-Portilla Y, Corsi-Cabrera M. Effect of diazepam on EEG power and coherent activity: sex differences. Psychoneuroendocrinol. 2002; 27(7):821-33.


8. Komiskey HL, Cook TM, Lin CF, Hayton WL. Impairment of learning or memory in the mature and old rat by diazepam. Psychopharmacol. 1981; 73(3):304-5.


9. Fang JC, Hinrichs JV, Ghoneim MM. Diazepam and memory: evidence for spared memory function.

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Pharmacol Biochem Behav. 1987; 28(3):347-52. 10. Tan KR, Rudolph U, Luscher C. Hooked

on benzodiazepines: GABAA receptor subtypes and

addiction. Trends Neurosci. 2011; 34(4):188-97.

11. Lima NG, De Sousa DP, Pimenta FC, Alves MF, De Souza FS, Macedo RO, et al. Anxiolytic-like activity and GC-MS analysis of (R)-(+)-limonene fragrance, a natural compound found in foods and plants.

Pharmacol Biochem Behav. 2013; 103(3):450-4. 12.de Almeida AA, Costa JP, de Carvalho RB, de Sousa DP, de Freitas RM. Evaluation of acute toxicity of a natural compound (+)-limonene epoxide and its anxiolytic-like action. Brain Res. 2012;

1448:56-62.

13.Coenen AM, van Luijtelaar EL. Pharmacological

dissociation of EEG and behavior: a basic problem in sleep-wake classification. Sleep. 1991; 14(5):464- 5.

14. Visser SA, Wolters FL, van der Graaf PH, Peletier LA, Danhof M. Dose-dependent EEG effects of zolpidem provide evidence for GABA(A) receptor subtype selectivity in vivo. J Pharmacol Exp Ther. 2003;304(3):1251-7.


15. Lerman JA, Kaitin KI, Dement WC, Peroutka SJ. The effects of buspirone on sleep in the rat. Neurosci Lett. 1986; 72(1):64-8.

Citrus oils produces sedative effects on EEG

Aromatherapy positively affects mood, EEG patterns of alertness and math computations

Diego MA, Jones NA, Field T, Hernandez-Reif M, Schanberg S, Kuhn C, McAdam V, Galamaga R, Galamaga M

The International Journal of Neuroscience, 1998

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ABSTRACT:

EEG activity, alertness, and mood were assessed in 40 adults given 3 minutes of aromatherapy using two aromas, lavender (considered a relaxing odor) or rosemary (considered a stimulating odor). Participants were also given simple math computations before and after the therapy. The lavender group showed increased beta power, suggesting increased drowsiness, they had less depressed mood (POMS) and reported feeling more relaxed and performed the math computations faster and more accurately following aromatherapy. The rosemary group, on the other hand, showed decreased frontal alpha and beta power, suggesting increased alertness. They also had lower state anxiety scores, reported feeling more relaxed and alert and they were only faster, not more accurate, at completing the math computations after the aromatherapy session.

CITATION:

Diego MA, Jones NA, Field T et al. Aromatherapy positively affects mood, EEG patterns of alertness and math computations. Int J Neurosci. 1998;96(3-4):217-224.

The Study of Eucalyptus Essential Oil Wave Inhalation on Brain Activities, Working Memory and Reaction Time

Sukhumaln Santaphongse1

Dr. WernerKurotschka2

Dr. Ariya Sarikaphuti3

Assistant Professor Dr. Wichian Sittiprapaporn4

Abstract

The purpose of this study was to investigate the effects of eucalyptus essential oil inhalation on the brainwaves changes, working memory performance and the speed of reaction times by testing on subjects‘ age group between 20 – 60 years old. Brainwaves changes were detected by BrainActor 2- channels EEG. Matching Parts and Figures Test was chosen for the working memory performance evaluation and SuperLab Pro was the program that determines the speed of reaction time. Results showed that when subjects were asked to complete Matching Parts and Figures Test before and after inhaled eucalyptus essential oil (20 ppm), performance of working memory was not significant difference, whereas speeds of reaction times were significantly increased. Brainwaves changes detected from BrainActor 2-channels EEG showed that during subjects inhaling eucalyptus essential oil (20 ppm), intensities of theta and alpha brainwave spectra were increased, but showed no significant change on theta, alpha and beta spectra after stop eucalyptus essential oil inhalation. Keywords: Eucalyptus essential oil/Working memory/Reaction Time/Brainwaves

1. Graduate Student, Master of Science in Anti-Aging and Regenerative Science, School of Anti- Aging and Regenerative Medicine, Mae Fah Luang University e-mail: ks2_158@hotmail.com

2. Major Advisor, Department of Anti-Aging and Regenerative Science, School of Anti-Aging and Regenerative Medicine, Mae Fah Luang University email: drkuro@aol.com

3. Co-advisor, Department of Anti-Aging and Regenerative Science, School of Anti-Aging and Regenerative Medicine, Mae Fah Luang University e-mail: unique21th@hotmail.com

4 Co-advisor, Department of Anti-Aging and Regenerative Science, School of Anti-Aging and Regenerative Medicine, Mae Fah Luang University e-mail: drwichian.s@gmail.com

Introduction

Humans have been plagued by illness since the beginning of time. Physical disorders not only hamper a patient‘s work performance but can lead to disabilities or death, bringing grief and hardship to families. At a macro level, death means the loss of resources for a country that values its human capital for continued progress and development. The state spends a fortune on prevention, treatment and rehabilitation programs for patients who are sick or disabled, causing economic and social issues for families and the nation. Certain types of illnesses and disorders cause severe imbalances in the body‘s essential make-up, resulting in negative changes to neurotransmission, loss of concentration, slower reaction time, impaired memories and decreased thinking ability. These conditions affect the body‘s ability to perform routine activities efficiently.

Electroencephalography (EEG) is a method to measure the electrical activity of the brain that occurs during neurotransmission, when information is transmitted between the brain‘s neurons. This reflects brain performance in terms of reaction time and brain wave frequencies. These frequencies depend on various factors such as pathology of the brain, emotion and concentration at a time. Many researches have been conducted by stimulating the brain for medical benefit, such as musical sounds that helps autistic children to speak and scents to reduce clinical depression. The use of aromas in medicine to cure disorders is known as aromatherapy.

Aromatherapy has been known for about for 6,000 years, with historical records suggesting it was first used in ancient Egypt in rituals that pay homage to their gods. Aromatherapy was initially used for medically treating illnesses by Greek physician, Pedanius

Dioscorides. Essential oils have also been used in aromatherapy for beauty treatments, healing scalded wounds, sterilization and relieving inflammation. The oils have been used as mind- soothing agents that help to adjust balance in the body and they have been known to effectively enhance performance, boosting reaction time of a brain that has been initially slowed down by exhaustion. They also enhance the efficiency of short-term memory and long-term memory, as well as working memory.

Propose of this study is to initiated the use of plant scents that are grown in Thailand to enhance memory functions or reaction time while working, enabling improved performance among users who live hectic lives and who are prone to stress. This research benefits users in accordance with anti-aging and regenerative principles with the purpose of enhancing quality of life and health. Users can effectively perform their duties and make meaningful contributions with utmost efficiency.

Objectives of the Study

1. To study the effects of Eucalyptus essential oil inhalation on Theta, Alpha and Beta brainwaves activities.

2. To study the effects of Eucalyptus essential oil inhalation on working memory.

3. To study the effects of Eucalyptus essential oil inhalation on reaction time.

Methodology

Subjects in this study includeก male and female volunteers whose ages range between20 – 60 years old . The subjects had no underlying deseases or diorders that m รเ affect the research prodecures . The subjects were acknowledge this fact and accept ed to join the research . The equipments and tests used in this study were an odor familiarity test (Winai Sayorwan, 2011), BrainActor 2-channels EEG, Matching Parts and Figures test(Levy J. U. & Levy N., 1992), Oxygen Concentrator, a mask and20 ppm. eucalyptus essential oilin sterile water.

The volunteers were asked to completethe odor familiarity test (Winai Sayorwan, 2554). The subjects who give highest or lowest scores in the evaluation were deselected from the next steps of the research. Electrode pads will be attached to volunteers scalp at the F3 and F4 position in accordance with the International10/20 system to evaluate brain wave activities. The research was proceeded in accordance with the experimental paradmig.

Collected data w as analyzed by calculating the quantity of each type o f brain waves with the following formula.r

The length of the longestspectrum in each brainwave type x 100

Total length of spectrum

The analysis of the subjects were conducted upon age, speed of reaction, scores from the working memory test , and quanity of each type of brain waves with the mean , percentage and standard deviation (SD). It will be analized and compared with the Student T Test or Paired T- Test. The confidence level was analyzed at p-value < 0.05.

Results

The average age of selected 20 subjects was 32.2 (+9.77)

male which was 30% from the whole subjects and 14 others were female which was 70% of the subjects.

The study on the effects of Eucalyptus essential oil inhalation on working memory, the result showed that the accuracy of the evaluation prior to inhalation of the vapor (50.58) and the post vapor inhalation (55.54) was not significantly difference (p = 0.243). The accuracy of the test results prior to the vapor inhalation (50.58) and the post inhalation of the Eucalyptus essential oil (52.41) also showed no significantly difference (p = 0.69). The accuracy of the test results conducted after the vapor inhalation (55.54) and after the inhalation of the Eucalyptus essential oil (52.41) also showed no significantly difference (p = 0.44).

The study on the effects of Eucalyptus essential oil on the reaction time, the result showed that the reaction time prior to the vapor inhalation (53.95 seconds) and after the vapor inhalation (46.66 seconds) was not significant difference (p = 0.07). Meanwhile, the reaction time after the inhalation of the Eucalyptus essential oil (41.80 seconds), Thus, the reaction time between before the vapor inhalation and after the inhalation of Eucalyptus essential oil appeared significantly different at .01 (p<.01), and the reaction time after the vapor inhalation comparing to after the inhalation of the Eucalyptus essential oil also showed significantly different at .01 (p<.01). The effects of the inhalation of Eucalyptus essential oil on brain waves, the result showed as follows:

Theta Brainwave: Changes that were found in the left hemisphere of the brain wave as follows:

1. While resting and eyes opened 1 minute prior to the experiment, the theta brainwave was at 8.61%, comparing to the during vapor inhalation that was at 11.42%, showed significantly different at .05 (p = .02).

2. While resting and eye opened 1 minute prior to the experiment, the Theta brainwave was at 8.61%, comparing to the during inhalation of Eucalyptus essential oil that was at 10.38%, showed significantly different at .05 (p = 0.02).

3. While inhaling the vapor, the theta brainwave was at 11.42%, comparing to when resting and eye opened 1 minute before ending the experiment that was at 8.55%, showed significantly different at .05 (p = 0.04).

4. During performed the spatial test after the vapor inhalation, the Theta brainwave was at 12.70%, comparing to during the inhalation of the Eucalyptus essential oil that was at 10.38%, showed significantly different at .05 (p = 0.02).

5. While inhaling the Eucalyptus essential oil, the Theta brainwave was at 10.38%, comparing to performing the spatial test after the inhalation of the Eucalyptus essential oil was at 12.63%, showed significantly different at.05 (p = 0.01).

6. While inhaling the Eucalyptus essential oil, the Theta brainwave was st 10.38%, comparing to during resting and eye opened 1 minute prior to the termination of the experiment was at 8.66%, showed significantly different at .05 (p = 0.01).

Changes that were found in the right hemisphere of the brain wave as follows.

1. While resting and eyes opened 1 minute prior to the experiment, the brain wave was at 9.37%, comparing to during the vapor inhalation was at 12.02%, showed significantly different at.05 (p = 0.05).

2. During the vapor inhalation, the brain wave was at 12.02%, comparing to during resting and eyes opened prior to the termination of the experiment was at 9.19%, showed significantly different at .05 (p = 0.03).

3. While inhalation of the Eucalyptus essential oil, the brain wave was at 10.81%, comparing to during resting and eyes opened 1 minute prior to the termination of the experiment was at 9.19%, showed significantly different at .05 (p = 0.02).The resulted showed no changes of Theta brainwave from both lobes of the brain in term of statistical different.

Alpha Brainwave:

Changes that were found in the left hemisphere of the brain wave as follows:

During the Eucalyptus essential oil inhalation, the Alpha brainwave was at 10.23%, comparing to during resting and eyes opened 1 minute prior to the termination of the experiment was at 8.13%, showed significantly different at 0.01 (p = 0.001).

Changes that were found in the right hemisphere of the brain wave as follows:

1. While resting and eyes opened 1 minute prior to the experiment, the Alpha brainwave was at 11.82%, comparing to during inhaling the Eucalyptus essential oil that was at 14.14%, showed significantly different at.05 (p = 0.05).

The resulted showed no changes of alpha brainwave from both lobes of the brain in term of statistical different

Beta Brainwave

When the experiments were conducted in different period of time and with both lobes, the result showed no changes of Beta brainwave in terms of statistical significance.

Discussion

There are not many reports on the Eucalyptus essential oil and changes of the brainwave; moreover, there have never been reports on studies on the Eucalyptus essential oil that 1,8- cineole is a major chemical constituent. According to a study on 1,8-cineole as a major substance, just like the Eucalyptus essential oil, only rosemary essential oil has 16%-55% 1,8- cineole (British Pharmacopeia Online 2012, 2011). From the previous studies, rosemary essential oil enhances memory and decrease reaction time (Moss et al., 2003) which is different from the latter experiment that is conducted with the same scent and result shows reaction time improvement. Its enhancement depends on the concentration of 1,8-cineole substance in the increasing blood flow (Moss and Oliver, 2012), which may result from its ability to inhibit

Acetylcholinesterase enzyme and enable Acetylcholine to work more effectively. This study on the Eucalyptus essential oil by using Matching Parts and Figures Test (Levy J. U. & Levy N., 1992), which is a spatial test, examines working memory and reaction time. It is found that the inhalation of the Eucalyptus essential oil with 20 ppm concentration has no effects on working memory, but enhances the reaction time. This result is different from the research on rosemary essential oil. The both research on the rosemary essential oil and this study on eucalyptus essential oil give different results may due to the difference in the concentration of both oils, the concentration of 1,8-cineole that the subjects got in their blood circulation, period of inhalation time and experimental procedure. The study on changes of brainwave spectra, the increase of Theta, Alpha and Beta brainwaves have not yet been found while conducting the spatial test after the inhalation of the Eucalyptus essential oil. Although the Eucalyptus essential oil can help increase the Theta and Alpha brainwaves spectra while inhaling. Theta and Alpha brainwaves are essential for concentration and analytical thinking, and enhance working memory (Zaehle et al., 2011). As the subjects get the low concentration of the Eucalyptus essential oil, the short inhalation time result in no effect on brainwaves during the working memory test . While Acetylcholinesterase inhibition ability remains unchanged and results in improve reaction time (Moss & Oliver, 2012) without changes of Alpha brainwave spectrum, which is consistent to this study.

This study employed different test , equipments and methodology that have been employed with the ealier research on rosemary esse ntial oil . Both research remain unclear on indicating that rosemary oil has a n ability to enhance working memory . Likewise, this study on the Eucalyptus essential oil has not yet answered the question whether or not the oil enhances the efficiency of working memory. Recommendation for further study is that the concentration of the oil and period of the inhalation can be varied in order to support the hypothesis that the Eucalyptus essential oil with 1,8-cineole as a major substance affects the efficiency o f working memory.

Conclusion

The study on the effects of Eucalyptus essential oil inhalation on working memory, the accuracy of the evaluation prior to inhalation of the vapor, the post vapor inhalation and after the Eucalyptus essential oil inhalation showed no significantly difference. The study of the effects of Eucalyptus essential oil inhalation on the reaction time, the reaction time prior to the vapor inhalation and after the vapor inhalation showed no significantly difference. Meanwhile, the reaction time after the Eucalyptus essential oil inhalation, the reaction time was lesser than prior to the vapor inhalation and after the vapor inhalation with statistical significance at .01.

Acknowledgement

We would like to express our sincere appreciation to the staff of School of Anti-Aging and Regenerative Medicine, Mae Fah Luang University for their professionalism in handling their work. In particular, our sincere gratitude extends to all my colleagues and others who have provided helpful opinions and suggestions at various occasions.

References:

British pharmacopeia online 2012. (2011). Retrieved April 3, 2014, from http://bp2012.infostar.com.cn/

Levy, J.U. and Levy, N. (1992). Matching part and figures, mechanical aptitude and spatial relation test

(3rded.). Acro: United State of America.

Moss, M. & Oliver, L. (2012). Plasma 1, 8 cineole correlates with cognitive performance following exposure torosemary essential oil aroma. Therapeutic Advance in Psychopharmacology, 2, 103-113.

Retrieved August 30, 2013, from http://tpp.sagepub.com/content/2/3/103.abstract

Moss, M., Cook, J., Wesnes, K. & Duckett, P. (2003). Aromas of rosemary and lavender essential oils diffentially affect cognition and mood in healthy adults. Int J

Neurosci,113(1),15-38.

Sayorwan, W. (2011). Effect of selected volatile oils commonly used in Thailand on physiological activities and emotion. Doctoral Dissertation. Chulalongkorn University, Bangkok.

Zaehle, T., Sandmann, P., Thorne J. D., Jäncke, L. & Herrmann C. S. (2011). Transcranial direct current stimulation of the prefrontal cortex modulates working memory performance: combined behavioural and electrophysiological evidence. BMC Neuroscience, 12, 1-12.

The Study of Eucalyptus Essential Oil Wave Inhalation on Brain Activities, Working Memory and Reaction Time

Effects of Inhalation of Essential Oils on EEG Activity and Sensory Evaluation

Ryoko Masago1), Tamiko Matsuda2), Yoshiaki Kikuchi3), Yoshifumi Miyazaki4), Koichi Iwanaga1), Hajime Harada5) and Tetsuo Katsuura5)

1) Graduate School of Science and Technology, Chiba University

2) MacGill University

3) Tokyo Metropolitan University of Health Sciences

4) Forestry and Forest Products Research Institute

5) Ergonomics Section, Department of Design and Architecture, Faculty of Engineering, Chiba University

Abstract. The purpose of this study was to investigate EEG changes in subjects directly after inhalation of essential oils, and subsequently, to observe any effect on subjective evaluations. EEG and sensory evaluation were assessed in 13 healthy female subjects in four odor conditions. Four odor conditions (including lavender, chamomile, sandalwood and eugenol) were applied respectively for each subject in the experiment. The results were as follows. 1) Four basic factors were extracted from 22 adjective pairs by factor analysis of the sensory evaluation. The first factor was “comfortable feeling”, the second “cheerful feeling”, the third “natural feeling” and the fourth “feminine feeling”. In the score of the first factor (comfortable feeling), the odors in order of high contribution are lavender, eugenol, chamomile and sandalwood. 2) Alpha 1 (8–10 Hz) of EEG at parietal and posterior temporal regions significantly decreased soon after the onset of inhalation of lavender oil (p<0.01). Significant changes of alpha 1 were also observed after inhalation of eugenol or chamomile. The change after inhalation of sandalwood was not significant. These results showed that alpha 1 activity significantly decreased under odor conditions in which subjects felt comfortable, and showed no significant change under odor conditions in which subjects felt uncomfortable. These results suggest a possible correlation between alpha 1 activity and subjective evaluation.

(J Physiol Anthropol, 19 (1): 35-42, 2000)

Introduction

Fragrances, in the form of plant essential oils, have been used since ancient times as a medicinal treatment.

This practice, more recently termed ‘aromatherapy’, has attracted much public attention (Tisserand, 1985). It is empirically known that fragrances affect our physical and mental conditions. As disorders attributable to mental stresses gradually come to pose a variety of serious problems in modern society, fragrances are increasingly expected to be useful for easily reducing the mental stresses that pervade in our daily lives.

Many attempts have been made in various research fields to clarify the physiological and psychological effects of odors (Hummel et al., 1992; Kobal et al., 1992; Lorig, 1989; Lorig et al., 1990; Lorig and Roberts, 1990; Nasˇ el et al., 1994; Sakuma et al., 1997; Sobel et al., 1998; Sugano, 1992). Further methods for identifying the sedating and exalting effects of odors have been discussed (Tisserand, 1985; Torii, 1986). However, the effects of odors are highly variable among individuals, and not constant even in a single individual. Therefore, it is appropriate to estimate these variables using various indices; more comprehensive evaluations, including types based on subjectivity, are required.

Evaluation techniques based on cerebral activities associated with sensory information processing are thought to be particularly important for evaluating the physiological effects of odors. However, such a technique has not yet been established; its relationship with subjective evaluation has not been clarified. The present study is focused on EEG changes during inhalation of essential oils, and the relationship of these changes to the corresponding subjective evaluations.

Method

Subjects

The subjects were 13 right-handed female students, ranging in age from 19 to 23 years (mean, 21 years). Subjects were screened for excessive nasal congestion, drug use, and neurological disorders prior to participation in the experiment. All subjects gave their informed consent before participation.

EEG recording

EEG was recorded from 12 scalp positions of the international 10/20 system (F3, F4, C3, C4, P3, P4, O1, O2, F7, F8, T5 and T6; all referenced to A1 + A2). EEG was amplified using multichannel biological amplifiers (Bio-Top 6R12-4, NEC Sanei Instrument) with a band-pass filtering between 0.1 and 32 Hz. EEG records contaminated by eye- blinks or motor artifacts were eliminated for each channel. EEG data ware digitally filtered off-line to a 2–30 Hz bandwidth.

Odor administration

Four odors (three essential oils and eugenol) were applied in the experiment. The essential oils were lavender (LAVENDER ANGUSTIFOLIA), sandalwood (SANRALUM ALUBUM) and chamomile (CHAMAEMELUM NOBILE) (Pranalom Co.). Lavender, sandalwood and chamomile are all assumed to be sedative stimulants (Torii, 1986). Eugenol is a disinfectant. For each odor, the subjective intensity was established at an easily sensed olfactory level based on the preliminary investigation. After inhalation of each odor, the subjects were asked to mark the intensity scale of that odor from 0 (insensible level) to 26 (unbearable level) points. Odors were presented to each subject by means of a funnel-shaped supplier fixed on the chest, situated approximately 15 cm under the nose. The flowrate of the oil was set at 2000 ml/min.

Procedure

Subjects individually entered the climatic chamber where the temperature was kept at 26°C, the relative humidity at 60% and illuminance at 20 lux. The subjects were instructed to sit quietly, close their eyes and to breathe normally during each condition. Then, an electrode cap was affixed to the head. For each condition, EEG was recorded during rest (30 sec) and administration of the odor (90 sec). The presentation order of odor stimuli was counterbalanced for each subject. After each condition, the subjects were asked to complete a questionnaire on sensory evaluation. The climatic chamber was ventilated during the interim time between conditions, which period was approximately 3 minutes.

Data analysis

EEG from each electrode was analyzed by using bio- medical software packages (BIMTAS and ATAMAP, Kissei Comtec Instrument). Ten-sec epochs of EEG activity were estimated by Fast Fourier Transform (FFT) for four frequency bands (4–8 (theta), 8–10 (alpha 1), 10–13 (alpha 2) and 13–30 (beta) Hz) for each electrode during inhalation of each odor. Each power during inhalation of

Fig. 1 The electrode positions and the lattice points for the t-map.

odor was compared with the power obtained from the 30- second (rest condition) EEG data by calculating the paired t-values every 10 seconds (A total of 9 epochs). The t- map was constructed by using the t-values and the interpolated values. The t-map is one of the image processing techniques, known as ‘significance probability mapping’. For purposes of constructing the t-map, the lattice points were set up as shown in Fig. 1. In these lattice points, the values for the non-measurement points were calculated by the following equations:

Then the t-map was constructed by using the following equation for interpolation:

where f (m, n) is the value of the lattice point.

For purposes of sensory evaluation, 22 odor-related adjective pairs were selected on the basis of our previous data (Miyazaki et al., 1993). This scale was digitized with scores from 1 to 7. Using the average values, basic factors were extracted by means of factor analysis (principle component method, varimax rotation). The factors whose eigenvalues were more than 1.0 were extracted.

Results

Odor intensity

The ratings of odor intensity showed no significant differences among odors.

Sensory evaluation

Four basic factors were extracted from the 22 adjective pairs. Three of the 22 adjective pairs were excluded because the eigenvalues were less than 1.0. The first factor was “comfortable feeling”, the second “cheerful feeling”, the third “natural feeling” and the fourth “feminine feeling” (Table 1). The accumulative contribution ratio was 80.3%. The first factor (comfortable feeling), which showed the highest contribution among the basic factors, included “Stimulating – Unstimulating “, “Pleasant- Unpleasant”, “Restful-Impatient” and so on (Table 1). Figure 2 indicates the score of the first factor. The odors in order of high score were lavender, chamomile, eugenol and sandalwood.

EEG data

These results are expressed by the t-maps (Fig. 3). There were remarkable changes of alpha 1 during the inhalation of the essential oils. On the other hand, the power of alpha 2, theta and beta did not remarkably change. There were remarkable alpha 1 changes for 10 seconds after the beginning of inhalation of each odor. The changes of alpha 1 activity showed difference among the essential oils. Temporal changes were similar for each odor. The alpha 1-power on lavender significantly decreased from 0 to 10 seconds (F3, O1, O2, P3, P4, T5 and T6: p<0.01), and at 10–20 seconds (C3, F7, O1, P3 and T5: p<0.01) during inhalation. Then, alpha 1 power was found to return to the rest level at 20–30 seconds during inhalation, and significantly changed again at 30–40 seconds (O1 and P3: p<0.01) during inhalation, and thereafter (40–50 sec: C3, C4, F4, F8, O1, O2, P3, P4 and T5, p<0.01; 50–60 sec: O1, O2 and P3, p<0.01; 60–80 sec: T5, p<0.01). These significant decreases (the red areas in Fig. 3) were greatest over the parietal and posterior temporal regions.

During the first 10-second period after the beginning of odor inhalation, there were significant decreases of alpha 1 power in the left parietal regions (lavender: p<0.01, eugenol: p<0.01, chamomile: p<0.01) and the left posterior temporal regions (lavender: p<0.05, eugenol: p<0.01) during the inhalation of these oils. On the other hand, such changes were not observed for sandalwood. For each odor, the t-maps of alpha 1 power are presented in Fig. 4.

Correlation between alpha 1 activity and sensory evaluation

Significant decrease of alpha 1 was observed for three odors (lavender, eugenol, and chamomile) (i.e., all odors except sandalwood) during the first 10-second period of inhalation (Fig. 5). For relative value of the alpha power to 100% in the resting condition, the alpha 1 power decreased 19.70% for lavender, 14.74% for eugenol and 16.81% for chamomile (p<0.05). The significant decrease was persistent during the period in which lavender was

presented. On the other hand, the decrease was not persistent for the other odors. For lavender, chamomile and eugenol, subjects estimated the duration of exposure as comfortable (Fig. 2). Alpha 1 showed no significant change for sandalwood, which was estimated as uncomfortable (Fig. 2). Thus, those odors that subjects felt comfortable while inhaling tended to correspond to decreases in alpha 1 activity.

To confirm the above finding, we divided the subjects into a “pleasantness” and an “unpleasantness”, based on their preference (Fig. 6). The preference ranges from 1, very pleasant to 7, very unpleasant on subjective evaluation. The preference score on pleasant group (pleasantness) was from 1 to 3. The preference score on unpleasant group (unpleasantness) was from 4 to 7. The alpha 1 power decreased in the pleasant group for 10 seconds after the inhalation of lavender, chamomile or eugenol. In this group, the positions showing significant alpha 1-decrease included F3, O1, O2, P3, P4, T5 and T6 (p<0.01) for lavender; F3, T6 (p<0.01), C3, C4, O1, P3 and P4 (p<0.05) for chamomile; and F7, O1, P3, T5 (p<0.01), C3, F8 and O2 (p<0.05) for eugenol. However, in the unpleasant group, the positions showing significant decrease (the red areas in Fig. 6) included only T5  (p<0.01) for lavender and F8 (p<0.01) and O1 (p<0.05) for eugenol. In the case of sandalwood, the significant decrease of alpha 1 was not observed in either group.

 

Discussion

In this study, we found significant changes in alpha 1 activity during the inhalation of essential oils. The alpha activity usually corresponded to some sensory stimulation in addition to the olfactory stimulation (Lorig and Isaac, 1983; Motokizawa and Furuya, 1973). The signal itself was a form of sensory stimulation that immediately blocked further alpha activity. Lorig (1989) referred to topographical maps that may clearly show differences that are obscure in a table of EEG values. Regarding EEG changes during stimulation or a task condition, as compared with changes during a rest condition, significant probability mapping (Duffy et al., 1981) such as t-map is often used. By using t-maps of alpha 1, we obtained several types of patterns corresponding to each odor.

As to effects of odor on EEG activity, several studies have revealed an increase of alpha or theta rhythms during the presentation of odor (Sawada et al., 1992; Van Toller et al., 1993). However, Brauchili et al. (1995) reported that the sedative effects of some odors remain unclear; an increase in alpha rhythm may be such an effect. In the presentstudy,alpha1showedsignificantdecreasewithno difference of beta and theta band during the presentation of a comfortable or pleasant odor. Therefore, the data obtained in the present study also bring into question the interpretation of more alpha activity in response to relaxation. Suppression of alpha 1 at some scalp electrodes indicates the neural activity around the brain regions under them (Kikuchi, 1996). These findings are in agreement with data reported on other sensory stimuli, namely, that the alpha rhythm is suppressed during visual stimulation (Michel et al., 1994) or during acoustic stimulation (Kaufman et al., 1992). Therefore, it is suggested that the decreases in alpha rhythm during inhalation of odor reflect local activity related to the olfactory information processes in the brain.

Alpha 1 changes were mainly observed in the parietal and posterior temporal regions. These regions are related to integrative sensory information processing, including that of olfactory sensation. Based on this result, more complicated and integrative neuronal activities related to odors considered to occur in these regions. In addition, it is supposed that these regions have some relationship to emotions or experience, and that this emotional or experimental information is related to memory. Moreover, a relationship with memory has been suggested. Ehrlichman and Halpern (1988) reported that a significantly greater percentage of memories were categorized as happy by subjects in the pleasant odor condition as compared with those memories categorized by subjects in the unpleasant odor condition. The activities found in the present study may be related to these processes.

Alpha 1 decreased when the odors that subjects had evaluated as comfortable were inhaled. However, alpha 1 did not change when the odor that subjects had evaluated as uncomfortable was inhaled. These results suggest that there may be some correlation between alpha 1 activity and subjective evaluation. Furthermore, the decrease of alpha 1 power was observed in the pleasant group for three odors, including lavender, eugenol and chamomile (i.e., excepting sandalwood), when the subjects were divided into a pleasant group and an unpleasant group according to their preference of odors. The degree of alpha 1 decrease corresponds to a decrease of pleasantness or comfortness; the subject’s preference (pleasant- unpleasant) of odors showed a high contribution in the first “comfortable feeling” factor (Fig. 6). Brauchli et al. (1995) suggested that olfactory stimulation by an unpleasant odor leads to a stronger cortical deactivation than does such stimulation by a pleasant odor. We expected the effects of odors in relation to positive or comfortable feelings. Therefore, the power of alpha 1 is thought to be one of the most useful indices of the comfortable or uncomfortable feelings of subjects.

Schiffman et al. (1994) found that the use of fragrance can improve the overall mood of women at mid-life. In that study, feelings of tension, depression and confusion were significantly alleviated in the presence of pleasant odors. Conclusively, it is important that we make aromatherapeutic use of odors in consideration of the physical and subjective effects, in order to bring our physical and mental conditions to be comfortable.

Acknowledgments. The authors gratefully acknowledge Dr. Misumi, Dr. Koizumi, the students of Tokyo Medical and Dental University for their cooperation acting as subjects and Mr. Ken Okayasu for his help with illustrations. This work was partly supported by Kobayashi pharmaceutical company.

References

Brauchli P, Rüegg PB, Etzweiler F, Zeier H (1995) Electrocortical and autonomic alteration by administration of a pleasant and an unpleasant odor. Chem Senses 20: 505-515

Duffy FH, Bartles PH, Burchfiel JL (1981) Significance probability mapping: An aid in the topographic analysis of brain electrical activity. Electroenceph Clin Neurophysiol 51: 455-462

Ehrlichman H, Halpern JH (1988) Affect and Memory: Effect of pleasant and unpleasant odors on retrieval of happy and unhappy memories. J Person and Soc Psychology 55: 769-779

Hummel T, Livermore A, Hummel C, Kobal G (1992) Chemosensory event-related potentials in man: relation to olfactory and painful sensations elicited by nicotine. Electroenceph Clin Neurophysiol 84: 192-195

Kaufman L, Curtis S, Wang JZ, Williamson SJ (1992) Changes in cortical activity when subjects scan memory for tones. Electroencepha Clin Neurophysiol 82: 266- 284

Kikuchi Y (1996) EEG. In Japan Society of Physiological Anthropology eds. Ningen kagaku keisoku handobukku. Gihodo, Japan, 333-343 (in Japanese)

Kobal G, Hummel T, Toller SV (1992) Differences in human chemosensory evoked potentials to olfactory and somatosensory chemical stimuli presented to left and right nostrils. Chem Senses 17: 233-244

Komori T, Fujiwara R, Tanida M, Nomura J (1995) Application of fragrances to treatments for depression. Jpn J Psychopharmacol 15: 39-42 (in Japanese)

Lorig TS (1989) Human EEG and odor response. Prog Neurobiol 33: 387-398

Lorig TS, Herman KB, Schwartz GE, Cain WS (1990) EEG activity during administration of low-concentration odors. Bulletin of the Psychonomic Society 28: 405- 408

Lorig TS, Issac W (1983) The effects of light reinforcement and noise on young and old squirrel monkeys. Experimental Aging Research 9: 97-100

Lorig TS, Roberts M (1990) Odor and cognitive alteration of the contingent negative variation. Chem Senses 15: 537-545

Michel CM, Kaufman L, Williamson SJ (1994) Duration of EEG and MEG suppression increases with angle in a mental rotation task. J Cog Neurosci 6: 139-150

Miyazaki Y, Motohashi Y, Kobayashi S (1992) Changes in mood by inhalation of essential oils in humans II: Effect of essential oils on blood pressure, heart rate, R-R intervals, performance, sensory evaluation and POMS. Mokuzai Gakkaishi 38: 909-913 (in Japanese with English abstract)

Miyazaki Y, Yatagai M, Kobayashi S (1993) Sensory evaluation of essential oils and their components. Mokuzai Gakkaishi 39: 843-848 (in Japanese with English abstract)

Motokizawa F, Furuya N(1973) Neural pathway associated with the EEG arousal response by olfactory stimulation. Electroencephalography and Clinical Neurophysiology 35: 83-91

Nasˇ el C, Nasˇ el B, Samec P, Schindler E, Buchbauer G (1994) Functional imaging of effect of fragrances on the human brain after prolonged inhalation. Chem Senses 19: 359-364

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(1994) The effect of pleasant odors and hormone status on mood of women at mid-life. Brain Res Bull 36: 19- 29

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77: 16-20 (in Japanese)

Received: July 21, 1999

Accepted: October 29, 1999

Correspondence to: Ryoko Masago, Ergonomics Section, Department of Design and Architecture, Faculty of Engineering, Chiba University, Yayoi-cho 1-33, Inage- ku, Chiba 263-8522, Japan

e-mail: mryoko@ergo1.ti.chiba-u.ac.jp

Effects of Inhalation of Essential Oils on EEG Activity and Sensory Evaluation

Evaluation of the Harmonizing Effect of Ylang-Ylang Oil on Humans after Inhalation

Evaluation of the Harmonizing Effect of Ylang-Ylang Oil on Humans after Inhalation

T. Hongratanaworakit

G. Buchbauer

Abstract

Scientific evaluations of the effects of fragrances on humans are rather scarce. The aim of this investigation was to study the ef- fects of ylang-ylang oil

Evaluation of the Harmonizing Effect of Ylang-Ylang Oil on Humans after Inhalation

Peppermint and Lavender: Attention & Memory Research

Peppermint and Lavender Essential Oils: Are They Therapeutic Aromas for Attention and Memory?

Abstract

Introduction –Previous study showed that aroma has direct and indirect psychological effects and the sense of smell stimulates our memory, feeling of creativity as well as emotions. Peppermint enhances memory and increases alertness in terms of mood while lavender has calming and sedating properties which decreases memory and attention based tasks. The aim of our study is to determine the effect of peppermint and lavender scents on the memory and attention of participants.

Methods – A randomized control trial was conducted and a total of 45 undergraduate students participated. Participants were stratified into male and female and then they were randomly assigned to three groups. The two intervention groups were exposed to either peppermint or lavender scent while the control group was not exposed to any scent. The first part of assessment was on the familiarity of 20 brands. The second part assessed the memory of participants to recollect all 20 brands. The third part assessed the attention of participants to identify the odd symbol from the grid picture. The data were analysed using Chi square, Fisher’s exact test, Independent sample T test ans ANOVA.

Results – In the attention test, the findings were significant (P<0.013) with mean score of peppermint group being 11.7, lavender group being 8.3 and control group being 8.9. Based on Bonferroni test in ANOVA, there is significant difference of attention score between peppermint and lavender groups (P < 0.018). However, the memory test was not significant with peppermint group scoring a mean of 8.0, lavender group being 7.6 and control group being 7.9

In conclusion, peppermint scent enhances the attention of the participants and lavender reduces the concentration and working memory of the participants.

Introduction

Human senses have significant connection to the increased ability to recall information. Sights, tastes and scents are known to bring back one’s past memory. [1] This is known as the recall process. It is quite selective, and does not represent the original image, but reconstructed. [2] At times, the recalling process occurs unexpectedly and presents with an ‘uncalled-for’ memory because of the trigger of a stimuli (scent), often as a result of its association. [2] According to Green in 1993, the sense of smell is important to our well being as it stimulates our memory, feeling of creativity and emotions. [3] The effects of aroma can include both direct and indirect psychological effect – even thinking about the smell have a similar effect to the actual smelling of the aroma.[4] Lavender has strong effect of stress relieving, relaxing, calming and sedative action while rosemary promotes alertness, analgesic effect as well as useful for fatigue and stress. [5] Studies conducted by Moss et al in 2003 revealed that lavender produced a decrease in the reaction time for memory and attention-based task. However, studies have shown that with regard to mood, the rosemary group was more alert when compared to the lavender group and reason for it being is because lavender’s sedating effect. [3, 5, 6] In fact, inhalation of lavender also helps in improving letter counting and mathematical tasks relative to inhalation of jasmine. [7] On the other hand, peppermint stimulates on the senses and is an excellent analgesic (headache). [5] A study done in Japan shows that peppermint helps in maintaining performance precision by directly raising the level of stimulation of subjects. [8] Ylang-ylang helps in relaxation by providing a harmonizing effect (stress, frustration, tension and insomnia). [5] A study conducted by Moss, Hewitt, Moss and Wesnes in 2008 showed that peppermint enhanced memory and in terms of mood, peppermint increased alertness while ylang-ylang increased calmness. [7, 8]

The objective of this study is to determine the effect of peppermint and lavender scents on the memory and attention of the participants.

METHODOLOGY

This was a randomized controlled trial (RCT) study done on the effect of various scents on attention and memory among the undergraduate medical students from a private medical college in Malaysia on June 2013.

We planned to study the effect of peppermint and lavender on attention and memory therefore two experimental groups (peppermint and lavender) and a control group was required. 15 experimental subjects and 15 control subjects were needed with a power of 80% and level of significance of 0.05.

Students of age ranging between 17 to 26 years old were included and students who had running nose on that day of experiment or with mental disabilities were excluded. A total of 48 volunteers were stratified into male and female and then randomized to three groups of peppermint, lavender and control group.

Data was collected using self-administered questionnaire and written consent was taken from each participants. In addition to basic demographic details, participants were also asked regarding their health status, sleep and knowledge on various aromas, essential oil and candles as well as their usage in their daily living.

Half an hour before the experiment started, we scented the room with either peppermint scent or lavender using the electric diffuser (GreenAireTM Air Revitalisor, rotating at 2300 revolution per minute) or unscented. The electric diffuser was placed at the corner of the room and it was not seen by the participants. Then, we asked the participants to enter the room and they were seated accordingly. They were not allowed to talk and discuss throughout the experiment.

For part 1, we used a brand game whereby participants were shown 20 pictures of brands comprising of 15 familiar and 5 unfamiliar brands. [9] They were given 10 seconds for each slide to identify the familiarity of the brand or logo and then tick them in the answer sheet. After that, we distributed questionnaires to all participants and they were given 5minutes to complete the questionnaires. This was also used as a way to distract the participants for the second part of the experiment.

For part 2, we gave a  memory test to all participants in which they were required to recall back all the 20 brands seen in part 1 and write them on the answer sheet given. [9] Each correct answer contributes to one mark. More than one alphabet spelling mistake was considered as wrong answer and the total mark was 20.

For part 3, we gave an attention test consists of 20 pictures. Each picture consists of several grids in which there will be one odd component in those grids. They were shown the odd component for three seconds followed by the grid picture. They had to find the odd component in the respective picture within seven seconds [10]. Each question contributes one mark. Total mark was 20. The diffusing rate and volume of aromatherapy were constant for all groups.

ANOVA test and Bonferroni test were used for analysis of quantitative variables whereas Chi square and Fisher’s exact were used to compare the qualitative variables. P value of <0.05 were considered statistically significant. Descriptive statistics such as mean, standard deviation, frequency and percentage were described.

Our study was approved by the ethic and consent committee from Melaka Manipal Medical College. The informed and written consent was taken from the participants through the questionnaire. Their privacy and confidentiality is maintained.

Results

Table 1

Baseline characteristics between three intervention groups

 

Based on table 1, there are no significant difference of the participants age, duration of sleep previous night before participation, duration of exercises, their ethnicity, smoking habits and use of essential oils or candles at home between three intervention groups.

Based on table 2, the mean memory score in peppermint group is 8.0, lavender group is 7.6 and in control group is 7.9. The participants in the peppermint group scored the highest, followed by the control group and then the lavender group. However, there is no significant difference of the memory score between the peppermint, lavender and control group.

Regarding attention, the mean score in the peppermint group is 11.7, lavender group 8.3 and unscented group 8.9. There is significant difference of attention score (P value 0.013), and the participants in the peppermint group scored the highest, followed by the control group and then the lavender group.

Figure 1

Attention among three intervention groups

 

Based on Bonferroni test in ANOVA, there is significant difference of attention score between peppermint and lavender groups (P value 0.018) as the mean score in peppermint group is 11.67 and lavender group is 8.33.

Discussion

The purpose of this study was to determine the effects of peppermint and lavender on memory and attention of the participants. Based on the study conducted, we found that there is significant difference of attention test score when compared with the peppermint, lavender and the control group. It indicates that these scents help in the performance and learning of the participants. Peppermint helps in increasing the attention span of the person. [7] With the exposure to peppermint aroma there is maintenance of performance and its function more directly by raising the level of stimulation in subjects. [11] A study by Brand & Ydstie 2007 further suggested that experimental subjects who were exposed to the scent of peppermint showed increased performance on tasks requiring sustained focus. The element of menthol in peppermint enhances the oxygen utilization by the brain which helps in boosting thinking and alertness. [12] Based on the study done by Victoria Anisman – Reiner’s, inhalation of peppermint essential oil stimulates and refreshes the mind and its fragrance awakens the mind as well as enhancing learning capacity.

The study conducted by Sakamoto showed that lavender positively effects the attention ability of the participants because it decreased the arousal of participants during the break period given in order to perform better in the later next task. [8] Fatigue, anxiety and stress tend to accumulate during the break period, hence reduced arousal during the break period maintained the higher working efficiency in the following task. [8] In our study the attention test was performed last and short break the participants had while we collected the answer sheet of the previous task could have reduced their arousal which helped the participants to perform better in the attention test. In fact, participants in our study from the peppermint group scored the highest mean score, followed by the control group and then the lavender group. The reason to it is because of the sedating effect of lavender that has reduced the ability of participants to pay attention. Studies revealed that lavender produced a decrement in performance for attention based tasks. [13] Similarly, study done by Ilmberger et al 2008 also shows the lavender’s calming and sedative effect. [14] With exposure to lavender, subject calculation rates initially dropped while performing mathematical equations and that may be interpreted as the relaxing effects of lavender to reduce cognitive function such as attention. [15] Futhermore, the electroencephalogram (EEG) study of normal human brain shows that alpha wave activity disappears with attention and theta waves are normally seen in sleep at any age. [16] Studies show lavender oil increased the power of theta (4-8 Hz) and alpha (8-13 Hz) brain activities. The topographic map showed more scattering power in alpha range waves particularly in bilateral temporal and central area. [17] Inhalation of lavender for 3 minutes increases alpha power of EEG as it decreases anxiety. The increase in theta (4-8Hz) and alpha (8-13Hz) may cause a range of general relaxation effects and waves significantly increased in all brain regions. This study indicates the EEG evidence of relaxation by lavender aromatherapy. [18]

Lavender has been found to influence activity of cyclic adenosine monophosphate whereby reduction of this cAMP with sedation. [19, 20] The mean score of the lavender group in our study was lower than the control group. Similarly in other study, attention was significantly slower in the lavender condition relative to the unscented group (control). [19] Paradoxically, lavender has also been found to attenuate the deterioration of work performance under conditions of fatigue. [8] On the other hand, Moss et al (2003) in their studies on analysis of performance of computerized cognitive assessment revealed that lavender produced a significant decrement in performance of working memory, and impaired reaction times for both memory and attention based tasks. [11]

Previous study showed that there was a connection between peppermint scent and the increased ability to recall memory. Peppermint was found to be effective in enhancing the tasks related to attention, virtual recognition memory, working memory and visual-motor response. [21] It also showed a marked increase in word recall accuracy enhanced learning and memory recall tasks. [22] However, as shown in other studies, [19] we found that there is no significant difference of memory score between three intervention groups. In the study by M. Moss, all the immediate, working and delayed memory were not significantly affected by the peppermint scent. In contrast, there are studies that showed peppermint enhanced the memory component and in terms of mood increased alertness. [7] Similarly, Raudenbush showed that peppermint has been demonstrated to enhance performance, in which the authors propose that this is due to the change in mood and consequently change in the level of motivation of the participants by the aroma. [23] It is therefore unlikely that the recorded improvement in memory test was due to the changes in mood and motivation. [19] In the study done by M. Morrin, it stated that the presence of a pleasant ambient odour caused subjects to expend additional processing efforts on particular tasks, so as a result, subject in the pleasantly scented condition exhibited superior recall function. [24] Similarly, The null effects of lavender on memory are consistent with Ludvigson and Rottman who found no effect of both lavender and cloves on memory. [25] This is due to damaging effect of lavender on memory. [22]

The limitation that we could acknowledge in this study is the amount of sleep in the previous night may affect the participants’ alertness during the experiment. The range of sleep our participants had been from 4.5-12 hours and majority of them had 5-6 hours of sleep. By ensuring participants to have equal hours of sleep during the night before the experiment would maintain the consistency in the alert level during the experiment. [26] Insufficient sleep leads to general slowing of the response level as well as increase in the variability of the performance. [27] Other limitation to consider is the limited number of test we used to access the memory performance. Further research on how the odor intensity affects the awareness on attention and memory of the participants could have been conducted.

Conclusion

Aroma has direct and indirect psychological effects and the sense of smell stimulates our memory, feeling of creativity as well as emotions. Peppermint helps in increasing the attention span but memory was not significantly affected. As lavender scent having its sedative effect, it decreased the participants’ working memory and ability to concentrate.

Acknowledgement

I would like to express my heartiest appreciation to my college for allowing me to conduct this research study and to approve it. I would like to extend my gratitude to all the participants who contributed in this study. Lastly, my sincere appreciation to Professor Dr Adinegara bin Lutfi Abas and Associate Professor Dr. Htoo Htoo Kyaw Soe from the Department of Community Medicine for guiding us extensively in the process of making this research study a reality.

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Peppermint and Lavender: Attention & Memory Research

Aroma of Rosemary & Lavender on Mood and Cognition in Adults

Intern. J. Neuroscience, 113:15–38, 2003 Copyright  2003 Taylor & Francis 0020-7454/03 $12.00 + .00

DOI: 10.1080/00207450390161903

AROMAS OF ROSEMARY AND LAVENDER ESSENTIAL OILS DIFFERENTIALLY AFFECT COGNITION AND MOOD IN HEALTHY ADULTS

MARK MOSS JENNY COOK

Human Cognitive Neuroscience Unit Division of Psychology

University of Northumbria Newcastle upon Tyne, UK

KEITH WESNES

Human Cognitive Neuroscience Unit Division of Psychology

University of Northumbria Newcastle upon Tyne, UK

Cognitive Drug Research CDR House

Portman Road

Reading, UK

PAUL DUCKETT

Human Cognitive Neuroscience Unit Division of Psychology

University of Northumbria Newcastle upon Tyne, UK

This study was designed to assess the olfactory impact of the essential oils of lavender (Lavandula angustifolia) and rosemary (Rosmarlnus officinalis) on cognitive performance and mood in healthy volunteers. One hundred and forty-four participants were randomly assigned to one of three independent groups, and subsequently performed the Cognitive Drug Research (CDR) computerized cognitive assessment battery in a cubicle containing either one of the two odors or no odor (control). Visual analogue mood questionnaires were completed prior to exposure to the odor, and subsequently after completion of the test battery. The participants were deceived as to the genuine aim of the study until the completion of testing to prevent expectancy effects from possibly influ- encing the data. The outcome variables from the nine tasks that consti- tute the CDR core battery feed into six factors that represent different aspects of cognitive functioning. Analysis of performance revealed that lavender produced a significant decrement in performance of working memory, and impaired reaction times for both memory and attention based tasks compared to controls. In contrast, rosemary produced a significant enhancement of performance for overall quality of memory and secondary memory factors, but also produced an impairment of speed of memory compared to controls. With regard to mood, compari- sons of the change in ratings from baseline to post-test revealed that following the completion of the cognitive assessment battery, both the control and lavender groups were significantly less alert than the rose- mary condition; however, the control group was significantly less con- tent than both rosemary and lavender conditions. These findings indi- cate that the olfactory properties of these essential oils can produce objective effects on cognitive performance, as well as subjective effects on mood.

Despite the prevailing wisdom that the sense of olfaction may be a vestige of our evolutionary past, the use of aromas to modulate affect and mood has been reported since the beginnings of written language, and is a widely continued practice today. The use of arti- ficially introduced ambient odors in public places such as offices, retail outlets, and hotel lobbies is widespread, as are the purported subjective psychological benefits of the odors themselves (Jellinek, 1997). The use of aromatherapy as a therapeutic treatment for affec- tive disorders has also widely reported in historical anecdotal litera- ture (Valnet, 2000), and referred to in herbal medical texts (Bartram, 1995). Though due to the lack of a suitable placebo, until recently little or no clear empirical evidence was available to support such claims (Diego et al., 1998). However, it is interesting to note that

Ballard and colleagues (Ballard et al., in press) reported the first double-blind clinical trial to demonstrate improvements in agitation levels in severe dementia patients following aromatherapy with Melissa (lemon balm).

The essential oils used in aromatherapy are highly concentrated essences extracted from plants through the process of distillation. Although synthetic analogues of a number of the components of these essential oils are commercially available, they are considered inferior to the natural products by herbal medicine practitioners (Price, 1995). Each essential oil is believed to produce reliable and predict- able effects on psychological state when inhaled (Sanderson & Ruddle, 1992), and a number of studies have investigated this possibility. The reputed sedative nature of lavender has consistently been dem- onstrated through the relief of anxiety and tension, and improve- ments of mood (Lorig & Schwartz, 1987b; Ludvigson & Rottman, 1989; Buchbauer et al., 1991). Similar subjective relaxing effects have been found for spiced apple (Schwartz et al., 1986b) and sandal- wood (Steiner, 1994). The presence of such effects has further been established by physiological and electrophysiological measurements. Diego and colleagues (Diego et al., 1998) studied electroencephalo- grams (EEGs) and found lavender inhalation to be associated with increased beta power, which is acknowledged as being associated with sedation. In addition, the contingent negative variation (CNV) variable of EEG has been shown to be diminished by both lavender and sandalwood oils, a finding consistent with decreased arousal (Torii & Fukuda, 1985; Torii et al., 1988). By comparison, pepper- mint, jasmine, and rosemary have been demonstrated to possess subjectively stimulating or arousing properties (Warm & Dember, 1990; Kovar et al., 1987; Diego et al., 1998). These effects, as well as being in line with reputation, have also subsequently been sup- ported by results from physiological and electrophysiological mea- surements that contrast those outlined above for sedating oils (Kubota et al., 1992; Parasuraman et al., 1992; Sugano, 1992).

It is a possibility that changes in subjective state brought about by aroma inhalation, and in particular changes in arousal and alert- ness, may impact upon cognitive performance. Indeed arousal has been demonstrated to interact with task demands, producing an in- verted-U performance versus arousal curve (Yerkes & Dodson, 1908).

A small number of studies that have attempted to investigate any possible influence of aromas on cognition have produced equivocal results, however. Diego et al. (1998) found the subjective mood and EEG effects for both lavender (sedating) and rosemary (arousing) as predicted. While both aromas improved the speed of maths com- putations, only lavender increased accuracy. Similarly, Warm and colleagues (Warm et al., 1991) reported that both arousing (pepper- mint) and relaxing (muguet) aromas produced significant increases in sensitivity on a visual sustained attention task compared to no odor controls. Why these two aromas did not produce contrasting effects on performance is not clear, but neither odor led to a subjec- tive experience of the task being less taxing than in the control condition. It may be that the impact of the aromas on task perfor- mance was independent of subjective feelings. Degel and Köster (1999) reported fewer errors on both letter counting and mathe- matical tasks following inhalation of lavender compared to jasmine. Furthermore, both odors led to significantly poorer performance on a creativity task compared to no odor controls. By comparison, Ludvigson and Rottman (1989) found lavender to impair arithmetic reasoning, but not memory, when compared to cloves, with no concomitant effect on mood for either odor. Ilmberger and colleagues (Ilmberger et al., 2001) reported no clear influence of either peppermint, jas- mine, ylang-ylang, or l,8-cineole (the major constituent of rosemary oil) on speed on a psychomotor task. Rather, they reported complex correlations between subjective evaluations and objective perfor- mance, and suggested that the influences of odor on the basic forms of attention are mainly psychological.

Interestingly, studies have also investigated situations where the expectation of an ambient odor is produced in participants but when none is actually presented (Knasko et al., 1990; Gilbert et al., 1997). Furthermore, the participants were misled into believing that the feigned odor would affect cognitive performance. However, the ob- jective test data demonstrated no differences to exist between the conditions, indicating that expectancies may be secondary to the effect of any actual odor presented.

Previous research has therefore produced mixed findings regard- ing the possible influence of aromas on cognitive performance. Dif- ferences in methodology and the types of tasks employed have also made it difficult to compare results across studies. The current study therefore aimed to definitively assess performance on a wide range of tasks relating to a number of established cognitive domains. To this end, the Cognitive Drug Research (CDR) battery was employed. The CDR battery has been used in over 200 phase 1 and phase 2 clinical trials world-wide, and has been demonstrated to be reliable, valid, and sensitive to changes in cognitive function (Wesnes et al., 1999; Moss et al., 1998; Scholey et al., 1999). Participants perfor- mance on the test battery was compared across conditions of ambi- ent rosemary aroma, ambient lavender aroma, or no odor (control). Subjective mood state was also assessed príor to and after the ex- perimental session to investigate the possible interaction of cogni- tive task performance and odor inhalation on ratings of calmness, contentedness, and alertness.

MATERIALS AND METHODS

Participants

One hundred and forty-four undergraduates and members of the general public volunteered to take part in this study. The composi- tion of the three experimental groups consisted of the follow- ing: rosemary condition: 28 females (mean age 25.3 years, SD 6.9), 20 males (mean age 24.5 years, SD 7.8); lavender condition: 27 females (mean age 23.8, SD 6.3); 21 males (mean age 24.7, SD 6.7); control condition: 30 females (mean age 24.9, SD 5.6), 18 males (mean age 26.2 SD 8.1). Prior to participation each volun- teer completed a health questionnaire. All participants self-reported that they were in good health and none were excluded from the study.

Aromas

“Tisserand” pure essential oils (Tisserand Aromatherapy, Newtown Road, Hove, Sussex, UK) of lavender and rosemary were used to produce the ambient aromas. Four drops of the appropriate oil (or water in the control condition) were applied to a diffuser pad for a

“Tisserand Aroma-stream.” The Aroma-stream was placed under the bench in the testing cubicles so as to be out of sight, and switched on for 5 min prior to the testing of each participant. Each aroma was above detection threshold and of approximately equivalent strength for each testing session as assessed by an independent party.

Testing Cubicles

Each testing cubicle measured 2.4 m long × 1.8 m wide × 2.4 m high and were maintained at a temperature between 18 and 22 de- grees Celsius throughout the testing sessions.

Cognitive Measures

A tailored version of the Cognitive Drug Research (CDR) comput- erized assessment system (installed on Viglen genie computers) was employed to evaluate cognitive performance. The CDR system in- cludes a number of measures that are specific to particular aspects of attention, working memory, and long-term memory. Stimuli are presented on a color monitor, and (with the exception of word re- call) responses are made using a simple response module containing two buttons labeled “Yes” and “No,” respectively. A suite of pro- grams controls all aspects of testing, including selection of appro- priate sets of stimuli for presentation and recording all responses.

The tests employed in this study were presented in the following order:

Word presentation. A series of 15 words were presented sequen- tially for 1 s, each with an interstimulus interval of 1 s. The words were a mix of one, two, and three syllables.

Immediate Word Recall. The computer display counted down 60 s, during which time participants wrote down as many of the words from the list as possible. Recall was scored for number of correct words and errors (words not presented in the list).

Picture Presentation. Twenty photographs were presented, with a stimulus duration of 2 s each, and interstimuli interval of 1 s. Simple Reaction Time. The word Yes was presented in the center of the screen. The participant had to press the Yes button as quickly as possible. There were 50 trials, and the intertrial interval varied randomly between 1 and 2.5 s. The reaction time was recorded in ms.

Digit Vigilance. A number was displayed constantly to the right of the screen. A series of 240 digits was presented one at a time in the center at a rate of 80 per min; 45 matched the constantly displayed digit. The participant had to press the Yes button as quickly as possible every time the digit in the center matched the one constantly displayed. Accuracy of response (%), reaction time (ms), and number of false alarms were recorded.

Choice Reaction Time. Either the word Yes or No was presented in the center of the screen. The participant had to press the Yes or No button as appropriate and as quickly as possible. There are 50 trials (25 “Yes” and 25 “No”), and the intertrial interval varied randomly between 1 and 2.5 s. Accuracy (%) and reaction time (ms) were recorded.

Spatial Working Memory. A schematic picture of a house was pre- sented for 5 s. The house had nine windows in a 3 × 3 pattern, four of which were illuminated. A series of 36 presentations of the same house in which just one window was illuminated fol- lowed, and the participant had to respond Yes if the window was one of the four lit in the original presentation, or No if it was not. Sixteen of the stimuli required a Yes response and 20 a No re- sponse. Reaction time and accuracy were recorded and a sensi- tivity index was calculated.

Memory Scanning. Five digits were presented singly at the rate of 1 every s for the participant to remember. A series of 30 digits was then presented. For each, the participant must press Yes or No according to whether the digit was thought to be one of the five presented initially. Fifteen stimuli required a Yes response and 15 a No response. This was repeated three times using a different 5 digits on each occasion. Reaction time was recorded and a sensitivity index calculated.

Delayed Word Recall. The computer counted down 60 s, during which time participants free-recalled as many of the words from the list as possible. Recall was scored as the number of correct words, and errors (words not presented in the list).

Word Recognition. The 15 words initially presented for the word

recall were presented again in random order, interspersed with 15 new words. The participant pressed Yes or No each time to sig- nal whether or not the word was from the original list. Reaction time and accuracy were recorded and a sensitivity index was calculated.

Picture Recognition. The 20 pictures presented earlier were shown again in random order, interspersed with 20 similar new ones. The participant signaled recognition by pressing the appropriate Yes or No button. Reaction time and accuracy were recorded, and a sensitivity index calculated.

“Pencil and Paper” Visual Analogue Scales. Subjective levels of alertness, calmness, and contentedness were presented prior to and following the computerized tests. Participants were required to indicate their current state by marking a line drawn between two bipolar adjectives. The entire battery took approximately 25 min to administer.

Primary Cognitive Outcome Measures

The above measures were collapsed into four global outcome fac- tors, and two subfactors derived from the battery by factor analysis, as previously utilized (Kennedy et al., 2000, 2001; Wesnes et al., 1997, 2000).

Quality of memory. This was derived by combining the percentage accuracy scores (adjusted for proportions of novel and new stimuli where appropriate) from all of the working and secondary memory tests: spatial working memory, numeric working memory, word recognition, picture recognition, immediate word recall, and de- layed word recall (with adjustments to the total percentage correct for errors on the latter two tasks). A 100% accuracy across the six tasks generated a maximum score of 600 on this index.

Examination of the factor pattern suggests that this global “quality of memory” factor can usefully be further divided into two sub- factors: “working memory” and “secondary memory”

Working memory subfactor. This was derived by combining the percentage accuracy scores from the two working memory tests: spatial working memory and numeric working memory. One hun-dred percent

accuracy across the two tasks generated a maximum score of 200

on this index.
Secondary memory subfactor. This was derived by combining the percentage accuracy scores (adjusted for proportions of novel and new stimuli where appropriate) from all of the secondary memory tests: word recognition, picture recognition, immediate word re- call, and delayed word recall (with adjustments to the total per- centage correct for errors on the latter two tasks). One hundred percent accuracy across the four tasks generated a maximum score of 400 on this index.

Speed of memory. This was derived by combining the reaction times of the four computerized memory tasks: numeric working memory, spatial memory, delayed word recognition, and delayed picture recognition (units are summed ms for the four tasks).

Speed of attention. This was derived by combining the reaction times of the three attentional tasks: simple reaction time, choice reaction time, and digit vigilance (units are summed ms for the three tasks).

Accuracy of attention. This was derived by calculating the com- bined percentage accuracy across the choice reaction time and digit vigilance tasks with adjustment for false alarms from the latter test. One hundred percent accuracy across the two tasks would generate a maximum score of 100.

The contribution of individual task measures to each of these factors and subfactors is illustrated schematically in Figure 1.

Subjective Mood Measure

The Bond-Lader visual analogue scales (Bond & Lader, 1974). The 16 visual analogue scales of Bond-Lader were combined as recom- mended by the authors to form three mood factors: “alert,” “calm,” and “content.”

Procedure

Participants were approached individually and asked if they would help in the validation of a new cognitive test battery. No mention of aromatherapy or essential oils was made. This deception was carried out in order to avoid the possibility of expectancy effects contami- nating the data. Recruitment took place one week prior to testing, and participants were randomly and unknowingly allocated to one of the three conditions: lavender, rosemary, or no odor (control). They were then given a time and day on which to attend the labora- tory. Testing took place in three different cubicles, and on three different days of the week (Monday, Wednesday, and Friday) to avoid cross contamination of odors. On arrival at the lab, each par- ticipant was once again reminded that he or she was there to assist in the validation of the new test battery and to try his or her best on all the tasks. Participants were then asked to complete the mood scales, supposedly to assess if the tasks affected mood. Participants were then taken into the cubicle where they completed the CDR battery followed by a second mood scale. Finally, they were de- briefed regarding the true nature of the experiment, and any ques- tions answered. If any of the participants commented on the pres- ence of an odor prior to or during the testing session, the researcher dismissed it with responses of the kind: “nothing to do with me” and “don’t know where it came from.” No participants indicated at any time that they felt the odor had affected them at all, or that they thought the study was investigating the effect of odor on perfor- mance or mood.

Statistics

Scores from the individual task outcome measures were combined to form the four global outcome measure factor scores, as well as the secondary memory and working memory factor scores. These and the individual task outcome measures making up the factors were analyzed using the statistical package Minitab 12 for Win- dows. The one-way analysis of variance (ANOVA) followed by Tukey pairwise comparisons were employed to identify where any differences between the three conditions may have existed. Analysis of subjective mood was made in a similar manner on the pre- to post-testing difference scores, reflecting any changes in mood state due to exposure to the aromas and/or as a result of completing the assessment battery.

RESULTS

The analyses of the individual task outcome measures that make up the factors are presented in Table 1. The results described here con- centrate on the primary cognitive outcome measures described above.

Quality of Memory Factor

An independent groups ANOVA revealed a significant differ- ence between groups, F(2,141) = 4.80; p = .010. Tukey post-hoc comparisons identified that the rosemary condition (mean = 363.91) produced significantly higher scores than the lavender condition (mean = 326.61), p < .05 (Figure 2a). No other significant differences were found.

 

Secondary Memory Subfactor

An independent groups ANOVA revealed a significant difference between groups, F(2,141) = 4.44; p = .014. Tukey post-hoc com- parisons identified that the rosemary condition (mean = 200.03) produced significantly higher scores than the lavender condition (mean = 174.24), and the control condition (mean = 176.60), p < .05 in each case (Figure 2b). No other significant differences were found.

Working Memory Subfactor

An independent groups ANOVA revealed a significant difference between groups, F(2,141) = 5.40; p = .006. Tukey post-hoe com- parisons identified that both the rosemary condition (mean = 169.92) and the control condition (mean = 172.74) produced significantly higher scores than the lavender condition (mean = 152.37), p < .05 and <.01, respectively (Figure 2c). No other significant differences were found.

Speed of Memory Factor

An independent groups ANOVA revealed a significant difference between groups, F(2,141) = 6.38; p = .002. Tukey post-hoc com- parisons identified that the control condition (mean = 3129.5 ms) produced significantly quicker responses than both the lavender con- dition (mean = 3565.5 ms) and the rosemary condition (mean = 3504.7 ms), p < .0l and <.05, respectively (Figure 2d). No other significant differences were found.

Speed of Attention Factor

An independent groups ANOVA revealed a significant difference between groups, F(2,141) = 3.57; p = 031. Tukey post-hoc com- parisons identified that the control condition (mean = 1013.9 ms) produced significantly quicker responses than the lavender condi- tion (mean = 1071.1 ms), p < .05 (Figure 2e). No other significant differences were found.

Accuracy of Attention Factor

An independent groups ANOVA revealed no significant differences between groups, F(2,141) = 1.20; p = .305.

Subjective Mood Measures

Analysis of the pre-test ratings indicated no differences between the three conditions on any of the mood variables prior to the experi- mental session: Alertness, F(2,141) = 0.87; p = .422. Contentedness, F(2,14l) = 1.18; p = .311. Calmness, F(2,141) = 0.52; p = .594. Subsequent analyses compared post-test minus pre-test change in mood scores.

Alertness

An independent groups ANOVA revealed a significant difference between groups, F(2,141) = 5.43; p = .005. Tukey post-hoc com- parisons identified that the rosemary condition produced an increase in alertness (mean change = 5.51), compared to decreases for both the control condition (mean change = –3.06), p < .05, and the lav- ender condition (mean change = –7.49), p < .01 (Figure 3a). No other significant differences were found.

Contentedness

An independent groups ANOVA revealed a significant difference between groups, F(2,141) = 9.72; p = .0001. Tukey post-hoc comparisons identified that the rosemary condition produced an in- crease in contentedness (mean change = 2.39) compared to controls (mean change = –9.58), p < .01. In addition, the lavender condition produced a decrease in contentedness (mean change = –2.79) that was significantly less than that for the control condition (mean change = –9.58), p < .05 (Figure 3b). No other significant differ- ences were found.

Calmness

An independent groups ANOVA revealed no significant differences between groups, F(2,141) = 0.73; p = .481.

DISCUSSION

The results of this study clearly support previous work indicating that essential oils can influence mood (Roberts & Williams, 1992; Buchbauer et al., 1991; van Toller & Dodd, 1988). More impor- tant, we have demonstrated that the inhalation of ambient aromas of essential oils can significantly affect aspects of cognitive perfor- mance. Further, due to the design employed in this study and the deliberate diversion of participants attention away from the odors, these effects are considered to be irrespective of participants expec- tations or beliefs.

The changes in mood recorded over the period of the cognitive testing can, to some extent, be matched to the objective test outcomes. Lavender essential oil is widely considered to possess sedat- ing properties, and rosemary is believed to be arousing and has been linked to memory at least as far back as the writings of Shake- speare (Hamlet Act4, scene5). These facets are broadly reflected in the effects on cognitive performance observed here.

The quality of memory factor was found to be impaired by lav- ender when compared to rosemary, but not when compared to controls. Consideration of the memory subfactors indicates that secondary memory possessed the same odor-performance relation- ship, although on this subfactor performance in the lavender condi- tion was on a par with controls, indicating enhancement for the rosemary condition rather than a decrement for lavender. For the working memory subfactor, however, lavender was significantly im- paired compared to both the rosemary and control conditions. A clear dissociation of the aroma effects on these two memory sys- tems is apparent here, with rosemary enhancing secondary memory and lavender having no effect, in contrast to lavender which im- paired working memory and rosemary which had no effect. A simi- lar profile of results to those obtained here for rosemary has been reported previously for the influence of oxygen administration on cognition (Moss et al., 1998) and for the acute administration of Ginseng (Kennedy et al., 2000). It is interesting to note that the distinction between secondary and working memory appears to be more than theoretical on the basis of the results reported here and elsewhere. It may be the case that the two systems are served to some degree by distinct neuropsychological and neurochemical path- ways that are differentially available for enhancement, although some natural interventions (most notably, chewing gum) appear capable of impinging on both in a positive manner (Wilkinson et al., 2002).

With reference to the speed of memory factor, both aromas sig- nificantly slowed performance as compared to controls. As this fac- tor encompasses reaction times from both working memory and secondary memory tasks, this may indicate a speed accuracy trade- off in both the enhancement found for rosemary, and the impair- ment found for lavender reported here. However, consideration of the individual task outcome measures that make up these factors indicates an interesting pattern. Reaction times were not signifi- cantly slowed by rosemary compared to the other conditions on the word and picture recognition tasks, which constitute the secondary memory tasks, which have a speed component associated with them. However, both tasks did show improvements in accuracy, and, as such, a clear speed accuracy trade-off can be discounted for rose- mary. In contrast, lavender did not produce significantly faster per- formance compared to controls on the spatial and numerical work- ing tasks on which accuracy was impaired. Indeed, participants were both slower and less accurate on these tasks. However, lavender did produce a slowing of reaction times on the secondary memory tasks that were not impaired in terms of accuracy. The reduction in speed here possibly facilitates a level of accuracy that may otherwise have been lost. The relationship between speed and accuracy may be important in the effects of lavender then, but not rosemary.

The speed of attention factor displayed a significant impairment for the lavender condition compared to controls, but not to rose- mary. This may have, in part, been predicted on the basis of laven- der’s putative sedating properties. Rosemary, however, would rea- sonably have been predicted to enhance attentional speed as a consequence of its arousing properties. Certainly the mood data in- dicated that the participants in the rosemary condition felt more alert than those in the lavender or control conditions. Performance for the rosemary condition, however, was numerically slower than the controls, and faster than the lavender group though neither com- parison was significant. In spite of increased subjective alertness, however, objective performance did not improve, which suggests that the enhancements observed for memory may be independent of subjective state.

Another possible explanation may be found in the inverted-U relationship between arousal and performance described in the Yerkes- Dodson law. Attentional tasks require the directing of psychological resources to events in the environment, and arousal levels (as moni- tored by changes in physiological parameters such as blood pres- sure and heart rate) are low (or even reduced compared to resting) for such tasks compared to tasks with a higher cognitive load (Lacey & Lacey, 1970, 1974; Turner & Carroll, 1985a, 1985b). It may well be the case that rosemary inhalation raises arousal levels to such an extent that enhancement is not possible for attentional tasks (due to overarousal). At the same time performance on the more cognitively demanding tasks relating to memory consolidation and retrieval is enhanced (due to optimal arousal being attained for these tasks).

Performance on the accuracy of attention factor was effectively equal across conditions, and consideration of the mean levels of accuracy in the tasks that combine to create this factor suggests that ceiling levels were being achieved. Accuracy levels of greater than 90% in the control condition indicates that there is very little room for enhancement in the participant group employed here, and the nature of the tasks is such that only serious cognitive deficits pro- duce large impairments in accuracy of performance compared to controls (Simpson et al., 1991). It is therefore perhaps not surpris- ing that no effect of condition was observed on this factor.

Returning to the mood data, as well as the effect of rosemary on levels of alertness, a significant effect was found for both lavender and rosemary compared to controls for degree of contentedness. Rosemary led to participants reporting higher levels of contented- ness after completion of the test battery than before the start. In addition, although lavender was associated with a small decrease in levels of contentedness from pre- to post-testing, this change was still significantly less than the decrease in contentedness observed in the control condition. It would appear therefore that the aromas employed here are capable of elevating mood, or at least maintain- ing good mood during the completion of a challenging test battery under laboratory conditions. These positive effects on mood are con- sistent with those identified in the aromatherapy literature under resting conditions (Buchbauer et al., 1991; van Toller & Dodd, 1988). In contrast, no significant effect was revealed for the calmness mood dimension, which may have been predicted to show an increase for lavender based on its reported sedative properties. It may be that the experimental situation experienced by the participants was such that although feeling content, they did not find themselves able to relax (i.e., increase calmness). This may also have been reflected in the finding that lavender did not significantly decrease feelings of alert- ness below those of controls. It may be possible that central or conscious mechanisms were able to override the effects of the aroma during testing at least for aspects of subjective mood, if not for the objective measures of cognitive functioning as described above.

In considering how essential oils may influence mood and cogni-

tion, such as that recorded here, a number of possibilities have been proposed, but again little hard evidence exists. Jellinek (1997) out- lined four mechanisms by which odors may exert effects. Two of these can be rejected with regard to the current study. The “semantic mechanism” describes contextual effects on memory and experi- ence that were not investigated in this study. The “placebo mecha- nism” describes the influence of expectancies on behavior and is discounted here because the experiment explicitly set out not to produce expectancies, and no participant indicated that he or she had any during the testing procedure. The “hedonic valence mecha- nism” asserts that the degree of pleasure/displeasure that is gained from an experience defines the moods that emerge from it, and that mood state affects cognitive and behavioral responses. Evidence sug- gests that hedonic valence is affected by aromas (Baron & Thomley, 1994; Ehrlichman & Bastone, 1992) and that aromas may therefore influence cognition via this route. Certainly, pleasant-smelling com- mercially produced air-fresheners have been shown to improve mood and task performance (Baron, 1990). In the current study, however, differential cognitive effects were found for two essential oils, both of which are considered to be pleasant smelling, and both of which increased contentedness in participants compared to controls. As such, a direct link to hedonic valence would appear too simple to explain these results.

Finally, the “pharmacological mechanism” describes how con- stituents of the essential oils may influence behavior through the central nervous or endocrine systems. Volatile compounds may en- ter the bloodstream by way of the nasal or lung mucosa, or may diffuse directly into the olfactory nerve and pass up to the limbic system in the brain—a region closely associated with arousal. Al- though the level of active compounds that may be absorbed by these routes is low compared to other modes of administration, essential oils have been detected in the blood of rodents exposed to the vapors of essential oils (Jirovitz et al., 1990, 1992; Kovar et al., 1987). A pharmacological mechanism would imply substance- specificity—a concept that would fit well with results described here, with each aroma producing a unique pattern of influence on the cognitive domains assessed. In addition, neuropharmacological research has provided insights into the possible modes of influence

of different plant-based substances that may be relevant here. Spe- cifically, Wake and colleagues (Wake et al., 2000) found that vari- eties of sage and melissa possessed nicotinic and muscarmnie acetyl- choline activity in homogenate preparations of human cortical cell membranes. The link between the cholinergic system and memory is well established, and it may be that rosemary also possesses such cholinergic activity—the results presented here suggest that it might. This possibility remains to be investigated. Lavender has also been demonstrated to act postsynaptically, and it is suggested that it mod- ulates the activity of cyclic adenosine monophosphate (cAMP) (Lis- Balchin & Hart, 1999). A reduction in cAMP activity is associated with sedation, a causal relationship that has been established for the effects of cannabis. It is possible that lavender produces sedative effects via the same route albeit with less intensity.

In summary, the cognitive effects recorded here are clear, spe- cific, and dependent upon ambient aroma. Furthermore, these ef- fects only mirror to some degree the changes in subjective mood state reported by the participants, and a simple change in levels of arousal is not entirely satisfactory as an explanation of these find- ings either. Recent work suggests that some of the essential oils employed in aromatherapy possess pharmacological properties that may be responsible for both the effects on mood and cognition attributed to them. However, the information is currently limited and further research is required if such properties and relationships are to be identified clearly. At the same time, research in our lab shall continue in an attempt to provide clear cognitive and mood profiles for the effects of a wide range of essential oils.

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Aroma of Rosemary & Lavender on Mood and Cognition in Adults