The purpose of this study was to understand the effect of essential oils and botanical extracts on electrophysiological activity of the brain. Previous studies have shown that using Zen MONQ Personal Essential Oil Diffuser increases brain activity, specifically in the alpha and theta frequencies, by 10% as compared to a placebo. We hypothesized that using Zen MONQ Therapeutic Fragrance® in a room diffuser can improve the meditative state by increasing alpha and theta wave power. To test this hypothesis, brain activity was measured during a 20-minute idiosyncratic meditation using an Emotiv electroencephalography (EEG) headset. The protocol was adapted from Hinterberger, et al1. We observed that using Zen MONQ Therapeutic Fragrance in a room diffuser increased alpha and theta wave power during the idiosyncratic meditation session, as well as during the preceding 60-second wait period. A 7% increase in alpha and theta activity was observed, supporting the hypothesis. The effect from the blend in a room diffuser was less robust than when the blend was used in a personal diffuser. This difference can be attributed to sustained delivery and less concentrated “dose” which can result in olfactory adaptation over time.
A 14-channel Emotiv EPOC wireless headset was used to obtain data. EEGs were sampled at 128 Hz through a 0.1 to 50 Hz filter. Data was recorded continuously for the entirety of experiment and epoched during post-processing.
After ensuring proper placement of EEG electrodes (Figure 1), baseline measurements were obtained. Participants were asked to rest in their meditative posture without meditating for 5 minutes with their eyes opened and 5 minutes with their eyes closed.
Figure 1: Guide to placing Emotiv EEG sensors
The room diffuser was then turned on, either prefilled 100 mL of filtered water (negative control) or 100 mL and 3 drops of MONQ’s Zen blend (treatment). Participants were asked to rest for 60 seconds immediately after the diffuser was turned on. Participants were then asked to meditate in their preferred way, also called idiosyncratic meditation, for 20 minutes.
A raw EEG dataset was exported from the EmotivPro software for each experiment and processed using EEGLAB, an open-source MATLAB toolbox for processing continuous EEG data. Each dataset was filtered with a high band pass FIR filter at 0.1 Hz, a low band pass FIR filter at 60 Hz, and a notch filter at 50 Hz. A continuous data rejection was performed and then the data was linearly re-transformed using the channel average as a reference. An individual component analysis was performed, followed by a principle component analysis to cluster the data into separately 14 channels, and 1 parent cluster. Wave powers were then calculated for the four waves: delta, theta, alpha, beta. For the scope of this study, the sum of alpha and theta wave powers was used as a metric for measuring relaxed states.
There was a notable increase in alpha and theta activity between the negative control (filtered water) and treatment (MONQ’s Zen) blend. There was a slight increase during the 60 seconds immediately after the diffuser was turned on (60-second wait). The difference between the negative control and treatment increased as the experiment progressed (Figure 1). The difference between the negative control and treatment was more pronounced during the second half of the meditation (Meditation2).
Figure 1: Zen increased alpha + beta waves through the duration of meditation session
This graph shows the progression of alpha + theta wave activity during the experiment. To measure baselines, participants were asked to rest for 5 minutes with their eyes open and 5 minutes with their eyes closed. The diffuser was then turned on and participants were asked to rest with their eyes open for 60 seconds as the diffuser filled the room. They were then asked to meditate for 20 minutes in their preferred way of meditation; for data analysis, the meditation was split into halves, with Meditation1 being the first 10 minutes and Meditation2 being the second 10 minutes. Filtered water was used as a negative control (blank) and MONQ’s Zen essential oil blend was used as the treatment. (n=7)
In order to remove the baselines, alpha+theta wave power during the EyesOpen and EyesClosed portions of the experiment were subtracted (Figure 2). There was a net increase of 1.18 μV2/Hz, or 19%, during the 60 seconds immediately after the diffuser was turned on. During the entirety of the meditation session, there was an increase of 1.58 μV2/Hz or 46%.
Figure 2: Zen increased alpha + theta waves during 60-second wait and subsequent meditation session
This graph shows an increase in alpha + theta wave power during the 60-seconds when the diffuser was started and the subsequent 20-minute meditation. Baselines have been subtracted as follows: 1) M-EC = entire 20 minute Meditation minus EyesClosed 2) 60sec-EO = 60 second wait minus EyesOpen 3) M1-EC = first 10 minutes of Meditation minus EyesClosed 4) M2-EC = second 10 minutes of Meditation minus EyesClosed. Zen increased alpha+theta wave power by an average of 1.5μV2/Hz in each condition. Filtered water was used as a negative control (blank) and MONQ’s Zen essential oil blend was used as the treatment. (n=7)
Finally, we compared the results from testing MONQ’s Zen blend in a room diffuser and in a personal diffuser (insert link to former study). The effect of Zen on the meditative state was similar but less pronounced (Figure 3). The personal diffuser increased alpha+theta wave power by 0.381 μV2/Hz, or 17%, immediately after the diffuser was used. Further, the personal diffuser increased alpha+theta wave power by 1.94 μV2/Hz, or 53%, during meditation. These results suggest that MONQ’s Zen blend has a similar effect on alpha+theta wave power in a room diffuser. However, the personal diffuser is still the most effective way to receive the benefits of the blend. The difference can be attributed to the higher concentrated “dose” in the personal diffuser, along with the sustained delivery, which together can result in olfactory adaptation over time.
Figure 3: Zen in a Room Diffuser (ZRD) has a slightly less, but similar effect on alpha + theta wave power compared to Zen in a Personal Diffuser (ZPD)
This graph compares the alpha + theta wave power between MONQ’s Zen essential oil blend in a personal diffuser (diagonally lined bars) and a room diffuser (dotted bars). On the left are the wave powers during blend sampling (three average breaths for ZPD and three drops in a room diffuser for ZRD). On the right are the wave powers for the meditation sessions where subjects meditated with their eyes closed for 20 minutes. Filtered water was used as a negative control (blank) and MONQ’s Zen essential oil blend was used as the treatment. (ZPD: n=5, ZRD: n=7)