Spearmint Aroma and Brainwave Dynamics: A QEEG Analysis of Theta-to-Alpha Ratio

Abstract

Theta and alpha brainwaves are prominent frequencies in the human brain associated with distinct states of consciousness and cognitive processes. Theta waves, oscillating at 4-8 Hz, are commonly observed during deep relaxation, meditation, and creative states. On the other hand, alpha waves, ranging from 8-12 Hz, are prevalent during wakeful relaxation and a state of alertness. The balance between theta and alpha rhythms reflects an individual's cognitive and emotional state, making it a valuable metric for investigating the effects of external stimuli such as aroma. To explore the effect of spearmint aroma inhalation on brainwave dynamics, a controlled study was conducted involving thirty female participants exposed to the scent of spearmint essential oil. Quantitative electroencephalography (QEEG) recordings were obtained from 19 scalp electrodes distributed in six brain regions before and after the exposure period to assess changes in theta-to-alpha ratios. Participants' subjective experiences were also documented to correlate with the neurophysiological findings. QEEG analysis revealed a significant increase in theta-to-alpha ratios following exposure to spearmint aroma compared to baseline measures in all the brain regions: Prefrontal (p=0.000), frontal (p=0.000), central (p=0.000), parietal (p=0.000), temporal (p=0.000) and occipital (p=0.000). This study provides empirical evidence supporting the beneficial effects of spearmint aroma on brainwave dynamics, as evidenced by the modulation of theta-to-alpha ratios.