Effect of electroacupuncture stimulation at different frequencies on brain waves

Frequency and intensity of stimulation are important parameters in electroacupuncture. This study investigated the effect of electro acupuncture at different frequencies and intensities via electroencephalography. Bilateral ST36 (zusanli) of 15 healthy participant volunteers were stimulated via two different modes of electroacupuncture: 2Hz (low frequency) with a highintensity mode (5-6mA), and 120Hz (high frequency) with a low-intensity (2-2.5mA) mode. Eight-channel EEG were recorded before and during the electro acupuncture stimulation. After eliminating artifacts from raw EEG data, power spectrum analysis was done according to frequency bands: theta (4-8Hz), alpha (8-13Hz), beta (13-30Hz), and gamma (30-50Hz) bands. With electroacupuncture stimulation, the absolute theta power was decreased compared with baseline in the overall region (P<0.05 in all channel with some minor exceptions). Moreover, high frequency electroacupuncture stimulation increased the absolute alpha power in the posterior region (P=0.047 in left; P=0.125 in right). Further, high frequency electroacupuncture stimulation decreased the absolute beta power in prefrontal region (P=0.006 in left; P=0.006 in right), and decreased the absolute gamma power in posterior region (P=0.035 in right). It is likely that electroacupuncture at ST36 affects brain waves differently depending on stimulation frequency.