Combined Thermal and Mechanical Stimulation on Acupoint LI4 Enhances Powers of Beta and Gamma Waves in Parietal and Temporal Lobes

Studies have shown that manual and electrical acupuncture have significant effects on brain functions. However, these treatments often evoke pain and fear. Non-invasive acupuncture therapies, such as mechanical (acupressure) and thermal (moxibustion), have been developed and shown to effectively relieve pain and treat various conditions. However, little is known about their influence on brain network function. The current study explored the effects of mechanical, thermal, and combined thermal and mechanical stimulations on acupoint Large Intestine 4 (LI4, Hegu) on EEG in fifty-two healthy participants. A 30-minute combined thermal and mechanical stimulation on LI4 enhanced the powers of the β and γ bands and reduced the ratio of θ/β in both the parietal and temporal lobes when compared with the same stimulation on the control point. In contrast, neither the mechanical nor thermal stimulation alone had such effects. The distinct impact of combined thermal and mechanical stimulation, as opposed to either method alone, underscores the importance of joint activation of thermosensory, touch, and pain-sensory fibers for effective acupoint stimulation. Furthermore, our findings provide insights into the use of combined thermal plus mechanical stimulation as an effective non-invasive alternative therapy.