A study on the effects of thermal pain stimulation at the oral mucosa in EEG

Abstract Objectives The aim of this study was to investigate how thermal pain stimulation on the oral mucosa affects the brain’s pain perception and brain network connectivity using electroencephalograms (EEGs) and to reveal the central systemic mechanisms of oral chronic pain such as burning mouth syndrome (BMS). Materials and methods EEG data were collected from 40 healthy volunteers (24 males and 16 females) at rest and during thermal stimulation of the oral mucosa at 45°C, 48°C, 51°C, and 54°C. The power of six frequency bands was calculated for the acquired EEG data. A directed transform function (DTF) was used to construct the network and calculate the network connection parameters. Results The results showed that subjective pain scores increased significantly with increasing temperature ( p < 0.001). Compared with the resting baseline state, the average power of both theta and alpha bands decreased with increasing temperature ( p < 0.001), while the average power of the gamma band increased ( p < 0.001). Moreover, the mean values decreased, as did the clustering coefficients and global efficiency in the low and middle frequency bands. Conclusions The thermal stimulation of the oral mucosa mainly affects the alpha power decreasing in the contralateral somatosensory area. Clinical Relevance This experiment provides a theoretical basis and technical support for studying the mechanism of transmission and perception of oral thermal pain through the trigeminal pathway to the central nervous system in human subjects and provides a theoretical basis for the central system mechanism of chronic pain syndromes such as BMS.