Sensorimotor peak alpha frequency is a reliable biomarker of pain sensitivity

Abstract

Previous research has observed that individuals with chronic pain demonstrate slower alpha band oscillations (8-12 Hz range) during resting electroencephalography (EEG) than do age-matched, healthy controls. While this slowing may reflect pathological changes within the brain that occur during the chronification of pain, an alternative explanation is that healthy individuals with slower alpha frequencies are more sensitive to prolonged pain, and by extension, more susceptible to developing chronic pain. To formally test this hypothesis, we examined the relationship between the pain-free, resting alpha frequency of healthy individuals and their subsequent sensitivity to two experimental models of prolonged pain, Phasic Heat Pain and Capsaicin Heat Pain, at two testing visits separated by 8 weeks on average (n = 61 Visit 1, n = 46 Visit 2). We observed that the speed of an individuals pain-free alpha oscillations was negatively correlated with sensitivity to both prolonged pain tests and that this relationship was reliable across short (minutes) and long (weeks) timescales. Furthermore, we used the speed of pain-free alpha oscillations to successfully identify those individuals most sensitive to prolonged pain, which we also validated on data from a separate, independent study. These results suggest that alpha oscillation speed is a reliable biomarker of prolonged pain sensitivity with the potential to become a tool for prospectively identifying pain sensitivity in the clinic.