Slowing in peak-alpha frequency recorded after experimentally-induced muscle pain is not significantly different between high and low pain-sensitive subjects

Peak alpha frequency (PAF) reduces during cutaneous pain, but no studies have investigated PAF during movement-related muscle pain. Whether high-pain sensitive (HPS) individuals exhibit a more pronounced PAF response to pain than low-pain sensitive (LPS) individuals is unclear. As a pain model, twenty-four participants received nerve growth factor injections into a wrist extensor muscle at Day0, Day2, and Day4. At Day4, a subgroup of twelve participants also undertook eccentric wrist exercise to induce additional pain. Pain numerical rating scale (NRS) scores and electroencephalography were recorded at Day0 (before injection), Day4, and Day6 for 3 minutes (eyes closed) with wrist at rest (Resting-state) and extension (Contraction-state). The average pain NRS scores in contraction-state across Days were used to divide participants into HPS (NRS-scores≥2) and LPS groups. PAF was calculated by frequency decomposition of electroencephalographic recordings. Compared with Day0, contraction NRS-scores only increased in HPS-group at Day4 and Day6 (P