Evidence for spinal disinhibition as a pain-generating… : PAIN Reports
arker of spinal disinhibition is impaired H-reflex rate-dependent depression (HRDD). Objectives: This study investigated whether patients with FMS exhibit evidence of spinal disinhibition. Methods: Thirty-one individuals with FMS and 20 healthy volunteers underwent testing of Hoffman reflex including HRDD, along with assessment of clinical signs and symptoms, pressure pain thresholds, temporal summation of pain (wind-up), and conditioned pain modulation (CPM). Small nerve fibre structure was quantified using intraepidermal nerve fibre density and corneal confocal microscopy. Results: Patients with FMS had significantly impaired HRDD at 1 Hz (P = 0.026) and 3 Hz (P = 0.011) and greater wind-up ratio (P = 0.008) compared with healthy controls. Patients with the most impaired HRDD also had the most inefficient CPM but HRDD was not associated with wind-up. Both HRDD and CPM were most impaired in patients with a shorter duration of disease. Conclusion: We demonstrate for the first time that
