Electrodermal and microcirculatory activity in patients with fibromyalgia during baseline, acoustic stimulation and cold pressor tests.

The peripheral sympathetic activity was studied in 27 patients with fibromyalgia and 29 healthy controls through simultaneous measurements of electrodermal variables and blood flow at palmar skin sites during baseline, acoustic stimulation, and cold pressor tests. Compared to the controls, the patient group showed a significantly larger overall increase in the skin electrical conductance and less vasoconstriction during acoustic stimulation and cold pressor tests. These findings imply an increased activity of cholinergic and decreased activity of adrenergic components of the peripheral sympathetic nervous system in patients with fibromyalgia.