Methods for assessing small peripheral nerve fiber function objectively are limited. The cutaneous silent period (CuSP), a transient supression of electromyographic voluntary activity that follows painful stimuli, could serve as an objective functional measure of the A delta fibers. The aim of this study was to evaluate function of small diameter A delta nerve fibers using the CuSP in normals and in patients with both focal (carpal tunnel syndrome - CTS) and generalised (polyneuropathies - PNP) peripheral nerve injuries. The objectives of the study were the following: 1. To determine the CuSP normal values by age, gender, side, height and weight in healthy controls. 2. To study the topography and extension of the CuSP by changing recording and stimulating sites in healthy controls. 3. To evaluate the CuSP in patients with CTS of different severity and to compare these results with those of healthy controls. 4. To estimate the CuSP onset latency and duration in relation with median nerve evoked compound muscle action potential amplitude, distal latency and conduction velocity in patients with CTS. 5. To evaluate the CuSP in patients with PNP of different types and to compare these results with those of healthy controls. 6. To estimate the CuSP onset latency and duration in relation with median nerve evoked compound muscle action potential amplitude, distal latency and conduction velocity in patients with PNP. We investigated the CuSP of the upper and lower limbs of 50 normal... [to full text]