Sensitivity was 5 μV/division, low-frequency filter was 20 Hz, high-frequency filter was 2 kHz, sweep speed was 2 ms/division, duration of pulse was 0.1 ms, and rate of pulse was 1/s. The machine used was not specified.

This study was performed in the supine position.

Following the antidromic method [1], the median sensory nerve conduction study was performed recording action potentials from the palmar cutaneous branch (PCB) over the midthenar eminence (Fig. 1). The active recording electrode (A) was placed on the skin of the midthenar eminence one-half the distance between the metacarpophalangeal joint of the digit I (thumb) and the midpoint of the distal crease. The reference (R) electrode was placed 3 cm distally on the phalanx of the digit I. The ground (G) electrode was positioned between the recording and the stimulating electrodes.