Sensitivity, low-frequency filter, high-frequency filter, sweep speed, duration of pulse, rate of pulse, and the machine used were not specified.

This study was performed in the supine position, with the elbow and fingers slightly flexed.

According to a previous standardized technique [1], the author used the antidromic method [2]; signals were recorded 14 cm distally from the wrist to a nonspecified finger (Figs. 1 and 2). Probably he recorded sensory potentials from digit II (R), placing the active electrode (A) to the base of the digit and placing the reference (R) 4 cm proximally to the active electrode, slightly distal to the distal interphalangeal joint. Ground (G) electrode position was not specified in the paper; it was probably placed over the midforearm or on the palm of the hand (the figure shows the ground electrode placed on the palm).

Following the antidromic method, the median nerve was stimulated at the elbow (S1), at the wrist (S2), and on the palm (S3). The proximal stimulation at the elbow (S1) was just above the crease of the antecubital fossa and medial to the biceps tendon at the elbow. It allowed determination of forearm mixed nerve conduction velocity. In the case of the stimulation at the elbow (S1), the authors suggested a 2–4 cm separation between the cathode (−) and anode (+), using a pair of standard 0.6 cm diameter electroencephalograph electrodes mounted on a plastic block for stimulating the nerve. At the wrist (S2), the active stimulating electrode (cathode) was applied 14 cm proximal to the active electrode at the base of digit II, over the median nerve at the wrist, between the tendons of the flexor carpi radialis (FCR) and the palmaris longus (PL) muscles (ideally proximal to the distal wrist crease). The anode (+) was proximal. On the palm (S3), the active stimulating electrode (cathode) was applied on the midpoint of the distance from the recording electrode site to the wrist stimulation site, so the distal short segment for sensory conduction velocity was 7 cm. The anode (+) was proximal.

Residual latency is the difference between the expected and observed terminal latencies obtained during the course of a nerve conduction determination. According to a previous standardized technique [3], the authors used the forearm nerve conduction measurement (stimulating the median nerve both at the wrist and at the elbow sites) for distal expected residual latency, and the length of the short segment was divided by the observed sensory conduction velocity to determine the expected short segment distal latency. After percutaneous stimulation of the nerve at the midpalmar site, the observed distal latency was obtained. The difference between the observed and expected distal latencies was the short segment residual. The residual latency index (RLI) was determined by dividing the short segment residual latency by the residual latency for the entire terminal nerve segment. In all patients, the forearm skin temperature, as determined by a surface electrode of a thermistor, equaled or exceeded 34 °C. Expected distal latency (DL) of the sensory nerve action potential (SNAP) recorded from digit II after stimulation at the wrist (14 cm segment) and residual latency (RL) for SNAP recorded from digit II after stimulation at the wrist (14 cm segment) were calculated as follows (distance between the cathode placed at the wrist and the active electrode placed at the base of digit II was 140 mm fixed):