Figure 1. Recording arrangement.

Stimuli were delivered at the wrist (cathode) using Ag–AgCl electrodes with the anode 10 cm distal on radial edge of the forearm. CMAPs were recorded over the thenar eminence, with the reference electrode on the proximal phalanx of the thumb. CSAPs were recorded using disposable Ag–AgCl ring electrodes on digit 2. The same ground was used for both motor and sensory recordings. Reusable ‘click-style’ sodium acetate heat pads were applied to the dorsal and palmar aspects of the distal forearm and hand, at wrist level (as indicated by the dotted lines), and the thermistor recorded the temperature close to the site of stimulation.