A New Electrodiagnostic Procedure for Measuring Sensory Nerve Conduction across the Carpal Tunnel

Stimulation with pad electrodes of sensory nerves in the palm of the hand and recording the response from the median nerve close to the wrist using conventional surface electrodes in controls gave nerve potentials usually about 100 μV after a latency of about 1.2 (initial deflection) to 1.6 (peak) ms. The latency of the peak tended to increase significantly in cases of carpal tunnel syndrome. This new method is simple to apply and will probably increase the diagnostic accuracy appreciably. It is suggested that it be used in parallel with the conventional procedures until more experience has been gained.