AN ELECTROPHYSIOLOGICAL METHOD TO ASSESS THE DISTRIBUTION OF THE SENSORY PROPAGATION VELOCITY OF THE DIGITAL NERVE IN NORMAL AND DIABETIC SUBJECTS

We report a new computer-assisted collision method to evaluate sensory conduction velocity (SCV) distribution in the digital nerve of the mi ddle finger in nor-mal subjects and in insulin-dependent diabetic subj ects without any neurological impairment. Distribution curves were mon omodally shaped in controls, indicating a greater proportion of fibers with relatively slow conduction velocity and a lesser proportion of f ibers with faster velocity. In most diabetic nerves, a monomodal trend of the SCV distribution indicated a definite reduction in high and in termediate SCV. In a small proportion of nerves, the SCV distribution tended to be bimodal, with an absolute maximum corresponding to lower velocities and a relative maximum to intermediate-fast velocities. Slo wing of the intermediate velocity, or loss of fibers of intermediate v elocity, can be hypothesized to represent the early electrical evidenc e of a subclinical polyneuropathy in insulin-dependent diabetic subjec ts.