Motor conduction velocity and the Hoffman reflex in diabetes.

The motor conduction velocity (MCV) and various parameters of the Hoffman reflex were studied in 55 diabetics compared to a control population of the same age. In the diabetics there were statistically significant alterations of the MCV, the Hmax/Mmax ratio and the H index, which are closely connected. These changes were more precise when there were clinical signs of neuropathy (absence of the Achilles reflex) but they still existed in the absence of signs. The older the diabetics, the more the electro-physiological parameters were altered. However, the H index is abnormal earlier than the Hmax-Mmax ratio or the MCV. Changes in the excitability cycle to double shock involve mainly phase IV of secondary facilitation and may be related to central disturbances.