PREVALENCE OF SUBCLINICAL NEUROPATHY IN DIABETIC-PATIENTS - ASSESSMENT BY STUDY OF CONDUCTION-VELOCITY DISTRIBUTION WITHIN MOTOR AND SENSORY NERVE-FIBERS

Nerve conduction velocity distribution (CVD) study is a newly-develope d electrodiagnostic method for detecting alterations in the compositio n of nerve fibres according to their conduction velocity. The presence of subclinical neuropathy was evaluated in 138 diabetic patients by C VD study of four motor nerves (external popliteal and ulnar nerves bil aterally) and two sensory nerves (median nerve bilaterally), and the d ata obtained were compared with standard electrophysiological paramete rs in the same nerve segments. CVD studies revealed an altered distrib ution pattern in 106 of 129 evaluable patients for motor nerves (82%) and in 67 of 115 evaluable patients for sensory nerves (58%), while st andard examination gave abnormal findings in 92 of 137 patients (67%) and in 33 of 118 patients (11%), respectively. Of the patients adequat ely evaluated by both techniques, 21 of 129 patients (16%) revealed al tered CVD data unaccompanied by slowing of maximum nerve conduction ve locity, and 37 patients of 101 (37%) showed similar findings for senso ry nerves. Subclinical alterations of motor and sensory nerve CVD were not significantly related to age or to metabolic control expressed as glycated haemoglobin levels; a significantly longer duration of disea se was found in patients with motor and mixed subclinical neuropathy w ith respect to non-neuropathic patients. The CVD study allowed us to d etect subclinical abnormalities of motor and sensory nerve fibres; oft en this is a more sensitive method than the standard electrodiagnostic study, This method can be very useful as a diagnostic tool and in res earch in the study of the progression of diabetic neuropathy.