F-WAVE AND M-RESPONSE CONDUCTION-VELOCITY IN DIABETES-MELLITUS

The F-wave (late muscle response) was used to estimate motor nerve condition velocity (MNCV) along the proximal segment of the fastest axons of the deep peroneal and ulnar nerve in 21 patients suffering from diabetes mellitus. In 6 patients there were neither objective nor subjective symptoms or signs of neuropathy. Measurements in these patients, and 21 sex- and age-matched control subjects were based on the shortest latency of 100 F-waves obtained from each point of stimulation. The MNCV was also estimated in the distal segment of the nerves with M[muscle]-response and F-wave method. In patients with subjective symptoms of neuropathy distal MNCV was more severely affected than proximal MNCV; the nerves of the lower limbs are more vulnerable than the upper limbs. In 6 patients with no symptoms or signs of neuropathy there was only a minimal showing in the segment knee to the ankle of the deep peroneal nerve. In 1 patient the proximal ulnar segment was affected while other parameters were normal. F-chronodispersion is also a very sensitive method for detecting motor nerve impairment in patients whose conventional MNCV studies are normal.