The use of F-wave and sural potential in the diagnosis of subclincal diabetic neuropathy in Saudi patients.

OBJECTIVE To compare nerve conduction parameters in asymptomatic diabetic patients and with no clinical signs of neuropathy and in control subjects. METHODS Forty-eight diabetic Saudi subjects (20 males, 28 females) and 48 age-and-sex-matched control subjects were studied. The mean age of patients +/- standard deviation was 45.6+/-11.7 years. The mean duration of diabetes from time of diagnosis was 10.8+/-3.1 years, and their mean fasting plasma glucose was 8.5+/-0.9 mmol/l. Nerve conduction studies were performed on the right lower limb. RESULTS In diabetic patients the tibial and peroneal nerve conduction velocity values were 48.6+/-4.7 and 46.3+/-5.2 m/s. They were not significantly different from controls (p>0.01). The tibial and peroneal distal motor latency values were 5.1+/-0.6 and 4.7+/-0.9 ms, and not significantly different from controls (p>0.01). The sural nerve distal sensory latency in patients was 3.2+/-0.7 ms and the sural sensory nerve action potential amplitude was 4.9+/-2.5 uV. These values were significantly different from controls (p<0.01). The tibial and peroneal minimal F-wave latency values in patients were 32.5+/-1.9 ms/m and 32.9+/-1.6 ms/m, and were significantly different from controls (p<0.001). The F-wave average duration values in patients were 11.8+/-1.5 ms for the tibial nerve and 9.0+/-1.4 ms for the peroneal nerve. These were significantly different from control (p<0.001). CONCLUSION The peroneal and tibial minimal F-latency and average F-duration provide the most sensitive nerve conduction; indicators for the diagnosis of subclinical neuropathy in diabetes.