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.