F wave parameters and F tacheodispersion in mild diabetic neuropathy.

F tacheodispersion and some F wave parameters have previously been suggested to be useful in the detection of peripheral nerve involvement in diabetic patients with normal nerve conduction studies. In this study, ulnar and tibial F wave parameters of diabetic cases with normal motor and sensory nerve conduction studies (Group 1) were calculated, F tacheodispersion histograms were constructed and compared with the same parameters obtained from the normal controls (Control group) and diabetic cases with abnormal motor and sensory nerve conduction examinations (Group 2). There was a tendency towards lower conduction velocities in ulnar and tibial tacheodispersion histograms of Group 1 and Group 2, as compared to Control group. Most of the F wave values were significantly abnormal in Group 2 in comparison to other two groups, whereas statistically significant differences between Group 1 cases and Control group were found in minimum ulnar F wave conduction velocity (FCVmin), mean ulnar FCV (FCVmean), tibial FCVmin and tibial FCVmean values. Unlike other methods, F waves give information about the entire length of the motor nerve fiber. In mild neuropathies, in which nerve fibers are damaged uniformly, testing the whole length of a nerve with this method may be beneficial in detection of a mild conduction abnormality.