F response characteristics in type I diabetes mellitus.

Ulnar and tibial F response parameters were characterized in 17 healthy controls and 26 subjects with type I diabetes mellitus meeting or exceeding criteria for mild diabetic peripheral neuropathy. The presence of mild diabetic peripheral neuropathy was determined by utilizing conventional nerve conduction studies, the neuropathy symptoms score and a neurologic examination. Ulnar and tibial nerve F response latency, amplitude, duration, chronodispersion and persistence were then compared between populations. The relationship between tibial F response persistence and minimal F response latency was assessed in both populations. In addition, the relationship between tibial F response persistence and tibial nerve conduction velocity and tibial nerve compound action potential characteristics (e.g., latency, amplitude and duration) was assessed in the diabetic population. The results indicate that ulnar F response latency and chronodispersion failed to differentiate the subject and control populations; however, significantly decreased ulnar F response amplitude and duration were noted in the diabetic population. In the tibial nerve, the F response persistence was significantly decreased in the diabetic population but persistence did not correlate with compound muscle action potential latency, amplitude, duration or nerve conduction velocity. Finally, the tibial F response latency, amplitude, duration and chronodispersion failed to differentiate the control and diabetic populations.