Peripheral and autonomic nerve function in long-term insulin-dependent diabetes.

In a cross sectional study, motor nerve conduction velocity (MNCV) and sensory nerve conduction velocity (SNCV), beat-to-beat variation (BBV) at rest and speed of pupillary dilatation (SPD) have been investigated in 127 nonketonuric long-term insulin-dependent diabetics aged 19-72 yr and in age-matched control subjects. 84% of the patients had electrophysiologic abnormalities, 58% had symptomatic peripheral neuropathy, 35% had abnormal cardiac parasympathetic tests and 26% had abnormal pupillary tests. The most frequent pathologic feature was a decreased sural SNCV (66%). Among the patients without symptomatic peripheral neuropathy, 71% showed electrophysiologic abnormalities. MNCV and SNCV in median, peroneal and sural nerves correlated with BBV (p less than 0.005), but only peroneal MNCV was related to SPD (p less than 0.005). There was also a relationship between BBV and SPD (p less than 0.05). Glycosylated hemoglobin (HbA1) levels correlated inversely with median MNCV (p less than 0.001), and SNCV (p less than 0.03), peroneal MNCV (p less than 0.05) and sural SNCV (p less than 0.05). Patients with abnormal peripheral or autonomic nerve function tests or symptomatic peripheral neuropathy had significantly higher HbA1 levels than those with normal tests (p less than 0.04) or asymptomatic patients (p less than 0.01). Median MNCV and SNCV, sural SNCV and BBV deteriorated with age (p less than 0.05) and median SNCV and peroneal MNCV deteriorated with the duration of diabetes (p less than 0.001). Our findings show an association between peripheral and autonomic nerve dysfunction in long-term insulin-dependent diabetics.(ABSTRACT TRUNCATED AT 250 WORDS)