Sensory nerve conduction velocity and vibratory sensibility in juvenile diabetics. Relationship to endogenous insulin

Sensory nerve conduction velocity (NCV) and the vibratory sense (biothesiometry) were determined in 67 children and adolescents with insulin dependent diabetes. Age at onset of diabetes varied between 1-14 years (mean +/- S.D. 6.5 +/- 3.6) and the duration of diabetes between 4-17 years (7.7 +/- 3.4). Within +/- 3 months of the nerve function tests blood was drawn for determination of C-peptide and insulin antibodies (IgG and IRI). A low NCV (less than 50 m/s) in the sural nerve and/or an abnormal vibratory sense (greater than or equal to 1.0 microns) were found in 34 patients (50.7%). Measurable fasting serum C-peptide 0.04-0.60 pmol/ml (0.17 +/- 0.15) was found in 16 patients (23.9%). All but one patients had insulin antibodies with IgG 0.130-11.029 mU/ml (2.957 +/- 2.509) and total IRI 10-9120 muU/ml (1204 +/- 1723). In multiple regression analysis we did not find any correlation between nerve function and sex, age, or age at onset of diabetes, and there was only a weak relationship between NCV and duration. However, there was a positive correlation between NCV and C-peptide (p less than 0.001). Vibration sense was also better among patients with C-peptide (p less than 0.05). The results support the view that insulin deficiency contributes to peripheral diabetic neuropathy.