The natural course of peripheral and autonomic neural function during the first two years after diagnosis of type 1 diabetes

Abstract
Motor and sensory nerve conduction velocities (MNCV, SNCV), beat-to-beat variation (BBV) at rest, speed of pupillary dilation (SPD), and pupillary latency time (PLT) were measured in 32 patients aged 12–36 years after 19±2 (mean±SEM) days and again after 3, 12, and 24 months of insulin treatment. Moreover, BBV under deep respiration was determined after 12 and 24 months, and thermal discrimination thresholds (TDT) as well as pain and vibration perception thresholds (PPT, VPT) were evaluated after 24 months. Mean HbA1 levels during months 3–24 within the normal range (7.2±0.2%; mean±SEM) were observed in 20 patients (group 1), while in 12 patients (group 2) mean HbA1 of months 3–24 was elevated (10.1±0.4%). There were no significant differences between both groups with regard to the nerve function tests at baseline and after 3 months. After 12 months mean median MNCV and median, ulnar, and sural SNCV were significantly lower in group 2 than in group 1 (ppp<0.05). These findings suggest that early deterioration of somatic nerve function after one year and of autonomic function after 2 years of diabetes may be prevented by effective glycemic control initiated immediately after diagnosis of the disease.