Electrophysiological study and glutamic acid decarboxylase 65 in detection of subclinical neuropathy in type 1 diabetes mellitus

ABSTRACT

To evaluate the role of electrophysiological studies and serum glutamic acid decarboxylase [GAD65Ab] in the detection of subclinical neuropathy, in Type 1 diabetes mellitus [TIDM]. This study was conducted on 30 patients of Type 1 diabetes mellitus within the first year of diagnosis and 20 controls. All subjects were evaluated for subjective neuropathy symptoms, neurological examination, electrophysiological findings, GAD65Ab, glycosylated hemoglobin [HbA1], cholesterol and triglyceride in serum. At least two abnormal independent neurophysiological nerve parameters were accepted as the criteria of peripheral nervous system involvement. Electrophysiological study showed peripheral nervous system involvement in 93.3% of patients. The percentages of affection were 90% in sural nerve, 82.4% in peroneal motor nerve, 68.5% in posterior tibial motor nerve, 62.2% in median motor nerve, 59.9% in ulnar motor nerve, 65.2% in median sensory nerve, and 60.5% in ulnar sensory nerve. Antibodies to GAD65 were detected in 18 of 30 patients [60%]. Patients with positive GAD65Ab had slower motor nerve conduction velocities in the median, ulnar, and peroneal nerves and prolonged sural nerve latency. There is a positive correlation between HbA1 levels and peripheral nerve dysfunction in the lower extremity. Highly significant correlation between HhA1 and GAD65 in patients group was noticed. Subclinical diabetic peripheral neuropathy can be detected by electrophysiological tests, especially for nerves of lower extremity. The poor glycemic control and GAD65Ab have an impact on peripheral nerve function