Correlation of HbA1c concentration and single-fiber EMG findings in diabetic neuropathy

Plasma-glycosylated hemoglobin (HbA1c), i.e., an indicator of metabolic control in diabetic patients, was measured and correlated with neuromuscular jitter and fiber density, which were obtained by single-fiber (SF) EMG assessment. Of the 112 diabetic patients who participated in this study, 34 clinically non-neuropathic patients were categorized in group III, and 78 patients with diagnosed clinical neuropathy were divided into groups I and II, with electrophysiological neuropathy and non-neuropathy, respectively, according to the measurements of nerve conduction. All patients received SFEMG tests and second verifications of levels of HbA1c. In group I (46 patients) and group II (32 patients), the levels of HbA1c were positively correlated with neuromuscular jitters and fiber densities; whereas, no correlation occurred in group III patients. SFEMG findings in diabetic patients provide a higher sensitivity in detecting diabetic neuropathy as compared to nerve conduction studies. The regression for correlation of HbA1c levels and SFEMG findings indicated that axonal degeneration and reinnervation processes with instability of neuromuscular junction in diabetic neuropathy are consistent with the metabolic control of this disease.