Hypoglossal nerve conduction findings in obstructive sleep apnea.

Denervation of oropharyngeal muscles in obstructive sleep apnea (OSA) has been suggested by needle electromyography (EMG) and muscle biopsy, but little is known about oropharyngeal nerve conduction abnormalities in OSA. We sought to compare hypoglossal nerve conduction studies in patients with and without OSA. Unilateral hypoglossal nerve conduction studies were performed on 20 subjects with OSA and 20 age-matched controls using standard techniques. Median age was 48 years in OSA subjects and 47 years in controls. Hypoglossal compound muscle action potential (CMAP) amplitudes were significantly reduced (P = 0.01, Wilcoxon signed-rank test), but prolongation of latencies in OSA subjects did not reach significance in comparison to those of controls. Among a subgroup of subjects without polyneuropathy (15 pairs), reduced amplitudes in OSA subjects retained borderline significance (P = 0.05). Hypoglossal nerve conduction abnormalities may distinguish patients with OSA from controls. These abnormalities could potentially contribute to, or arise from, OSA.