Postoperative audiovestibular assessment of obstructive sleep apnea patients

Background In obstructive sleep apnea syndrome, the impact of hypoxia on different body systems is of utmost importance. Brainstem is greatly sensitive to the effects of hypoxia including auditory and vestibular nuclei. Our aim in the current study is to evaluate hypoxic effect of OSAS on the audiovestibular system using auditory brainstem response, cervical vestibular evoked myogenic potential, and video nystagmography and to determine whether this effect is reversible postoperatively. Results In OSAS patients, the mean absolute and interpeak latencies of ABR were significantly prolonged compared to controls and remained so postoperatively. No statistically significant difference between pre- and postoperative values was found. The differences in the mean latencies of P1 and N1 of the cVEMP responses between the two groups were insignificant. However, there was a significant difference in P1N1 amplitude. On the other hand, the difference in the mean amplitude of the P1N1 wave in the study group postoperatively was not significant. The VNG results included bilateral canal paresis in four, unilateral in two, and spontaneous nystagmus in two patients. Also, two patients showed pursuit abnormality and two had saccadic abnormality which did not improve postoperatively. Conclusions Patients with moderate to severe OSAS experience both auditory and vestibular deficits which do not reverse 3 months after corrective surgery.