The effect of obstructive sleep apnea syndrome on the central auditory system

Abstract

Background/aim: Obstructive sleep apnea syndrome (OSAS) is a disease characterized by repeated hypoxia attacks during sleep. Theeffect of hypoxia on the central nervous system is a well-known entity. In this study we aimed to investigate the effect of OSAS on thecentral auditory system.Materials and methods: Twenty-one OSAS patients diagnosed by polysomnography (PSG) and 10 control subjects were included inthe study. After a thorough otorhinolaryngology examination, all subjects underwent pure tone audiometry (250 to 8000 Hz frequency).The subjects with normal otoscopic examination and hearing threshold were included in the study. All participants underwent speechdiscrimination analyses and auditory time processing and sequencing tests, i.e. frequency pattern test (FPT) and duration pattern test(DPT).Results: Although hearing was normal in the OSAS patients, significant loss was observed in the speech discrimination rates comparedto the control group (P < 0.05). Significant disruption was also detected in the FPT and SPT in the OSAS patients (P < 0.05).Conclusion: Repeated hypoxic episodes in OSAS resulted in statistically significant impairments in the central auditory pathways, evenif the hearing threshold was within normal limits.