An evaluation of vestibular functions in patients with obstructive sleep apnea syndrome

Sleep is a period of inactivity and regeneration allowing the organism to rest and it prepares the body for the day. The deterioration of sleep quality may result in many negative health effects. Among the sleep-related breathing disorders that cause sleep disorders, Obstructive Sleep Apnea Syndrome (OSAS) is the most common one. Sleep deprivation affects the posterior parietal cortex and the processing of vestibular information. In this study, it was aimed to evaluate the possible effects periodic hypoxia on vestibular reflexes and proprioceptive perception in patients with OSAS. The study included 18-65-year-old 40 participants diagnosed with moderate and severe OSAS based on the polysomnography test and who met the inclusion criteria in the patient group and 21 healthy individuals in the control group. All individuals were evaluated with Dizziness Handicap Inventory (DHI), Epworth Sleepiness Scale (ESS), ocular vestibular evoked myogenic potentials (oVEMP), cervical vestibular evoked myogenic potentials (cVEMP), video head impulse test (vHIT), videonystagmography (VNG), sportKAT 3000, and bedside tests. In terms of DHI scores, both total score and physical, emotional, and functional domain scores were higher in the moderate and severe OSAS groups compared to the control group (p<0.05). In the Video Head Impulse Test, a statistically significant difference was found between EU the groups in terms of anterior SSK VOR and posterior SSK VOR gains (p<0.05). A negative correlation was found between the lateral gain asymmetry and RALP gain asymmetry and the awake blood O2 level in the OSAS groups. There was a difference between the groups in terms of saccades detected in the evaluation of lateral SSK in the Video Head Impulse Test (p<0.05). There was a statistically significant difference between the groups in terms of wave response rates at cervical VEMP 100 dB nHL and oVEMP 100-110 dB nHL (p<0.05). When the static and dynamic balance scores of the OSAS and control groups were evaluated, there was a difference between the groups in terms of both balance scores (p<0.05). There was no statistically significant difference between groups in terms of the VNG and bedside tests (p>0.05). In line with the findings obtained in the present study, it was concluded that vestibular reflexes and proprioceptive perception may be affected due to periodic/chronic hypoxia in patients with moderate and severe OSAS.