Vestibular Assessment of Obstructive Sleep Apnea Patients

Abstract Background: Obstructive sleep apnea (OSA) is a common disorder. Over recent years, there appears to be a significant number of the idiopathic dizzy patients who simultaneously suffer from some sort of sleep disturbance, either subjectively or objectively. Only one retrospective review has investigated the potential association between sleep disturbance and symp-toms of dizziness, but it was done in a cursory manner. Aim of Study: The aim of the study was to assess vestibular function in obstructive sleep apnea patients using computerized dynamic postugraphy, to study the relationship between oxygen saturation and vestibular function in obstructive sleep apnea patients and to study if there is correlation between clinical findings and polysomnography results. Patients and Methods: A prospective interventional study carried out on a group of 30 patients with OSA confirmed diagnosis, according to the American Academy of Sleep Medicine classification as a study group that were selected from patients (age range 20-60 years) attending the ENT outpatient clinic at Al-Hussein University Hospitals with clinically suspected OSA after being investigated with poly-somnography. Control group consisted of 30 normal adult volunteers, age, sex and body weight matched with the study group, and without any history of sleep-disordered breathing, otologic, neurologic or vestibular disorders, and sleep apnea was excluded by polysomnography. All the patients included in this study were subjected to thorough history taking, general examination, complete otorhinolaryngologic examination, overnight polysomnography and vestibular assessment in the form of sensory organization test (SOT) using computerized dynamic postugraphy (CDP). Results: The results show that there was a statistically significant positive correlation between RDI and desaturation index (Pearson's r=0.639 with p-value <0.001). In addition, results also show that there was a positive correlation between body weight and both RDI & average low O2 during all desaturations but not statistically significant (Pearson's r=0.379 & 0.223 with p-value 0.39 & 0.236 respectively). Moreover, as expected RDI is positively correlated to desaturation index and negatively correlated to the average low O2 during all desaturations, with statistical significance (p-value <0.001 & <0.01 respectively). Similar findings were found in the control group No statistically significant correlation between the study and control groups as regards SOT results of CDP.
Conclusion: This study is one of the first studies to evaluate OSA patients with computerized dynamic posturgra-phy, and with control group. No statistically significant correlation between BMI, neck circumference and RDI, and the SOT results of CDP could be found. To rationale this result, central vestibular system can compensate for possible unilateral or single factorial affection. Also, CDP is a functional test as opposed to the pathological nature of caloric testing. Obesity remains one of the main risk factors for obstructive sleep apnea (OSA), and OSA is strongly associated with obesity. Therefore, it seems clear that induction of OSA by obesity involves a mechanical factor. Neck circumference is strongly correlated with BMI. Both BMI and neck circumference influence the severity of OSA (RDI). Increase in neck circumference directly aggravates the severity of OSA, and is consequently reflected on oxygen concentration in during sleep apnea. Similar correlation regarding BMI, but not statistically significant.