The Laryngoscope C 2014 The American Laryngological, V

Rhinological and Otological Society, Inc.

Vestibular Functions Were Found to Be Impaired in Patients With Moderate-to-Severe Obstructive Sleep Apnea Serkan Kayabasi, MD; Ayse Iriz, MD; Melih Cayonu, MD; Bugra Cengiz, MD; Aydin Acar, MD; Suleyman Boynuegri, MD; Banu Mujdeci, PhD; Adil Eryilmaz, MD Objectives/Hypothesis: Obstructive sleep apnea (OSA) and balance disorders are common chronic diseases seen in the general population. The aim of this study was to evaluate vestibular functions in individuals with OSA. Study Design: Cross-sectional clinical study. Methods: Patients who were referred to the sleep clinic in our hospital were classified into two groups according to a polysomnographic test: a moderate-to-severe OSA group and a mild OSA group. A vestibular system assessment of all patients was performed subjectively with the Dizziness Handicap Inventory (DHI) survey and objectively with videonystagmography. Results: The current investigation produced four major findings: 1) Apnea-hypopnea index was significantly correlated with age and body mass index, whereas it was not correlated with Epworth Sleepiness Scale scores. 2) There was a significant difference in study groups in terms DHI scores, particularly in the physical subgroup. Moderate-to-severe OSA patients had higher scores in the physical subgroup of DHI. 3) Nystagmus and canal paresis rates were significantly higher in the moderate-to-severe OSA group when compared to the mild OSA group. 4) Results of the Romberg test, tandem Romberg test, cerebellar examinations, and positional tests were normal in both. Conclusions: Abnormal vestibular responses are common in individuals suffering from severe OSA, and dizziness has negative effects on the quality of life in these individuals. Key Words: Obstructive sleep apnea, vertigo, dizziness, vestibular function. Level of Evidence: 4 Laryngoscope, 00:000–000, 2014

INTRODUCTION Obstructive sleep apnea (OSA) is characterized by recurrent episodes of upper respiratory tract obstruction as either breathing cessation (apnea) or reduction of airflow (hypopnea) during sleep, heavy snoring, and daytime sleepiness. Risk factors of OSA are well described at present; however, its mechanisms and effects on patients’ quality of life remain unclear.1 OSA affects many systems in the human body and is becoming more commonly recognized because of its significant negative effects on systems such as the cardiovascular system, the central nervous system and the cognitive system. In particular, cognitive deficits in OSA patients have been documented in several studies. These

From the Department of Otorhinolaryngology (S.K.), Aksaray State Hospital, Aksaray, Turkey; Department of Otorhinolaryngology (A.I.), Gazi University Medicine Faculty, Ankara, Turkey; Department of Otorhinolaryngology (M.C.), Amasya University, S.S. Training and Research Hospital, Amasya, Turkey; Department of Otorhinolaryngology (B.C.), Kars State Hospital, Kars, Turkey; Department of Otorhinolaryngology (A.A., S.B., A.E.), Ankara Numune Training and Research Hospital, Ankara, Turkey; Department of Hearing, Speech and Vestibular Disorders (B.M.), Ankara Numune Training and Research Hospital, Ankara, Turkey. Editor’s Note: This Manuscript was accepted for publication October 12, 2014. The authors have no funding, financial relationships, or conflicts of interest to disclose. Send correspondence to Melih Cayonu, MD, Department of Otorhinolaryngology, Amasya University S.S. Training and Research Hospital, Kirazlidere, 05100 Turkey. E-mail: [email protected] DOI: 10.1002/lary.25021

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deficits take the form of impairments to memory, executive functioning, attention, and fine motor coordination. Sleep fragmentation and sleep deprivation have been proposed as mechanisms underlying cognitive impairment in OSA patients.2–5 Vertigo is the illusion of motion due to acute tonic neural activity imbalance of the vestibular system. This imbalance causes the individual to experience a whirling motion internally or a sensation of their surrounding environment turning.6 However, to the best of our knowledge, there has only been one study investigating the effects of OSA on the vestibular system.7 Thus, the aim of this study was to investigate the possible effects of OSA on the vestibular system in terms of clinical features and quality of life.

MATERIALS AND METHODS Patients and Study Design We conducted a cross-sectional clinical study at the Otorhinolaryngology Department of Ankara Numune Training and Research Hospital. All investigations were performed in accordance with the Declaration of Helsinki on biomedical studies involving human subjects, and informed consent was obtained from all participants before the study began. The participants were selected from patients who presented with a clinical suspicion of OSA and were admitted to the sleep lab of Ankara Numune Training and Research Hospital. Prior to the onset of the sleep study, data were registered for each participant individually, including age, gender, height,

Kayabasi et al.: Vestibular Hypofunction in Severe OSA


and weight to calculate body mass index (BMI), medical history, and a list of current medications. Exclusion criteria included patients with histories of malignancy, head trauma, neurologic and psychiatric disorders, metabolic, cardiovascular, and endocrine disorders, or with previous diagnoses of neurotological disease (i.e., labyrinthine diseases, benign paroxysmal positional vertigo). First, an otorhinolaryngologic examination including endoscopic nasopharyngoscopy and Muller’s maneuver was performed, and then examinations were performed for OSA. Patients were classified into two groups according to the polysomnography (PSG) results. Group 1 consisted of patients with mild OSA, and group 2 consisted of patients with moderate-to-severe OSA. Two ageand sex-matched groups were formed, consisting of a total of 50 patients who met the study criteria. After the groups were constituted, the vestibular system functions of the participants were evaluated. None of the participants was excluded from the study or left the study after being grouped according to PSG results.

Evaluation of Vestibular Functions Participants were evaluated as follows: 1) physical vestibular system examination, 2) pure-tone audiometry (PTA) (recording the average of 0.5, 1, 2, and 4 kHz), 3) evaluation of eye movement disorders using ocular motility tests recorded by videonystagmography (VNG), 4) tests of caloric vestibular responses with cold-water stimulation recorded by VNG, and 5) application of the Turkish version of the Dizziness Handicap Inventory (DHI) survey. Vestibular system examination was performed via Romberg and tandem Romberg tests in all of the participants. During the cerebellar examinations, dysmetria and dysdiadochokinesia were evaluated. Eye movements were recorded by means of a video-based system (Micromedical Technologies, Chatham, IL). Saccadic and smooth pursuit eye movements, optokinetic nystagmus, and any spontaneous and positional nystagmus were recorded. Bithermal caloric testing was also performed with suppression fixation. Saccades were tested for accuracy, velocity, and latency. Smooth-pursuit and optokinetic tracking were analyzed for symmetry and gain. A standard caloric test was performed on each subject, with a constant flow of air at temperatures of 26 C and 48 C for a constant period of time (80 seconds).8 The maximum slow-phase velocity of nystagmus was calculated following each irrigation, and Jongkees’s formula was used to determine canal paresis (CP). It was considered abnormal if CP was >20%. The Turkish version of the DHI survey was applied to the patients. DHI is a survey that consists of 25 questions that evaluate the patient’s quality of life emotionally, physically, and functionally. It is used for evaluating the effects of dizziness on quality of life in clinical research and studies.9–11 Three different scores that reflected the physical, functional, and emotional effects were determined using the DHI and were evaluated separately and together. Scores range from 0 to 100, where higher scores indicate more severe handicap. Scores >10 points should be referred to balance specialists for further evaluation. Also, evaluation of test results are as follows: 16 to 34 points (mild handicap), 36 to 52 points (moderate handicap), and 54 points (severe handicap). The relationship of head, eye, and neck movements with dizziness was assessed via the physical score, and the effects of dizziness on head, eye, and neck movements were assessed via the functional score. The functional score also evaluated the ability of an individual to carry out his or her

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work, home, and social activities. The emotional score evaluated the extent to which dizziness affected a patient’s quality of life. Examples of problems include lack of concentration, fear of being home alone, and problems in family and social relationships.

Evaluation of Patients Who Were Suspected of OSA A validated Turkish version of the Epworth Sleepiness Scale (ESS) questionnaire12 was completed (eight items with a four-point scale [0–3]), as previously described,13 for every participant included in the study. All participants underwent a full-night PSG study with at least 7 hours of recording time (Alice 5 Diagnostic Sleep System; Philips Respironics, Philips Healthcare, Woerden the Netherlands). Sleep staging was scored according to the criteria of the American Academy of Sleep Medicine (AASM) published in 2007.14 Apnea was defined as the cessation of airflow for 10 seconds. Hypopnea was defined as a 30% reduction of airflow lasting 10 seconds and associated with a 4% decrease in oxyhemoglobin saturation. The number of apneas and hypopneas per hour of sleep was calculated to obtain the apnea-hypopnea index (AHI). Also, respiratory effort-related arousal (RERA) events were calculated according to the AASM criteria. The participants were classified into two different groups according to the diagnostic criteria for OSA. The classification was based on the AASM criteria per reported AHI values from the overnight PSG study: group 1 consisted of patients with mild OSA (five events/hour  AHI

Vestibular functions were found to be impaired in patients with moderate-to-severe obstructive sleep apnea.

Obstructive sleep apnea (OSA) and balance disorders are common chronic diseases seen in the general population. The aim of this study was to evaluate ...
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