The impact of ankylosing spondylitis on audiovestibular functions.

In this study, we aimed to evaluate the audiovestibular functions in the patients with ankylosing spondylitis (AS). This prospective study was performed in collaboration by the Otolaryngology and Rheumatology Departments of Bozok University School of Medicine between May 1, 2012, and January 1, 2013. We studied 80 subjects consisting of 40 AS patients (37 men and 3 women) in whom the diagnosis confirmed by the criteria of New York and 40 healthy controls (35 men and 5 women). All participants were evaluated by routine audiologic (including tympanometric evaluation, pure-tone audiograms, speech tests) and vestibular studies (including spontaneous nystagmus, gaze, optokinetic, saccadic movements, smooth pursuit, caloric test and Dix-Hallpike tests). The tympanometric values did not show a statistically significant difference between the AS group and the healthy subjects (p > 0.05). At low frequencies (250, 500, 1,000, and 2,000 Hz) pure-tone audiologic evaluations also proved statistically non-significant results at mean air conduction thresholds (ACT) and bone conduction thresholds (BCT) between the AS and control groups (p > 0.05). At high frequencies (4,000, 6,000, and 8,000 Hz), the ACTs and BCTs in AS group were lower than control group which was statistically significant (p < 0.05). The results of spontaneous nystagmus, gaze, optokinetic, canal paresis and saccadic movement tests between the two groups were statistically insignificant (p > 0.05). The comparison of smooth pursuit and Dix-Hallpike tests reached statistical significance (p < 0.05). Videonystagmographic test (VNG) revealed central abnormalities in 7 patients (17.5 %), peripheral abnormalities in 16 patients (40 %), and mixed abnormalities in 3 patients (7.5 %). Our findings suggest a possible association between AS and audiovestibular system dysfunction. We assume that the hearing and vestibular disturbances in AS are more prevalent than previously recognized.