Abstract 684, Date 1:00 pm, Sunday, February 17, 2008 (48 hours) Session D17: Poster
Vestibular Function in Patients with Otosclerosis and Balance Disorders
*Alexis Bozorg Grayeli, Olivier Sterkers, Michel Toupet
Introduction : Vestibular function in patients with otosclerosis and balance disorders not related to the immediate postoperative course are rare and seldom described or explored. The aim of this study was to investigate the clinical aspects of these disorders and to assess the audio-vestibular functions of these patients. Materials and methods: Among 13800 patients examined for balance disorders between 2002 and 2006, 98 (0.7%) presented with otosclerosis. In this group, 73 (28 not operated on, 27 operated on one side, and 18 operated on both sides for hearing rehabilitation) and undergoing audio-vestibular assessment (clinical examination, audiometry, videonystagmography with caloric and rotatory tests, subjective vertical) were included in this retrospective series. Results: Patients complained of dizziness in 42 cases (58%), symptoms compatible with benign paroxysmal positional vertigo in 38 cases (52%), and rotatory vertigo in 18 cases (25%). In non operated patients labyrinthine the reflectivity measured by the caloric test was highly correlated between left and right ears (R=0.59, P< 0.005, ANOVA) while there was no left-right correlation for the hearing loss (air and bone conduction pure tone thresholds). This observation suggested that the labyrinthine involvement was bilateral even in patients with unilateral or asymmetrical audiometric signs. In patients operated on unilaterally, the vestibular reflectivity was lower on the operated side than on the non operated ear suggesting a surgery-induced deficit. There was no correlation between the sensorineural component of the hearing loss (bone conduction pure tone thresholds) and the vestibular reflectivity. The subjective vertical was not significantly deviated in these patients probably due to the compensation mechanisms. Conclusions: Balance disorders in patients with otosclerosis can be associated to canal or otolithic dysfunction. Vestibular function as measured by reflectivity remains symmetrical in non operated patients even in cases of unilateral or asymmetrical hearing loss while operated patients with persistent imbalance show vestibular deficit on the side of surgery.