RESUMO
Otosclerosis is accompanied with vestibular symptoms in many cases. In 1968 black et al, discovered the co existence of endolymphatic hydrops with Otosclerosis. Many researchers tried to find out correlation between air conduction thresholds and endolymphatic potentials [Gibson and Arenberg,1997; soliman et al, 1999], but few research work tried to find out such a correlation with bone conduction thresholds. This research work was designed to study changes in endolymphatic potentials in conductive and mixed hearing loss associating vertigo in otosclerotic patients. Moreover, to correlate between the bone conduction thresholds and the electrocochleographic potentials ratio in both groups. 40 patients diagnosed as having Otosclerosis were included in the current study 20 patients with Conductive hearing loss and complaining of vertigo [GC]. 20 patients with mixed hearing loss and complaining of vertigo [GM] with 20 normal subjects acted as a control group [GN]. Results of the current study showed a high incidence of endolymphatic hydrops in patients with Otosclerosis. In spite of the increased incidence of endolymphatic hydrops in patients with cochlear Otosclerosis, than in patients with purely stapedial Otosclerosis, no statistically significant difference could be reached. Moreover, no direct correlation could be elicited between bone conduction thresholds and SP/AP amplitude ratio in either group