Analysis Of Multiple Auditory Steady State Responses In Guinea Pigs With Semicircular Canal Occlusion

Benign paroxysmal positional vertigo (BPPV) is the most common peripheral vestibular disorder, accounting for' about 25% of referrals in specialized dizziness clinics. It can be defined as transient vertigo induced by a rapid head position change, associated with a characteristic paroxysmal positional nystagmus. BPPV is normally a self-limited disease with spontaneous recovery, the common therapy is expectant treatment, surgical intervention being recommended only for those small numbers of patients in whom it becomes persistent and incapacitating (> 12 months duration).The pathomechanism of BPPV remains obscure, both cupulolithiasis and canalolithasis are potentially valid mechanisms. Semicircular canal occlusion is a new operative was originally based on the concept that cupulolithiasis is the underlying cause of BPPV. It is believed that blockage of the membranous duct eliminates endolymph movement within the canal effectively fixing the cupula. Thus, at the time, it was believed that the cuplua would no longer respond to the gravitational effect on the fixed cupular deposit, thus eliminating the BPPV. However, the modern canalolithiasis theory postulates the existence of free-floating dense otolithic particles in the endolymph of the posterior semicircular canal. BPPV is caused by gravity-dependent movements of otoconial debris that collects in the endolymph of...