Efficacy of physical therapy for intractable cupulolithiasis in an experimental model.

OBJECTIVE: To investigate what kinds of stimuli are effective in detaching otoconia from the cupula in three experimental models of cupulolithiasis. METHODS: Three experimental models of cupulolithiasis were prepared using bullfrog labyrinths. Three kinds of stimuli were applied to the experimental models. In experiment one (gravity), the labyrinth preparation was placed so that the cupula-to-crista axis was in the horizontal plane with the canal side in the downward position. In experiment two (sinusoidal oscillation), the labyrinth preparation was placed 3 cm from the rotational centre of a turntable, which was sinusoidally rotated with a rotational cycle of 1 Hz and a rotational angle of 30°. In experiment three (vibration), mechanical vibration was applied to the surface of the bony capsule around the labyrinth using a surgical drill. RESULTS: In experiments one, two and three, the otoconial mass was respectively detached in 2 out of 10 labyrinth preparations, none of the labyrinth preparations, and all of the labyrinth preparations. CONCLUSION: Vibration was the most effective stimulus for detaching the otoconia from the cupula in these experimental models of cupulolithiasis.