Vol. 94 No. 9 September 2001

Benign Paroxysmal Positional Vertigo
–Clinical Epidemiology and Pathophysiology –

Noriaki Takeda  (The University of Tokushima School of Medicine)

   Benign paroxysmal positional vertigo (BPPV) is the most common type of vertigo due to peripheral vestibular lesion. BPPV is classified according to different canal’s origin : posterior canal BPPV, anterior canal BPPV and horizontal canal BPPV. In most cases with posterior canal BPPV, canalolithiasis that is free-floating otolith is to cause the syndrome. The movement of canalolithiasis by changes in position of the head induces endolymphatic flow in the posterior canal, resulting in the accompanying nystagmus. The rotation axis of the nystagmus is perpendicular to the affected posterior canal. The canalith repositioning procedure is recommended for the treatment of BPPV. The purpose of this procedure is to relocate free-floating otolith from the posterior canal into the vestibule of the vestibular labyrinth. Horizontal BPPV is induced by lateral movement of the head. The direction-changing horizontal geotropic nystagmus is caused by canalolithiasis of the horizontal canal and the direction-changing horizontal ageotropic nystagmus is caused by cupulolithiasis. Anterior canal BPPV is rare. Because an imbalance in the function of the utriculi in patients with BPPV, otolith detached form the utricular macula is suggested to be a sauce of canalolithiasis and cupulolithiasis.

Key words : bengin paroxysmal positional vertigo, canalolithiasis, cupulolithiasis, canalith repositioning procedure