Pathophysiology of Nystagmus in Benign Paroxysmal Positional Vertigo

Lee, Tae Kyeong; Sung, Ki Bum

Abstract

Benign paroxysmal positional vertigo (BPPV) is easily diagnosed when the specific pattern of nystagmus is demonstrated by adequate provoking maneuver. Therefore, recognizing the pattern of nystagmus is important to determine the affected ear and whether the otoconia is free-floating in the canal or attached to the cupula. However, the latency and the duration of nystamus can be various depending on the type of otoconia and even the direction of nystagmus is atypical in some cases. In addition, not all the positionally-induced nystamus are ascribed to benign semicircular canal pathology. Atypical pattern and refractory for the canalith repositioning maneuver can raise the possibility for the central positional vertigo or nystagmus. Physicians are often perplexed if the pattern of nystagmus by positioning maneuver is not the expected one. For those account, physicians should be well equipped with the knowledge of the pathophysiology of nystamus in BPPV. The pathophysiology and the various patterns of nystagmus in BPPV are discussed in this review.