Clinical Characteristics of Horizontal Canal Benign Positional Vertigo: Analysis of 97 Cases

ABSTRACT

BACKGROUND: Horizontal canal benign positional vertigo (BPV) is characterized by direction-changing nystagmus beating to the lowermost ear (geotropic) or to the uppermost ear (apogeotropic) induced by head turning while the patient is lying down. The clinical features of horizontal canal BPV has rarely been studied in a large group of patients in Korea. METHODS: Ninety-seven patients with horizontal canal BPV were recruited from September 2000 to August 2003. The diagnosis of BPV was based on the typical nystagmus concurrent with vertigo elicited by positioning maneuvers. The type was divided into geotropic or apogeotropic. The demographic features, spontaneous nystagmus, positional nystagmus, results of head thrusting and head shaking, and nystagmus induced by lying down were analyzed. RESULTS: The patients included 68 (70.1%) women and 29 (29.9%) men. Mean age of the patients was 61.1 +/- 13.8 with no difference between women and men. They were divided into 54 (55.7%) geotropic and 43 (44.3%) apogeotropic types. The horizontal nystagmus was also provoked by Hallpike maneuver in 15 cases. Horizontal nystagmus was also induced by lying down from sitting to supine position in 7 patients; 3 apogeotropic and 4 geotropic. The nystagmus was ipsilesional in 2 of apogeotropic cases and contralesional in 2 of geotropic cases. CONCLUSIONS: In horizontal canal BPV, horizontal nystagmus may be induced by Hallpike maneuver or lying down as well as head turning in supine position. The direction of nystagmus induced by lying down may help deciding the side of the canal involved.