Benign positional vertigo: clinical and oculographic features in 240 cases.

We report the clinical and oculographic features in 240 patients with benign positional vertigo (BPV). In each case, after a rapid position change from the sitting to head-hanging position, a stereotyped torsional paroxysmal positional nystagmus was visually observed and recorded with electronystagmography (ENG). The mean age of onset was 54 years, with a range of 11 to 84 years. In slightly more than one-half of the cases (122/240) a likely diagnosis was determined. The most common identifiable causes were head trauma (17%) and viral neurolabyrinthitis (15%). Females outnumbered males approximately two to one in the idiopathic group. Abnormalities on bithermal caloric testing were found in 47% of patients. Only two patients, both with well-documented neurologic disorders, had central signs on ENG. Our data are consistent with a peripheral, posterior semicircular canal origin of BPV.