HORIZONTAL SEMICIRCULAR CANAL VARIANT OF BENIGN POSITIONAL VERTIGO

We report the clinical features and results of quantitative eye-moveme nt testing in 13 patients with episodic positional vertigo and nonfati guing direction-changing horizontal positional nystagmus (beating to t he right with the head turned to the right and beating to the left wit h the head turned to the left). The benign history and lack of associa ted neurologic findings support a peripheral localization of the lesio n. This syndrome probably represents a horizontal semicircular canal v ariant of benign positional vertigo. Free-floating debris in one horiz ontal canal may explain many of the clinical and oculographic findings .