A 63-year-old woman had disabling positional vertigo for four months. She showed intense direction-changing apogeotropic nystagmus. Conservative treatment failed to resolve her vertigo. From the findings of the nystagmus, cupulolithiasis of the right lateral canal was suspected. Plugging of this canal successfully eliminated the nystagmus and positional vertigo. Positional vertigo can sometimes be disabling and unresponsive to conservative therapy. Careful analysis of the nystagmus may allow selection of the most appropriate treatment.
