Benign paroxysmal positional nystagmus in hospitalized subjects receiving ototoxic medications

Objective: To investigate the occurrence of benign paroxysmal positional nystagmus in subjects undergoing treatment with potentially ototoxic medications. Study Design: Prospective and retrospective record reviews. Setting: Tertiary referral neurotology clinic; clinical research and technology center. Subjects: Ninety-nine hospitalized subjects undergoing treatment of infectious disease or carcinoma with potentially ototoxic medications. Interventions: Records review, tests of vestibular function. Main Outcome Measure: Results of Hallpike positional tests for benign paroxysmal positional nystagmus (electro-oculography). Results: Forty-one (41%) of 99 subjects were female and 58 (59%) were male. Age range was 15 to 73 years (mean, 47 years). Forty-nine (50%) of 99 subjects had an unequivocally positive Hallpike test for benign paroxysmal positional nystagmus in one or both ears. The occurrence of benign paroxysmal positional nystagmus in the Hallpike-positive population was distributed equally across age decades. Of the 49 subjects with benign paroxysmal positional nystagmus, 22 (44%) were female and 27 (56%) were male. Conclusions: Benign paroxysmal positional nystagmus is the most common cause of vertigo in the general population, including subjects receiving ototoxic drugs. Complaints of vertigo in subjects receiving ototoxic drugs therefore may or may not indicate onset of ototoxicity. Occurrence of benign paroxysmal positional nystagmus in subjects receiving ototoxic drugs was independent of gender or age. The high occurrence rate of benign paroxysmal positional nystagmus in subjects receiving potentially ototoxic medications is consistent with the observation that benign paroxysmal positional nystagmus occurs in combination with many pathologic conditions. Benign paroxysmal positional nystagmus presenting in subjects receiv-ing ototoxic drugs may complicate the clinical identification of ototoxicity and obfuscate clinical decision-making processes.