Electro-otolithography: new insight into benign paroxysmal positioning vertigo

Early vestibular evoked potentials were recorded with an extratympanic electrode. The recording principle was adding responses that were phase-locked to a recording frequency. The recording frequency was empirically determined to match harmonically an individual response frequency, thus allowing averaging. This new technique was evaluated in benign paroxysmal positioning vertigo. Normal data were obtained from 12 patients without vestibulocochlear symptoms and were compared with data from 18 symptomatic patients with diagnoses of benign paroxysmal positioning vertigo. All symptomatic patients were treated with a canalith repositioning maneuver, and all responded, in that they no longer had attacks of vertigo. Of the five patients who could be reassessed, all five no longer had attacks of vertigo, but three complained of persisting postural imbalance. Repeat electro-otolithography results continued to be abnormal in these patients, whereas in the remaining two patients responses were normal, consistent with the treatment outcome. The results suggest that electro-otolithography is a valuable addition to the otoneurological test battery. Successful canalith repositioning can abolish attacks of vertigo, although not necessarily a persisting imbalance, which patients frequently describe as a temporary and momentary instability. This is most likely related to a remaining otolithic deficit.