Neurologic and otologic findings in Fisher's syndrome.
We performed neurologic and otologic examinations in 14 patients with Fisher's syndrome to determine whether its manifestations inducing acute ophthaloplegia, ataxia and areflexia may involve the auditory and vestibular systems. Tests included pure tone audiometry, auditory brainstem response, observations of nystagmus, smooth pursuit test, saccade test, optokinetic nystagmus test, and the caloric test. One patient showed downbeat nystagmus and lateral gaze nystagmus without restriction of eye movement, two patients showed dysmetria on saccades without restriction of eye movement, and three patients showed superimposed saccadic eye movement on smooth pursuit without lateral gaze nystagmus. The abnormalities in those six cases could not be explained by solely muscular weakness, but also appeared to involve the central oculomotor system. In the other patients, nystagmus could be explained by muscular weakness alone. Additionally, three patients, including two patients with dysmetria on saccades, showed a unilateral diminished response to caloric testing with no severe restriction of eye movements. In evaluating the auditory brainstem response of these three patients, one patient, who showed abnormality on the saccade and caloric tests, showed an elongation of wave I latencies and of wave I-III interpeak latencies at both ears, and one other patient showed an elongation of wave III-V interpeak latencies at both ears. This disorder may involve the peripheral and central auditory systems as well as the peripheral vestibular system.