Results of serial Vestibular testing in unilateral Ménière's disease

To determine the prevalence and character of vestibular abnormalities and the changes in vestibular function that occur in unilateral Ménière's disease. Retrospective case review. Ambulatory patients at a tertiary care facility. Entry criteria included a diagnosis of unilateral Ménière's disease and test results from at least two vestibular test sessions at the Johns Hopkins Otologic Vestibular Laboratory. One hundred twenty-two cases were evaluated. Electronystagmographic evaluation, including caloric testing; audiometric tests; and medical records. Caloric weakness was demonstrated in 58% of patients on the involved side and in 19% on the normal side. Complete paralysis was found in 7%. Directional preponderance was seen in 33% of patients and completely normal scores in 27%. During the course of the disease, responses become weaker in 26% of patients and stronger in 11%. Of 39 patients tested more than twice, 26% showed both increases and decreases in caloric responses. After an acute attack, only one of eight patients showed a depressed response on the diseased side, and three showed an increased response. Spontaneous nystagmus, seen within 24 hours of an attack in 54 cases, was directed away from the diseased ear in only about one half of the cases. Benign paroxysmal positional vertigo was found in 44% of these patients. Possible pathophysiologic explanations for the various test results in Ménière's disease are discussed. Interpretation of caloric test results should take into account the absolute value of the slow phase eye speed scores, in addition to the right-left difference score. Also, established standards for the normal range of fluctuation in both absolute and comparative scores should be used when more than one test session has been undertaken.