Stapedius reflex and brainstem auditory evoked responses in multiple sclerosis patients.

The stapedius reflex (SR), its adaptation and the brainstem auditory evoked potential (ABR) were recorded in a group of 53 multiple sclerosis patients. All cases were classified as definite according to Schumacher's criteria, and their grade of disability in Hyllested's system was 1-4: no cases of the gravest (grades 5 and 6) disability were included in the series. The peripheral hearing (pure-tone audiogram and speech threshold) was normal in 44 and slightly impaired in 8 cases. SR was abnormal in 6 (11%) and borderline in 11 (21%), whereas the ABR was considered abnormal in 21 (40%) patients. Deviant SR and ABR findings had only slight or no correlation to clinical data. Intercorrelation between SR and ABR abnormality was better but not implicit and a few cases with deviant ABR showed normal SR: The frequency of abnormal and borderline SR findings was clearly higher in bilateral than in unilateral ABR abnormality. Subclassification of ABR into an upper and a lower type of pathology did not correlate with SR abnormality.