Audio-vestibular findings in patients with vestibular neuritis.

19 patients with the clinical diagnosis vestibular neuritis, i.e., cases with unilaterally ENG verified abolished or reduced caloric reactions but without symptoms of central nervous involvement or hearing impairment, participated in the study. In addition to ENG examinations and Békésy audiometry all patients were submitted to stapedius reflex tests and auditory brainstem response examinations (ABR) for signs of subclinical auditory nerve engagement. In all but one of the 19 patients the caloric reactions improved; 8 of the 13 patients available for tests after one year recovered completely. The ABR was normal in all cases but the stapedius reflex thresholds were pathologically elevated and remained so in about half of the subjects throughout the observation time; reflex decay was not present in anyone. Cases with pathologically elevated stapedius reflex thresholds showed a tendency to slower recovery of the vestibular function than the group with the normal reflexes. The results were interpreted to indicate lack of eighth nerve or CNS engagement. The possibility that subjects with reflex threshold elevation may constitute a group with constitutional weakness of the audio-vestibular apparatus disposed for vestibular disease is discussed.