Evaluation of brainstem function in patients with spasmodic dysphonia using vestibular evoked myogenic potentials and auditory brainstem responses

CONCLUSION: The vestibular area is closer than the auditory region to nucleus ambiguus. If a 'shared' lesion involves regions of adjacent nuclei of the brainstem in patients with spasmodic dysphonia then vestibular area involvement is more possible than that of the auditory region. OBJECTIVES: The authors hypothesize that lower brainstem lesions and involvement of descending pathways of the spinal tract may be the site of lesion in patients with spasmodic dysphonia. PATIENTS AND METHODS: Ten patients with spasmodic dysphonia were tested using the auditory brainstem response (ABR) and vestibular evoked myogenic potentials (VEMPs). RESULTS: No ABR abnormalities were found in right ears. Results of ABR on the left ear showed that one patient had abnormal ABR. This patient had severe sensorineural hearing loss on the left side. VEMPs displayed normal response in two patients bilaterally. First positive (p13) and second negative (n23) waves of VEMP could not be recorded in three cases unilaterally and in five patients bilaterally.