Central auditory evaluation of patients with spasmodic dysphonia

Spasmodic dysphonia is a focal laryngeal dystonia characterized by inappropriate contractions of the intrinsic laryngeal musculature. The prevalence of associated neurological findings has led to detailed investigation of the central nervous system. Previous research revealed latency abnormalities in patients' auditory brainstem responses. The present study further investigated central auditory findings in patients with spasmodic dysphonia, including brainstem and cortical function. Fourteen normal-hearing patients with spasmodic dysphonia were tested using the auditory brainstem response (ABR) and SCAN-A test of central auditory processing. The ABR estimated brainstem transmission time and evaluated auditory pathway integrity at a high stimulus rate. SCAN-A assessed the auditory cerebral cortex. Implications of these findings are discussed. We found no ABR abnormalities in subjects with spasmodic dysphonia. Positive SCAN-A findings were negligible. The ABR findings contradict previous reports.