Acoustic impairment is a distinguishable clinical feature of Asidan/SCA36

Objective: To investigate acoustic function of Asidan/spinocerebellar ataxia type 36 (SCA36) in which sensorineural hearing loss may be found as one of extracerebellar symptom that can be a distinguishable feature from other degenerative ataxias. Methods: Acoustic function in the groups of normal control (n = 31), Asidan/SCA36 (n = 13), cortical cerebellar atrophy (CCA, n = 28), multiple system atrophy of cerebellar predominance (MSA-C, n = 48), SCA31 (n = 4), and other forms of SCAs (n = 14) was evaluated by pure tone average (PTA) calculated by the results of audiogram and brainstem auditory evoked potentials (BAEPs). Results: PTA was significantly decreased in Asidan/SCA36 in comparison to normal control and other ataxic groups, but not significant within other ataxic groups and normal control. In comparison to other groups, Asidan/SCA36 showed a constant depression at 7 different frequencies in audiogram, especially at 4000 and 8000 Hz. BAEPs in 2 Asidan/SCA36 cases suggested possible involvement in the inner ear or the peripheral part of the auditory system. PTA in Asidan/SCA36 cases significantly correlated with their severity of ataxia. Conclusions: In addition to signs for motor neuron involvement, acoustic impairment in Asidan/SCA36 is another characteristic clinical feature that is distinguishable from other forms of SCAs.