Auditory evoked potentials in Rett syndrome.

This study was designed to assess auditory function in subjects with Rett syndrome, a rare neurologic disorder that is characterized by progressive symptoms of dementia, ataxia, respiratory disorder, and communication disorder. Auditory evoked potentials, including the auditory brainstem response (ABR), middle latency response (MLR), and late vertex response (LVR), were recorded in 36 subjects with Rett syndrome. Results showed a systematic decline in auditory function from the peripheral to the central auditory system, with normal ABR in all subjects, normal MLR in 50 percent of subjects, and normal LVR in 36 percent of subjects. Results suggest that hearing sensitivity and the functional integrity of eighth nerve and auditory brainstem pathways are not affected in subjects with Rett syndrome. However, abnormality of both the MLR and LVR suggest the presence of central auditory disorder.