Objectives: We aimed to identify the frequency with which the following conditions were present as a second disability in cochlear-implanted, prelingually deaf persons: mild and moderate mental retardation; learning disability; attention deficit/hyperactivity disorder; cerebral palsy; congenital blindness; and autism. We also aimed to document the development of auditory perception in patients having one of these additional disabilities.

Study design: A retrospective study was designed to pursue the above aims.

Methods: We examined the records of 398 cochlear-implanted, prelingually deaf patients who had received a cochlear implant at least one year previously. Patients were selected who showed a delay in motor, cognitive or emotional development. The selected cases were referred for psychological evaluation in order to identify patients with additional disabilities. We then compared these patients' auditory perception prior to and one year following cochlear implantation.

Results: A total of 60 (15 per cent) cochlear-implanted, prelingually deaf patients were diagnosed with additional disabilities. These were classified as: mild mental retardation in eight cases (13.33 per cent); moderate mental retardation in five (8.33 per cent); learning disability in 20 (33.33 per cent); attention deficit/hyperactivity disorder in 15 (25 per cent); cerebral palsy in five (8.33); congenital blindness in three (5 per cent); and autism in four (6.66 per cent). All patients showed significant development in speech perception, except for autistic and congenitally deaf-blind patients.

Conclusion: Although cochlear implantation is not contraindicated in prelingually deaf persons with additional disabilities, congenitally deaf-blind and autistic patients showed limited development in auditory perception as a main outcome of cochlear implantation. These patients require unique rehabilitation in order to achieve more auditory development.