Hypothesis: Speech perception outcomes for cochlear implantation of children vary over a wide range, and it is hypothesized that central pathologic states associated with certain causes of hearing impairment account for a substantial part of the variance.
Study design: A retrospective analysis was carried out to ascertain the relationships between speech perception, etiologic factors, and central pathologic states as indicated by preoperative delayed motor milestones and/or cognitive delays.
Setting: Data were obtained from the pre- and postoperative records of patients attending a hospital cochlear implant clinic.
Patients: Results for 75 consecutive patients up to age 5 years who underwent implantation were included in the study.
Intervention: Patients received a 22-electrode cochlear prosthesis and were seen by the clinic for regular tune-up and assessments. Home- and school-based habilitation was recommended by the clinic.
Main outcome measures: Speech perception measures were classified on a five-point scale to allow for different evaluation procedures at different ages and developmental stages.
Results: The incidence of motor and cognitive delays were fairly evenly spread across etiologic factors, except for cytomegalovirus, which had a much higher than average incidence. Children with motor and/or cognitive delays were significantly slower than other children in the development of speech perception skills after implantation. Etiologic factors did not have a statistically significant effect on speech perception outcome.
Conclusions: It is likely that central pathologic states account for a substantial part of the variance among children using cochlear implants. Specific indicators of central pathologic states should be used to assess a child's prognosis in preference to less specific information based on etiologic factors alone.