Objective: The aim of this study is to assess of cochlear implantation in children with auditory neuropathy and cochlear nerve aplasia by using Categories of Auditory Performance (CAP) and Speech Intelligibility Rating (SIR).
Methods: Twenty one children with cochlear implants participated in this study. They all received cochlear implant surgery at our hospital from January 2004 to October 2010. All children had hearing aid trial and hearing and speech rehabilitation before surgery at least three months.Nine children (7 male, 2 female) were diagnosed with auditory neuropathy, twelve (7 male, 5 female) with cochlear nerve aplasia. Twenty children (10 male, 10 female) with sensorineural hearing loss served as a control group. All the children received cochlear implant for more than six months. Forty two children with normal hearing served as another control group which were divided into three subgroups according to their age.Group A included 18 children aged under two yrs, group B consisted of 16 children aged from two to four yrs and group C comprised eight children aged above four yrs. CAP and SIR were used to evaluate among all the children and the scores were compared.
Results: The CAP scores of children with auditory neuropathy, cochlear nerve aplasia, sensorial neural hearing loss and the three subgroups children with normal hearing were 4.44 ± 1.50, 4.83 ± 1.69, 4.55 ± 1.66, 5.22 ± 1.11, 6.75 ± 0.45 and 7.00 ± 0.00 respectively, and SIR scores were 2.66 ± 1.11, 2.33 ± 1.15, 2.40 ± 0.75, 2.56 ± 1.04, 4.12 ± 0.81 and 5.00 ± 0.00 respectively. There were significant differences among the six groups for CAP scores(χ(2) = 35.481, P < 0.001) and SIR scores(χ(2) = 40.549, P < 0.001).No significant differences for CAP and SIR scores were observed between children with auditory neuropathy/cochlear nerve aplasia and sensorial neural hearing loss as well as group A (P > 0.05 for each), and there were significant differences were shown between children with auditory neuropathy/cochlear nerve aplasia and group B as well as group C (P < 0.01 for each aplasia).
Conclusions: The auditory and speech capabilities of children with auditory neuropathy and cochlear nerve deficiency can can get benefits from cochlear implants as children with sensorineural hearing loss, however not achieve the level of those with normal hearing after cochlear implantation. The long term effects still need follow-up and evaluation.