Acquisition of early auditory milestones with a cochlear implant.

OBJECTIVE

Speech acquisition after cochlear implant is a long process. Various studies have followed the auditory milestones in the early period after implantation. The aim of the present study was to track the development of hearing skills in the early period after cochlear implantation and evaluate which factors influence the process.

METHODS

195 records of children implanted in the Hadassah Medical Center were examined retrospectively. Data on etiology, age at implantation and type of implant were collected. In addition, information on the rate of progress was measured: the first time that there was detection and identification of Ling sounds, the first time it was possible to obtain SDT (speech detection threshold), SRT (speech reception threshold) and an audiogram, and the first accurate repetition of VCV (vowel consonant vowel) sounds.

RESULTS

Results show a consistent pattern of auditory milestone acquisition similar to that of normal development, from milestones that do not require decoding beginning with SDT, detection of Ling sounds followed by an audiogram which requires cooperation, to tasks that involve decoding starting with SRT and repetition of Ling sounds and finally VCV repetition. The children implanted before 24 months of age achieved the auditory milestones later than children implanted between 2 and 6 years, apparently since these tasks involve cognitive abilities which are not yet developed in the youngest children. Previous hearing experience improved the rate of acquisition of the auditory milestones and progress was faster in the second implanted ear compared to the first implanted ear.

CONCLUSION

More research is needed to address the relationship between acquisition of early auditory milestones and performance with the cochlear implant later on in life.