Electrically evoked middle latency responses in children with different cochlear implant ages and durations

WANG Zijian; MA Furong; PAN Tao; LU Zhaoyi

doi:10.3969/j.issn.1672-2922.2015.03.018

Abstract：Objective This research, using electrically evoked middle latency responses (EMLR) as a measure of auditory performance, aimed to investigate the effect of age at cochlear implant on auditory perfor-mance and to study dynamic changes in auditory performance after cochlear implant, in the hope of providing theoretical foundation for guiding future cochlear implantation and rehabilitation training. Methods There were 42 prelingual deafness children included in this research, divided into 2 groups by age at cochlear im-plant, i.e. before 3 years (n=28) or after (n=14) (mean=2.98±1.64 years);and into 4 groups by duration of implant use, i.e. less than 6 months (n=12), 6 to 12 months (n=16), 12 to 24 months (n=4) and more than 24 months (n=10) (mean=15.06±15.53 months). EMLRs were tested and results analyzed for each group. Result EMLRs were induced in 38 of the 42 children (90.48%). The PaNb amplitude was 2.34 ± 1.26μV in children who received implants before 3 years of age, and 1.48 ± 0.49 μV in those implanted after 3 years of age (p<0.05). Pa latency was 30.52±0.85 ms in children who had used cochlear implant for 6 to 12 months, and 25.98± 1.80 ms in those who had used implant for more than 24 months (p<0.05). Conclusion The age at cochlear im-plant and the duration after cochlear implantation affect auditory performance in children with prelingual deaf-ness, which appears to be bettern in those implanted before 3 years of age than after. Auditory performance ap-pears to rapidly improve in the first 2 years after implantation, suggesting that rehabilitation training in the first 2 years after cochlear implant is very important.