ABSTRACT
Objective To investigate the effects of cochlear implantation on residual hearing and to evaluate the potential impact of long -term electrical stimulations on residual hearing .Methods 58 hearing impaired children with cochlear implants were included in this study .All subjects could cooperate with behavioral audiometry .Audio-metric evaluations were carried out pre -implantation and 3 ,12 ,24 months post -implantation respectively .Of 58 subjects ,43 were followed up more than 1 year and 17 were followed up more than 2 years .Results All 58 subjects showed significant differences (P0 .05) at 1 ,2 and 4 kHz .Of 17 subjects followed up more than 2 years ,there were significant differences (P<0 .05) between pre- and various return visits post-implantation .Post-implantation return visits ,there were significant differences between 3 months and 12 , 24 months at 0 .25 and 0 .5 kHz respectively ,not any significant differences on 1 ,2 and 4 kHz .There were no sig-nificant differences on each frequency between 12 months and 24 months post- implantation .Conclusion Residual hearing after cochlear implantation could decrease to some extent for various reasons .There were significant differ-ences between 3 and 12 months post-implantation at 0 .25 and 0 .5 kHz .Not any significant differences were ob-served between 12 months and 24 months post-implantation at each frequency .