[Meta-analysis on effectiveness of prelingually deaf patients at different ages following cochlear implantation]

To assess the clinical effeetiveness of prelingually deaf children after cochlear implantation at different ages so as to provide reasonable expectations for the patients and guidance for the clinical treatment.

Electronic databases PubMed, YZ365. COM, WANFANG DATA, CMJD, CHKD, CNKI were searched using relevant keywords. Extracted data included author, year of publication, diagnosis, et al. Reported treatment outcomes were clustered into speech discrimination and hearing abilities. Meta-analyses were performed on studies with numerical results using random or fixed effects model.

There were eight randomized control studies including 442 patients. Comparing speech perception of prelingually deaf children after cochlear implantation younger than three years old (experimental group) and 3-6 years old (control group), three and six months after operation showed that experimental group performed significantly worse than control group; 12 months after operation showed that experimental group performed significantly better than control group. Comparing hearing abilities, three and six months after operation showed that experimental group performed significantly worse than control group; 12 months after operation showed showed that experimental group performed significantly better than control group. Comparing speech perception of younger or older than 4. 5 years old children showed that after 1.5-2 years of operation children implanted younger than 4.5 years of age performed significantly better than children implanted older than 4.5 years old. Comparing speech perception of 7-12 years old children showed that after 3, 6, 12 months of operation patients of 7-12 years old performed significantly better than those children older than 12 years old. Comparing speech perception of implantation younger or older than 18 years old (7-14 yeas old was group A, > 14-18 yeas old was group B, older than 18 yeas old was group C) showed that after one and four years of operation A > B > C, and there were significant differences among them. Comparing warble tone threshold average (WTA) showed that after one year of operation A < B < C, and there were significant differences among them. However, after four years of operation, there was no significant difference among them.

Prelinguistically deafened patients younger than three years old with cochlear implantation, insisting on scienctific rehabilitation training for a long period of time can receive the optimal recovery effect. The older patients are suggested as early as possible receiving cochlear implantation. The longer they are implanted, the better results they will receive. Moreover, the younger age they are implanted, the faster postoperative language progress they will receive. Further controlled studies with longer follow-up periods and more person included may make the effectiveness of cochlear implantaion more reliable.