Systematic analysis of the benefits of cochlear implants on voice production.

PURPOSE To perform a systematic analysis of the research regarding vocal characteristics of hearing impaired children or adults with cochlear implants. RESEARCH STRATEGY A literature search was conducted in the databases Web of Science, Bireme, and Universidade de São Paulo's and CAPES' thesis and dissertations databases using the keywords voice, voice quality, and cochlear implantation, and their respective correspondents in Brazilian Portuguese. SELECTION CRITERIA The selection criteria included: title consistent with the purpose of this review; participants necessarily being children or adults with severe to profound pre-lingual or post-lingual hearing loss using cochlear implants; and data regarding participants' performance on perception and/or acoustic analysis of the voice. RESULTS Twenty seven papers were classified according to the levels of evidence and quality indicators recommended by the American Speech-Language-Hearing Association (ASHA). The designs of the studies were considered of low and medium levels of evidence. Six papers were classified as IIb, 20 as III, and one as IV. CONCLUSION The voice of hearing impaired children and adults with cochlear implants has been little studied. There is not an effective number of studies with high evidence levels which precisely show the effects of the cochlear implantation on the quality of voice of these individuals.