The Influence of Sound Deprivation on Audiologic Outcomes after Cochlear Implantation

The cochlear implant is a prosthesis that is capable to replace listening capability among patients with sensorineural hearing loss. Many studies suggest a negative relationship among duration of sound deprivation and audiometric gain (by means of speech perception test) after cochlear implantation. We evaluated surgical and audiologic results among post-lingual deafened adults, in different times of sound deprivation, and correlated with social isolation, presence of vertigo or tinnitus, and the speech therapy yield, between pre- and post-operative stages. A retrospective study was conducted on patients with post-lingual hearing loss, aged over 18 years old who underwent cochlear implant surgery in a public hospital from 2004 to 2014. Audiological, socio-demographic questionnaire, and manifestations of vertigo and tinnitus, during pre- and post-operative stages, were compared and correlating to the different periods of sound deprivation. Two groups were studied. The group A was composed of 38 participants (14 male and 24 female) with sound deprivation of less than 10 years; and group B was composed of 17 participants (8 male and 9 female) with sound deprivation longer than 10 years. We found no differences regarding age, sex, duration of sound deprivation, mean pure-tone audiometric results (pre- and post-surgery), and speech perception tests (pre-operatively). After one year of the surgery, we observed a significant difference between both groups, with a better performance to group A. The results of speech perception test, after cochlear implantation in group B, were worse than the results obtained in group A, although these correlations are not determinant whether to perform cochlear implant surgery or not.