Connexin-Associated Deafness and Speech Perception Outcome of Cochlear Implantation

Abstract

To compare performance after cochlear implantation in children with mutations in connexin (Cx) 26 (GJB2) or Cx30 (GJB6) and children with deafness of unknown etiology. Design: Genetic analysis and speech perception evaluation was performed in the children with and without Cx mutations who had undergone cochlear implantation. Speech perception performance was retrospectively analyzed 6, 12, 24, 36, and 48 months after implantation. Test material was selected according to the child's age and cognitive and language abilities. Setting: The study took place at speech and hearing and genetic centers of a hospital in the central part of Israel and the genetics departments of 3 additional centrally located hospitals. Patients: A total of 30 children who had undergone cochlear implantation were selected for the study, with control patients matched according to age at implantation, duration of implant use, and mode of communication. There was no evidence for additional disabilities or handicaps in either group. Main Outcome Measures: Speech perception measurements included a questionnaire, as well as closed and open-set tests. Results: Overall, the 2 groups showed significant improvement in speech perception results after implantation. Four years after implantation, both groups achieved mean open-set speech perception scores of approximately 60%, 75%, and 90% for monosyllabic, 2 syllables, and words in sentences tests, respectively. Conclusions: There were no apparent differences in speech perception performance after implantation between the children with Cx mutations and children with deafness of unknown etiology. These data have important implications as a prognostic indicator when counseling candidates for cochlear implantation.

Speech Perception Outcomes after Cochlear Implantation in Children with GJB2/DFNB1 associated Deafness

“…The results show that cochlear implantation is effective in the development of speech perception after cochlear implantation in GJB2-related deafness to a similar extent as in deafness due to unknown etiology. These findings are in agreement with findings obtained by other authors (4,13,(15)(16)(17)(18)(19)(20)(21)(22). A recent long term follow-up of cochlear implantation in children with GBJ2-related deafness in Japan showed similar developments in speech performance in comparison with hearing loss due to other etiologies (23).…”

Predictive Value of GJB2 Mutation Status for Hearing Outcomes of Pediatric Cochlear Implantation

“…However, results of subgroup analysis indicated that when control groups were matched carefully with respect to the factors that are known to affect language development and speech perception in children with impaired hearing, such as age at implantation, etiology of hearing loss, and absence of comorbidities, there was no significant advantage of harboring a GJB2 mutation over hearing loss of unknown etiologies or other types of genetic deafness with no additional disabilities. This finding supports the results of several studies 5,13,25,30,32 . Deafness etiology is unknown in about 40% of all investigated cases of pediatric deafness 33 .…”

Clinical Application of Screening for GJB2 Mutations before Cochlear Implantation in a Heterogeneous Population with High Rate of Autosomal Recessive Nonsyndromic Hearing Loss

“…To the contrary, a perfectly matched, yet smaller study, on CI patients found that there is no advantage in connexin-associated deafness over other patients [17]. The same results had been reported through another two-center study earlier [18].…”

“…As indicated in our study, if the patients are selected through a delicate physical examination and other necessary investigations before CI, the acceptable outcome of the implantation would be assured. This will once again emphasize the importance of selecting a comparable control group in making a final conclusion [17]. The similarity of response to CI is also claimed in a recent study [19].…”