Duration of Deafness and Age at CI Impact Outcomes

Cochlear implantation (CI) has become an accepted treatment option for individuals ≥12 months of age who have bilateral severe-to-profound sensorineural hearing loss (SNHL). SNHL affects 1 to 3 of every 1000 children born in the United States and other developed countries. Approximately 4000 infants are born in the United States each year with bilateral severe-to-profound hearing loss. Results of a study on CI in prelingually deafened adolescents found that shorter length of deafness and earlier age at CI showed significantly greater improvement in word and sentence testing, compared with those undergoing CI surgery in late adolescence [Arch Pediatr Med. 2012;166(1):35-41]. Because few studies have evaluated the effects of factors such as age at CI, duration of deafness, cause of SNHL, and mode of communication on speech perception outcomes in adolescents, researchers sought to determine the efficacy of CI in prelingually deafened children and adolescents and to evaluate potential predictive variables. Using an institutional, retrospective medical record review, researchers identified 67 adolescent patients 10 to 17 years of age with bilateral severe-to-profound SNHL who did not benefit from conventional amplification and underwent unilateral CI from 1986 through 2009. The study population included patients with congenital deafness and those with postnatal, prelingual progressive or sudden deafness, defined as children with severe-to-profound hearing loss before age 3 regardless of hearing status at birth or cause of deafness. The cohort was further divided into 5 main groups according to diagnoses for hearing loss: (1) congenital, (2) idiopathic progressive, (3) hearing loss due to ototoxic medication, (4) meningitis, and (5) other (including cytomegalovirus infection and fever). The mean length of deafness was 11.5 years, and the mean age at CI was 12.9 years. The primary end point was performance on standard speech perception testing conducted preoperatively, 1 year postoperatively, and last follow-up/end of study (EOS) using the Consonant-Nucleus-Consonant (CNC) monosyllabic word test and Hearing in Noise Test (HINT) sentences. The findings showed a highly significant increase in mean scores for both HINT sentence and CNC word testing from the preoperative testing to year 1 (mean change score, 51.10% and 32.23%, respectively; P<.001), and from the preoperative to EOS (mean change score, 60.02% and 38.73%, respectively; P<.001), with a significantly greater increase during the first year (P<.001). Furthermore, there was a highly significant correlation between improvements in performance scores on the CNC word and HINT sentence speech perception tests and for age at CI and length of deafness at the 1-year testing (age at CI, −0.51, P<.001 and −0.36, P=.009, respectively; length of deafness, −0.65, P<.001 and −0.51, P<.001, respectively). A significant improvement was also found for both tests and for age at CI and length of deafness at preoperative to EOS testing (age at CI, −0.46, P=.003 and −0.33, P=.04, respectively; length of deafness, −0.63, P<.001 and −0.45, P=.004, respectively). The researchers noted that the number of patients in each group was small, and possible “subtle differences in performance outcomes between different causes of deafness were not observed owing to a lack of statistical power. Conversely, the length of deafness before CI rather than cause of deafness may be the stronger determination of success,” said the authors. In summary, the researchers stated, “although studies are currently under way to further examine contributing factors to outcomes in the adolescent population, CIs should be considered a viable option for hearing rehabilitation for this group so long as patient and family expectations are realistic and appropriate.”