Bilateral or unilateral cochlear implantation for deaf children: an observational study

Objective Cochlear implantation in one ear (unilateral implantation) has been the standard treatment for severe-profound childhood deafness. We assessed whether cochlear implantation in both ears (bilateral implantation) is associated with better listening skills, higher health-related quality of life (health utility) and higher general quality of life (QOL) than unilateral implantation. Design Cross-sectional observational study. Setting University of York. Participants Fifty severely-profoundly deaf and 56 normally-hearing children recruited via a charity, the UK National Health Service and schools. Interventions Thirty of the deaf children had received bilateral cochlear implants; 20 had unilateral cochlear implants. Main outcome measures Performance measures of children's listening skills; parental-proxy valuations of the deaf children's health utility obtained with the Health Utilities Index Mark 3 and of their QOL obtained with a visual analogue scale. Results On average, bilaterally-implanted children performed significantly better than unilaterally implanted children on tests of sound localisation and speech perception in noise. After conservative imputation of missing data and while controlling for confounds, bilateral implantation was associated with increases of 18.5% in accuracy of sound localisation (95% CI 5.9 to 31.1) and of 3.7 dB in speech perception in noise (95% CI 0.9 to 6.5). Bilaterally-implanted children did not perform as well as normally-hearing children, on average. Bilaterally-and unilaterally-implanted children did not differ significantly in parental ratings of health utility (difference in medians 0.05, p > 0.05) or QOL (difference in medians 0.01, p > 0.05). Conclusions Compared with unilateral cochlear implantation, bilateral implantation is associated with better listening skills in severely-profoundly deaf children.