Abstract
BACKGROUND: Very early bilateral cochlear implant (CI) provision is today's established standard for children. Therefore, the assessment of preverbal and verbal performance in very early stages of development is becoming increasingly important. Performance data from cohorts of children were evaluated and presented based on diagnostic assessment using chronological age (CA) and hearing age (HA). METHODS: The present study, as part of a retrospective multicentre study, included 4 cohorts (N = 72-233) of children with bilateral CI without additional disabilities. Their results in the German parent questionnaires Elternfragebögen zur Früherkennung von Risikokindern(ELFRA‑1 and ELFRA-2) subdivided for CA and HA were statistically analysed. The data were also analysed in terms of mono-/bilingualism and age at CI provision. RESULTS: Overall, verbal performance in relation to CA was lower than in relation to HA. Preverbal skills were largely CA appropriate. Children with bi-/multilingual language acquisition performed significantly lower. Verbal performance in ELFRA‑2 referenced to CA was negatively correlated with age at CI provision. CONCLUSION: In the case of early CI provision, CA should be the preferred reference mark in preverbal and verbal assessment in order to obtain exact individual performance levels and avoid bias in results. The percentiles determined are of limited use as generally valid reference values to which the individual performance of bilaterally implanted children could be compared. Further multicentre studies should be initiated.