Surgical timing for bilateral simultaneous cochlear implants: When is best?

Hearing loss is considered the most common congenital disease and the prevalence of neonatal deafness can be estimated between 1 and 2 cases per 1000 live births. Infant deafness must be diagnosed as early as possible and an effective therapeutic intervention needs to be carried out in order to avoid the serious consequences of hearing deprivation during the evolutionary period: alterations in the development of central auditory pathways and lack of language acquisition. The cochlear implant (CI) has proved to be the best instrument to solve the problem of auditory deprivation. In particular, the bilateral CI gives the patient access to binaural hearing which results in benefits in terms of sound localisation and discrimination. The optimal age of application of the CI is a widely discussed topic in the scientific community and the current guidelines indicate a period between 12 and 24 months of age, even though the supporters of the application before 12 months of age are nowadays increasing.

The study is observational, retrospective, monocentric. 49 paediatric patients (<18 years) with simultaneous bilateral CIs were included. The audiometric threshold and speech tests were carried out during the follow-up 3, 6 and 12 months after the CIs activation and when the patient reached 2 years of age.

The statistical analysis showed that undergoing bilateral implantation surgery before 2 years of age allows a satisfactory audiometric performance, while there are no particular benefits in performing the surgery before 1 year of age. As far as the speech outcome is concerned, the statistical analysis didn't show significant correlation between the earlier age of implantation and better speech performance if the operation is carried out before 2.5 years of age.

The results of the study indicate that the optimal age to perform the simultaneous bilateral CIs surgery is between 12 and 24 months, without demonstrating any particular benefit in carrying out the procedure before 1 year of age. This may be clinically relevant in terms of avoiding the risks of diagnostic mistakes and reducing the related surgical risk in children under 1 year of age.