Children with severe hearing impairment or deafness are preferably recognised and treated with a cochlear implant (CI) before the age of one year, as early stimulation of the auditory sense is essential for the development of spoken language. Today, children with deafness are offered a bilateral CI, as it allows for improved speech perception in noise and sound localisation. However, the indications for cochlear implantation have been extended to include children with asymmetric hearing loss, in order to avoid the development of aural preference syndrome, which may limit the effect of a CI later.