Restauration of the Auditory and Cognitive Functions in Cochlear Implanted Deaf Children in FNIRS

Inclusion Criteria: * Inclusion criteria: Cohort 1 : * 10-24 months old children will be included. * All participants have to be affiliated to the social health security system and parental consent is obligatory. * All congenitally deaf patients will have a severe to profound hearing loss and about to be fitted with a cochlear implant. * Normally hearing counterparts shall have normal hearing as evidenced by acoustical otoemissions (AOE) in both ears. Cohort 2 : * 3-7 years old children will be included. * All participants have to be affiliated to the social health security system and parental consent is obligatory. * All congenitally deaf patients will have a cochlear implant, and they will have been implanted before 2 years of age. * Normally hearing counterparts shall have normal hearing as evidenced by acoustical otoemissions (AOE) in both ears. Exclusion Criteria: * Exclusion criteria include psycho-neurological diseases, other sensorineural or motor deficiency, familial bilingualism, medications affecting vigilance and child whose both parents benefit from a legal protection measure