Development of a Deaf Child With a Cochlear Implant.

INCLUSION CRITERIA: To achieve this study, two cohorts will be formed: * A cohort of deaf children aged 12 to 30 months: * Be reached a bilateral profound sensorineural hearing loss (greater than 90 dB hearing loss, as classified by the International Bureau for Audiophonology, 1997); * Raise a cochlear implant; * Being affiliated to a social security scheme. * Consent representatives of parental authority (or at least one of the two) * A cohort of deaf children from 6 to 9 years: * Be reached a bilateral profound sensorineural hearing loss; * Be holder of a cochlear implant for at least 3 years; * Consent representatives of parental authority (or at least one of the two). * A group of normal hearing typically developing children: this group will provide benchmarks for perception tests. It consists of two sub-groups: * Children with normal hearing typically developing 12 to 30 months; children whith a general, linguistic and normal psychomotor evaluated on the basis of prior clinical examination at baseline and on the compilation of their health record. They must not present psychomotor retardation or language. * Children with normal hearing in typical development 6 to 9 years. * Be matched in age and sex with deaf children (a pairing with a child on the criteria defined above). In terms of developmental age, we can consider as having comparable in terms of age development of children with: * +/- 6 months for the population of children 6 to 9 years * +/- 1 month for the population of children 12 to 30 months. * Have a typical development, evaluated by a grade level for their age; * Consent representatives of parental authority (or at least one of the two). EXCLUSION CRITERIA: Will be excluded from our study subjects where there is an inability to meet the tests, either in situations: * Impossible to understand instructions * Blindness * Impossible to meet the tests * Multihandicap * A legal impossibility. Furthermore, children will be excluded for which there is a refusal on the part of the parents or of the child to participate in the study (for children old enough to express their opinion).