Treatment with cochlear implantation is now offered to proximately 95 % of children with deafness in Norway. More than 500 children have been operated at Oslo University Hospital. The study is a cross-sectional study aimed to investigate speech perception, language skills, quality of life in all childhood cochlear implant (CI) recipients in Norway from 1988-2012. Factors such as child characteristics, characteristics with the family, the cochlear implant, the rehabilitation situation, choice of communication mode, school and work situation are surveyed to see if these factors can be associated with variations in outcome. The study will include pre and post lingual deaf children and children with multiple disabilities. Participants are recruited and examined in conjunction with their annual CI control at the hospital. It will be conducted a series of tests determining listening, speech and language development, non-verbal intelligence. Questionnaires are used to collect background information and quality of life experience. The questionnaires include self-report forms for different age groups, and a parent report form. The patient will be tested for the most common genetic causes of deafness. Additional data will be collected from patient records and from local health register at Oslo University Hospital.

Test protocol includes:

Hearing and Language assessment:

Single syllable word perception, Hearing in noise test (HINT), Mullen Scale of Early Learning, British Picture Vocabulary Scale, Peabody Picture Vocabulary Test - Fourth Edition, Clinical Evaluation of Language Fundamentals (CELF) - Fourth Edition 4 , Raven progressive matrices, Motor Coordination + Visual Perception (VMI), Wechsler Preschool and Primary Scale of Intelligence (WPPSI), Wechsler Intelligence Scale for Children (WISC) and Wechsler Adult Intelligence Scale (WAIS).

Quality of Life assessment:

Satisfaction of Life Scale for Children Pediatric Quality of Life Inventory TM (PedsQL TM) Questionnaire for quality of life assessments (KINDL)

Inclusion Criteria:

• All people in Norway that have received Cochlear implants as a child and that have one or more than one year with CI experience.

Exclusion Criteria:

• Cochlear implant users with less than one year with CI experience and people implanted after 18 years of age.

All people in Norway that have received Cochlear Implants as a child.