Perception and Equilibrium After Cochlear Implantation (ORIENTIMPLANT)

The cochlear implant is an electrical hearing aid that restores the perception of surrounding sounds and speech intelligibility in profoundly deaf patients. During surgery, the labyrinthine break necessary for insertion into the cochlea of the implantable part may cause a malfunction of the vestibular system which can induce dizziness, balance and perception (of the gravitational vertical) disorders. Vestibular compensation and new sonic interactions could alter the balance control and the visual and postural spatial orientation perceptions. The usual treatment includes the monitoring of the patient's quality of life, of the vestibular function and of hearing. This study adds an assessment of spatial orientation and of posture.

The same assessment will be performed 4 times (3 days before surgery, 3 days, 45 days, and one year after surgery). The measure is the average difference between the gravitational vertical and the tilt of the platform (in degree) over 20 trials.

The same assessment will be performed 4 times (3 days before surgery, 3 days, 45 days, and one year after surgery). The measure is the average difference between the gravitational vertical and the tilt of the rod (in degree) over 20 trials.

The same assessment will be performed 4 times (3 days before surgery, 3 days, 45 days, and one year after surgery). The composite equilibrium (%) score is calculated over the six conditions of the Sensory Organization Test (Equitest, Neurocom, USA).

The same assessment will be performed 4 times (3 days before surgery, 3 days, 45 days, and one year after surgery). The area covered by the centre of pressure in static posturography (eyes open and eyes closed) is calculated during trials within a specific and controled sound environment [quiet - implant OFF, quiet - implant ON, white noise (70 dB) - implant ON, the semantic content (70 dB) - implant OFF]

The same assessment will be performed 4 times (3 days before surgery, 3 days, 45 days, and one year after surgery). Vestibular function is quantified by means of videonystagmography (pendular and caloric tests)

The same assessment will be performed 4 times (3 days before surgery, 3 days, 45 days, and one year after surgery). Speech recognition (in %) is quantified with cochlear phonemic lists of Lafon at 70 dB with and without leep reading.

The same assessment will be performed 4 times (3 days before surgery, 3 days, 45 days, and one year after surgery). Score of the quality of life (QoL) questionnaire (WHOQOL-BREF).

The same assessment will be performed 4 times (3 days before surgery, 3 days, 45 days, and one year after surgery). Self-rated score of the Dizziness Handicap Inventory (DHI).

Inclusion Criteria: Profound deaf patients who are scheduled for a cochlear implantation Patients gave their written informed consent Patients are affiliated to the french social welfare Exclusion Criteria: Disorders from the motor and/or somesthetic systems (especially the lower limbs) Contraindications to the scheduled functional assessments