Cerebral palsy (CP) is defined as a group of movement and posture disorders that cause activity limitation due to brain damage during fetal development or in the first year of life. Motor activities, and in particular walking, can be affected by many factors including sensory deficits, biomechanical and postural limitations, muscle weakness and spasticity. Theories of gait training guide rehabilitation management strategies. Among these, intensification, variability and specific training of walking parameters (speed, step length, cadence) have shown their effectiveness. Delivering sensory feedback during gait rehabilitation exercises is a complementary approach to improve motor learning during rehabilitation. On the other hand, motivation is a key factor in the success of rehabilitation. The addition of walking exercises performed through a serious game in augmented reality (AR) appears relevant for the rehabilitation of children with CP after surgery.

The serious game ARRoW-CP is based on the latest advances in the literature in terms of gait rehabilitation protocol but also on the results of a clinical study conducted by our team, to identify the best feedback modalities to be delivered during the serious rehabilitation game.

This study is a randomized control trial.

Participants are children with cerebral palsy having a single event multi level surgery. They are involving in a rehabilitation protocol in the same rehab center.

Two groups are formed:

• control group: classic rehab+children have treadmill gait protocol during 4 weeks
• test group : classic rehab+children have gait training with the ARROW CP serious game.

ARROW CP game is developed for augmented reality headset (Microsoft Hololens). It delivers feedback in real time and with delay on participant gait performance. This game has been developed by researchers (Fondation Ellen Poidatz, France).

The aims of this study are:

1. . To determine the impact on spatiotemporal gait parameters of intensive gait rehabilitation involving the use of a serious AR game in children and adolescents with cerebral palsy.
2. To explore the effects of playing a serious game on functional abilities
3. To assess motivation, satisfaction and adherence to treatment

Inclusion Criteria:

• A clinical diagnosis of CP mentioned in the medical record
• Minor child for the entire duration of the protocol, i.e. between 10 and 17 years of age (the child must be less than 18 years of age at the time of the last check-up scheduled 1 year after inclusion in the study)
• Global Motor Function Classification System (GMFCS) levels I to III
• Functional Mobility Scale 50 meters rating superior or equal to 2 (ability to walk on 50m using a walker or frame without help from another person)
• Ability to cooperate, understand and follow simple instructions to play.
• Patient affiliated to the French social security system
• Voluntary patient whose parents have given their consent for their child to participate in the study
• Patient who has undergone multisite surgery of the lower limbs including bone procedures at least 7 weeks before the start of the procedure

Exclusion Criteria:

• A diagnosis of photosensitive epilepsy mentioned in the medical file AND/OR a mention in the child's medical file or by the parents or by the child of a history of epileptic seizures occurring during the practice of a video game
• A visual, cognitive or auditory impairment at a level that would interfere with playing the game. The patient must have normal or corrected vision and hearing.

Pre-test and post-test evaluation are made by one physiotherapist ignoring the patient's arm.