Intensive interventions based on the principles of motor skill learning, like Hand-Arm Bimanual Therapy Including Lower Extremities (HABIT-ILE), have demonstrated excellent effectiveness in improving motor function and daily life independence of children with cerebral palsy (CP). Patients living far from big cities do not have easy access to such interventions, usually applied in the form of camps. This randomized controlled trial will include 48 children with bilateral CP and aims to test a home version of HABIT-ILE with the use of a specifically designed virtual device and a remote supervision. For this purpose, two types of two weeks intensive treatment programs will be compared: Hand and Arm Bimanual Intensive Therapy Including Lower Extremities at home ("HABIT-ILE at home") and "classic HABIT-ILE". Moreover, this study also aims to assess whether the patient's abilities are better with a follow-up at home after two weeks of HABIT-ILE therapy than without follow-up post therapy. Four groups will be compared: HABIT-ILE at home therapy with a follow-up at home, HABIT-ILE at home therapy without follow-up, classic HABIT-ILE therapy with a follow-up at home and classic HABIT-ILE therapy without follow-up. Children will be assessed at 3 time points: before therapy, after therapy and 3 months after the start of therapy.

Cerebral Palsy (CP) is the most common cause of physical disability in children: it occurs in 1 to nearly 4 children in 1000 newborns worldwide. This major public health issue caused by abnormal brain development or damage during brain development result in different symptoms that vary from one patient to another. Even if all children with CP will develop motor symptoms (abnormal movement patterns and posture) some of them will also develop non-motor symptoms such as pain (75%), intellectual deficits (50%), language disorders (25%), epilepsy (25%), behavioral and sleep disorders (20-25%). The consequences of these symptoms are very variable and result in long-term functional deficits in the activities of daily living, such as dressing, eating, going to the bathroom, etc. To improve these patients' autonomy, intensive therapies based on motor skill learning (MSL) have been shown to be especially effective. Among these therapies, Hand-Arm Bimanual Intensive Therapy including Lower Extremities (HABIT-ILE) has been developed over the last decade in the MSL-IN laboratory of UCLouvain and has shown impressive improvements in children with CP. It is based on an intensive training of bimanual activities, with a systematic inclusion of lower limbs and trunk motor control. This therapy is given in the form of a rehabilitation camp of at least 50 hours on site. Therefore, the implementation of a classic HABIT-ILE, in day-camp requires a great commitment from the families who must travel to the camp location for two weeks of therapy. In addition, for patients living far from big cities or unable to travel, access to these therapies can be really complex. Moreover, these camps are applied in a group of 8-12 children. Each participant is accompanied by at least one therapist (physiotherapist or occupational therapist and sometimes student) trained in HABIT-ILE therapy. This implies that a HABIT-ILE camp requires minimum 12 trained therapists. Nonetheless, there is a lack of therapists that makes the implementation of these camps still challenging. In addition, the health requirements related to COVID-19 make it difficult to implement any kind of therapy and to assess patients' progress. Therefore, this health crisis has highlighted the importance of being able to offer home-based therapy. To answer the problematics of pandemic, accessibility and of lack of HABIT-ILE therapists, the idea of implementing HABIT-ILE at home was born. How could we implement MSL principles at home? Some of the key components of MSL are intensity, shaping of the task (with part- task and increasing difficulty), goal-oriented therapy, positive reinforcement and hands-off (voluntary movements by the patients, not guided by the therapist). To incorporate those principles and ensure the validity of the therapy, guidance by a trained HABIT-ILE supervisor is necessary. This supervision will be provided through remote telerehabilitation sessions. Virtual reality is well suited to implement MSL-IN principles and allows for remote communication with patients. Tele-reeducation devices are numerous: from classic commercials video game found in stores to devices made for rehabilitation. Alone these devices do not allow the implementation of all the principles of motor skill learning but with the supervision of therapists trained in HABIT-ILE supervision, this objective could be achieved. With the help of new technologies, will the HABIT-ILE supervisors be able to implement HABIT-ILE at home in a reliable and standardized way for children with CP aged 6 to 18 ? This RCT aims to assess if HABIT-ILE at home is not inferior to HABIT-ILE in camp regarding physical abilities, functional activities and participation of the participants.

Moreover, if the maintenance of skills during HABT-ILE camp at 3- and 6-months post-therapy has been proven, the question of improving them has not been investigated yet. Indeed, we know that in order to maintain the skills learned during the HABIT-ILE therapy, it is necessary to practice them on a daily basis. If a skill is not used it will lead to a cortical reorganization of the motor cortex at the expense of this skill. Thus, there is a persistent cycle of decreased utilization that leads to unfavorable cortical reorganization that leads to decreased utilization, etc. It is called "learned non-use". In order to reduce this phenomenon and thus improve the transfer of the HABIT-ILE skills into the daily life of the children, we wonder about the benefit of a post-therapy follow-up. Once again, the use of tele-rehabilitation can provide us a solution of daily delocalized therapy directly implemented at the patient's home and supervised remotely. Could the transfer of learned skills be improved with a follow-up at home post therapy? In order to answer this question, after the two weeks of both HABIT-IL modality, we will set up a HABIT-ILE telerehabilitation follow-up for 9 weeks. This study therefore also aims to assess if the patient's abilities could be potentialize with a follow-up than without a follow-up after two weeks of HABIT-ILE therapy.

Inclusion Criteria:

• Children with confirmed diagnosis of bilateral Cerebral Palsy
• Age 5 to 18 years old
• Ability to interact and understand simple instructions in order to complete assessments and therapy
• Availability of a caregiver for 6h30 per day during two weeks of therapy

Exclusion Criteria:

• Uncontrolled seizure
• Botulinum toxin injection in the last 6 months before the first assessment or during the therapy
• Intensive therapy in the last 6 months before the first assessment or during the therapy
• Surgery that could affect the assessments or therapy in the last 6 months before the first assessment or during the therapy
• Severe visual or cognitive impairments interfering with treatment and or assessments
• Any typical contraindication for MRI

There is not a plan to make IPD available.

The primary aim, the GMFM, will be videotaped and the scoring will be done by a blind evaluator. In secondary outcomes, the BoHA will be blind scored.