This study aims to assess the effectiveness of a motor rehabilitation protocol that includes mixed reality activities, compared to conventional rehabilitation, on postural stability in children and adult patients with neurological impairments.

Conventional motor rehabilitation techniques applied to postural stability, locomotion or the upper limbs suffer from certain limitations. Studies in this field have highlighted the length and repetitiveness of these programs, which can lead to patient fatigue and pain. Combined with the lack of recreation and ecology in conventional therapies, which are often decontextualized and highly simplified, all these factors contribute to the lack of transposition of the improvements obtained into daily life activities (DLAs).

For several years now, the use of virtual reality (VR) and mixed reality (MR) have emerged as one of the most interesting solutions for overcoming these limitations. These technologies enable patients to take part in rehabilitation protocols under more controlled, progressive and attractive conditions, encouraging better patient adherence. These aspects guarantee effective rehabilitation and generalization of benefits to DLAs. In addition, they involve visuomotor coordination (skills involving the coordination of movements of different body segments with visual information previously perceived during execution), which is a cognitive ability widely transposable to DLAs.

Although some previous studies have investigated the effects of VR for motor rehabilitation, this technology also presents practical limitations related to the discomfort induced by the head-mounted displays (cybersickness, and physical discomforts caused by the weight of the display). Moreover, the use of VR tends to isolate the patient from their environment and therefore limits interaction with practitioners. Nevertheless, findings have shown the benefits of a VR protocol applied to motor rehabilitation in children and teenagers with cerebral palsy. The accuracy precision and fluidity of upper limb movements was improved, and the adherence to the protocol was strong.

In the line of these findings, the present protocol has several objectives: (1) to use MR, which seems to offer more possibilities while avoiding the disadvantages associated with VR, (2) to extend the applications of the proposed virtual rehabilitation tasks to other major motor functions - postural stability and locomotion as additional targets - and (3) to deploy these new rehabilitation methods to other patients likely to benefit from them (i.e. those with a functional disorder of neurological origin affecting their motor skills).

This study will include 120 patients with motor deficiencies of neurological origin, who will be randomly divided into two groups: one group receiving three weekly mixed reality rehabilitation sessions for four weeks, and a control group only following its usual care in the same period. Participants will be randomly matched for pathology, postural stability scores, age and sex. The effectiveness of the rehabilitation protocol will be evaluated through several clinical indicators of postural stability, locomotion and limb mobility as well as psychometrical measurements of fatigue, pain, motivation and quality of life.

Inclusion Criteria:

- Adult patient (18 years old or older) with motor disorders related to a deficit in postural stability (mini-BESTest ≤ 25) which may be associated with a deficit in the use of upper limbs and locomotion, consecutive to : 1) either acquired neurological impairments (ischemic or hemorrhagic stroke in sub-acute or chronic phase, head trauma, benign tumor operated on with complete removal, cerebral anoxia) , or 2) a neurodegenerative affection (Parkinson's disease, Multiple Sclerosis).

OR

• Child or teenager patient (6 to 17 years old) with motor disorders related to a deficit in postural stability (mini-BESTest ≤ 25) which may be associated with a deficit in the use of upper limbs and locomotion, consecutive to 1) either spastic, dyskinetic or ataxic cerebral palsy, or 2) a similar impairment without diagnosis or of another etiology.
• Patient able to walk with or without technical aids and to perform voluntary upper limb movements.
• Patient able to understand and follow instructions or adapted communication.
• Patient having given written informed consent concerning his/her participation in the protocol OR (for children) whose parents have given their written informed consent.
• Patient covered by social security.

Exclusion Criteria:

• Patient with a severe intellectual disability.
• Patient with a severe attention deficit disorder.
• Patient whose epilepsy is not stable.
• Patient with pain preventing participation in the intended tasks of the protocol.
• Patient with an illness, medical condition or treatment incompatible with participation in the protocol.
• Patient with multiple sclerosis with relapse less than 3 months old.
• Simultaneous participation in other interventional research (1) that may exclude participation in the present study or (2) for which the exclusion period has not ended and whose nature may possibly impact the results of the present research.

In addition, the vulnerable persons mentioned in Articles L. 1121-5, L.1121-6 and L.1121-8 of the French Public Health Code are excluded from the study:

• Pregnant, nursing or parturient women.
• Persons deprived of their liberty by judicial or administrative decision, hospitalized without consent or admitted to a health or social institution for purposes other than research.
• Adults under legal protection or unable to express their consent.

The care providers will perform the 4-week rehabilitation program for the experimental group. The outcome assessors will only be in charge of the pre and post-test phases, and will not be informed on which group each participant was assigned to. All participants will receive a pseudonym which provides no information on their respective group.