Changes in the rehabilitation service that no longer allowed the recruitment of patients

Motor impairment is one of the most common result of a stroke, which causes disability and difficulties in activities of daily living. This motor impairment can concern the upper limb or the lower limb, or both. Several studies investigates the efficacy of different treatment approaches on upper limb and hand function. None of them combined exercise in a virtual context with Action Observation Therapy, consisting in watching an action before doing it.

This study evaluates the addition of Action Observation Therapy (AOT) to Virtual Reality (VR) in the rehabilitation of upper limb impairment in subacute stroke patients. Half of participants will see a video demonstrating the exercise to be performed before its actual execution, while the other half will see a video of a natural landscape followed by the same exercises the other group performs. All the patients will receive additional usual treatment.

In this study, the intervention will be conducted using a system composed by multiple devices, which are:

• HTC Vive (HTC, headset e Steam station): three-dimensional viewer used for the implementation of the immersive virtual environment, allows both the visualization of the videos and of the exercises to be performed;
• Leap Motion Controller (infrared camera): contactless device for tracking the movement of the patient's fingers and hand;
• Zed Mini (RGB binocular camera and depth camera): Stereo Labs' Zed Mini stereoscopic camera is mounted on the HTC Vive viewer to allow virtual elements to be overlapped within the environment;
• Cometa Wavetrack (transmitter/receiver and Inertial Measurement Units): system for upper limb movement tracking through the use of four wireless inertial sensors applied to the chest, to the arm and to the forearm of the participant through elastic bands and to the hand of the participant through skin-compatible double-sided adhesive patches.

All the devices have been tested to ensure safety of the participants and are provided with the appropriate documentation of declaration of conformity according to the European reference regulations. A careful risk analysis was carried out to ensure the safety of the participants.

All the devices will be working simultaneously during each session of treatment. For the experimental group, the instrumentation will be used to see the video of the exercises that the participants will be later asked to perform and to actually perform them; in the control group, it will be used to see a video of a natural landscape with a 180° perspective and to perform the same exercises than the experimental group.

The devices will be used both for the execution of the exercises both to collect information listed in the outcomes section as secondary outcomes: in particular, these information will be provided by the Leap Motion and by the Cometa Wavetrack devices.

Inclusion Criteria:

• Participant who suffered from an ictus 3 to 6 months before (subacute phase);
• Baseline scoring of the Upper Extremity portion of the Fugl Meyer between 20 and 60.

Exclusion Criteria:

• Other neurological pathologies (including previous strokes);
• Visual field impairments;
• Neuropsychological deficits that prevents the understanding of the instructions or the execution of the treatment (e.g. aphasia, apraxia, neglect);
• Baseline scoring of the Mini Mental State Examination (MMSE) lower that 24 (MMSE < 24);
• Orthopaedic or musculoskeletal limitations that do not allow the execution of the treatment;
• Clinical instability;
• Inability to understand the instructions needed to perform the test and the planned evaluations;
• People with electronic medical devices such as pacemakers;
• Medical history of epilepsy.