Myosuit Chronic Stroke Protocol

A stroke, either ischemic or haemorrhagic, is a vascular condition that can suddenly cause the loss of neurological functions [1]. The disability derived from a stroke can imply reduced communication and limited activities of daily living in the long term. Specifically, reduced mobility and equilibrium, walking asymmetry and spasticity of the impaired limb are the principal factors related to long-term limited physical activity and moderate dependency of the patient on the caregiver [2,3]. A walking deficit can have severe consequences on the energetic cost and the risk of falling, as well as on the participation and personal identity of the person [4].

Moreover, another psychological area that can be affected is self-efficacy, defined as the individual capabilities to take actions for obtaining results. Hence, for a person affected by stroke, self-efficacy is crucial and connected to his/her adaptation to the new condition [5].

For these reasons, walking rehabilitation is essential to recover lower limbs' function, restore self-efficacy and re-establish the social participation of patients [6].

Robotics has been demonstrated in being a suitable and effective tool in order to assist and treat post-stroke patients [7], thanks to its capability to deliver intensive and task-oriented training. One of the most common modalities to classify robotics devices is according to their structure, and the modality to interface with the patients. In these regards, we can distinguish between exoskeletons and end-effector robots, given their characteristics to wear the patient and guide him/her through the distal handle of the mechanical chain, respectively. Moreover, among the exoskeletons, the exosuits are a sub-group of robotics devices designed in lighter materials and that assist the patients by actively moving the hip, knee or ankle.

The lightweight of exosuits makes them suitable both for ecological and therapy-related settings, as well as assistance applications. It is also worth noticing that the absence of a rigid structure requires the patients to have an active component in the walking activity. Previous studies highlighted how these devices can have a supportive capacity during the propulsion phases of gait, assisting the patients throughout the walk [8].

The Myosuit device is a wearable exosuit capable to provide assistance during the walk, sit to stand transition and stair climb [9]. Its assistance is provided with an exo-tendon mechanism. More in detail, online analysis of inertial signals allows to segment the gait phases and to assist at the extension of the knee and hip [9].

Many previous studies show promising results in the deambulation of spinal cord injuries or patients with lower-limb disorders [9,10]. These results were evaluated both in terms of kinematics and the safety of the patients. However, the studies conducted to highlight the urgency for the validation of the device in bigger and different cohorts [9,10].

Given this framework, the aim of this work is to conduct a pilot study on the effects of a lower-limb exosuit, the Myosuit device, on post-stroke patients. The effects of the device will be analysed in terms of usability of the device, self-efficacy, and functional parameters of gait.

Inclusion criteria

• Clinical stability, evaluated through the administration of the MEWS scale (Modified Early Warning Score);
• To be able to stand up from a chair without exceeding a trunk angle of 45° to the left or right during the movement;
• To be able to walk for 10 m without the support of another person but, if necessary, with conventional aids different than knee othesis (e.g. stick, crutch, ankle/foot orthesis). The aid considered should have single-support;
• Height between 150 cm and 195 cm;
• Weight between 45 kg and 110 kg;
• FAC (Functional Ambulation Calssification) ≥3;
• MAS (Modified Ashworth Scale) ≤2;
• HADS (Hospital Anxiety and Depression Scale) with normative values (>10/21 for each scale);
• MoCA (Montreal Cognitive Assessment) (Equivalent scoring > 1 with the Italian correction from Santangelo et al._ 2015);
• To be able to understand and sign the informed consent.

Exclusion criteria

• Presence of an active (or with effects) neurological or psychiatric pathology occurred before the vascular event;
• Severe bilateral hearing or sight loss;
• Functional Reach Test <15.24;
• Flexion retruction of hip and knee greater than 10° and not reducible;
• Presence of genu varum or geru valgum greater than 10°;
• Pregnancy;
• Previous stroke.