Assessment of Feasibility, Functionality and Usability of an Hybrid Assistive Exoskeleton for Upper Limb: a Pilot Study

People affected by stroke or brachial plexus injuries experience huge impairment in using upper limbs for everyday life activities. Brachial plexus is responsible of sensory-motor innervation of the whole upper limb, the shoulder and also a part of the chest. The majority of such injuries is caused by traumatic events that involve young and healty people in most cases and motor impairment varies together with either the type (complete or incomplete) or the site of injury. It follows the need to realize devices capable of restoring people everyday life independence.

To assist these patients, the most common solutions are passive ortheses that give support to shoulder and forearm without actively enhancing limb functionalities. MyoPro (by MIT, Myomo1) is the only active device available for elbow and wrist, even not completely proven for everyday life yet. It comes from scientific evidences that gravity compensation and functional electrical stimulation (FES) are considerable techniques for rehabilitation of brachial plexus injuries and post-stroke patients. According to the most recent results, hybrid systems that combine FES with robotic joints seem to give interesting benefits in such the contexts taken into account.

The goal of this clinical trial is to assess feasibility, functionality and usability of a new assistive, hybrid, active and portable orthesis for upper limb aimed at improving motor functionality of brachial plexus injuries patients. Complying with weight and size requirements, the device under investigation is designed to assist the whole upper limb with its two modules: a robotic exoskeleton to actively give assistance to shoulder and elbow and a FES module to assist wrist and hand.

The main points the clinical trial aims to address concern:

• number and type of adverse events (device failures and malfunctioning, subjects injuries) during use
• evaluation of change in performance with and without the device
• usability and satisfaction after use
• effectiveness

Post-stroke and brachial plexus injuries patients (with Medical Research Council Scale for Muscle Strength equal to or more than 2) will be enrolled and asked to perform the following tasks with and without wearing the device:

• box and block test
• vertical reaching
• activities of daily living (ADLs) such as eating and drinking

Study procedure consists of 6 session outlined as follows:

• Session 1: enrollment
• Session 2: tuning and familiarization with device modules
• Session 3: tasks execution and outcomes measurement
• Session 4: tasks execution and outcomes measurement
• Session 5: tasks execution and outcomes measurement
• Session 6: extra session for any tasks from sessions 3,4,5 which required further investigations Each session will last 90 minutes at most. A preliminary phase will envolve healthy subjects that will be asked to perform the same tasks listed above. These tests will be useful to evaluate performances, functionalities and effectiveness of the modular solutions adopted, to improve the user experience of the device and to finalise the experimental procedure to follow with patients.