Improving Grasp Function in People With Sensorimotor Impairments by Combining Electrical Stimulation With a Robotic Hand Orthosis (SENSIBLE-EXO)

Improving Grasp Function in People With Sensorimotor Impairments by Combining Electrical Stimulation With a Robotic Hand Orthosis

Improving Grasp Function in People With Sensorimotor Impairments by Combining Electrical Stimulation With a Robotic Hand Orthosis

Hand motor and sensory impairments resulting from neurological disorders or injuries affect more than 50 million individuals worldwide. Conditions such as stroke, spinal cord injury (SCI), and traumatic brain injury (TBI) can cause long-term hand impairments, greatly impacting daily activities and social integration. Since traditional physiotherapy has limited effectiveness in rehabilitation, assistive devices helping in performing in daily activities have emerged as a necessary solution. Soft exoskeletons offer advantages as they are more comfortable and adaptable for the user, but they often struggle to generate sufficient force. On the other hand, electrical stimulation garments, like e-sleeves, show promise by stimulating nerves and muscles in the forearm. However, achieving precise and stable movement control remains challenging due to difficulties in electrode placement for targeted stimulation. Furthermore, none of the currently available devices are capable of artificially restoring lost sensation in users' hands, limiting their ability to manipulate with fragile objects. Recognizing these limitations, our study proposes a solution that combines a standard hand soft exoskeleton with: (i) electrical stimulation to the fingers' flexor and extensor muscles to generate artificial muscle contractions synchronized with the exoskeleton motion, compensating for the lack of gripping force, and (ii) electrical stimulation to the nerves to artificially restore the lost sensation of touch, enabling users to receive feedback on the force they are applying when interacting with the environment. The investigators refer to this proposed combination as Sensible-Exo. To achieve this goal, our project aims to evaluate the functional improvements in assistive and rehabilitative scenarios using SensoExo in comparison to use only the exoskeleton or having no support at all. The exoskeleton will be coupled with an electrical stimulating sleeve capable of delivering non-invasive electrical stimulation in the form of Functional Electrical Stimulation (FES) and Transcutaneous Electrical Nerve Stimulation (TENS). A glove with embedded force and bending sensors will be used to modulate the electrical stimulation. Additionally, apart from studying the enhancement of functional tasks, the investigators will explore improvements in body perception, representation, and multi-sensory integration. Indeed, the investigators also aim at identifying the way patients perceive their body by means of ad-hoc virtual reality assessments that has been developed. Before each assessment patient will perform some predefined movement in virtual reality to familiarize with it and increase embodiment. During the study, participants will perform a range of tasks based on their residual abilities, including motor tasks (e.g., grab and release, Toronto Rehabilitation Institute Hand Function Test, grip force regulation test, virtual egg test), cognitive tasks (dual tasks), and assessments of body representation and perception. Some of these tasks will be conducted in Virtual Reality environments, both with and without active stimulation.

Change in the area with tactile feedback in the hand with electrical stimulation and with no electrical stimulation

Change in functional tasks performance with sensory feedback and without sensory feedback quantified by the number of successful grasp and release tasks

Change between functional tasks with sensory feedback and with no sensory feedback in number of virtual egg successful grasping

Joint kinematics measurements will be measured with motion capture systems during functional performance of the subjects

To measure embodiment subjects will be asked after VR sessions to indicate where they feel their arm without looking at the limb in real world. This is a measure of embodiment.

To measure embodiment subjects will be asked after VR sessions to indicate how long they feel their arm without looking at the limb in real world. This is a measure of embodiment.

Change from baseline performance between tasks accomplished with sensory feedback and with no sensory feedback in Embodiment

Embodiment will be measured with questionnaires (from -3 to +3, +3 totally agrees; two questions are from 1 to 10 (to measure vividness, where 10 is max vividness) and from 1 to 100 (to measure prevalence, where 100 is max duration of the embodiment feeling))

This will be measured in virtual reality by means of ad-hoc Body Landmark test. This is a body representation measurements.

up one week before first session; thorugh study completition (average 1 month); up one week after last session

This will be measured in virtual reality by means of ad-hoc Hand Peri personal Space test. This is a body representation measurements.

up one week before first session; thorugh study completition (average 1 month); up one week after last session

Inclusion Criteria: Impairment of the motor and sensory functions of the hand in chronic stage The subject should have good proximal arm function (i.e. good shoulder abduction and elevation) Exclusion Criteria: Cognitive and communication deficits impairment Prior or current psychological diseases such as borderline, schizophrenia, Depression or Maniac Depression Major comprehension and memory deficits Pregnancy Epilepsy Pacemaker Cybersickness

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