Pilot Study: Home Use of Wearable Grasping Neuroprosthesis in Vascular Hemiparesis

Pilot Study Evaluating the Usability and Functional Impact of Prolonged Home Use of a Wearable Grasping Neuroprosthesis in Subjects With Vascular Hemiparesis - GRASP-HOME

Stroke is the leading cause of acquired motor disability in adults. Six months post-stroke, 50% of patients have not regained active finger extension, and 80% retain a grasping deficit, most commonly an inability to actively open the hand. This motor impairment significantly impacts daily activities, social interactions, professional life, and overall quality of life. Despite numerous treatments available in rehabilitation centers during the subacute phase, no functional assistive devices are currently usable at home. Since 2018, our team, in collaboration with the CAMIN-INRIA team, has developed a Grasp Neuroprosthesis (GNP). This device uses functional electrical stimulation to restore grasping function in hemiplegic subjects, enhancing autonomy in daily bimanual tasks. The GNP has been evaluated in hospital settings through two studies, defining preferred control modalities and demonstrating significant functional impact. Additionally, another study tested a wearable version of the GNP used autonomously at home for two months. This study showed the feasibility and functional benefits of home GNP use, provided the device is customizable to the patient's characteristics and environment. Initial results indicate improved quality of life and increased autonomy with GNP use. The wearable GNP consist of a forearm orthosis made of soft fabric, integrating an electrode array and a stimulator (CE medical marking for home use), connected via WiFi to a microprocessor positioned in a pouch. The microprocessor incorporates information from inertial measurement units and a microphone, allowing the user to control the electrical stimulator on demand. The stimulation targets the extensor muscles of the long fingers and the thumb, enabling the user to open the hand on demand. We propose extending the home use of the GNP to two patients for one year. Each subject will be followed for one year, with evaluations in a hospital setting at the beginning and end of the period, monthly follow-ups at home throughout the year, and on-demand video consultations.

Inclusion CriteriA/

• Adult patient who participated in and completed the GRASP-AGAIN study and achieved functional improvement through the use of NAP.

• Motor deficit of an upper limb resulting from a single ischemic or hemorrhagic stroke, hemispheric or brainstem, confirmed by brain imaging (CT scan or MRI);

• Brain lesion occurring more than one month prior;

• Presence of at least one of the following two disabilities:

  • Inability to actively extend the long fingers (open the hand) to actively grasp an empty glass (upper and lower diameters of 7 and 6 cm respectively, height of 12 to 15 cm, weight of 125 g, identical to the material used for the Action Research Arm Test scale) with a palmar grip, without the aid of the other hand, while the subject is able to hold the glass passively in the hand;
  • Inability to actively extend the thumb to grasp the handle of a soup spoon (flat, like a key) without the aid of the other hand, using a thumb-index finger pulp-lateral grip (grasping task in the Wolf Motor Function Test), while the subject can passively hold the handle of a spoon or a key previously placed between the thumb and index finger;

• Patient receiving care within the standard healthcare pathway;

• Ability to sit in a chair and remain focused for at least 1.5 hours;

• Free, informed, and written consent signed by the participant and the investigator (no later than the day of enrollment and before any examination required for the research);

• Individual affiliated with or covered by a social security scheme

Exclusion Criteria:

• The person is in labor or breastfeeding;
• The person is pregnant, the diagnosis being guided by questioning (date of last menstrual period, desire for pregnancy, contraception) and possibly confirmed by a blood test for beta hCG;
• Musculotendinous contractures or joint stiffness of the fingers and wrist preventing passive opening of the fingers;
• Limited approach ability preventing the hand from being positioned in front of the abdomen (without contact) at the level of the midline sagittal plane, while the subject is seated;
• Paretic pain in the upper limb limiting the performance of the standardized grasping task;
• Major sensory disturbances corresponding to a Somatosensation subscore of the modified Erasmus Nottingham Sensory Assessment French version (EmNSA-F, see Appendix A) upper limb <10/44;
• Severe aphasia with a Boston Diagnostic Severity Aphasia Examination Severity Scale score ≤ 3, see Appendix B, indicating that there may be a marked decrease in verbal fluency or ease and rapidity of comprehension, without significant limitation of expression or communication;
• Known gestural apraxia, within the limits of the subject's motor abilities (ideomotor apraxia, ideational apraxia, dressing apraxia, or reflexive apraxia);
• Unilateral spatial neglect demonstrated with the bell test (see Appendix B'), if the difference between omissions in the left and right visual fields is greater than or equal to 6;
• The extensor digitorum communis and/or extensor pollicis longus muscles cannot be stimulated with the neuroprosthesis, meaning that sufficient extension of the long fingers and/or thumb for grasping tasks is not achieved with electrical stimulation well tolerated by the patient;
• The person has a pacemaker;
• Presence of uncontrolled epilepsy;
• Presence of unstable cardiovascular disease (coronary artery disease, severe hypertension, heart failure);
• Presence of a dermatological condition contraindicating the application of surface electrodes;
• The person is participating in another research study with an ongoing exclusion period;
• The person is under legal guardianship or conservatorship;
• The person refuses to sign the consent form;
• It proves impossible to provide the person with informed consent and ensure their compliance due to impaired physical and/or psychological health.