Using a neuroprosthesis to help stroke patients regain grip function

Inclusion Criteria:

* Concerning the study population: Paresis of an upper limb from a single ischemic or hemorrhagic, hemispheric or brainstem stroke, as evidenced by brain imaging (CT or MRI); Stroke more than one month old; Impossibility to actively expand the fingers 2 to 5 (opening of the hand) to intentionally grab an empty glass (identical to the material used for the Action Research scale Arm Test), with a palmar grip (cylindrical grip), while the subject can hold the glass passively placed in the hand and/or the thumb to voluntarily grab the handle of a tablespoon (flat, like a wrench) with a key-grip (identical to that of the Wolf Motor Function Test), while the subject can hold the spoon previously placed passively between thumb and index; Ability to sit on a chair at least during 1h30.
* Concerning legislative aspects: Free, informed and written consent signed by the participant and the investigator (at the latest on the day of inclusion and before any investigation required by the research); Affiliate or beneficiary of the French health insurance system; The person is of age (at least 18 years old); Women and men are included; The patient is available for a follow-up of 5 days as part of his hospitalization performed as part of routine care.

Exclusion Criteria:

* Concerning the study population: The person is parturient, or is breastfeeding; The person is pregnant, the diagnosis being guided by the interrogation (date of the last menstruation, desire of pregnancy, contraception) and possibly confirmed by a blood test (beta hCG); Musculotendinous retractions or joint stiffness of the fingers and wrist preventing passive opening of the hand sufficient to perform at least one of the functional tasks evaluated; Limitation of the approach which does not make it possible to carry out the task of gripping in front of the trunk, the subject sitting; Upper limb pain limiting achievement of the primary standardized grasping task; Major sensory disorders corresponding to a sub-score Somesthesia of the modified Erasmus Nottingham Sensory Assessment French version (EmNSA-F) for the upper limb \<10/44; Severe aphasia with aphasia severity scale of the Boston Diagnostic Severity Aphasia Examination, indicating that there may be a clear decrease in verbal fluency or ease and speed of understanding, with no significant limitation expression or communication; Unilateral spatial negligence highlighted with the bells test if the difference between the omissions in the left and right fields is greater than or equal to 6; Extensor digitorum communis muscle and/or pollicis extensor longus muscle not stimulable with the neuroprosthesis, i.e. a sufficient extension of fingers and/or thumb for grasping tasks is not obtained with an electrical stimulation well supported by the patient.
* Concerning the associated pathologies: The person is carrying a pacemaker; Presence of unstable epilepsy; Presence of unstable cardio-vascular disease (coronary heart disease, major hypertension, heart failure); Presence of a dermatological problem against indicating the application of surface electrodes.
* Concerning associated treatments: The person should not receive an injection of botulinum toxin in the upper limb during the period of inclusion in the protocol, or in the 30 days prior to inclusion.
* Concerning legislative aspects: The person is participating in another research protocol including an exclusion period still in progress; The person is under the protection of justice or guardianship; The person refuses to sign the consent; It is not possible to give the person informed information and to make sure of the subject's compliance due to impaired physical and/or psychological health.