Inclusion Criteria- first acute event of cerebrovascular stroke
- unilateral paresis,
- ability to understand and follow simple instructions,
- ability to remain in a sitting posture, even through seat belts for trunk fixation.
Exclusion Criteria- bilateral impairment,
- severe sensory deficits in the paretic upper limb,
- cognitive impairment or behavioral dysfunction that would influence the ability to comprehend or perform the experiment,
- refusal or inability to provide informed consent
- other current severe medical problems.