The overall objective of this study is to assess whether robot-assisted upper-limb group rehabilitation can be effectively delivered by using a camera-based system equipped with machine learning algorithms to track the quality of the exercise performance and provide feedback accordingly. To address this question, we plan to carry out a randomized clinical trial to compare outcomes in subjects receiving robot-assisted upper-limb rehabilitation during individual (i.e., one-on-one) sessions and in subjects receiving robot-assisted upper-limb rehabilitation during group (i.e., up to three subjects) sessions.

The proposed study is a single-blinded randomized clinical trial to evaluate the effect of using the PostureCheck (a camera-based system equipped with machine learning algorithms to track the quality of the exercise performance) on motor gains in group and individual robot-assisted upper-limb. Study participants (stroke survivors) will be recruited at the Spaulding Rehabilitation Hospital - Boston. Subjects will be randomly assigned to one of the two different groups: individual- or group-therapy using a covariate-adaptive allocation procedure to ensure important covariates, such as baseline Fugl-Meyer Assessment of the Upper Extremity (FMA-UE) scores and proprioceptive deficits, are balanced between groups.

Inclusion Criteria:

• Have had a history of ischemic cerebrovascular accident (CVA) within middle cerebral artery (MCA) or anterior cerebral artery (ACA) territory
• CVA occurred between six months and six years ago
• Moderate to severe UE impairment, FMA-UE score between 15 and 45
• Mini-Mental State Examination (MMSE) score >23 and being able to safely follow three-step commands

Exclusion Criteria:

• Advanced musculoskeletal pathology or recent fractures in the impaired UE
• Previous diagnosis of neurological diseases other than stroke
• Severe limitation of passive range of motion or spasticity (Modified Ashworth Scale for spasticity at <3 for UE muscles)
• Hemorrhagic CVA or involvement of the posterior cerebral artery
• Aphasia sufficient to limit ability to express needs or discomfort verbally or non-verbally
• Impaired visual acuity (Severe visual impairments as assessed by the NIH Stroke Scale Visual Field subscale. (score >0))
• Severe hemispatial neglect as assessed by the Line Bisection Test (score >2)
• Severely impaired trunk control (<4)
• Individuals who present with the following on the intended limb:
• Open wounds
• Fragile skin
• Under contact precautions due to an active infection
• Participation in another therapy focused on recovery of the impaired arm
• Subjects with cardiac pacemakers, electronic pumps or any other implanted medical devices, that are not US-certified
• Any Condition that would prevent safe use of the Burt system; such as proprioceptive deficits that impair the ability to process haptic or visual feedback, or unstable shoulder joint as assessed by physical examination
• Current pregnancy (self-report)
• The concern is strictly towards women who are in the 2nd or 3rd trimester and the eventuality of the arm of the BURT accidentally impacting the woman's belly. The system does have safety features (including a virtual safety wall, to keep the device away from the patient's body) but we are taking this as an extra precaution against any potential harm