STARTEffectiveness of START (Startle Adjuvant Rehabilitation Therapy) in Enhancing Arm Function Post-Stroke

The goal of this clinical trial is to test the effectiveness of START (Startle Adjuvant Rehabilitation Therapy) in improving arm function after a stroke. The main questions it aims to answer are 1) Does startle rehabilitation therapy improve functional arm performance after training on a specific task and 2) Can training benefits, if any, be seen in other untrained tasks? Researchers will enroll participants across a wide range of upper extremity impairments post-stroke. Participants will be enrolled in three consecutive days of in-person training on an upper extremity task followed by a single-day follow-up session one month after training is completed. Each training session will last for approximately 3 hours per day. Participants will be randomly assigned to one of two groups; 1) Arm training with START and 2) Arm training without START. Study participants and assessors will be blinded to the type of training received. Before the training, participants will be clinically assessed to determine impairment level. During training, participants will be asked to perform; 1) a simulated feed task which involves transferring kidney beans using a spoon from one cup (start position) to another cup (end position) in front of them OR 2) A functional reaching task where participants will maintain a tool (spoon) in their hand while extending their arm forward towards an end position based on the severity of arm impairment as determined by the clinical assessment. Researchers will compare the % change in trained task scores, muscle activity, and arm movement outcome measures at three-time points; baseline on day 1, at the end of training on day 3, and one month after training.