The goal of this research study is to increase understanding of error augmentation by applying it to visual feedback during motion tracking with a Leap Motion device - a recently developed optical hand tracking tool - and the LookingGlass - a new, portable virtual reality environment.

In conjunction with the Leap, large, three dimensional work spaces can provide an immersive and virtual augmented environment for rehabilitation. Previously, experiments have utilized the Virtual Reality Robotic and Optical Operations Machine (VRROOM) to create such visually immersive environments. The Robotics lab as part of the Arms and Hands Lab on the 22nd floor of the Shirley Ryan Abilitylab has developed a portable version of this system, which is more compact and clinic-compatible. Combining this visual 3D system with the Leap creates a novel, more capable apparatus for studying error augmentation.

This research study will have 3 different arms: 1.) a healthy group of individuals (Healthy Arm), 2.) a group of stroke survivors within 8 months of stroke (Acute Arm), and 3.) a group of stroke survivors that had their stroke more than 8 months ago (Chronic Arm).

Each Arm will use the Leap motion tracker and the Looking Glass to participate in a reaching intervention. The healthy arm will only participate in 1 visit with an intervention with and without error augmented visual feedback. The Acute Arm and the Chronic Arm will both have 2 groups: 1.) Error Augmented Visual Feedback group and 2.) Non-Augmented or Veridical Visual Feedback group.

The Chronic Arm will have a structured intervention and evaluation protocol: Study staff will administer outcome assessments at 3 time points: a.) prior to intervention, b.) post intervention, and c.) 2 months after the conclusion of intervention. Intervention will occur over the span of 6-8 weeks with the goal of 3 1-hour sessions per week.

The Acute Arm will have a less structured intervention that will occur while the participant is an inpatient at Shirley Ryan AbilityLab. Study staff will administer outcome assessments at at least 2 time points: a.) prior to intervention, b.) post intervention just prior to discharge from Shirley Ryan AbilityLab. Between initial and post intervention evaluations, midpoint evaluations will take place at a maximum of once per week if the participant's schedule, activity tolerance, and length of stay allows. Intervention will consist of 1-hour sessions occurring according to the availability of the participant at the rate of no more than 2 sessions in a 24 hour period.

Investigators hope to investigate these questions:

1. Can the movement of healthy individuals be characterized with error augmented visual feedback and veridical visual feedback?

2. Will error augmented visual feedback or veridical visual feedback result in greater movement ability improvement?

   Investigators hypothesize that in the Chronic Arm, those what trained with error-augmented visual feedback will have improved movement ability compared to those who trained with veridical visual feedback.

3. Is treatment with the looking glass and leap system feasible with an inpatient population?

Investigators hypothesize that this treatment will be feasible for an inpatient population.

Inclusion Criteria:

• 8 months post stroke
• FMUE 15-50
• Active shoulder and elbow flexion-extension when supported against gravity to accomplish a forward mediolateral and inferior-superior reaching movements of 30 cm

Exclusion Criteria:

• Bilateral paresis
• Severe sensory deficits in the affected limb
• Severe spasticity preventing movement (MAS 4 or greater at elbow)
• Aphasia, cognitive impairment or affective dysfunction that influence ability to participate in the experiment
• Inability to provide informed consent
• Severe current medical problems
• Diffuse/multiple lesion sites or multiple strokes
• Hemi-spatial neglect or visual field cut preventing subjects from seeing the target
• Inability to maintain the testing positions
• Botox injections in the affected Upper Extremity within the past 4 months
• Concurrent participation in Upper Extremity rehab (research or prescribed therapy)
• Participation in previous, similar robotics intervention studies
• Pregnant women, children and teenagers, prisoners