Increasing the use of the more affected arm is a common goal for both adults and children after stroke, however, it is difficult to measure. Accelerometers have been used to assess the symmetry of arm use between the limbs, but do not give information about the actual movements the arms perform. Together with Dr. Stephen Guy in computer science, we are developing a video-based analysis method for clinicians to assess bilateral arm use during naturalistic movement. Using a single camera, we capture video of a participant engaging with objects designed to be used with both hands. We can then extract movement information from the videos. We are creating an interactive software tool in which evaluators can view the videos while also seeing summative plots that can condense the information from a 20-minute video into a single figure capturing the movement and use of both arms. This interdisciplinary collaboration will result in a freely available tool that can improve clinical assessments of bilateral arm use to facilitate clinical decision making. We are also working to gamify video-based assessments of bilateral coordination that can also be used as treatments.