Many survivors of stroke habitually refrain from using their more-involved arm during common daily activities despite retaining sufficient motor capability to perform movements. This phenomenon of "learned non-use" is a leading cause of disability. Our project will assess the functional utility and subjective patient experience using a personal exercise cueing system designed to increase arm use by motivating arm activity in the days and weeks following stroke. Our work is based on the premise that motor recovery may be enhanced by increasing the amount of hemiparetic arm exercise in the earliest stages of recovery, wherein inpatients spend most of their time idle and alone. As an adjunct to conventional therapy, we developed low-cost wearable technology to motivate and monitor unsupervised exercise of the hemiparetic arm during idle-time. We expect that the proposed system will give patients more agency over their own therapy, increase their level of participation, and ultimately increase their functional independence. This project takes critical first steps evaluating technology and procedures designed to motivate idle-time exercise during acute stroke recovery. The low-cost system uses vibrotactile cues to encourage exercises designed to progressively engage paretic arm use. The system uses accelerometry to monitor paretic and non- paretic arm use, and to infer compliance with prescribed exercises. The system requires minimal intervention by a skilled therapist. Survivors of stroke will evaluate the system for two weeks in the inpatient rehabilitation unit of a local hospital. The work is needed to show that our approach can motivate increased exercise without significant therapist oversight, and to determine if patients find the system usable, motivating, and satisfactory to use. Thus, our Aims are: Aim 1: To establish the functional utility of a personal exercise cueing system in an inpatient setting during the days and weeks following stroke. We will analyze accelerometry data to verify that the system can motivate greater hemiparetic arm activity during cued exercise intervals vs. intervals without cues. Aim 2: To characterize the subjective patient experience using a personal exercise cueing system during acute recovery on the inpatient rehabilitation unit. At the end of the 2-week inpatient experience, participants will be asked to complete questionnaires assessing their perceptions of system usability, intrinsic motivation, and their satisfaction in using the system in its intended environment. We expect that participants will have positive subjective experiences using the system as inpatients. Project success will provide critical support for future clinical trials that will be designed to optimize and evaluate the efficacy of early idle-time exercise interventions to increase hemiparetic arm use and quality of life after stroke. This R21 project will also provide pilot data that will inform the design of those larger follow-on studies...