One in six people will have a stroke; over half will incur chronic upper extremity (UE) impairment. While intensive rehabilitation reduces impairment, most individuals do not perform enough movement practice early after stroke when plasticity is heightened. Our hypothesis is that there is a threshold level of UE motor drive needed to provoke true UE recovery, yet individuals do not routinely exceed this threshold during inpatient rehabilitation. To solve this, Flint Rehab and UC Irvine propose to test a novel, pragmatic rehabilitation strategy for enabling individuals with even severe arm impairment to increase UE motor drive early after stroke. We will leverage a ubiquitous piece of technology–the manual wheelchair–based on two key observations. The first is a pivotal study by Feys et al. that had 100 inpatients with subacute stroke rock themselves in rocking chairs by repetitively reaching forward with their impaired arm 500- 1000 times per day; these patients had significantly greater increases in UE Fugl-Meyer (FM) score of 17 points at a five-year follow up compared to control. This is a remarkable effect, yet this therapy remains unimplemented in routine clinical practice. A second observation: 70% of stroke inpatients (and nearly all with more severe impairments) spend several hours each day sitting passively in manual wheelchairs, often with their paretic arm strapped into an arm trough. Further, when they move in their wheelchair, they are pushed, or taught to use their “good” arm and leg. Our core idea is to use a novel, moveable wheelchair armrest called Boost to enable inpatients to perform the repetitive arm therapy validated by Feys while seated in their wheelchair. Boost quickly clicks into a wheelchair frame just like a conventional wheelchair armrest and incorporates an innovative linear mechanism that enables UE activation in two modes: 1) with the chair remaining stationary, or 2) with the user contributing to propelling their wheelchair with their impaired arm. This latter mode transforms the "good arm + good leg" compensatory wheelchair propulsion technique into “good arm + good leg + impaired arm” propulsion. We hypothesize that use of Boost during inpatient therapy will enable individuals with stroke to achieve the threshold level of UE motor drive required to provoke UE recovery in routine practice, significantly improving recovery compared to conventional treatment. We have already pilot tested a functional prototype of Boost with positive results. Thus, for this Direct-to-Phase II SBIR our aims are to: Aim 1) Develop a commercial-ready model of Boost with clinical and end-user feedback; Aim 2) Perform a randomized controlled trial of Boost with inpatients with subacute stroke (N=58). At project end, we will have validated the clinical feasibility and efficacy of Boost and optimized it for production and mass distribution. If our plan is successful, we will have demonstrated that wheelchair-based “rocking therapy” can hel...