Understanding the Contributions of Proprioceptive Impairment on Arm Capacity and Real-World Performance After Stroke - PROJECT SUMMARY/ABSTRACT A recent emphasis in stroke rehabilitation research focuses on capturing how an individual’s paretic arm capacity (what one can do when prompted in the clinic) compares to an individual’s daily performance (what one does spontaneously in the real-world). Historically, motor capacity and performance after stroke have been considered congruent. However, recent work has demonstrated that motor capacity and performance are not equal at various time points of stroke rehabilitation. In fact, we often see improvements in capacity with stroke rehabilitation, but fail to observe comparable improvements in real-world performance. Learned non-use is the phenomenon describing the incongruence between capacity and performance, which can have detrimental effects on full recovery. For example, an individual may show improved outcomes on an in-clinic upper extremity assessment (i.e., Fugl Meyer) thereby able to be discharged from outpatient rehabilitation services, but rarely use their arm in daily life despite their increased ability. Decreased real-world usage can lead to a cycle of disuse, which can plateau or negatively affect recovery. Previous animal studies have used a limb deafferentation model that eliminates sensory information to study learned non-use. This deafferentation model eliminates proprioception, the sense of body position and movement in space, but does not affect motor function. This work showed that animals significantly decreased spontaneous use of the arm when proprioception was eliminated regardless of continued motor capacity. Despite an established connection in animal models, there is a critical gap to understand the connection between proprioception and learned non-use in individuals with stroke. The overall objective of this proposal is to evaluate the relationship between proprioceptive impairment and learned non-use– which accounts for both paretic arm capacity and performance. Our central hypothesis is that proprioceptive impairments of the upper limb will have a negative effect on paretic arm capacity, performance, and, subsequently, learned non-use. In Aim 1, we will identify the contributions of proprioception on paretic arm capacity, using both clinical and laboratory measures. In Aim 2, we will understand the moderating effects of proprioception on learned non-use, using a self-report clinical measure and activity monitors to capture real- world paretic arm performance. We anticipate that stroke participants with proprioceptive deficits will have lower capacity to utilize the paretic arm. Additionally, we anticipate that proprioception is a moderator of learned non- use, accounting for the innate relationship between capacity and performance. Completion of this proposal will provide greater knowledge about proprioception as a potential mechanism underlying learned non-use after stroke. Without this knowledge, typical interventions used for learned non-use may not be effective because they address only the behavioral consequences of a potentially underlying sensory deficit. The overall impact of this proposed research lies in understanding how proprioceptive deficits contribute to paretic arm activity– consisting of both in-clinic capacity and real-world performance.
