Assessing and training of proprioception for individuals with chronic stroke

Abstract

Proprioception is the perception of our body’s location and movement in space and is critical for coordinated movement. Proprioception is comprised of several sub- components, including position sense and kinesthesia. Position sense is the perception of our body’s static location in space, and kinesthesia is the perception of our body’s dynamic location in space. Importantly, proprioception – particularly that of the upper limb – has been shown to be impaired in many individuals with stroke. After stroke, proprioceptive impairments have been shown to be common, with ~50% of individuals post-stroke having impairment in position sense and ~60% having impairment in kinesthesia. Despite studies that have identified general characteristics of proprioceptive impairment after stroke, our understanding of exactly how these impairments can impact function after stroke is limited. To date, it is unknown if the magnitude of kinesthetic impairment is consistent across different movement characteristics, how position sense impairments of the limb impact integration with other sensory systems, and if proprioceptive training can be used to facilitate improvements in upper limb sensorimotor control. ☐ In Aim 1, we found that movement speed and distance can modulate proprioceptive accuracy, suggesting that when assessing proprioceptive capacity, one should consider how the reference movement speed and length can affect estimation of proprioceptive error. Since our group recently found that not all individuals post- stroke could use vision to compensate for proprioceptive deficits, in Aim 2 we probed if dysfunctional proprioceptive signals from the limb impaired the ability to make accurate eye movements. We found that individuals post-stroke showed markedly different eye behavior compared to age-matched controls, suggesting that an impaired proprioceptive reference signals can impact other sensory systems. In Aim 3, we expanded current methods to reduce and optimize assessment time for individuals with stroke for the complex proprioceptive assessment implemented in Aim 1. Additionally in Aim 3, we found that a one-day proprioceptive training paradigm was able to improve motor and proprioceptive behavior of the upper limb in some individuals with stroke. Overall, the current work demonstrated that proprioceptive impairments after stroke are complex but can potentially be improved via targeted proprioceptive training. This work highlights the importance of a more comprehensive view of proprioceptive deficits post-stroke that includes movement characteristics and its effects on different systems, motivating future work that considers novel proprioceptive assessments and deeper exploration into proprioceptive training post- stroke.