Examining Proprioceptive Error Across Distances in Individuals With Stroke

• Arianna Eimont, Neuroscience, University of Delaware

• Jennifer Semrau, Kinesiology and Applied Physiology, University of Delaware

Proprioception is the perception of the position and movement of the limbs in space and is essential for motor function. Impairments in proprioception after stroke significantly impact functional abilities. Previous work from our group and others has found that environmental characteristics (distance, speed) can impact the perception of limb movement. These results provided the foundation for exploring how similar mechanisms operate during dynamic proprioceptive behaviors, which are more representative of everyday movements. We hypothesized that in individuals with stroke, timing errors during dynamic limb-matching tasks increase at further distances, reflecting reduced spatial localization and impaired sensory integration. 

We recruited 16 participants with chronic stroke and 9 age-matched controls. Participants completed a robotic-based proprioceptive timing task, both with and without vision. Here, the Kinarm robotic exoskeleton passively moved the arm along a circular path to four different distances. Participants pressed a button when they felt that their hand was aligned with a visual target. Means and standard deviation of timing error were compared across distances and demonstrated that visual feedback significantly improved performance across all distances for controls and individuals with stroke (p < 0.001). The rate of change (slope) across distances did not differ between controls and stroke, regardless of the presence of visual feedback. However, we observed significant increases in variability as a function of increasing distance in individuals with stroke (p < 0.001). 

Preliminary results demonstrate that controls and individuals with stroke improved significantly with the inclusion of visual feedback on a proprioceptive timing task.  No significant interaction was observed across distances for either group. We observed greater temporal variability in individuals with stroke, suggesting noisier proprioceptive signaling, which resulted in greater errors. These results suggest that visual compensation for proprioceptive impairments may be altered in stroke survivors, and that these discrepancies are amplified with longer task requirements.