Fig. 2

Proprioceptive accuracy at each tested robot speed. In the left column (A, C, E, G), the box plots display proprioceptive error in each of four parameters (EPE, RL, PSR, IDE) for age-matched controls (black) and individuals with stroke (gray). For stroke participants, left-facing triangles indicate individual stroke participants with the left side of the body as their more affected side, and right-facing triangles indicate individuals with the right side of the body as their more affected side. We observed that across each of the parameters in the left column that stroke participants showed significantly more error compared to age-matched controls at each of the tested robot speeds. In the right column (B, D, F, H) data was fit using ordinary least squares for individual participants to determine the intercept (\({\beta }_{0}\)) and slope (\({\beta }_{1}\)) of the average resultant behavior within groups. Here, the goal was to examine changes in pattern and/or magnitude of proprioceptive error as a function of robot speed. Solid lines indicate the bootstrapped average fit for age-matched controls (black) and individuals with stroke (gray). Insets indicate fit coefficients (\({\beta }_{0}\) and \({\beta }_{1}\)), with individual participant coefficient data included on the box plot. Overall, we found that for the parameters tested, the pattern (slope) was similar between age-matched controls and individuals with stroke, but that the magnitude (intercept) was significantly different for all individuals with stroke suggesting that while stroke increases the overall magnitude, the pattern of error response is preserved when the speed of the reference movement is changed. *p ≤ 0.05, **p ≤ 0.01