Abstract
There is considerable evidence that after a stroke, ipsilesional deficits increase as contralesional impairment increases. Here, we asked if the relationship between the motor capacities of the two limbs differs based on the side of stroke. Forty-two pre-morbidly right-handed chronic stroke survivors (left hemisphere damage, LHD = 21) with mild-to-moderate paresis performed distal items of the Wolf Motor Function Test (dWMFT). We found that compared to RHD, the relationship between contralesional arm impairment (Upper Extremity Fugl-Meyer, UEFM) and ipsilesional hand motor capacity was stronger (R2LHD= 0.42; R2RHD < 0.01; z = 2.12; p = 0.03) and the slope was steeper (t = −2.03; p = 0.04) in LHD. Similarly, the relationship between contralesional dWMFT and ipsilesional hand motor capacity was stronger (R2LHD= 0.65; R2RHD= 0.09; z = 2.45; p = 0.01) and the slope was steeper (t = 2.03; p = 0.04) in LHD compared to RHD. Multiple regression analysis confirmed the presence of an interaction between contralesional UEFM and side of stroke (β3= 0.66 ± 0.30; p = 0.024) but only trended towards significance for the interaction between contralesional dWMFT and side of stroke (β3= −0.51 ± 0.34; p = 0.05). Results were confirmed after removal of potential outliers. Our findings suggest that the relationship between contra- and ipsi-lesional motor capacity depends on the side of stroke, such that the inter-limb relationship is stronger for stroke survivors with left hemisphere damage compared to those with right hemisphere damage.
Footnotes
The Statistical Analysis and Results sections have been revised to include primary analysis with and without outliers. Additionally, a comparison of covariance and slopes has now been included.