Impaired ability to shift weight onto the non-paretic leg in right-cortical brain-damaged patients

: Stroke patients experience postural instability that can impede functional improvements in their gait. However, the precise functions of the dominant and non-dominant hemispheres in controlling static standing posture and weight-bearing remain unclear.

: To investigate differences in balancing ability between right-handed patients with right and left hemispheric lesions.

: Weight shifting was quantitatively evaluated to determine the ability of patients to control their balance in a static posture and during conscious weight shifting onto the paretic or non-paretic leg. Participants were enrolled from a consecutive series of stroke patients attending a rehabilitation program (n=49; 31 male, 18 female; mean age 69.3+/-9.4 years). Age-matched normal controls were recruited as volunteers (n=12; 4 male, 8 female; mean age 67.9+/-4.9 years).

: Patients with cortical lesions in the right hemisphere were able to shift less weight onto the non-paretic leg than patients with cortical lesions in the left hemisphere (p<0.05). There were no correlations between the existence of unilateral spatial neglect and the percentage of weight shifted onto the non-paretic leg, static standing posture (r=0.27, p=0.40) or dynamic standing posture (r=-0.37, p=0.24). In contrast, there was a significant correlation between the percentage of weight consciously shifted onto the non-paretic leg and the existence of anosognosia (r=0.74, p=0.006), but not between static standing posture and anosognosia (r=-0.15, p=0.63).

: Patients with right cortical hemispheric lesions were able to shift less body weight onto their non-paretic leg. These patients should be encouraged to practice shifting their weight towards their non-paretic leg to improve their balance.