Is Visuospatial Hemineglect Longitudinally Associated with Postural Imbalance in the Postacute Phase of Stroke?

Abstract

Introduction. The purpose of this study was to determine the longitudinal association of visuospatial hemineglect with postural imbalance in postacute stroke patients and to establish whether this relationship is confounded by other determinants. Methods. A prospective cohort study of 53 postacute stroke patients consecutively admitted for inpatient rehabilitation was conducted. Transfers and standing balance were assessed with the Berg Balance Scale (BBS) and walking balance with the Functional Ambulation Categories (FAC). Repeated measurements took place at baseline (36.6 ± 10.4 days after stroke) and after 6 and 12 weeks. Visuospatial hemineglect was assessed by an asymmetry index, derived from the Letter and Star Cancellation Tests. Random coefficient analysis was used to analyze the longitudinal impact of visuospatial hemineglect on the BBS and FAC. The association between hemineglect and outcome was corrected for the following potential confounders: age, severity of paresis of the lower leg, sensory deficits, and presence of hypertonia. A covariate was considered to be a confounder if the regression coefficient of hemineglect on outcome changed by >15%. Results. Visuospatial hemineglect was significantly associated with BBS and FAC. The relation between hemineglect and both BBS and FAC was confounded by severity of paresis of the lower limb. After controlling for severity of paresis, hemineglect remained independently associated with BBS, whereas the association with FAC lost significance. Conclusion. Visuospatial hemineglect is an independent covariate that is longitudinally associated with postural imbalance after stroke. These findings suggest that hemineglect is an important factor for controlling static and dynamic standing balance during the first months poststroke.