Postural balance following stroke: towards a disadvantage of the right brain-damaged hemisphere.

In the light of studies published in the last ten years, we have suspected a differential influence of the sides of hemispheric cerebral lesions on po sture and balance. A study was aimed at verifying this hypothesis, the meth od of which being original because many possible confounding factors such a s age, sex as well as topography and size of the brain lesion have been tak en into account in the statistical analysis. Inclusion criteria were: right -handed patients, first stroke, no previous disease which might have affect ed balance. Their postural abilities (ranging from 0 to 36) were assessed 9 0 +/- 3 days after stroke onset on a clinical scale. This clinical assessme nt was used here because it could be easily performed in all patients, irre spective of the severity of their impairment. Lesion locations were determi ned using the Atlas by Talairach and Tournoux and the number of cerebral ar eas altered gave an estimation of the lesion size. The first fifty patients consecutively admitted to rehabilitation and responding to the inclusion c riteria were thus examined (25 with a right and 25 with a left hemispheric lesion; 14 women and 36 men; mean age 57.2 = yrs). The main result was lowe r postural performances in right brain-damaged patients than in left brain damaged patients (21.5 vs 29.4; p = 0.01). Postural abilities were also inv ersely related to age (r = -0.28; p = 0.04), lesion size (r = - 0.41; p = 0 .003) and were lower in women than in men (22.1 vs 28.8; p = 0.02). This st udy therefore confirms the existence of a right hemispheric dominance for p ostural control. The existence of inverse correlation between postural abil ities and the number of omitted targets in cancellation task on one hand (r = - 0.63, p < 0.001), the ipsilesional bias in line bissection on the othe r hand (r = - 0.36; p = 0.01), argued for a relationship between the main r esult of this study and the well known cerebral organization of spatial inf ormation processing, based on a right hemisphere dominance for spatial atte ntion and/or representation. The 'postural neglect' concept is discussed.