The Relationship between the Subjective Visual Vertical and Static Postural Balance in Stroke Patients / The Japanese Journal of Rehabilitation Medicine

ABSTRACT

It has been pointed out that a biased perception of the subjective visual vertical (SVV) in stroke patients might be related to balance deficits and impaired activities of daily living (ADL). The relationship between SVV and static balance in stroke patients, however, still remains unclear. Thus we examined the relationship between SVV and standing balance in 29 hemiparetic patients with a first-ever supratentorial stroke. We measured the rotation angle formed by a subjective vertical and the gravitational vertical (rotation to the non-paretic side was set as positive) 8 times, and employed the mean value as the SVV value. We also calculated the absolute rotation angle for each time and employed the mean value as the absolute SVV value. Then we evaluated postural balance using four stabilometer parameters length of center of pressure per time (LNG/T), envelopment area (ENV), root mean square (RMS) and weight-bearing asymmetry (WBA) during standing. The relationship between the SVV values or the absolute SVV values and the four stabilometer parameters were analyzed using the Spearman's rank correlation coefficient. The mean values for SVV and absolute SVV of all participants were -0.3±2.3° and 2.0±1.5°, respectively. The absolute SVV value and each of the four parameters were positively correlated with statistical significance (LNG/T ; <i>r</i>=0.44, ENV ; <i>r</i>=0.41, RMS ; <i>r</i>=0.46, WBA ; <i>r</i>=0.40), while there was no statistically significant correlation between the SVV value and each of them. These results suggest that the SVV bias size is possibly related to standing balance in stroke patients.