Standing balance during internally produced perturbations in subjects with hemiplegia: validation of the balance scale.

Abstract

To examine the concurrent validity of the Berg Balance Scale (BBS) in subjects with hemiparesis after stroke by correlating functional balance performance on the BBS with laboratory measures of balance (center of pressure [CP] and electromyographic [EMG] activity of leg musculature during rapid arm flexion and during quiet stance). Concurrent validation study. Consistency of performance was determined through repeat measures obtained from 13 subjects. Laboratory. Twenty-four volunteers with longstanding hemiparesis from cerebrovascular accident (CVA) were tested. BBS scores were compared with CP excursion speed during (1) self-initiated rapid unilateral arm flexion with the nonhemiplegic arm and (2) quiet stance. The peak tangential arm acceleration and the sequence of EMG events in the posterior leg muscles were monitored during the arm flexion movement. In the arm flexion condition, BBS performance was significantly correlated with arm acceleration and CP excursion speed (multiple regression R = .81). BBS performance was also related to the presence of anticipatory activation of ipsilateral hamstrings during the rapid arm flexion movement. BBS performance and CP excursion speed during quiet stance were also significantly related (r = .76). The initial and repeat measures were not significantly different in magnitude (paired tests of difference, p < .01). The BBS appears to reflect differing abilities to tolerate the internally produced perturbation to standing balance associated with forward arm flexion in individuals with hemiparesis from CVA.