Abstract WP152: Exploration of the Factors That Influence Spontaneous Bimanual Arm Use After Stroke: Implications for Clinical Rehabilitation

Abstract

After a stroke, returning to activities of daily living requires the use of the two hands together for bimanual tasks, such as cutting bread, buttoning a shirt etc. Here, we sought to first, identify spontaneous volitional arm use patterns adopted for two distinct bimanual tasks, and, next, determine if and to what extent the degree of impairment, side of stroke, task demands, self-reported confidence, and single-limb (paretic and non-paretic) measures of functional performance can predict the observed task use patterns. Fifty pre-morbidly right-handed stroke survivors (Upper Extremity Fugl-Meyer, UEFM 42±10, 25 right-hemiparesis, RHP) performed 2 bimanual tasks (letter-envelope and photo-album) without explicit instructions. Arm use patterns were classified by: 1) whether one or both arms were used, and 2) the nature of paretic arm use. Logistic regression and receiver-operator characteristics (AUC) were used to examine the influence of impairment (UEFM, more severe < 41, less severe ≥ 41), side of lesion, task demand, self-reported confidence (CAHM), and single-limb functional performances (paretic and non-paretic log-transformed distal component time-scores of Wolf Motor Function test, ln-WMFT) on bimanual arm use. Those more severely impaired and LHP were less likely to choose a bimanual strategy for either task (β = 14.64, p<0.001). For the photo-album task, probability of bimanual use was greater for RHP than LHP group, especially in less impaired; whereas, for the letter-envelope task, probability of use for RHP > LHP only in the more impaired (β = -1.45, p< 0.001). LHP, but not RHP, who reported greater confidence in the use of the paretic arm were more likely to use a bimanual strategy (ρ > 0.34, p<0.05). Finally, paretic arm ln-WMFT was a fair predictor of use patterns for both LHP (AUC = 0.79) and RHP (AUC = 0.80) groups, while the non-paretic arm time-score was a good predictor of use patterns only for the RHP (AUC = 0.85), but not the LHP group (AUC = 0.55). Taken together, spontaneous bimanual arm use is modified by impairment, task demands, confidence in paretic arm, and non-paretic arm function, but the effect depends on the side of stroke. Thus, consideration of side of lesion is important when developing interventions to improve bimanual arm use.