Relationship between adjustability of grasping force and upper limb/hand function in individuals with cerebrovascular disorders

Activities of daily living, including grasping, holding, and pinching, are essential for independence but often become difficult for individuals with cerebrovascular disease owing to upper limb paralysis. We investigated the relationship between adjustability of grasping force (AGF), defined as the ability to adjust grasping force, and upper limb/hand functional performance. Twelve individuals with mild cerebrovascular disorders participated in this preliminary cross-sectional study. Assessments included the AGF task using iWakka, the Fugl-Meyer Assessment, Simple Test for Evaluating Hand Function, Action Research Arm Test (ARAT), and Motor Activity Log (MAL). AGF was quantified using the AGF score, calculated as the absolute error between target and actual grasping force; lower AGF scores indicate better AGF. Partial Spearman's rank correlations, adjusted for age, revealed that AGF score (isometric section) on the less-affected side was negatively and positively correlated with ARAT and MAL (Quality of Movement) on the less-affected and more-affected sides, respectively. These findings suggest that better AGF on the less-affected side may enhance motor performance on that side but could be associated with lower perceived movement quality on the more-affected side. This highlights the complex role of the less-affected side in post-stroke function and suggests that rehabilitation strategies should consider AGF on both sides of the body.