Kinematic Assessment of Upper Limb Impairment in Stroke Survivors Through IMUs During Box and Block Test

Motor deficits requiring clinical evaluation are common in stroke survivors. The aim of this study is to find kinematic indices for the objective assessment of stroke-related motor impairment during the box and block test (BBT). We tracked the movement of the trunk, pelvis, and upper limb during the test using eight inertial measurement units (IMUs). Two groups of subjects were involved: ten stroke survivors (53.6 ± 19.8 years) with different levels of motor disability (Upper Extremity Fugl-Meyer score of 54.4 ± 6.4), and 14 healthy subjects (43.6 ± 15.3 years). The data obtained were processed using validated procedure. The BBT task was divided into three subphases: reach, transfer, and coming back. The dominant side of healthy subjects, the affected and the unaffected sides of patients were compared in terms of the calculated indices by means of Kruskal–Wallis test. As expected, significant differences were found between the dominant side of the control group and the affected side of patients (p < 0.05). Most significant differences were found in parameters related to hand kinematics. A significant strong correlation (rs) was found between the mean value of the indices and the score that patients achieved in the BBT (0.6 < |rs| < 0.8 and p < 0.05). The study of the entire kinematic chain of pelvis, trunk, and upper limb revealed a compensation strategy used by stroke patients.