A quantitative analysis of the kinematics of reaching by hemiplegic stroke patients using microsensor motion capture

Objective To evaluate the feasibility of using a microsensor motion capture unit (MCU) to assess the reaching characteristics of hemiplegic stroke patients. Methods Twenty-three hemiplegic stroke patients with an average age of (61 ± 11) years and ten normal subjects of matching age were asked to sit on a chair and use the affected arm (for the patients) or the right arm (for the normal subjects) to reach for a cup on a table just in front of the shoulder at arm's length away.Four small sensor boxes which could detect movement and its speed and smoothness in three dimensions were fixed to the subject's spine,upper arm,forearm and hand.The test was repeated four times after two trial runs.The average velocity,peak velocity,degree of joint dispersion,entropy of acceleration,joint coordination and active range of motion ( AROM ) of the shoulder were analyzed.The patients and normal subjects were statistically compared.The results were correlated with Fugl-Meyer upper extremity scores using Spearman correlation analysis. Results All of the measured variables showed significant differences between the patients and normal subjects.In the correlation study,the average velocity,peak velocity,AROM of the shoulder and joint coordination showed significant correlation with the Fugl-Meyer scores.There was,however,no significant correlation between degree of dispersion of the shoulder or elbow joints or the entropy of acceleration ( which represented the quality of movement) and Fugl-Meyer upper extremity scores. Conclusions The results suggest that microsensor MCUs can quantitatively assess the kinematics of reaching among hemiplegic stroke patients.They can provide valuable and objective data about the functional quality of multiple joint movements in three dimensions. Key words: Stroke; Hemiplegia; Reaching; Kinematics; Quantitative analysis