The Pediatric Upper Limb Motion Index and a temporal-spatial logistic regression: Quantitative analysis of upper limb movement disorders during the Reach & Grasp Cycle

This study describes a novel pediatric upper limb motion index (PULMI) for children with cerebral palsy (CP). The PULMI is based on three-dimensional kinematics and provides quantitative information about upper limb motion during the Reach & Grasp Cycle. We also report key temporal-spatial parameters for children with spastic, dyskinetic, and ataxic CP. Participants included 30 typically-developing (TD) children (age= 10.9 +/- 4.1 years) and 25 children with CP and upper limb involvement (age= 12.3 +/- 3.7 years), Manual Ability Classification System (MACS) levels I-IV. The PULMI is calculated from the root-mean-square difference for eight kinematic variables between each child with CP and the average TD values, and scaled such that the TD PULMI is 100 +/- 10. The PULMI was significantly lower among children with CP compared to TD children (Wilcoxon Z= -5.06, p < .0001). PULMI scores were significantly lower among children with dyskinetic CP compared to spastic CP (Z= -2.47, p < .0135). There was a strong negative correlation between PULMI and MACS among children with CP (Spearman's rho= -.78, p < .0001). Temporal-spatial values were significantly different between CP and TD children: movement time (Z= 4.06, p < .0001), index of curvature during reach (Z= 3.68, p = .0002), number of movement units (Z= 3.72, p = .0002), angular velocity of elbow extension during reach (Z= -3.96, p < .0001), and transport(1) :reach peak velocities (Z= -2.48, p = .0129). A logistic regression of four temporal-spatial parameters, the Pediatric Upper Limb Temporal-Spatial Equation (PULTSE), correctly predicted 19/22 movement disorder subtypes (spastic versus dyskinetic CP). The PULMI, PULTSE, and key temporal-spatial parameters of the Reach & Grasp Cycle offer a quantitative approach to analyzing upper limb function in children with CP. (c) 2012 Elsevier Ltd. All rights reserved.