Construct Validity of a Task-Oriented Unimanual Strength Measurement in Children with Unilateral Cerebral Palsy

Abstract

Aim: Investigate aspects of construct validity of parameters “mean peak force” and “number of successful attempts” of the press button task using the Task-oriented Arm-hAnd Capacity (TAAC) in children with unilateral cerebral palsy (CP) by comparing them to outcomes of comparative measures using Consensus-based Standards for the selection of health Measurement INstruments guidelines. Methods: 118 children with unilateral CP (mean age 1 year 2 months, standard deviation 3 year 5 months) were included. Fourteen a priori hypotheses were formulated for each parameter of the TAAC. Strength and direction of the relationship between the TAAC and comparative measures were investigated by calculating Pearson correlation coefficients. Results: For the parameter “mean peak force” 8/14 (57%) hypotheses could be supported. For the parameter “number of successful attempts” 13/14 (93%) hypotheses could be supported. Conclusion: The hypothesized construct of the parameter “mean peak force” is only partially in line with our idea about the potential relationship of the compared constructs. The relationship needs to be reconsidered to some extent. The hypothesized construct of the parameter “number of successful attempts” is in line with our idea about the potential relationship of the compared constructs and can be considered to have good validity compared to the other measures. Thus, the construct of this parameter adds new and meaningful information as an outcome measure for functional strength measurements.