Construct validity, reliability, and responsiveness of the Wrist Position Sense Test for use in children with hemiplegic cerebral palsy

Introduction We investigate the construct validity, test re-test reliability, and responsiveness of the Wrist Position Sense Test (WPST) for children with hemiplegic cerebral palsy (CP). Methods Twenty-eight children with spastic hemiplegic CP [mean age 10.8 years; SD 2.4 years] and 39 typically developing (TD) children [mean age 11 years; SD 2.9 years] participated in a cross-sectional study to investigate construct validity and association with an upper limb activity measure, the Box and Block Test (BBT). Twenty-two TD children were tested at a second time-point to examine reliability. Test responsiveness was determined by random allocation of 17 children with CP to a treatment (n = 10) or control (n = 7) group with assessments completed at four time-points. Results Significantly greater differences were observed in mean error of indicated wrist position (p < 0.01) in children with CP at baseline (M = 21.6 degrees, SD = 21.6 degrees) than in TD children (M = 12.8 degrees, SD = 11.0 degrees). Larger WPST errors were associated with poorer performance on the BBT (p < 0.01) indicating a substantial association, and there were no consistent differences between time-points indicating test re-test reliability within a TD population. The WPST demonstrated responsiveness to intervention with a statistically significant reduction in mean error following treatment (p < 0.001), not seen in the control group (p = 0.28). Conclusion The WPST demonstrated construct validity in this preliminary study. Scores were associated with an upper limb activity measure, and scores changed significantly following somatosensory training. These findings support further research and future psychometric investigation of the WPST in children with CP. Key Points for Occupational Therapy This study provides psychometric knowledge about the WPST tool The WPST shows promise as a discriminative measure with preliminary evidence of responsiveness and intra-rater reliability Until further testing, the WPST can be used cautiously in future research studies to measure wrist position sense