Performance of Upper Limb module for Duchenne muscular dystrophy.

AIM: To report the differences between Performance of Upper Limb (PUL) versions 1.2 and 2.0, compare the measurement ability of the two versions, and compare their longitudinal performance in Duchenne muscular dystrophy.

METHOD: Rasch analysis was performed on the dual data from three centres to confirm whether the two scales measure the same construct. Change scores in natural history for the different domains were compared for the two versions.

RESULTS

Rasch analysis demonstrated that both versions measure the same construct and that the PUL 2.0 was a better fit to the construct of motor performance and better able to detect change at 12 months in all levels of ability than the PUL 1.2. This was also true when change scores were reviewed over 2 years.

INTERPRETATION: Our results confirm that the PUL 1.2 and 2.0 versions detect change in all domains over 2 years. They also demonstrate that simplifying the original scoring of the PUL 1.2 for the revised PUL 2.0 maintains the validity of the construct and enhances the scale measurement qualities.

WHAT THIS PAPER ADDS: The original and revised Performance of Upper Limb (PUL) scales measure the same construct. Both scales detected change in all domains over 2 years. The PUL 2.0 enhances the measurement qualities of the scale.