Validity of the Functional Classification of the Upper Extremities for Duchenne Muscular Dystrophy

Some upper-limb function assessments can evaluate treatments in the non-ambulatory stage of Duchenne muscular dystrophy (DMD). The Functional Classification of the Upper Extremities (FCUE) was developed for DMD in Japan. The FCUE is easier to use than the Performance of Upper Limb (PUL) and is more detailed than the Brooke Upper Extremity Scale. This study aimed to determine the concurrent validity of FCUE with other methods of assessment for DMD.

This retrospective study reviewed the medical records of 39 boys with DMD from the National Center of Neurology and Psychiatry to evaluate the concurrent validity of the FCUE and PUL using non-parametric Spearman rank correlation (ρ). We also determined the concurrent validity of the Brooke Upper Extremity Scale and PUL for comparison.

The ρ value between the FCUE and PUL was -0.914 (P<0.001). The FCUE showed robust concurrent validity with the PUL. That correlation between the FCUE and Brooke Upper Extremity Scale gave a ρ value of -0.854 (P<0.001).

The FCUE had a higher concurrent validity with the PUL than with the Brooke Upper Extremity Scale. The FCUE is considered a valid assessment tool of upper-limb function in boys with DMD. Selecting the best assessment method depends on the severity of the patient's condition and a balance between assessment accuracy and evaluation time.