Physical performance testing in mucopolysaccharidosis I: a pilot study

Objective: To develop and field-test a physical performance measure (MPS-PPM) for individuals with Mucopolysaccharidosis I (MPS I), a rare genetic disorder. Methods: Motor performance and endurance items were developed based on literature review, clinician feedback, feasibility, and equipment and training needs. A standardized testing protocol and scoring rules were created. The MPS-PPM includes: Arm Function (7 items), Leg Function (5 items), and Endurance (2 items). Pilot data were collected for 10 subjects (ages 5-29 years). We calculated Spearman's rho correlations between age, severity and summary z-scores on the MPS-PPM. Results: Subjects had variable presentations, as correlations among the three sub-test scores were not significant. Increasing age was related to greater severity in physical performance (r = 0.72, p