Comparison of effects of a motorized standing program on bone mineral density, lower extremity muscle length and health related quality of life in an ambulatory and non-ambulatory boy with DMD

Purpose. (1) Evaluate if the use of a motorized standing program is feasible for boys with DMD; (2) Compare lower extremity muscle length, bone mineral density and health related quality of life (HRQoL) with a standing program in an ambulatory and a non-ambulatory boy with DMD. Materials & Methods. Two boys with DMD engaged in a standing program using a motorized power wheelchair. An A1-B1-A2 single subject design was employed. Primary outcome variables included lower extremity muscle length and bone mineral density. HRQOL was also collected. Data Analysis. The two Standard Deviation Band width Method was employed to examine change over time in primary outcome variables quantitatively within subjects across the three study phases. Results. Lower extremity muscle length of hip flexors, hamstrings and plantar flexors declined significantly in Subject 1 with standing following loss of ambulation. In contrast, muscle length of hip flexors and plantar flexors remained stable and hamstring muscle length improved significantly with standing in Subject 2, who was non-ambulatory throughout the standing intervention. Lumbar bone mineral density declined significantly in Subject 1 with standing, coinciding with loss of ambulation, but remained stable in Subject 2. Conclusion. A standing program using a power sit to stand wheelchair of 30 minutes per day, 3-4 days was feasible for both an ambulatory and a non-ambulatory boy with DMD, but positive effects on muscle length and bone mineral density are overshadowed the negative effects of ambulation loss.