T2 Relaxation Time and Activity in Boys with Duchenne Muscular Dystrophy

Abstract Duchenne muscular dystrophy (DMD) is an inherited neuromuscular disorder characterized by progressive muscular degeneration. It is unknown what amount of activity is beneficial or detrimental to dystrophic muscle. This study examined functional mobility, activity, and T2 relaxation time in boys with DMD. DMD subjects were divided into two groups (active vs. inactive), and functional ability was tested using the 10m walk/run test. T2 relaxation times (4 echo times; at 3T) were used as a construct of muscle damage and composition. A trend was noted for the relationship between daily step counts and time for 10 m walk/run in DMD. For DMD subjects, there was a weak, negative relationship between average step count and T2 of the leg muscles (r= -0.278 to -0.308). The relationship between time spent in sedentary activity and T2 values of the leg muscles demonstrated a moderately positive, linear relationship (r= 0.377 to 0.440). Overall, the results show that there may be a relationship between T2 and activity in boys with DMD, and suggest that active DMD boys tend to have better functional abilities than inactive DMD. Further research is needed to better understand how activity impacts functional ability and muscle pathology in this patient population.

Full text: http://ufdc.ufl.edu/UF00091523/00666