Assessment of muscle involvement in patients with Duchenne muscular dystrophy via segmental multifrequency...

We investigated the usefulness of segmental multifrequency bioelectrical impedance analyses (MBIA) for assessing muscle involvement in Duchenne muscular dystrophy (DMD) patients. Bioelectrical impedance data of the upper arm, thigh, and lower leg were obtained from 29 boys with DMD (ages 2-17 years old; mean 10.8 ± 3.9 years) at three institutions along with 41 healthy controls (ages 3-16; mean 9.8 ± 3.5 years). Then the muscle density index (MDI: 1- Z₂₅₀/Z₅) was calculated using segmental MBIA and compared between groups. The MDI was lower in boys with DMD, relative to controls, with older DMD patients exhibiting a significant decrease in MDI. The MDI of patient thighs was significantly correlated with the percent muscle volume index (%MVI), as measured using computed tomography (r = 0.79). MDI values for the upper arm, thigh, and lower leg were all significantly correlated with the Brooke and the Vignos scales, respectively, with correlation coefficients of 0.56-0.77. Finally, MDI was significantly greater in the glucocorticoid-treated group, relative to the untreated group in all regions. Taken together, these data show that segmental MBIA is feasible for evaluating muscle involvement and might serve as an outcome measure in DMD.