Influence of gait analysis on decision-marketing for lower extremity surgery

Energy efficiency of walking in males with Duchenne muscular dystrophy: is there an impact with steroid use?

S SIENKO THOMAS MA A, C E BUCKON MS A, A NICORICI BS B,
A BAGLEY PHD B, C M MCDONALD MD B, M D SUSSMAN MD A

  1. 1. Shriners Hospitals for Children Portland, OR;
  2. 2. Sacramento, CA, USA

Objectives: To determine whether differences in energy efficiency variables exist between males with Duchenne muscular dystrophy (DMD) and age-matched controls, and to determine the influence of corticosteroids on these variables in males with DMD.

Design: Prospective, cross-sectional multicenter population study.

Participants: Eighteen males with DMD, nione receiving steroids (mean age 7y 9mo, range 4y 3mo-14y 10mo) and nine steroid naïve (mean age 8y 1mo, range 5y6mo-12y6mo), and 10 age-matched controls, (mean age 7y 11mo, range 5y6mo-11y8mo), from two Shriners hospitals. Inclusion criteria for the participants with DMD: confirmed diagnosis, minimum age of 4 years, and ability to ambulate.

Method: A Cosmed K4b 2 energy consumption unit and Polar heart rate monitor were used to determine the energy cost and energy efficiency index (EEI) of walking. Heart rate and VO2 were measured during resting and walking in addition to velocity and distance walked in 10 minutes. The males with DMD were divided into two groups: those receiving steroids or those who were steroid naïve.  Analyses of variance with Scheffe post-hoc tests were used to determine differences between the three groups. Significance was set at p<_0.05. Pearson’s product moment correlation coefficients were used to determine the relationship between energy cost, EEI, and distance walked in 10 minutes.

Results: No significant difference was found between any of the groups for resting VO2, energy cost, heart rate walking or EEI (table D:8). Significant differences were found between the control group and both groups of participants with DMD for walking VO2, distance walked in 10 minutes, velocity, and heart rate resting. There was no significant difference for any energy efficiency variables between the groups of males with DMD. A significant correlation was seen between energy cost and distance walked r=-0.714, p=0.0008, which was not seen between EEI and distance walked r=-0.177, p=0.5024.

Conclusions: This study demonstrates that dystrophic changes in skeletal and cardiac muscle seen in males with DMD lead to a reduced energy efficiency during ambulation and a resting tachycardia. The males with DMD receiving corticosteroids showed a trend toward increased walking speed, reduced energy cost, and greater distance walked than males who were steroid naïve. Longitudinal studies with a larger group of children are necessary to determine whether this trend continues over time as males’ age, weight , and disease severity increase, and muscle strength decreases.

Acknowledgements: Shriners Hospitals for Children, grant no. 8951 for funding this research.

 
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