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Measurements of Motor Function and Other Clinical Outcome Parameters in Ambulant Children with Duchenne Muscular Dystrophy
Published on: January 12, 2019
Phase angle as a predictor of motor function decline in children with Duchenne muscular dystrophy
Qin Hu1,2, Xiaoyong Chen1, Shaojie Luo1
1Department of Rehabilitation Medicine, West China Second University Hospital of Sichuan University (WCSUH- SCU), Chengdu, 610041, China.
Insights
Phase Angle (PhA) changes earlier than motor function in Duchenne muscular dystrophy (DMD) boys, correlating strongly with disease progression. Leg PhA is a sensitive, non-invasive tool for predicting lower limb motor function loss in DMD.
Area of Science:
- Biophysics
- Neurology
- Pediatrics
Background:
- Duchenne muscular dystrophy (DMD) is a progressive genetic disorder causing muscle degeneration.
- Phase Angle (PhA) reflects cell membrane integrity and has potential as a biomarker in neuromuscular diseases.
- Limited research exists on PhA's utility in pediatric neuromuscular conditions like DMD.
Purpose of the Study:
- To investigate the correlation between segmental Phase Angles (PhAs) and motor function in children with DMD.
- To evaluate the effectiveness of segmental PhAs as a measure for assessing motor function in DMD.
- To identify novel biological indicators for tracking clinical progress in DMD.
Main Methods:
- Retrospective longitudinal cohort study of 399 boys with DMD (2016-2023).
- Spearman correlation analysis to assess the relationship between PhA and motor function (NSAA score).
- ROC curve analysis to determine the predictive value of PhA and PhA combined with age for lower limb motor function loss.
Main Results:
- Segmental PhAs peak earlier (5-6 years) than motor function decline (NSAA score peak 6-7 years).
- Strong significant correlation found between PhAs and NSAA score, particularly leg PhA (r=0.753).
- Leg PhA showed the highest predictive value for lower limb motor function loss (AUC 0.725-0.863); combined with age, predictive ability improved significantly (AUC 0.929-0.951).
Conclusions:
- Phase Angle (PhA) changes precede motor function decline in DMD, indicating its sensitivity as a progression marker.
- PhA demonstrates a strong correlation with motor function and can predict disease progression in DMD.
- PhA offers a simple, rapid, and non-invasive method for predicting lower limb motor function loss in children with DMD.
Background:
Duchenne muscular dystrophy (DMD) is a recessive muscle degeneration disorder that involves the gradual loss of functional muscle mass. The Phase Angle (PhA) can indicate changes in cell membrane integrity and intercellular space. It has been recognized as a valuable tool for assessing disease severity and predicting patient outcomes. However, there is limited research on the application of PhA in children with neuromuscular diseases, including DMD.
Objective:
More biological indicators are needed to reflect clinical progress in DMD children. We specifically examined the correlation between segmental PhAs and motor function and evaluated the effectiveness of segmental PhAs as a measure for assessing motor function in DMD children.
Methods:
A retrospective longitudinal cohort study of 399 boys with DMD in West China Second University Hospital (2016-2023) was performed. The correlation between PhA and motor function were analyzed through spearman correlation analysis. The predictive value of PhA and PhA combining age for lower limb motor function loss was analyzed by ROC curve.
Results:
The time of peak of PhAs are earlier than NSAA score (peak at 6-7years old). The Trunk Phase Angle (TR-PhA) reaches its peak at 6 years old, while other PhAs reaches its peak at 5-6 years old and subsequently declines over time. There was a significant correlation between PhAs and the NSAA score, with the strongest correlation observed in leg PhA (r = 0.753, P < 0.001). PhAs in legs demonstrate the strongest correlation and highest predictive value for lower limb motor function loss(AUC from 0.725 to 0.863). Additionally, PhAs combined with age had more excellent predictive ability for lower limb function loss than PhAs((AUC from 0.929 to 0.951).
Conclusion:
1) The phase Angle (PhA) increases first and then decreases with the progression of DMD disease; the phase Angle (PhA) changes earlier than motor function and presents a good correlation, which is a sensitive index to predict the progression of DMD disease. PhA could serve as a simple, fast, and non-invasive tool for predicting the loss of lower limb motor function in DMD children.
