Comparison of 3 instruments to measure muscle strength in children: A prospective study

Area of Science:

• Pediatric Neurology
• Clinical Diagnostics
• Musculoskeletal Research

Background:

• Accurate muscle strength assessment is crucial for diagnosing pediatric myopathies.
• Current diagnostic procedures for suspected myopathy in children can be invasive and burdensome.
• Identifying reliable, non-invasive tools is essential to improve diagnostic accuracy and patient care.

Purpose of the Study:

• To determine the most valid and reliable instrument for measuring muscle strength in children aged 4-11 years.
• To evaluate the potential of different instruments in improving the diagnostic procedure for suspected myopathy.
• To reduce the need for muscle biopsy in children by enhancing diagnostic capabilities.

Main Methods:

• Prospective study involving 22 children (aged 4-11 years) with suspected myopathy.
• Comparison of three muscle strength assessment tools: hand-held dynamometry, Jamar dynamometer, and a novel Motor Performance Test.
• Validity assessed using logistic regression and receiver operating characteristic (ROC) analysis, with Area Under the Curve (AUC) as a measure of diagnostic power.

Main Results:

• The Motor Performance Test demonstrated the highest validity in distinguishing between children with and without myopathy.
• Hand-held dynamometry showed lower validity and significant variability across muscle groups.
• The Jamar dynamometer exhibited very low validity, particularly in early-stage myopathy.

Conclusions:

• The Motor Performance Test is the most valid and reliable instrument for identifying myopathy in pediatric patients.
• This objective, non-invasive, and child-friendly test can enhance diagnostic procedures.
• Implementation of the Motor Performance Test may help exclude more children without myopathy from undergoing muscle biopsy.