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A new motor performance test in a prospective study on children with suspected myopathy
Willeke A van den Beld1, Gitty A C van der Sanden, Ton Feuth
1Interdisciplinary Child Neurology Centre and Department of Rehabilitation Medicine, University Medical Centre Nijmegen St Radboud, Nijmegen, the Netherlands. w.vandenbeld@reval.umcn.nl
Insights
A new motor performance test can help diagnose myopathy in children, potentially avoiding painful muscle biopsies. This non-invasive approach assesses muscle strength and endurance, offering high diagnostic accuracy for early detection.
Area of Science:
- Pediatric Neurology
- Diagnostic Medicine
- Clinical Assessment
Background:
- Muscle biopsy is an invasive diagnostic procedure for suspected myopathy in children.
- There is a need for non-invasive, child-friendly diagnostic tools to assess muscle function.
Purpose of the Study:
- To develop and validate a novel motor performance test for diagnosing myopathy in pediatric patients.
- To assess the diagnostic accuracy of the developed test in differentiating children with and without myopathy.
Main Methods:
- A prospective study involving 22 pediatric patients with suspected myopathy.
- Development and refinement of a seven-item motor performance test measuring muscle strength and endurance.
- Logistic regression and receiver operating characteristic (ROC) analysis were used to assess validity and diagnostic power.
Main Results:
- A five-item motor performance test (Heels, Circuit, Stairs, Jump, Gowers) was finalized after excluding items unsuitable for younger children.
- The diagnostic prediction model demonstrated high accuracy, with an ROC area under the curve of 0.92 (95% CI 0.87-0.98).
- Bootstrap correction yielded an ROC area of 0.89 (95% CI 0.87-0.92), indicating robust diagnostic capability.
Conclusions:
- The developed motor performance test is a valid, non-invasive, and child-friendly tool for diagnosing myopathy.
- This test has the potential to significantly improve the diagnostic procedure for pediatric myopathy.
- Implementation of this test could spare children from undergoing unnecessary and painful muscle biopsies.
Abstract:
In the development of a new diagnostic motor performance test to spare more children from painful muscle biopsy, seven functional items were used to measure muscle strength and muscle endurance in a prospective study on new patients. Over a 2-year period, 22 patients (12 males, 10 females; mean age 8y 1mo [SD 2y 6mo], range 4-11y) were recruited for the study. They had all been referred with suspected myopathy. The motor performance test was administered before muscle biopsy. Validity of the seven items was assessed using logistic regression analysis and receiver operating characteristic (ROC) analysis. Two items were withdrawn from the test because they were not suitable for children aged 4 to 5 years. The five remaining items were: Heels, Circuit, Stairs, Jump, and Gowers. A full logistic regression model including these five items was fitted to the total population of 90 patients suspected of having myopathy (from this study and our previous study) to make the best prediction of whether myopathy was present. The ROC area under the curve of the diagnostic prediction model was 0.92 (95% confidence interval [CI] 0.87-0.98) and 0.89 (95% CI 0.87-0.92) after bootstrap correction. This indicated the high diagnostic power that can be expected for future, similar patients. This non-invasive and child-friendly motor performance test can improve diagnostic procedure and, therefore, spare more children from unnecessary muscle biopsy.
