Related Experiment Video
Updated: Aug 11, 2026
Utility of Dissociated Intrinsic Hand Muscle Atrophy in the Diagnosis of Amyotrophic Lateral Sclerosis
Published on: March 4, 2014
Acoustic and surface EMG diagnosis of pediatric muscle disease
D T Barry1, K E Gordon, G G Hinton
1Department of Physical Medicine and Rehabilitation, University of Michigan Medical Center, Ann Arbor 48109-0042.
Insights
The ratio of acoustic myography (AMG) to surface electromyography (EMG) amplitude effectively distinguishes muscle disease in children. This non-invasive method shows significant diagnostic potential for pediatric neuromuscular conditions.
Area of Science:
- Biomedical Engineering
- Neurology
- Pediatrics
Background:
- Assessing muscle mechanical output relative to electrical activity is crucial for diagnosing neuromuscular disorders.
- Surface electromyography (sEMG) measures electrical activity, but a direct measure of mechanical output is needed for comprehensive assessment.
Purpose of the Study:
- To evaluate the ratio of acoustic myography (AMG) amplitude to surface electromyography (EMG) amplitude as a diagnostic marker for muscle disease in children.
- To compare AMG/EMG ratios in children with muscle disease to those in healthy children.
Main Methods:
- AMG and EMG amplitudes were recorded from 16 children diagnosed with muscle disease and 11 healthy children (ages 7-16).
- A linear discriminant function was used to establish normal AMG/EMG ratio ranges.
- Diagnostic accuracy was assessed using sensitivity and specificity.
Main Results:
- A significant difference (P < 0.01) was observed in AMG/EMG ratios between children with muscle disease and healthy controls.
- The linear discriminant function achieved 82% sensitivity and 91% specificity in diagnosing muscle disease.
- These findings indicate the potential of surface recordings for diagnosing muscle conditions.
Conclusions:
- The AMG/EMG amplitude ratio is a promising, non-invasive tool for diagnosing muscle disease in children.
- Surface recordings, particularly when combined with additional muscles or evoked twitches, may enhance diagnostic accuracy for pediatric neuromuscular conditions.
Abstract:
The ratio of acoustic myography (AMG) amplitude to surface electromyography (EMG) amplitude is proposed as a measure of mechanical output compared with electrical activity of the contractile system. AMG to EMG ratios were measured from 16 children with muscle disease diagnosed by clinical criteria, EMG, and/or muscle biopsy. These were compared with the ratios from 11 normal volunteers spanning the same age range (7-16 years). AMG to EMG ratios were significantly (P less than 0.01) different for the two populations. Using a linear discriminant function to define the normal range for AMG to EMG ratios yielded a sensitivity of 82% (13 of 16 abnormals diagnosed) and a specificity of 91% (10 of 11 normals). These findings suggest that surface recordings may provide significant diagnostic information in muscle disease. The accuracy may be improved further by using additional muscles (e.g., paraspinals) and evoked twitches.
Related Concept Videos
01:15Myasthenia Gravis: Diagnostic Tests
The edrophonium test is a diagnostic tool for myasthenia gravis. It involves...
01:28Disorders of the Skeletal Muscle
Musculoskeletal disorders
Musculoskeletal disorders involve injuries and conditions affecting the skeletal muscles and associated connective tissues. These disorders can arise from acute biomechanical stresses or chronic overuse and can occur across different age groups. Common injuries include sprains, fractures, and muscular strains, often resulting from...