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Electromyography in congenital nemaline myopathy
C Wallgren-Pettersson1, K Sainio, T Salmi
1Children's Hospital, University of Helsinki, Finland.
Muscle & Nerve
|July 1, 1989
Summary
Electromyography (EMG) in congenital nemaline myopathy (CNM) shows progressive abnormalities with age, including neuropathic features. These findings clarify earlier conflicting reports and suggest active muscle fiber degeneration and regeneration in CNM.
Area of Science:
- Neurology
- Clinical Electrophysiology
- Myology
Background:
- Congenital nemaline myopathy (CNM) presents with variable electromyography (EMG) findings.
- Earlier reports on EMG in CNM show discrepancies, necessitating further investigation.
Purpose of the Study:
- To clarify conflicting electromyography (EMG) findings in congenital nemaline myopathy (CNM).
- To investigate the progression of EMG abnormalities in CNM patients over time.
Main Methods:
- Conventional electromyography (EMG) performed on 13 CNM patients.
- Comparison with 18 prior EMG examinations of the same patients.
- Computerized fiber density analysis and single-fiber EMG for neuromuscular jitter.
Main Results:
- EMG abnormalities progressed with age, showing "neuropathic" features in distal muscles.
- Increased fiber density observed in 90% of patients.
- Abnormal neuromuscular jitter detected in 2 out of 3 patients.
- Normal motor and sensory nerve conduction velocities in all patients.
Conclusions:
- The study explains previously conflicting EMG reports in CNM.
- Findings suggest active muscle fiber degeneration and regeneration occur in CNM.
- "Neuropathic" motor unit potentials may be secondary to myopathic disease activity.