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Muscle sounds in Parkinson's disease
1Medical Research Council Human Movement and Balance Unit, Institute of Neurology, London, UK.
Lancet (London, England)
|February 22, 1997
Summary
Parkinson's disease alters muscle sound, changing the Piper rhythm from 40-50 Hz to 10 Hz. Dopaminergic treatment restored normal muscle sound and improved motor function in patients.
Area of Science:
- Neurology
- Biophysics
- Motor Control
Background:
- Muscle activity during contraction produces a 40 Hz sound, known as the Piper rhythm.
- This acoustic signal correlates with electromyographic findings and may reflect cortical motor organization.
Purpose of the Study:
- To investigate the acoustic properties of muscle activity in Parkinson's disease patients.
- To determine if antiparkinsonian treatment affects the Piper rhythm.
Main Methods:
- Auscultation of wrist extensor muscles in seven Parkinson's patients and seven healthy controls.
- Assessment was performed during wrist extension and flexion-extension movements, with and without dopaminergic medication.
Main Results:
- Healthy individuals exhibited a 40-50 Hz Piper rhythm.
- Parkinson's patients off medication showed a 10 Hz muscle activity during strong wrist extension.
- Dopaminergic treatment normalized the Piper rhythm and improved motor performance.
Conclusions:
- The Piper rhythm is linked to the proper function of pallidal projections to motor cortex.
- Parkinson's disease disrupts this, leading to a dominant 10 Hz muscle discharge, impairing muscle function.
- Treatment restores normal muscle discharge patterns.