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Gradations in a pattern of neuromuscular activity associated with stuttering
1Department of Audiology and Speech Sciences Purdue University, West Lafayette, IN.
Journal of Speech and Hearing Research
|December 1, 1992
Summary
Stuttering may involve tremor-like muscle activity (EMGs) in the lip, jaw, and neck. This study found varying patterns of muscle oscillations and amplitudes, suggesting no single physiological cause for stuttering in all individuals.
Area of Science:
- Neuroscience
- Speech-language pathology
- Biomedical engineering
Background:
- Stuttering is a complex speech disorder with debated physiological underpinnings.
- Understanding the motor control aspects of stuttering is crucial for developing effective interventions.
Purpose of the Study:
- To investigate the electromyographic (EMG) activity patterns in lip, jaw, and neck muscles during conversational speech in individuals who stutter.
- To determine if specific oscillatory patterns and muscle activation amplitudes correlate with stuttered speech events.
Main Methods:
- Electromyography (EMG) recordings were obtained from lip, jaw, and neck muscles of 17 participants who stutter.
- Averaged power spectra and coherence analyses were computed for pairs of EMG signals.
- Motor patterns were analyzed across a continuum, from low to high amplitude oscillations.
Main Results:
- Tremor-like oscillations (5-15 Hz) and high EMG amplitudes were observed in a continuum of motor patterns associated with stuttering.
- Individuals with more pronounced oscillations and higher coherence at the oscillation frequency exhibited more distinctly stuttered speech.
- In some individuals, stuttered and fluent speech showed similar EMG amplitudes, indicating variability in physiological manifestations.
Conclusions:
- The physiological events characterizing stuttering are not uniform across all individuals.
- High-amplitude oscillations and other motor patterns occur with varying intensity in different people who stutter.
- This suggests a spectrum of motor control differences rather than a single etiological factor for stuttering.
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