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Updated: Jul 8, 2026
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Infant Auditory Processing and Event-related Brain Oscillations
Published on: July 1, 2015
Normal intracortical excitability in developmental stuttering
Martin Sommer1, Stephan Wischer, Frithjof Tergau
1Department of Clinical Neurophysiology, University of Göttingen, Göttingen, Germany. msommer@gwdg.de
Summary
Persistent developmental stuttering (PDS) shows normal intracortical excitability, unlike task-specific dystonias. Increased motor thresholds in PDS suggest reduced cortical neuronal membrane excitability, not weakened inhibition.
Area of Science:
- Neuroscience
- Speech-Language Pathology
Background:
- Persistent developmental stuttering (PDS) exhibits clinical similarities to task-specific dystonias.
- Task-specific dystonias are characterized by abnormally weak intracortical inhibition.
Purpose of the Study:
- To investigate intracortical inhibition and facilitation in individuals with PDS.
- To compare cortical excitability in PDS with speech-fluent controls.
Main Methods:
- Transcranial magnetic stimulation (TMS) was used to assess motor cortical excitability.
- Resting and active motor thresholds, intracortical inhibition, and facilitation were measured in the abductor digiti minimi muscle representation.
- 18 subjects with PDS and 18 controls participated.
Main Results:
- Individuals with PDS had increased resting and active motor thresholds compared to controls.
- Intracortical inhibition and facilitation were found to be normal in PDS.
- These findings suggest reduced motor cortical neuronal membrane excitability in PDS.
Conclusions:
- Normal intracortical excitability in PDS makes a direct pathophysiological analogy with focal dystonia less likely.
- The elevated motor threshold in PDS indicates altered cortical excitability, potentially related to membrane properties rather than inhibitory circuits.
