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Abnormal parasympathetic vagal function in patients with spasmodic dysphonia.
Annals of Internal Medicine
|April 1, 1984
Summary
Patients with spasmodic dysphonia exhibit impaired gastric and cardiac vagal function, suggesting potential central nervous system or cranial nerve abnormalities. These findings highlight the complex neurological underpinnings of this voice disorder.
Area of Science:
- Neurology
- Gastroenterology
- Otolaryngology
Background:
- Spasmodic dysphonia is a voice disorder characterized by involuntary spasms of the vocal cords.
- The role of the vagus nerve in spasmodic dysphonia is not fully understood.
Purpose of the Study:
- To investigate gastric and cardiac vagal function in patients with spasmodic dysphonia.
- To explore potential central nervous system or cranial nerve involvement.
Main Methods:
- Gastric acid output was measured in response to sham feeding.
- Cardiac vagal function was assessed via heart rate variability during deep respiration and Valsalva maneuver.
- Auditory brainstem response was evaluated.
Main Results:
- Patients showed significantly reduced gastric acid secretion compared to controls.
- Reduced heart rate fluctuation during deep respiration (sinus arrhythmia) was observed.
- Impaired heart rate response during and after the Valsalva maneuver was noted.
- Abnormal auditory brainstem responses were found in a majority of patients.
Conclusions:
- Findings suggest impaired gastric and cardiac vagal function in spasmodic dysphonia.
- Results indicate possible central brainstem or cranial nerve abnormalities.
- Further research is warranted to elucidate the precise neurological mechanisms.
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