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Brainstem pathology in spasmodic dysphonia
Kristina Simonyan1, Christy L Ludlow, Alexander O Vortmeyer
1Laryngeal and Speech Section, Medical Neurology Branch, National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, Maryland 20814-1416, USA. simonyak@ninds.nih.gov
Abstract:
Spasmodic dysphonia (SD) is a primary focal dystonia of unknown pathophysiology, characterized by involuntary spasms in the laryngeal muscles during speech production. We examined two rare cases of postmortem brainstem tissue from SD patients compared to four controls. In the SD patients, small clusters of inflammation were found in the reticular formation surrounding solitary tract, spinal trigeminal, and ambigual nuclei, inferior olive, and pyramids. Mild neuronal degeneration and depigmentation were observed in the substantia nigra and locus coeruleus. No abnormal protein accumulations and no demyelination or axonal degeneration were found. These neuropathological findings may provide insights into the pathophysiology of SD.
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