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March 1991

Heterogeneity in Spasmodic Dysphonia: Neurologic and Voice Findings

Author Affiliations

From the Dallas (Tex) Center for Vocal Motor Control (Drs Pool, Freeman, Finitzo, Hayashi, Chapman, Devous, Close, Kondraske, Mendelsohn, Schaefer, and Watson); the Neuroscience Research Center (Drs Pool and Finitzo); The University of Texas at Dallas—Callier Center (Drs Freeman, Finitzo, Hayashi, Chapman, and Watson); the Departments of Radiology (Drs Devous and Mendelsohn) and Otolaryngology (Drs Close and Schaefer), The University of Texas Southwestern Medical Center at Dallas; and the Department of Biomedical Engineering, The University of Texas at Arlington (Dr Kondraske).

Arch Neurol. 1991;48(3):305-309. doi:10.1001/archneur.1991.00530150075021

• Spasmodic dysphonia is a disturbance of phonation with laryngeal spasms. We report voice and neurologic examination findings in 45 subjects. Neurologic abnormalities were found in 32 subjects (71.1%). Rapid alternating movement abnormalities, weakness, and tremor were common. Incoordination and spasticity were rare. Lower extremity findings were frequent. Abnormalities were bilateral. Spasmodic dysphonia severity was related to age. Type, severity, and duration of vocal symptoms were not different for subjects with or without neurologic abnormalities. Vocal tremor was more frequent in neurologically abnormal subjects. Involvement of a pallidothalamic—supplementary motor area system could account for neurologic findings, brain imaging findings, and clinical heterogeneity. The view emerging is that spasmodic dysphonia is a manifestation of disordered motor control involving systems of neurons rather than single anatomical sites.