Effects of Levodopa on Laryngeal Muscle Activity for Voice Onset and Offset in Parkinson Disease The laryngeal pathophysiology underlying the speech disorder in idiopathic Parkinson disease (IPD) was addressed in this electromyographic study of laryngeal muscle activity. This muscle activity was examined during voice onset and offset gestures in 6 persons in the early stages of IPD who were not receiving medication. The purpose was ... Research Article
Research Article  |   December 01, 2001
Effects of Levodopa on Laryngeal Muscle Activity for Voice Onset and Offset in Parkinson Disease
 
Author Affiliations & Notes
  • Sally Gallena
    Laryngeal and Speech Section Medical Neurology Branch National Institute of Neurological Disorders and Stroke Bethesda, MD
  • Paul J. Smith
    Mathematical Statistics Program Department of Mathematics University of Maryland College Park
  • Thomas Zeffiro
    Human Motor Control Section Medical Neurology Branch National Institute of Neurological Disorders and Stroke Bethesda, MD
  • Christy L. Ludlow
    Laryngeal and Speech Section Medical Neurology Branch National Institute of Neurological Disorders and Stroke Bethesda, MD
  • Corresponding author: e-mail: ludlowc@ninds.nih.gov
Article Information
Hearing Disorders / Special Populations / Genetic & Congenital Disorders / Older Adults & Aging / Attention, Memory & Executive Functions / Speech, Voice & Prosody / Speech / Research Articles
Research Article   |   December 01, 2001
Effects of Levodopa on Laryngeal Muscle Activity for Voice Onset and Offset in Parkinson Disease
Journal of Speech, Language, and Hearing Research, December 2001, Vol. 44, 1284-1299. doi:10.1044/1092-4388(2001/100)
History: Received October 30, 2000 , Accepted August 14, 2001
 
Journal of Speech, Language, and Hearing Research, December 2001, Vol. 44, 1284-1299. doi:10.1044/1092-4388(2001/100)
History: Received October 30, 2000; Accepted August 14, 2001
Web of Science® Times Cited: 54

The laryngeal pathophysiology underlying the speech disorder in idiopathic Parkinson disease (IPD) was addressed in this electromyographic study of laryngeal muscle activity. This muscle activity was examined during voice onset and offset gestures in 6 persons in the early stages of IPD who were not receiving medication. The purpose was to determine (a) if impaired voice onset and offset control for speech and vocal fold bowing were related to abnormalities in laryngeal muscle activity in the nonmedicated state and (b) if these attributes change with levodopa. Blinded listeners rated the IPD participants' voice onset and offset control before and after levodopa was administered. In the nonmedi-cated state, the IPD participants' vocal fold bowing was examined on nasoendo-scopy, and laryngeal muscle activity levels were compared with normal research volunteers. The IPD participants were then administered a therapeutic dose of levodopa, and changes in laryngeal muscle activity for voice onset and offset gestures were measured during the same session. Significant differences were found between IPD participants in the nonmedicated state:those with higher levels of muscle activation had vocal fold bowing and greater impairment in voice onset and offset control for speech. Similarly, following levodopa administration, those with thyroarytenoid muscle activity reductions had greater improvements in voice onset and offset control for speech. In this study, voice onset and offset control ifficulties and vocal fold bowing were associated with increased levels of aryngeal muscle activity in the absence of medication.

Acknowledgments
Junji Koda and Karen Rhew assisted with the conduct of the research. The authors gratefully acknowledge the participation of Julie Barkmeier, Julia Edgar, and Geralyn Schulz, who conducted the blinded speech ratings.
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