Effect of Duration of Pitch-Shifted Feedback on Vocal Responses in Patients With Parkinson's Disease Study of the pitch-shift reflex is useful for the investigation of how auditory feedback is used in the control of voice fundamental frequency. The present study was an attempt to learn if the basal ganglia are involved in central mechanisms of the pitch-shift reflex by comparing measures of the reflex ... Research Article
Research Article  |   October 01, 2001
Effect of Duration of Pitch-Shifted Feedback on Vocal Responses in Patients With Parkinson's Disease
 
Author Affiliations & Notes
  • Swathi Kiran
    Department of Communication Sciences and Disorders Speech Physiology Laboratory Northwestern University Evanston, IL
  • Charles R. Larson
    Department of Communication Sciences and Disorders Speech Physiology Laboratory Northwestern University Evanston, IL
  • Contact author: Swathi Kiran, PhD, Speech Language Pathology, Communication Sciences and Disorders, Northwestern University, Evanston, IL
    Contact author: Swathi Kiran, PhD, Speech Language Pathology, Communication Sciences and Disorders, Northwestern University, Evanston, IL×
  • Corresponding author: E-mail: s-kiran@northwestern.edu
Article Information
Special Populations / Older Adults & Aging / Speech, Voice & Prosody / Speech / Research Articles
Research Article   |   October 01, 2001
Effect of Duration of Pitch-Shifted Feedback on Vocal Responses in Patients With Parkinson's Disease
Journal of Speech, Language, and Hearing Research, October 2001, Vol. 44, 975-987. doi:10.1044/1092-4388(2001/076)
History: Received February 21, 2001 , Accepted April 24, 2001
 
Journal of Speech, Language, and Hearing Research, October 2001, Vol. 44, 975-987. doi:10.1044/1092-4388(2001/076)
History: Received February 21, 2001; Accepted April 24, 2001
Web of Science® Times Cited: 18

Study of the pitch-shift reflex is useful for the investigation of how auditory feedback is used in the control of voice fundamental frequency. The present study was an attempt to learn if the basal ganglia are involved in central mechanisms of the pitch-shift reflex by comparing measures of the reflex in a group of Parkinson's disease patients with those measures in a group of control participants. The effect of varying duration of the pitch-shift stimulus (PSS) on the voice fundamental frequency (F0) response in 10 Parkinson's disease (PD) patients and 10 age-matched unaffected participants was investigated. Participants were instructed to vocalize into a microphone while their voice was fed back to them over headphones. This feedback of the vocal signal was shifted in pitch either up or down, with the duration of this shift systematically manipulated at 100 ms, 500 ms, and 1000 ms. Although the participants were on medication, making interpretation of the results problematic with regard to basal ganglia function, it was reasoned that positive effects could nevertheless suggest basal ganglia involvement in this reflex and motivate further research. Results indicated that both groups responded to increased stimulus duration of the pitch-shift stimulus with increases in reflex peak time, magnitude, and end times. However, PD patients had significantly longer peak times and end times than control participants for stimulus durations of 100 ms. These results suggest that basal ganglia dysfunction may affect mechanisms relating to the execution and termination of the pitch-shift reflex for brief stimulus durations. The results also support hypotheses of impaired sensory integration of auditory feedback in PD patients.

Acknowledgments
This research was supported by NIH Grant No. DC02764. Our thanks to Mr. Rokny Akhavein for development of software routines used in the data analysis.
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