Short-Latency Changes in Voice F0 and Neck Surface EMG Induced by Mechanical Perturbations of the Larynx During Sustained Vowel Phonation Nineteen healthy young adult males with normal voice and speech attempted to sustain the vowel /u/ at a constant pitch (target: 180 Hz) and a constant and comfortable loudness level while receiving a sudden mechanical perturbation to the larynx (thyroid prominence) via a servo-controlled probe. The probe moved toward or ... Research Article
Research Article  |   February 01, 2000
Short-Latency Changes in Voice F0 and Neck Surface EMG Induced by Mechanical Perturbations of the Larynx During Sustained Vowel Phonation
 
Author Affiliations & Notes
  • Shimon Sapir
    The Wilbur James Gould Voice Research Center The Denver Center for the Performing Arts Denver, CO
  • Kristin K. Baker
    The Wilbur James Gould Voice Research Center The Denver Center for the Performing Arts Denver, CO
  • Charles R. Larson
    Northwestern University Evanston, IL
  • Lorraine Olson Ramig
    University of Colorado Boulder and The Wilbur James Gould Voice Research Center The Denver Center for the Performing Arts Denver, CO
  • Corresponding author: e-mail: ssapir@star.dcpa.org
Article Information
Speech, Voice & Prosody / Speech / Research Articles
Research Article   |   February 01, 2000
Short-Latency Changes in Voice F0 and Neck Surface EMG Induced by Mechanical Perturbations of the Larynx During Sustained Vowel Phonation
Journal of Speech, Language, and Hearing Research, February 2000, Vol. 43, 268-276. doi:10.1044/jslhr.4301.268
History: Received April 9, 1999 , Accepted July 14, 1999
 
Journal of Speech, Language, and Hearing Research, February 2000, Vol. 43, 268-276. doi:10.1044/jslhr.4301.268
History: Received April 9, 1999; Accepted July 14, 1999

Nineteen healthy young adult males with normal voice and speech attempted to sustain the vowel /u/ at a constant pitch (target: 180 Hz) and a constant and comfortable loudness level while receiving a sudden mechanical perturbation to the larynx (thyroid prominence) via a servo-controlled probe. The probe moved toward or away from the larynx in a ramp-and-hold fashion (3.3-mm displacement, 0.7 N force, 20-ms rise time, 250-ms duration) as the subjects attempted to maintain a constant probe-larynx pressure. Eighty stimuli were applied in each direction, one stimulus per phonation. Pairs of surface electromyography (EMG) electrodes were attached to the skin of the anterior neck over laryngeal, infralaryngeal, and supralaryngeal areas. The rectified EMG signals, the voltage analog of the voice fundamental frequency (VAF0), and the voltage analog of the probe displacement were digitized and signal-averaged relative to the onset of the stimulus. Sudden perturbation of the larynx induced an instantaneous decrease or increase in VAF0, depending on the direction of the probe's movement, and a short-latency increase in the EMG (30–35 ms) and VAF0 (55–65 ms). We argue that the instantaneous VAF0 change was related to a mechanical effect, and the short-latency VAF0 and EMG changes to reflexogenic effects—the latter most likely associated with both intrinsic and extrinsic laryngeal sensorimotor mechanisms. Further physiological studies are needed to elucidate the sources of the VAF0 and EMG responses. Once elucidated, the present method may provide a powerful noninvasive tool for studying laryngeal neurophysiology. The theoretical and clinical implications of the present findings are addressed.

KEY WORDS: voice, physiology, reflexes, speech, noninvasive

Acknowledgments
This research was supported by grants #R29 DC00591-01A1 and #R01 DC01150 from the National Institute on Deafness and Other Communication Disorders.
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