Vocal Tremor Analysis With the Vocal Demodulator Acoustic analysis of vocal tremor has the potential to make significant quantitative and diagnostic contributions to the study of vocal disorders. This paper presents a new device for analysis of vocal tremor. The Vocal Demodulator produces amplitude- and frequency-demodulated outputs and measures the frequency and level (percent) of low-frequency tremor ... Research Article
Research Article  |   June 01, 1992
Vocal Tremor Analysis With the Vocal Demodulator
 
Author Affiliations & Notes
  • William S. Winholtz
    Recording and Research Center Denver, CO
  • Lorraine Olson Ramig
    Department of Communication Disorders and Speech Science University of Colorado-Boulder, and Recording and Research Center Denver, CO
Article Information
Speech / Research Articles
Research Article   |   June 01, 1992
Vocal Tremor Analysis With the Vocal Demodulator
Journal of Speech, Language, and Hearing Research, June 1992, Vol. 35, 562-573. doi:10.1044/jshr.3503.562
History: Received February 4, 1991 , Accepted September 23, 1991
 
Journal of Speech, Language, and Hearing Research, June 1992, Vol. 35, 562-573. doi:10.1044/jshr.3503.562
History: Received February 4, 1991; Accepted September 23, 1991

Acoustic analysis of vocal tremor has the potential to make significant quantitative and diagnostic contributions to the study of vocal disorders. This paper presents a new device for analysis of vocal tremor. The Vocal Demodulator produces amplitude- and frequency-demodulated outputs and measures the frequency and level (percent) of low-frequency tremor components in sustained phonation. A standard microphone is used to transduce the voice signal for input to the demodulator. The input fundamental frequency (Fo) range is 70–1200 Hz, and frequency response of the amplitude and frequency demodulation is 2.5–25 Hz. Five parameters are displayed in real time: Fo, amplitude-modulation frequency, amplitude-modulation level, frequency-modulation frequency, and frequency-modulation level. Validation, calibration, and reliability data from synthesized test signals with modulation, as well as phonation from subjects with vocal tremor, subjects producing vibrato, and subjects with normal voice are presented. Research and clinical applications of this device are suggested.

Acknowledgments
The authors thank Ingo Titze and Ron Scherer for their helpful review of an earlier manuscript of this paper. Manuscript preparation was supported in part by NIH grant R01 DC01150-01. Application of the demodulator was supported in part by NIH grant R01 DC00387-04. The data presented here were supported in part by OE-NIDRR grant H133G00079.
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