title: Discriminating simulated vocal tremor source using amplitude modulation spectra.
abstract: OBJECTIVE
  Sources of vocal tremor are difficult to categorize perceptually and acoustically. This article describes a preliminary attempt to discriminate vocal tremor sources through the use of spectral measures of the amplitude envelope. The hypothesis is that different vocal tremor sources are associated with distinct patterns of acoustic amplitude modulations.
  
  
  METHODS
  Statistical categorization methods (discriminant function analysis) were used to discriminate signals from simulated vocal tremor with different sources using only acoustic measures derived from the amplitude envelopes.
  
  
  METHODS
  Simulations of vocal tremor were created by modulating parameters of a vocal fold model corresponding to oscillations of respiratory driving pressure (respiratory tremor), degree of vocal fold adduction (adductory tremor), and fundamental frequency of vocal fold vibration (F0 tremor). The acoustic measures were based on spectral analyses of the amplitude envelope computed across the entire signal and within select frequency bands.
  
  
  RESULTS
  The signals could be categorized (with accuracy well above chance) in terms of the simulated tremor source using only measures of the amplitude envelope spectrum even when multiple sources of tremor were included.
  
  
  CONCLUSIONS
  These results supply initial support for an amplitude-envelope-based approach to identify the source of vocal tremor and provide further evidence for the rich information about talker characteristics present in the temporal structure of the amplitude envelope.
authors.affiliation: Department of Speech, Language, and Hearing Sciences, University of Arizona, Tucson, Arizona. Electronic address: kathyc@email.arizona.edu.
authors.forename: Kathy M
authors.initials: KM
authors.lastname: Carbonell
authors.affiliation: Department of Speech, Language, and Hearing Sciences, University of Arizona, Tucson, Arizona.
authors.forename: Rosemary A
authors.initials: RA
authors.lastname: Lester
authors.affiliation: Department of Speech, Language, and Hearing Sciences, University of Arizona, Tucson, Arizona.
authors.forename: Brad H
authors.initials: BH
authors.lastname: Story
authors.affiliation: Department of Speech, Language, and Hearing Sciences, University of Arizona, Tucson, Arizona.
authors.forename: Andrew J
authors.initials: AJ
authors.lastname: Lotto
mesh_terms: D006801:Humans; D013061:Speech Acoustics; D013068:Speech Production Measurement / Q000379:methods; D014827:Vocal Cords / Q000503:physiopathology*; D014832:Voice Disorders / Q000503:physiopathology*; D014833:Voice Quality / Q000502:physiology*
keywords: Acoustic analysis; Envelope modulation spectra; Vocal tremor