title: Perceptual structure of adductor spasmodic dysphonia and its acoustic correlates.
abstract: OBJECTIVE
  To examine the perceptual structure of voice attributes in adductor spasmodic dysphonia (ADSD) before and after botulinum toxin treatment and identify acoustic correlates of underlying perceptual factors. Reliability of perceptual judgments is considered in detail.
  
  
  METHODS
  Pre- and posttreatment trial with comparison to healthy controls, using single-blind randomized listener judgments of voice qualities, as well as retrospective comparison with acoustic measurements.
  
  
  METHODS
  Oral readings were recorded from 42 ADSD speakers before and after treatment as well as from their age- and sex-matched controls. Experienced judges listened to speech samples and rated attributes of overall voice quality, breathiness, roughness, and brokenness, using computer-implemented visual analog scaling. Data were adjusted for regression to the mean and submitted to principal components factor analysis. Acoustic waveforms, extracted from the reading samples, were analyzed and measurements correlated with perceptual factor scores.
  
  
  RESULTS
  Four reliable perceptual variables of ADSD voice were effectively reduced to two underlying factors that corresponded to hyperadduction, most strongly associated with roughness, and hypoadduction, most strongly associated with breathiness. After treatment, the hyperadduction factor improved, whereas the hypoadduction factor worsened. Statistically significant (P<0.01) correlations were observed between perceived roughness and four acoustic measures, whereas breathiness correlated with aperiodicity and cepstral peak prominence (CPPs).
  
  
  CONCLUSIONS
  This study supported a two-factor model of ADSD, suggesting perceptual characterization by both hyperadduction and hypoadduction before and after treatment. Responses of the factors to treatment were consistent with previous research. Correlations among perceptual and acoustic variables suggested that multiple acoustic features contributed to the overall impression of roughness. Although CPPs appears to be a partial correlate of perceived breathiness, a physical basis of this percept remained less clear.
authors.affiliation: School of Audiology and Speech-Language Pathology, The University of Memphis, Memphis, Tennessee 38105, USA. mcannito@memphis.edu
authors.forename: Michael P
authors.initials: MP
authors.lastname: Cannito
authors.forename: Maki
authors.initials: M
authors.lastname: Doiuchi
authors.forename: Thomas
authors.initials: T
authors.lastname: Murry
authors.forename: Gayle E
authors.initials: GE
authors.lastname: Woodson
mesh_terms: D000162:Acoustics; D000328:Adult; D000368:Aged; D000704:Analysis of Variance; D001905:Botulinum Toxins / Q000627:therapeutic use; D055154:Dysphonia / Q000175:diagnosis* / Q000188:drug therapy / Q000503:physiopathology / Q000523:psychology; D005260:Female; D006801:Humans; D007828:Laryngoscopy; D008297:Male; D008875:Middle Aged; D015588:Observer Variation; D011237:Predictive Value of Tests; D025341:Principal Component Analysis; D015203:Reproducibility of Results; D012815:Signal Processing, Computer-Assisted; D016037:Single-Blind Method; D013018:Sound Spectrography; D013061:Speech Acoustics; D013067:Speech Perception; D013068:Speech Production Measurement; D016896:Treatment Outcome; D014833:Voice Quality; D055815:Young Adult
chemical_list: D001905:Botulinum Toxins