title: The interobserver and test-retest variability of the dysphonia severity index.
abstract: OBJECTIVE
  The purpose of this study was to investigate the interobserver variability and the test-retest variability of the Dysphonia Severity Index (DSI), a multiparametric instrument to assess voice quality.
  
  
  METHODS
  The DSI was measured in 30 nonsmoking volunteers without voice complaints or voice disorders by two speech pathologists. The subjects were measured on 3 different days, with an interval of 1 week.
  
  
  RESULTS
  The difference in DSI between two observers (interobserver difference) was not significant. The intraclass correlation coefficient for the DSI was 0.79. The standard deviation of the difference between two duplicate measurements by different observers was 1.27.
  
  
  CONCLUSIONS
  Differences in measurements between different observers were not significant. The intraclass correlation coefficient of the DSI was 0.79, which is to be considered good. Differences in DSI within one patient need to be larger than 2.49 to be significant.
authors.affiliation: Department of Otorhinolaryngology, Erasmus MC-University Medical Center Rotterdam, The Netherlands.
authors.forename: Marieke M
authors.initials: MM
authors.lastname: Hakkesteegt
authors.forename: Marjan H
authors.initials: MH
authors.lastname: Wieringa
authors.forename: Michael P
authors.initials: MP
authors.lastname: Brocaar
authors.forename: Paul G H
authors.initials: PG
authors.lastname: Mulder
authors.forename: Louw
authors.initials: L
authors.lastname: Feenstra
mesh_terms: D000328:Adult; D005260:Female; D006801:Humans; D008297:Male; D015588:Observer Variation; D010700:Phonetics; D012016:Reference Values; D015203:Reproducibility of Results; D012720:Severity of Illness Index; D013061:Speech Acoustics; D013068:Speech Production Measurement; D013066:Speech-Language Pathology; D014832:Voice Disorders / Q000175:diagnosis*; D014833:Voice Quality