title: Reliability of OperaVOX against Multidimensional Voice Program (MDVP).
abstract: OBJECTIVE
  To evaluate the agreement between OperaVOX and MDVP.
  
  
  METHODS
  Cross sectional reliability study.
  
  
  METHODS
  University teaching hospital.
  
  
  METHODS
  Fifty healthy volunteers and 50 voice disorder patients had supervised recordings in a quiet room using OperaVOX by the iPod's internal microphone with sampling rate of 45 kHz. A five-seconds recording of vowel/a/was used to measure fundamental frequency (F0), jitter, shimmer and noise-to-harmonic ratio (NHR). All healthy volunteers and 21 patients had a second recording. The recorded voices were also analysed using the MDVP. The inter- and intrasoftware reliability was analysed using intraclass correlation (ICC) test and Bland-Altman (BA) method. Mann-Whitney test was used to compare the acoustic parameters between healthy volunteers and patients.
  
  
  RESULTS
  Nine of 50 patients had severe aperiodic voice. The ICC was high with a confidence interval of >0.75 for the inter- and intrasoftware reliability except for the NHR. For the intersoftware BA analysis, excluding the severe aperiodic voice data sets, the bias (95% LOA) of F0, jitter, shimmer and NHR was 0.81 (11.32, -9.71); -0.13 (1.26, -1.52); -0.52 (1.68, -2.72); and 0.08 (0.27, -0.10). For the intrasoftware reliability, it was -1.48 (18.43, -21.39); 0.05 (1.31, -1.21); -0.01 (2.87, -2.89); and 0.005 (0.20, -0.18), respectively. Normative data from the healthy volunteers were obtained. There was a significant difference in all acoustic parameters between volunteers and patients measured by the Opera-VOX (P < 0.001) except for F0 in females (P = 0.87).
  
  
  CONCLUSIONS
  OperaVOX is comparable to MDVP and has high internal consistency for measuring the F0, jitter and shimmer of voice except for the NHR.
authors.affiliation: Ear Institute, University College London, London, UK; Royal National Throat Nose Ear Hospital, University College London Hospital NHS Trust, London, UK; Faculty of Medicine, Universiti Kebangsaan Malaysia, Kuala Lumpur, Malaysia.
authors.forename: M
authors.initials: M
authors.lastname: Mat Baki
authors.forename: G
authors.initials: G
authors.lastname: Wood
authors.forename: M
authors.initials: M
authors.lastname: Alston
authors.forename: P
authors.initials: P
authors.lastname: Ratcliffe
authors.forename: G
authors.initials: G
authors.lastname: Sandhu
authors.forename: J S
authors.initials: JS
authors.lastname: Rubin
authors.forename: M A
authors.initials: MA
authors.lastname: Birchall
mesh_terms: D000328:Adult; D003430:Cross-Sectional Studies; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D063731:Mobile Applications; D015203:Reproducibility of Results; D012737:Sex Factors; D013061:Speech Acoustics; D014832:Voice Disorders / Q000175:diagnosis* / Q000503:physiopathology*; D014833:Voice Quality / Q000502:physiology*