Reliability of Opera VOX against Multidimensional Voice Program ( MDVP )

Objective To evaluate the agreement between Opera VOX and MDVP . Design Cross sectional reliability study. Setting University teaching hospital. Methods Fifty healthy volunteers and 50 voice disorder patients had supervised recordings in a quiet room using Opera VOX 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). Conclusion Opera VOX is comparable to MDVP and has high internal consistency for measuring the F0, jitter and shimmer of voice except for the NHR .