Multidimensional Voice Program (MDVP) and amplitude variation parameters in euphonic adult subjects. Normative study.

The introduction, in the late 70s, of the first digital spectrograph (DSP Sonograph) by Kay Elemetrics has improved the possibilities of spectroacoustic voice analysis in the clinical field. Thanks to the marketing, in 1993, of the Multi Dimensional Voice Program (MDVP) advanced system, it is now possible to analyse 33 quantitative voice parameters which, in turn, allow evaluation of fundamental frequency, amplitude and spectral energy balance and the presence of any sonority gap and diplophony. Despite its potentials, the above-mentioned system is not widely used yet, partly on account of the lack of a standard procedure. Indeed, there are still only a few case reports in the literature taking into consideration prescriptive aspects related both to procedure and analysis. This study aims to provide the results of amplitude perturbation parameter analysis in euphonic adult patients. In our opinion, these are the most significant parameters in determining the severity of a phonation disorder. The study has been carried out on 35 patients (24 female, 11 male, mean age 31.6 years, range 19-59). The voice signal has been recorded using a 4300 B Kay Computer Speech Lab (CSL) supported by a personal computer including a SM48 Shure-Prolog microphone located at a distance of 15 cm and angled at 45 degrees. Input microphone saturation has been adjusted to 6/9 of the CH1 channel. The voice sample consisted in a held /a/ and the analysis has been carried out on the central 3 seconds of the recording. The analysis has been carried out using a 5105 MDVP software version 2.3 and the signal digitalised at a 50 kHz sample rate. In order for the sample to be as free from intensity or frequency changes as possible, each patient underwent a training session (including at least 3 phonation tests) before the recording. The study included only emissions between 55 and 65 dB and with spectrum stability. Environmental noise has constantly been monitored and maintained below 30 dB. Data from the 24 female patients showed: absolute Shimmer (ShdB) = 0.203 dB, relative shimmer (Shim %) = 2.226, amplitude perturbation quotient (APQ) = 1.758, smoothed amplitude perturbation quotient = 3.309, peak amplitude variation (vAm) = 7.042. Data from the 11 males showed: absolute Shimmer (ShdB) = 0.269 dB, relative shimmer (Shim %) = 2.892, amplitude perturbation quotient (APQ) = 2.611, smoothed amplitude perturbation quotient (SAPQ) = 3.433, peak amplitude variation (vAm) = 6.385. Statistical analysis (t test) showed no statistically significant difference between sexes, thus a single set of rules was used for both sexes.