Appendix A:
List of voice parameters extracted by the Multi-Dimensional Voice Program (MDVP) and GRBAS scale.
Parameters
1. Acoustic parameters
1) Fundamental frequency measurements
Average fundamental frequency (F0)
Symbols
Definition
Hz
Average value of all extracted period-to-period fundamental
frequency values. Voice break areas are excluded.
2) Frequency perturbation measurements
Jitter percent (Jitt)
%
Relative evaluation of the period-to-period (very short-term)
variability of the pitch within the analyzed voice sample. Voice
break areas are excluded.
3) Amplitude perturbation measurements
Shimmer percent (Shim)
%
Relative evaluation of the period-to-period (very short term)
variability of the peak-to-peak amplitude within the analyzed
voice sample. Voice break areas are excluded.
4) Noise-related measurements
Noise-to-harmonic ratio (NHR)
-
Average ratio of the inharmonic spectral energy to the
harmonic spectral energy in the frequency range 70-4200 Hz.
This is a general evaluation of noise present in the analyzed
signal.
5) Tremor-related measurements
Fo-tremor intensity index (FTRI)
%
Average ratio of the frequency magnitude of the most intensive
low-frequency modulating component (Fo-tremor) to the total
frequency magnitude of the analyzed voice signal.
Amplitude tremor intensity index (ATRI)
%
Average ratio of the amplitude of the most intense
low-frequency amplitude modulating component (amplitude
tremor) to the total amplitude of the analyzed voice signal.
6) Subharmonic component-related measurements
Degree of subharmonic (DSH)
%
Estimated relative evaluation
components in the voice sample.
7) Voice irregularity-related measurements
Degree of voiceless (DUV)
%
Estimated relative evaluation of non-harmonic areas (where Fo
cannot be detected) in the voice sample.
2. Perceptual parameters
Grade of hoarseness (G)
-
Roughness voice (R)
Breathiness voice (B)
Asthenia voice (A)
Strained voice (S)
-
The G scale is quantitative in nature and reflects the overall
impression of abnormality in voice.
Voice is harsh, rough, and raspy.
Continuously breathy, and thin.
Voice is weakness.
Voice (phonation) sounds strained or strangled (an apparently
effortful squeezing of voice through glottis).
of
subharmonic
to
Fo