| Fo (Hz) |
Average vocal fundamental frequency |
| Fhi (Hz) |
Maximum vocal fundamental frequency |
| Flo (Hz) |
Minimum vocal fundamental frequency |
| Jitter (%) |
Jitter in percentage |
| Jitter (Abs) |
Absolute value |
| RAP |
Relative amplitude perturbation |
| PPQ |
Period perturbation quotient |
| DDP |
Difference of differences between cycles, divided by average period |
| Shimmer |
Local shimmer |
| Shimmer (dB) |
Shimmer in decibels |
| Shimmer:APQ3 |
Three point amplitude perturbation quotient |
| Shimmer:APQ5 |
Five point amplitude perturbation quotient |
| MDVP:APQ |
Amplitude perturbation quotient |
| Shimmer:DDA |
Average absolute difference between consecutive differences between amplitudes of consecutive periods |
| NHR |
Noise-to-harmonics ratio |
| HNR |
Harmonics-to-noise ratio |
| RPDE |
Recurrence period density entropy |
| DFA |
Detrended fluctuation analysis |
| Spread1 |
Nonlinear measure of fundamental frequency |
| Spread2 |
Nonlinear measure of fundamental frequency |
| D2 |
Correlation dimension |
| PPE |
Pitch period entropy |
