Data_Dictionary

Data Dictionary:
ATTRIBUTE INFORMATION:

    subject# - Integer that uniquely identifies each subject
    age - Subject age
    sex - Subject gender '0' - male, '1' - female
    test_time - Time since recruitment into the trial. The integer part is the number of days since recruitment.
    motor_UPDRS - Clinician's motor UPDRS score with real scores at baseline, 3 month, and 6 month, linearly interpolated
    total_UPDRS - Clinician's total UPDRS score with real scores at baseline, 3 month, and 6 month, linearly interpolated
    Jitter - variations in fundamental frequency between pitch periods
    Jitter(%),Jitter(Abs),Jitter:RAP,Jitter:PPQ5,Jitter:DDP - Several measures of variation in fundamental frequency
    Shimmer - amplitude - variations in speech amplitude between pitch periods
    Shimmer,Shimmer(dB),Shimmer:APQ3,Shimmer:APQ5,Shimmer:APQ11,Shimmer:DDA - Several measures of variation in amplitude
    NHR,HNR - Two measures of ratio of noise to tonal components in the voice (H - harmonics or tonal components and also called signal, N - noise).
    RPDE - A nonlinear dynamical complexity measure. Stands for Recurrence Period Density Entropy
        Addresses ability of vocal folds to sustain simple vibration and quantifies the deviations from exact periodicity.
        Represents uncertainty of measurement of exact period for the signal
        Dysphonias (horseness and crackiness) usually increase RPDE
    DFA - Signal fractal scaling exponent.
        Characterizes extent of turbulent noise in the speech signal. Quantifies similar randomess in noise that is due to sporadic air flow through the vocal tract
        Breathiness dysphonias increase this metric
    PPE - A nonlinear measure of fundamental frequency variation. Stands for Pitch Period Entropy
        Measures impaired control of stable pitch during sustained phonation
        Significantly distinguishes between healthy and PD-impaired speech

Supporting terminology:

    F0 - fundamental frequency whic is the vibration frequency of the vocal folds (men ~120 hz, female ~200hz)
    pitch period - inverse of F0, and duration of fundamental frequency. Used to for feature creation by finding min and max amplitudes of speech within a pitch period