AUC	area under a curve
FreqD	dominant frequency
FreqHP	frequency of high-end spectra peak
HC	healthy controls
IQR	interquartile range
LR	logistic regression
MRI	magnetic resonance imaging
PD	Parkinson’s disease
RF	radiofrequency
RMS	root mean square
ROI	region of interest
ROC	receiver operating characteristic
RMS	root mean square
SD	standard deviation
SN	substantia nigra
TCS	transcranial sonography
UPDRS	the Unified Parkinson’s disease rating scale
US	ultrasound