AHI	Apnea/hypopnea index
BMI	Body mass index
ECG	Electrocardiogram
EDF	European data format
ESS	Epworth sleepiness scale
HF	High frequency
HRV	Heart rate variability
HRVi	Heart rate variability triangular index
IRRR	Inter-quartile range of the RR time series
KNN	k-nearest neighbour
LDA	Linear discriminant analysis
LF	Low frequency
LFHF	ratio of Low frequency on high frequency
MADRR	Median of the absolute values of the RR time series
pNN50	Proportion of interval differences of successive RR intervals greater than 50 ms
ODI	Oxygen desaturation index
OPLS	Orthogonal partial least squares
PCA	Principal Component analysis
PSG	Polysomnography
rMSSD	Root mean square of successive differences
ROC	Receiver operating characteristic
SA	Sleep apnea
SAS	Sleep apnea syndrome
SDNN	Standard deviation of the NN intervals
SVM	Support vector machine
ULF	Ultra low frequency
VLF	Very low frequency