Systems and methods for quantitatively characterizing slow wave activities and states in sleep

A method for quantitative sleep characterization, comprising:

• acquiring a surface electroencephologram (surf-EEG) waveform from an individual by a probe;
• decomposing the surf-EEG signal into a plurality of intrinsic mode functions (IMFs) by a computer processor in communication with the probe, wherein the plurality of IMFs comprises a first group of IMFs and a second group of IMFs;
• calculating a ratio comprising a power of at least one of the IMFs in the first group in the numerator and a power of at least one of the IMFs in the second group in the denominator, wherein the power of an IMF is proportional to the square of the amplitude or intensity of the IMF;
• and
• identifying a period in the surf-EEG waveform as slow wave sleep (SWS) if the ratio associated with the period is above a predetermined threshold.

A method for quantitative sleep characterization, comprising:

• acquiring a surface electroencephologram (surf-EEG) signal from an individual by a probe;
• decomposing the surf-EEG signal into a plurality of intrinsic mode functions (IMFs) by a computer processor in communication with the probe;
• comparing, by the computer processor, an amplitude of at least one of the IMFs to an amplitude threshold (At) at a plurality of sampling points in a moving window;
• determining the number of sampling points in the moving window that have the amplitude of the least one of the IMFs above At;
• and
• identifying the moving window as slow wave sleep (SWS) if the number of sampling points having associated amplitudes above At is above an incidence threshold (Int) in the moving window.

A computer program product comprising a computer useable medium having computer readable program code functions embedded in said medium for causing a computer to:

• receive a surface electroencephologram (surf-EEG) signal acquired by a probe from an individual;
• decompose the surf-EEG signal into a plurality of intrinsic mode functions (IMFs) that comprise a first group of IMFs and a second group of IMFs;
• calculate a ratio comprising an amplitude or a power of at least one of the IMFs in the first group in the numerator and a corresponding amplitude or power of at least one of the IMFs in the second group in the denominator;
• and
• identify a period in the surf-EEG waveform as slow wave sleep (SWS) if the ratio associated with the period is above a predetermined threshold.