Table 2 Sleep features included in the Sleep Cognitive Index (SCI) model (BAI used a subset of features used in SCI, i.e., the last two feature domains).
From: Decoding information about cognitive health from the brainwaves of sleep
Domain | Feature | # using central electrode^ | # using electrodes from three regions |
|---|---|---|---|
Macro-structure | TST: total sleep time (N1, N2, N3, and REM) in minutes | 1 | |
WASO: wake after sleep onset in minutes | 1 | ||
SE: sleep efficiency, time of sleep divided by TST | 1 | ||
TBB: total time in bed, time of sleep and awake | 1 | ||
SL: latency from lights off to the first epoch of sleep in minutes | 1 | ||
RL: latency from lights off to the first epoch of R in minutes | 1 | ||
Perc_X: % of time spent in each sleep stage | 4 | ||
Spindle (N2 and N3) | AMP: mean spindle amplitude (uV or mV units) | 2 | |
DENS: spindle density (count per minute) | 2 | ||
DUR: mean spindle duration (core + flanking region) | 2 | ||
FFT: mean spindle frequency | 2 | ||
FWHM: mean spindle full width at half maximum | 2 | ||
NOSC: mean number of oscillations per spindle | 2 | ||
SYMM2: mean spindle folded-symmetry metric | 2 | ||
Spindle-SO coupling (N2 and N3) | COUPL_ANGLE: circular mean of SO phase at spindle peak | 2 | |
COUPL_MAG: intra-trial phase clustering metric (ITPC) | 2 | ||
COUPL_OVERLAP: # of spindles overlapping a SO | 2 | ||
COUPL_PV: asymptotic p-value for the ITPC statistic | 2 | ||
Slow oscillations (SO) (N2 and N3) | SO: # of SO detected | 2 | |
SO_AMP: median amplitude (of negative peak) | 2 | ||
SO_DUR: median SO duration | 2 | ||
SO_NEG_DUR: median negative peak duration | 2 | ||
SO_POS_DUR: median positive peak duration | 2 | ||
SO_RATE: # SO per minute | 2 | ||
Median SO slope: SO_SLOPE_NEG1: + to − zero-crossing to negative peak SO_SLOPE_NEG2: negative peak to − to + zero-crossing SO_SLOPE_POS1: − to + zero-crossing to positive peak SO_SLOPE_POS2: positive peak to + to − zero-crossing | 2 × 4 | ||
Waveform for each stage* | Line length, an integrated measure of signal waveform amplitude and frequency | 2 × 5 | 2 × 5 × 3 |
Kurtosis, heavy-tailness of the distribution of the waveform | 2 × 5 | 2 × 5 × 3 | |
Frequency for each stage* | Relative delta / theta / alpha band power, each band has 95% percentile, min, mean, standard deviation across 2-s subepochs within a 30-s epoch | 4 × 3 × 5 | 4 × 3 × 5 × 3 |
Delta-to-theta/delta-to-alpha/theta-to-alpha power ratio, each ratio has 95% percentile, min, mean, standard deviation across 2-s subepochs within a 30-s epoch | 4 × 3 × 5 | 4 × 3 × 5 × 3 | |
Kurtosis of delta / theta / alpha /sigma band spectrogram | 4 × 5 | 4 × 5 × 3 | |
Total number of features | 212 | 532 | |
