METHOD FOR DETECTING THE STATE OF DEEP SLEEP Russian patent published in 2022 - IPC G16H50/00 A61B5/291 

FIELD: medicine.

SUBSTANCE: invention relates to the field of experimental medicine, in particular to a method for automated determination of the state of deep sleep based on the analysis of electroencephalogram (EEG) signals. The objective of this invention is the development of a method for determining the state of deep sleep (slow sleep phase) by an EEG signal, at least one channel of an electroencephalogram, which can be carried out both using a digital microprocessor device and without its use with the help of analog bandpass filters and comparison schemes. The expected result is achieved by the fact that in the method for detecting the state of deep sleep, including the registration of an electroencephalogram (EEG), filtering of the EEG signal to eliminate interference, analysis of spectral characteristics within the epoch for each frequency band delta, theta, alpha and beta, according to the solution, the epochs are chosen of the same duration; for each epoch in each band spectral power density P_Δ, P_Θ, P_Α, P_B and total spectral power density P_Σ = P_Δ + P_Θ + P_Α + P_B is calculated, two threshold values of the spectral power density are chosen: the maximum power P_w in the wakeful state and the maximum power P_s while asleep, such that P_s > P_w; if the result of the movement of the patient, electrical noise and other accidental causes P_Σ ≥ P_s, this epoch is excluded from the analysis; values of P_Σ ≤ P_w correspond to the wakefulness of the patient; while asleep, the total power density satisfies P_w < P_Σ < P_s; the value of a Boolean variable NREM = (P_Δ > P_A) & (P_Δ > P_B) & (P_Θ > P_A) & (P_Θ > P_B) & (P_Δ > (P_A + P_B)) & (P_Δ > P_Θ) is calculated; in a series of N consistently registered epochs the number L of events {(NREM = 1) & (P_w < P_Σ < P_s)} is determined; a conclusion about the state of deep sleep is made if the relative frequency H_N3 = L/N exceeds the specified threshold value H_N3.

EFFECT: possibility of detecting the patient’s deep sleep state by the signal of at least one EEG channel and signaling the onset of this state, which does not require prior training using standard EEG recordings.

3 cl, 2 dwg