Patent ID: 6507754
Filing Date: 2003-01-14
Classification: A61B,Y10S

Abstract:
A device for medically monitoring in real time of a patient from an analysis of electroencephalogram or EEG signals, comprising:an amplifier configured to receive and amplify the EEG signals; an analog/digital multiconverter configured to convert the EEG signals into digital data; and a processor configured to process the digital data and to provide an output and a warning indicative of a medical problem with the patient, wherein the processor is programmed to perform the following functions: construct reference dynamics of a normal state of the patient by prerecording a long normal EEG segment Sref; compare the reference dynamics with dynamics of a distant test segment St; and compute similarities over the entire prerecorded EEG segment by sliding the test segment St periodically over the prerecorded EEG segment so as to provide information about a possible medical onset occurring with the patient, wherein the programmed processor performs the comparing function by: building a skeleton of the reference dynamics by randomly selecting a sub-set of points of the reference dynamics so as to provide an adapted reference dynamics picture X(Sref) of the reference dynamics; and estimating dynamic similarities between the adapted reference dynamics picture X(Sref) and a projection X(St) of a 16-dimensional reconstruction of the test segment St on the principal axes of the reference dynamics, wherein the dynamic similarities are estimated using a statistical measure based on the following cross correlation integral: C&af;(Sref,St)=1Nref&it;Nt&it;&Sum;i=1,Nref&it;&Sum;j=1,Nt&it;Î˜&af;(&LeftDoubleBracketingBar;Xi&af;(Sref)-Xj&af;(St)&RightDoubleBracketingBar;-r)â€ƒwhere &THgr; is the Heaviside step function, &par; &par; is the euclidian norm, NrefNt denotes the number of elements in each set, and r is a distance, and wherein the following cross-correlation ratio is used: Î³&af;(Sref,St)=C&af;(Sref,St)/C&af;(Sref,Sref)&it;C&af;(St,St)where &ggr; ranges from 0 to 1 and provides a sensitive measure of closeness between two dynamics.