Patent No. 6549804 System for the prediction, rapid detection, warning, prevention or control of changes in activity states in the brain of a subject

 

Patent No. 6549804

System for the prediction, rapid detection, warning, prevention or control of changes in activity states in the brain of a subject (Osorio, et al., Apr 15, 2003)

Abstract

A system (10) analyzes signals representative of a subject's brain activity in a signal processor (12) for information indicating the subject's current activity state and for predicting a change in the activity state. One preferred embodiment uses a combination of nonlinear filtering methods to perform real-time analysis of the electro-encephalogram (EEG) or electro-corticogram (ECoG) signals from a subject patient for information indicative of or predictive of a seizure, and to complete the needed analysis at least before clinical seizure onset. The preferred system then performs an output task for prevention or abatement of the seizure, or for recording pertinent data.

Notes:

SUMMARY OF THE INVENTION

The present invention solves the problems and overcomes the limitations of prior art, while providing pioneering advances in the state of the art. Its preferred embodiment enables (1) the accurate, automated, real-time detection of seizures, as well as the determination of their site of origin, propagation path and speed through regions of the brain, and their duration and intensity; (2) the prediction of the onset of the clinical component of seizures; (3) the prediction of the onset of the electrographic component of seizures; (4) the online self-adaptation, or offline adaptation of (1-3) to each individual, (5) the automated use of (1-3) for diagnosis, quantitative analysis, imaging, warning, treatment, and storing of data; and (6) the miniaturization of the system to a portable or implantable device.

The adaptation of the system to each individual takes into account, seizure type and location, and changes in the signal(s) over time, making use of any existing preictal, ictal, or postictal "fingerprints" for the subject. The speed of analysis and levels of sensitivity and specificity can also be adjusted to desired levels, and the method can be implemented in either digital or analog form (or a combination).

The preferred embodiment of the invention uses intracranial or scalp electrodes to obtain signals representative of current brain activity and a signal processor such as a personal computer or micro-processor, for continuous monitoring and analysis of these signals, detecting important changes or the appearance of precursors predictive of an impending change, as soon as they occur. The output of this analysis is then fed to a device which produces an immediate response (e.g., warning, treatment or storage) to the change or predicted change in state. The signal processing includes an adaptive analysis of frequency, energy, wave shape and dynamics, phase relationships, measures of rhythmicity, "sequency," and temporo-spatial stereotypia, variability, dimension, complexity of the signal, and noise reduction.