Electroencephalographic method and system for the quantitative description of patient brain states
First Claim
1. The method of determining the brain state of a patient including the steps of:
- (a) attaching a plurality of electrodes to the scalp of a comatose patient or a patient with other brain dysfunctions to detect the patient'"'"'s brainwaves in the form of electroencephalographic (EEG) and evoked response (EP) data;
(b) amplifying the electrical signals detected at each electrode;
(c) using a programmed computer based system as the control for stimulating the patient with a series of multi-sensory stimulations to elicit evoked responses from cortex and brain stem;
(d) obtaining and analyzing on-line digital EEG or EP data by connecting analog-digital converters to each amplifier, and digitizing all data as it is gathered;
(e) obtaining sets of on-going EEG and average evoked response data for the patient and using said computer based system to extract diagnostically useful features from such sets of data, and automatic construction of a Z-transform for each such feature based upon a comparison with stored normative data obtained by computing mean values and standard deviations for each feature from groups of subjects or patients without head trauma or brain dysfunction;
(f) computing a state vector for the patient comprising a vector sum based upon those Z-transformed features which are significantly deviant from normative values; and
(g) visually displaying the length (severity), orientation (quality) and change with time of said state vector.
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Abstract
A method and system for the quantitative description of human abnormal brain states, for example, to distinguish cerebral death from a barbiturate induced deep coma, includes an electroencephalograph (EEG) system utilizing scalp electrodes and amplifiers. A computer based system controls a multimodal stimulator (clicks, flashes, etc.) to provide evoked response data for different sensory systems. The ongoing EEG and averaged response data are processed quantitatively and compared with previously stored normative data, describing brain states in patients free of head trauma, to calculate a set of Z-transformations. The Z-transformations define Z, the brain state vector (BSV), which may be visually displayed. The length, direction and change of BSV over time provide an evaluation of the anatomical location of any damage, the severity of functional impairment and the rate of improvement or deterioration of the patient'"'"'s state in order to aid in selection and guidance of treatment.
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Citations
23 Claims
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1. The method of determining the brain state of a patient including the steps of:
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(a) attaching a plurality of electrodes to the scalp of a comatose patient or a patient with other brain dysfunctions to detect the patient'"'"'s brainwaves in the form of electroencephalographic (EEG) and evoked response (EP) data; (b) amplifying the electrical signals detected at each electrode; (c) using a programmed computer based system as the control for stimulating the patient with a series of multi-sensory stimulations to elicit evoked responses from cortex and brain stem; (d) obtaining and analyzing on-line digital EEG or EP data by connecting analog-digital converters to each amplifier, and digitizing all data as it is gathered; (e) obtaining sets of on-going EEG and average evoked response data for the patient and using said computer based system to extract diagnostically useful features from such sets of data, and automatic construction of a Z-transform for each such feature based upon a comparison with stored normative data obtained by computing mean values and standard deviations for each feature from groups of subjects or patients without head trauma or brain dysfunction; (f) computing a state vector for the patient comprising a vector sum based upon those Z-transformed features which are significantly deviant from normative values; and (g) visually displaying the length (severity), orientation (quality) and change with time of said state vector. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14)
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15. A system for determining the brain state of a patient including:
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(a) a plurality of electrodes adapted to be attached to the scalp of a comatose patient or a patient with other brain dysfunctions to detect the patient'"'"'s brainwaves in the form of electroencephalograph (EEG) and evoked response (EP) data; (b) preamplifiers; (c) a stimulator means for stimulating the patient in a series of multi-sensory stimulations and stimulations of separate modalities to elicit evoked responses; (d) a programmed computer based system means for the control of said stimulator means, including the use of microprocessors for such purposes; (e) analog-digital converter means connected to said amplifier means for obtaining on-line digital EEG and EP data; (f) means for obtaining sets of on-going EEG and average evoked response data for the patient and automatically constructing a Z-transform for each analytic measure extracted from such sets of data based upon a comparison with normative data from groups of patients without head trauma or other brain dysfunctions; (g) means for computing a state vector for the patient comprising a vector sum based upon those Z-transformed features significantly deviant from the normative data; and (h) means for visually displaying the length and change of time of said state vector. - View Dependent Claims (16, 17, 18, 19, 20, 21, 22, 23)
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Specification