Abstract: In an electroencephalographic (EEG) system the number of EEG electrodes is greater than the number of amplification channels. A switching system switches the EEG electrodes to the amplification channels to provide a sequence of segments of data from each EEG electrode. The segments are compared to each other and with normal data to provide statistically reliable information regarding the normality of the patient's brain waves. In one embodiment, both EEG and EKG electrodes are alternatively connected to EKG amplifiers.

Abstract: In a medical imaging system a patient is injected with a radiopharmaceutical spontaneously emitting positrons and a PET (Positron Emission Tomography) scan is taken along parallel planes of a portion of the subject's body to produce a slice image composed of pixels arranged in a pattern. The intensity of each pixel is automatically, in a computer system, converted to digital data. The computer system then normalizes the pixels of the slice as to location by calculating the location of each pixel in an ideal or normal slice. The computer system then calculates a Z transform, on a pixel-by-pixel basis, compared to the slices from a normal group to obtain a topographic color-coded map showing the degree of abnormality at each pixel location.

Abstract: The Heart State Analyzer (HSA) is a system and method in medical non-invasive electrocardiographic (EKG) analysis of human heart beats for the early detection of certain heart diseases in which a large number of electrodes, for example, 32 to 64, are attached on the chest, back and sides of the patient, i.e., "body surface". The electrical signals detected by the electrodes ae converted to digital data, treated to remove muscle artifact and other noise, and then analyzed mathematically to determine the presence or absence of abnormal body surface potential distributions, or of unusual beat morphologies, compared statistically to the self-norm "typical beat" of the patient and also compared to a data base compiled from comparable normal population groups. The results of the statistical analysis are displayed as topographical maps of the body surface, color coded to represent the presence of significant derivations from the norms, defined as "abnormality", i.e.

Abstract: In an electroencephalographic method and system for the quantitative analysis of brain waves, a programmed sequence of stimuli is automatically presented to a subject to evoke averaged evoked responses (AER's). The AER's are automatically analyzed by factor analysis in which each waveshape is reconstituted, as closely as possible, by a set of "basis waveshapes" (factors) held in memory. The "factor scores" (contributions of each factor) are Z transformed as a comparison against results from a normal population, and displayed as color-coded topographic maps of the head.

Abstract: An EEG (electroencephalograph) system detects a patient's brain waves from electrodes pressed against the patient's scalp, amplifies the analog brain waves and converts them into digital signals. The digital brain waves are processed to reduce electrical interference, muscle artifact and other noise, and then compared on a statistical basis against the patient's self-norm and population norms derived from groups of normal and abnormal groups of patients under specified conditions. The results of the statistical analysis, on an almost real-time basis, are displayed on a CRT color monitor.

Abstract: An electroencephalograph (EEG) system for the detection of a patient's brain waves includes a group of electrodes removably attached to the patient's scalp, low-noise high-gain amplifiers and analog/digital converters. A digital comb filter is used to improve the signal-to-noise ratio and has self-optimizing capability. In the digital comb filter, the band pass frequencies are automatically selected by comparing, at each tooth of the comb, the phase variance parameter, under the brain conditions of the presence and absence of a synchronized stimulus producing an evoked potential brain wave.

Abstract: During open-heart surgery an EEG (electroencephalograph) system detects a patient's brain waves, amplifies the brain wave signals and converts them into digital data. The cardiopulmonary bypass pump (heart-lung machine) is connected to blood flow and blood temperature transducers whose measurements, in digital form, are used to calculate a standard of normal electro-physiological responses to blood flow and temperature changes with which the patient's actual brain wave responses will be compared. A visual display indicates to the surgical team, as to each of eight brain sectors, whether the patient's brain waves show that remedial action may be required. The digitalized brain wave signals, after processing to reduce muscle artifact and other noise, are displayed, in one embodiment, as intensity modulated time segments, using a moving window type of display in which the current segment is statistically compared to the group of immediate prior segments to provide a current self-norm (NORMS n).

Abstract: Disclosed are a method and a system for determining if a patient's brain electrical activity reflects a significant evoked response to a sensory stimulus. A test measure of the difference between two sets of averaged waveforms, one in the absence and another in the presence of the stimulus, is derived on the basis of (i) mean values of spectral measures of the two sets and (ii) the variance of these spectral measures. This test measure is matched against acceptance and rejection levels which are defined on the basis of both (i) the number of averaged waveforms in each set and (ii) the desired degree of probability of avoiding false positive or false negative results.