Abstract: A reusable appliance for acquisition from a patient of EEG signals comprising a micro-miniature, micro-power, low noise multi-channel data-acquisition system powered by a fiber optic illuminator and photovoltaic cell thus eliminating the need for inductively coupled power converters. The appliance also uses disposable EEG electrodes which are similar in size and very low cost.

Abstract: A patient module comprising an 8 channel EEG pre-amplifier whose signal acquisition and processing characteristics are optimized for use in the operating room and intensive care unit. This patient module comprises at least an optimized multistage input filter, an optimized input stage circuit topography, ultra-isolation, oversampling, a multiplexer inter-sample charge dump, and high performance low-frequency-enhanced shielding.

Abstract: A system which classifies patients according to their level of awareness or consciousness using measures derived solely from electroencephalograph (EEG) signals. The system comprises multiple observes of characteristics of signals, including artifact detectors, especially magnitude artifact detectors, eye blink detectors, stationarity/RMS detectors, slew rate detectors, and burst suppression detectors, and determination of power in certain frequency bands. The system produces a single derived probabilistic measure of conscious awareness called the patient state index (PSI) and displays values of trends in that index and values of an artifact index, an EMG index, and a suppression ratio in order to give the operator current information on the quality of the signal input. The PSI is derived from a statistical analysis using empirically derived population norms and other parameters.

Abstract: A system which classifies patients according to their level of awareness or consciousness using measures derived solely from electroencephalograph (EEG) signals. The system comprises multiple observers of characteristics of signals, including artifact detectors, especially magnitude artifact detectors, eye blink detectors, stationarity/RMS detectors, slew rate detectors, and burst suppression detectors, and determination of power in certain frequency bands. The system produces a single derived probabilistic measure of conscious awareness called the patient state index (PSI) and displays values of trends in that index and values of an artifact index, an EMG index, and a suppression ratio in order to give the operator current information on the quality of the signal input. The PSI is derived from a statistical analysis using empirically derived population norms and other parameters.

Abstract: This invention defines a system for monitoring the brain activity of a human patient under anesthesia in order to determine the patient's level of consciousness. The system uses a plurality of receptors which are mounted in predetermined anatomical positions on the patient's head. The receptors are secured by adhesive foam patches. The appliance fits snugly to the head with the aid of self-adjusting strip that carry imbedded electrical circuitry for the receptors. Electrical connectivity in locations where scalp hair is most likely to be present is improved by the use of braille-tip electrodes fitted with large gel reservoirs.

Abstract: This invention defines a system for monitoring the brain activity of a human patient in order to monitor a patient's brain electrical activity. The system uses a plurality of receptors which are mounted in predetermined anatomical positions on the patient's head. The receptors are secured by adhesive foam patches. The appliance fits snugly to the head with the aid of self-adjusting strap that carry imbedded electrical circuitry for the receptors. Electrical connectivity in locations where scalp hair is most likely to be present is improved by the use of braille-tip electrodes fitted with large gel reservoirs.

Abstract: The invention provides novel organic polymer hydrogels comprising oligo(polyhydroxylalkyl)silylmethacrylate, particularly tetraethylene glycol .alpha.-.omega. bis(dimethoxysilylpropylmethacrylate), crosslinkers for use in constructing organic polymers, especially polyacrylates, particularly polyacrylamides. A preferred class of polymers are particularly suited to coating biomedical electrodes and sensors. Generally, these polymers are formed from a solution of 2-50% (w/v) monomer and 0.1-20% (w/v) crosslinker and 20-98% (w/v) an electrically conductive solution of a salt in water or a water-miscible solvent. These usually acrylic polymers generally have bulk resistivity of less than 1000 Ohms at 1 kHz, tack of between 20 and 150 g, hardness between 100 g and 500 g, 10 to 70% stress relaxation, thermal stability over a -40.degree. to 70.degree. C. range, structural stability to saturating salt concentrations, and are capable of between 150 and 1500% elongation.

Abstract: A switch apparatus for performing diagnostic and/or therapeutic procedures on a patient by the use of first and second electrodes which are placed on a patient. A defibrillator unit and another medical device utilizing radio frequency energy from a radio frequency generator unit comprises a multi-function adapter unit. The adapter unit is coupled to the first and second electrodes, to the defibrillator unit and to the electrosurgery unit for switching between the defibrillation unit and another medical device to permit performing diagnostic and therapeutic procedures on the patient.

Abstract: The invention provides novel organic polymer hydrogels comprising oligo(polyhydroxylalkyl)silylmethacrylate, particularly tetraethylene glycol .alpha.-.omega. bis(dimethoxysilylpropylmethacrylate), crosslinkers for use in constructing organic polymers, especially polyacrylates, particularly polyacrylamides. A preferred class of polymers are particularly suited to coating biomedical electrodes and sensors. Generally, these polymers are formed from a solution of 2-50% (w/v) monomer and 0.1-20% (w/v) crosslinker and 20-98% (w/v) an electrically conductive solution of a salt in water or a water-miscible solvent. These usually acrylic polymers generally have bulk resistivity of less than 1000 Ohms at 1 kHz, tack of between 20 and 150 g, hardness between 100 g and 500 g, 10 to 70% stress relaxation, thermal stability over a -40.degree. to 70.degree. C. range, structural stability to saturating salt concentrations, and are capable of between 150 and 1500% elongation.

Abstract: A switch apparatus for performing diagnostic and/or therapeutic procedures on a patient by the use of first and second electrodes adapted to be placed on the patient and by the use of a defibrillator unit and another medical device utilizing radiofrequency energy from a radiofrequency generator unit comprising a multi-function adapter unit adapted to be coupled to the first and second electrodes and adapted to be coupled to the defibrillator unit and to the electrosurgery unit for switching between the defibrillation unit and another medical device to permit performing the diagnostic and therapeutic procedures on the patient utilizing the same first and second electrodes.

Abstract: A medical electrode for use with a power supply for providing a more uniform current distribution for contacting an exposed surface of skin of a living body comprising a flexible carrier layer formed of an insulating material. A layer of conductive material is carried by the carrier layer. The layer of conductive material is separated into at least two segments with a space therebetween so that the two segments are electrically isolated from each other. A continuous layer of hydrogel material overlies the segments and is disposed in said space. The hydrogel material has a resistivity greater than the resistivity of the skin of the patient. A connector is adapted to be connected to the source of power whereby substantially equal current flow can be achieved from each segment through the skin of the patient without sharp transitions in current flow between the segments and the space between the segments.

Abstract: Headpiece for making EEG measurements on the head of a patient in the form of a human being utilizing electrode positioning system requiring the use of a plurality of electrodes in predetermined anatomical positions on the head comprising a plurality of longitudinally extending and transversely extending strips of an elastic material to form a pattern having openings therein. A plurality of electrode assemblies are mounted on the strips in spaced-apart positions. Straps are secured to the strips for securing said strips and the electrode assemblies mounted thereon to the head of the patient by stretching of the strips so that the electrode assemblies are positioned in the desired anatomical positions on the head regardless of the size of the head of the human being.

Abstract: Electrode construction having a support structure. A conductive material is carried by the support structure. The conductive material has a length which is at least as great as its width.

Abstract: Contact member comprised of a mass of nonconductive material having a low durometer and conductive elements dispersed in the mass of material in sufficient quantity to establish contact between the elements to provide a resistivity in the range of 10 to 100 ohm-cm.

Abstract: Precordial electrode strip for use on the torso of patients of different sizes comprising an elongate strip of flexible insulating material. A plurality of precordial electrodes are disposed in longitudinally spaced apart positions on the strip. A plurality of precordial leads are carried by the strip. At least one lead is connected to each of said precordial electrodes. A single connector is connected to said precordial leads for making connection to each of said precordial electrodes.

Abstract: Large surface area electrode for use with a power supply having a more uniform current density distribution for contacting the exposed surface of a living body having a contour. The electrode comprises a layer of flexible conductive material of a predetermined geometrical shape and having first and second surfaces. The layer is normally relatively flat and is capable of assuming contours of the skin of the body when the electrode is placed in contact with the body with the first surface of the layer engaging the exposed surface of the body. The layer of conductive material has a central portion and a surrounding ring portion. The central portion and the surrounding ring portion have outer margins with edges. A flexible carrier layer is provided which is secured to the second surface of the layer of flexible conductive material and serves to support the central portion and the said surrounding portion so that the surrounding portion is spaced from and insulated from the central portion.

Abstract: Electrode adapted to be placed in contact with the skin of a patient for reducing the surface resistivity of the skin of the patient and comprising a member formed of a dry-conductive material and having an outer surface adapted to be placed in contact with the skin of the patient. A composition is disposed on at least a portion of the surface of the member. The composition as is the surface of a plurality of water-containing vesicles.

Abstract: Contact comprised of a mass of nonconductive material having a low durometer and conductive elements dispersed in the mass of material in sufficient quantity to establish contact between the elements to provide a resistivity in the range of 10 to 100 ohm-cm.