Method and apparatus for measuring the bioelectrical activity under an electrode resting on a patient

Claim 5

Apparatus for measuring bioelectrical activity of a patient comprising a signal electrode adapted to be placed on a patient, a plurality of auxiliary electrodes adapted to be placed on the patient, adjacent said signal electrode, means connecting said auxiliary electrodes to provide a mean potential value thereof, difference determining means connected to determine the difference value between said mean potential value and the potential of said signal electrode, and recording means coupled to said difference determining means to record the difference value as indicative of the bioelectrical activity under and within the proximity of said signal electrode, said connecting means being connected only to auxiliary electrodes adjacent said signal electrode wherein said means connecting said auxiliary electrodes comprises resistors connected to respective auxiliary electrodes and to a neutral point, the magnitude of the resistance values of said resistors being respectively dependent on the spacing between each said auxiliary electrode and the signal electrode.

Claim 6

Apparatus for measuring bioelectrical activity of a patient comprising a signal electrode adapted to be placed on a patient, a plurality of auxiliary electrodes adapted to be placed on the patient, adjacent said signal electrode, means connecting said auxiliary electrodes to provide a mean potential value thereof, difference determining means connected to determine the difference value between said mean potential value and the potential of said signal electrode, and recording means coupled to said difference determining means to record the difference value as indicative of the bioelectrical activity under and within the proximity of said signal electrode, said connecting means being connected only to auxiliary electrodes adjacent said signal electrode wherein said means connecting said auxiliary electrodes comprises resistors connected to respective auxiliary electrodes and to a neutral point, the magnitude of the resistance values of said resistors being respectively dependent on the spacing between each said auxiliary electrode and the signal electrode.

Claim 7

Apparatus for measuring bioelectrical activity of a patient comprising a signal electrode adapted to be placed on a patient, a plurality of auxiliary electrodes adapted to be placed on the patient, adjacent said signal electrode, means connecting said auxiliary electrodes to provide a means potential value thereof, difference determining means connected to determine the difference value between said mean potential value and the potential of said signal electrode, and recording means coupled to said difference determining means to record the difference value as indicative of the bioelectrical activity under and within the proximity of said signal electrode, said connecting means being connected only to auxiliary electrodes adjacent said signal electrode, an electrode-support device supporting said signal electrode and said auxiliary electrodes, said electrode-support device being made of insulating material, said signal electrode being centrally disposed in the electrode-support device and said auxiliary electrodes being peripherally disposed on said electrode-support device, said auxiliary electrodes forming a polygon if connected.

Claim 8

Apparatus for measuring bioelectrical activity of a patient comprising a signal electrode adapted to be placed on a patient, a plurality of auxiliary electrodes adapted to be placed on the patient, adjacent said signal electrode, means connecting said auxiliary electrodes to provide a means potential value thereof, difference determining means connected to determine the difference value between said mean potential value and the potential of said signal electrode, and recording means coupled to said difference determining means to record the difference value as indicative of the bioelectrical activity under and within the proximity of said signal electrode, said connecting means being connected only to auxiliary electrodes adjacent said signal electrode, an electrode-support device supporting said signal electrode and said auxiliary electrodes, said electrode-support device being made of insulating material, said signal electrode being centrally disposed in the electrode-support device and said auxiliary electrodes being peripherally disposed on said electrode-support device, said auxiliary electrodes forming a polygon if connected.

Claim 9

Apparatus for measuring bioelectrical activity of a patient comprising a signal electrode adapted to be placed on a patient, a plurality of auxiliary electrodes adapted to be placed on the patient, adjacent said signal electrode, means connecting said auxiliary electrodes to provide a mean potential value thereof, difference determining means connected to determine the difference value between said mean potential value and the potential of said signal electrode, and recording means coupled to said difference determining means to record the difference value as indicative of the bioelectrical activity under and within the proximity of said signal electrode, said connecting means being connected exclusively to auxiliary electrodes adjacent said signal electrode, at least one of said plurality of auxiliary electrodes being also operable as an adjacent signal electrode and having a plurality of further auxiliary electrodes disposed adjacent thereto but spaced relative to said first-mentioned signal electrode, thereby to provide a plurality of signal electrodes comprising said first-mentioned signal electrode and said adjacent signal electrode each having adjacent auxiliary electrodes and said first-mentioned signal electrode also functioning as one of the auxiliary electrodes for said adjacent signal electrode, said mean potential value providing means comprising a plurality of first differential amplifiers having a high input and a low output impedance and two inputs and two corresponding outputs; each electrode being connected to one input of a respective first differential amplifier, a reference electrode adapted to be placed on a patient, the other inputs of said first differential amplifiers being commonly connected to said reference electrode, the outputs of said first differential amplifiers corresponding to said reference electrode being connected to a common output point, said difference determining means comprising an output differential amplifier for each signal electrode, and said mean potential value providing means further comprising resistor networks including resistors connected to the electrode outputs of those first differential amplifiers corresponding to the electrodes which are disposed adjacent the signal electrode at which the voltage is to be measured, said resistors being connected to a common neutral point for receiving said mean potential value, one input of said output differential amplifier being connected to the signal electrode output of the associated first differential amplifier and the other input of said output differential amplifier being connected to the neutral point of said resistor network.

Claim 10

Apparatus for measuring bioelectrical activity of a patient comprising a signal electrode adapted to be placed on a patient, a plurality of auxiliary electrodes adapted to be placed on the patient, adjacent said signal electrode, means connecting said auxiliary electrodes to provide a mean potential value thereof, difference determining means connected to determine the difference value between said mean potential value and the potential of said signal electrode, and recording means coupled to said difference determining means to record the difference value as indicative of the bioelectrical activity under and within the proximity of said signal electrode, said connecting means being connected exclusively to auxiliary electrodes adjacent said signal electrode, at least one of said plurality of auxiliary electrodes being also operable as an adjacent signal electrode and having a plurality of further auxiliary electrodes disposed adjacent thereto but spaced relative to said first-mentioned signal electrode, thereby to provide a plurality of signal electrodes comprising said first-mentioned signal electrode and said adjacent signal electrode each having adjacent auxiliary electrodes and said first-mentioned signal electrode also functioning as one of the auxiliary electrodes for said adjacent signal electrode, said mean potential value providing means comprising a plurality of first differential amplifiers having a high input and a low output impedance and two inputs and two corresponding outputs; each electrode being connected to one input of a respective first differential amplifier, a reference electrode adapted to be placed on a patient, the other inputs of said first differential amplifiers being commonly connected to said reference electrode, the outputs of said first differential amplifiers corresponding to said reference electrode being connected to a common output point, said difference determining means comprising an output differential amplifier for each signal electrode, and said mean potential value providing means further comprising resistor networks including resistors connected to the electrode outputs of those first differential amplifiers corresponding to the electrodes which are disposed adjacent the signal electrode at which the voltage is to be measured, said resistors being connected to a common neutral point for receiving said mean potential value, one input of said output differential amplifier being connected to the signal electrode output of the associated first differential amplifier and the other input of said output differential amplifier being connected to the neutral point of said resistor network.