Electroencephalograph monitoring
First Claim
1. Apparatus for monitoring a brain electroencephalogram (EEG) comprising:
- at least three electrodes providing voltage signals indicative of brain EEG,an insulated carrier on which the electrodes are mounted and which is constructed to be held to the scalp of the brain to be monitored,first circuit means for providing a first signal which is a function of the voltage signals at two of the electrodes,second circuit means for providing a second signal which is, at least partially, a function of the voltage signal at a third of the electrodes,adjustment means capable of so adjusting at least one of the first and second signals so that any electrocardiograph (ECG) components of the first and second signals become equal to one another, anddifference means for deriving an output signal representative of the difference between the first and second signals after the adjustment by the adjustment means.
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Accused Products
Abstract
Apparatus for monitoring those signals in the brain which give rise to electroencephalograms (EEG) is described. The apparatus is particularly applicable to the fetus where EEG signals often contain a component of those signals which give rise to electrocardiographs (ECG). In the apparatus ECG signals picked up by electrodes in an electrode assembly forming part of the apparatus are eliminated by deriving two signals having equal ECG components, the two signals being subtracted from one another to provide a signal representing EEG. The electrodes may be concentric annular electrodes, for example, or relatively small disc electrodes spaced apart at the vertices of an equilateral triangle.
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Citations
12 Claims
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1. Apparatus for monitoring a brain electroencephalogram (EEG) comprising:
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at least three electrodes providing voltage signals indicative of brain EEG, an insulated carrier on which the electrodes are mounted and which is constructed to be held to the scalp of the brain to be monitored, first circuit means for providing a first signal which is a function of the voltage signals at two of the electrodes, second circuit means for providing a second signal which is, at least partially, a function of the voltage signal at a third of the electrodes, adjustment means capable of so adjusting at least one of the first and second signals so that any electrocardiograph (ECG) components of the first and second signals become equal to one another, and difference means for deriving an output signal representative of the difference between the first and second signals after the adjustment by the adjustment means. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11)
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12. Apparatus for monitoring a brain electroencephalogram (EEG) comprising:
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at least three electrodes, an insulated carrier on which the electrodes are mounted and which is constructed to be held to the scalp of the brain to be monitored, and means for (a) deriving a first difference signal from the voltages on a first and a second of the electrodes, (b) deriving a second difference signal from the voltages on the second electrode and a third of the electrodes, (c) automatically providing respective signals, from the first and second difference signals, which have substantially equal components due to an electrocardiograph (ECG), and (d) subtracting one of the signals having an ECG component from the other such signal.
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Specification