Monitoring of the cerebral state of a subject
First Claim
1. A method for monitoring the cerebral state of a subject, the method comprising the steps of:
- obtaining physiological signal data from a subject, the physiological signal data including EEG signal components;
deriving at least one of a first and second parameters from the physiological signal data, wherein the first parameter is indicative of the sum of spectral values of the physiological signal data in a first frequency band lying above high frequency EEG activity and the second parameter is indicative of the relative magnitudes of a first sum of k-th order spectral values and a second sum of n-th order spectral values, wherein the second sum is calculated over a second frequency band lying above high frequency EEG activity, and wherein k is an integer greater than two and n is an integer greater than one; and
forming a state index which is dependent on the at least one parameter derived in the deriving step, the state index being indicative of the cerebral state of the subject.
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Abstract
The invention relates to a method and apparatus for monitoring the cerebral state of a subject. At least one of a first and second parameters is derived from the physiological signal data obtained from the subject, wherein the first parameter is indicative of the sum of spectral values of the physiological signal data in a first frequency band lying above high frequency EEG activity and the second parameter is indicative of the relative magnitudes of a first sum of k-th order spectral values and a second sum of n-th order spectral values. The second sum is calculated over a frequency band lying above high frequency EEG activity (k>2 and n>1). A state index is then formed, which is dependent on the at least one parameter and indicative of the cerebral state of the subject. The first and second parameters may be used in the Bispectral Index (BIS™) algorithm.
54 Citations
34 Claims
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1. A method for monitoring the cerebral state of a subject, the method comprising the steps of:
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obtaining physiological signal data from a subject, the physiological signal data including EEG signal components;
deriving at least one of a first and second parameters from the physiological signal data, wherein the first parameter is indicative of the sum of spectral values of the physiological signal data in a first frequency band lying above high frequency EEG activity and the second parameter is indicative of the relative magnitudes of a first sum of k-th order spectral values and a second sum of n-th order spectral values, wherein the second sum is calculated over a second frequency band lying above high frequency EEG activity, and wherein k is an integer greater than two and n is an integer greater than one; and
forming a state index which is dependent on the at least one parameter derived in the deriving step, the state index being indicative of the cerebral state of the subject. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17)
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18. An apparatus for monitoring the cerebral state of a subject, the apparatus comprising:
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means for receiving physiological signal data from a subject, the physiological signal data including EEG signal components;
first calculation means for deriving at least one of a first and second parameters from the physiological signal data, wherein the first parameter is indicative of the sum of spectral values of the physiological signal data in a first frequency band lying above high frequency EEG activity and the second parameter is indicative of the relative magnitudes of a first sum of k-th order spectral values and a second sum of n-th order spectral values, wherein the second sum is calculated over a second frequency band lying above high frequency EEG activity, and wherein k is an integer greater than two and n is an integer greater than one; and
second calculation means for forming a state index which is dependent on the at least one parameter, the state index being indicative of the cerebral state of the subject. - View Dependent Claims (19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30)
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31. An apparatus for monitoring the cerebral state of a subject, the apparatus comprising:
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a first data processing unit configured to receive physiological signal data from a subject, the physiological signal data including EEG signal components;
a second data processing unit configured to derive at least one of a first and second parameters from the physiological signal data, wherein the first parameter is indicative of the sum of spectral values of the physiological signal data in a first frequency band lying above high frequency EEG activity and the second parameter is indicative of the relative magnitudes of a first sum of k-th order spectral values and a second sum of n-th order spectral values, wherein the second sum is calculated over a second frequency band lying above high frequency EEG activity, and wherein k is an integer greater than two and n is an integer greater than one; and
a third data processing unit configured to form a state index which is dependent on the at least one parameter, the state index being indicative of the cerebral state of the subject.
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32. A computer program product for an apparatus monitoring a patient, the computer product comprising:
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a first program code portion for receiving physiological signal data obtained from a subject, the physiological signal data including EEG signal components; and
a second program code portion configured to derive at least one of a first and second parameters from the physiological signal data, wherein the first parameter is indicative of the sum of spectral values of the physiological signal data in a first frequency band lying above high frequency EEG activity and the second parameter is indicative of the relative magnitudes of a first sum of k-th order spectral values and a second sum of n-th order spectral values, wherein the second sum is calculated over a second frequency band lying above high frequency EEG activity, and wherein k is an integer greater than two and n is an integer greater than one. - View Dependent Claims (33, 34)
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Specification