Method and apparatus for determining the cerebral state of a patient with fast response
First Claim
1. A method for ascertaining the cerebral state of a patient, including a state resulting from the administration of a drug, said method rapidly indicating changes in such state and comprising the steps of:
- (a) obtaining EEG signal data from the patient;
(b) obtaining EMG signal data from the patient, the EMG signal data being primarily of a higher frequency than the EEG signal data which is primarily of lower frequency;
(c) analyzing a sample of sequential EEG signal data to obtain a first indication indicative of the cerebral state of the patient, the length of an EEG signal data sample being such as to provide a cerebral state indication of desired accuracy;
(d) analyzing a sample of sequential EMG signal data temporally related to the EEG signal data sample to obtain a second indication indicative of electromyographic activity in the patient, an EMG signal data sample of shorter length than that of the EEG signal data sample being used to obtain said second indication due to the higher frequency of the EMG signal data; and
(e) producing a composite indication of the cerebral state of the patient from the first and second indications obtained at steps (c) and (d) indicative of the cerebral state of the patient, which composite indication can be updated at a repetition rate determined by the shorter sample length of the EMG signal data to rapidly indicate changes in the cerebral state of the patient.
1 Assignment
0 Petitions
Accused Products
Abstract
A method and apparatus for ascertaining the cerebral state of a patient. The method/apparatus may find use in ascertaining the depth of anesthesia of the patient. In one embodiment, the entropy of the patient'"'"'s EEG signal data is determined as an indication of the cerebral state. A frequency domain power spectrum quantity is obtained from the patient'"'"'s EMG signal data. The latter quantity can be updated more frequently than the EEG entropy due to its higher frequency. The EEG entropy indication and the EMG power spectrum indication can be combined into a composite indicator that provides an immediate indication of changes in the cerebral state of the patient. In another embodiment, the frequency range over which the entropy of the biopotential signal from the patient is determined is broadened to encompass both EEG signal data and EMG signal data and the entropy so determined used as an indication of the patient'"'"'s cerebral state.
-
Citations
57 Claims
-
1. A method for ascertaining the cerebral state of a patient, including a state resulting from the administration of a drug, said method rapidly indicating changes in such state and comprising the steps of:
-
(a) obtaining EEG signal data from the patient; (b) obtaining EMG signal data from the patient, the EMG signal data being primarily of a higher frequency than the EEG signal data which is primarily of lower frequency; (c) analyzing a sample of sequential EEG signal data to obtain a first indication indicative of the cerebral state of the patient, the length of an EEG signal data sample being such as to provide a cerebral state indication of desired accuracy; (d) analyzing a sample of sequential EMG signal data temporally related to the EEG signal data sample to obtain a second indication indicative of electromyographic activity in the patient, an EMG signal data sample of shorter length than that of the EEG signal data sample being used to obtain said second indication due to the higher frequency of the EMG signal data; and (e) producing a composite indication of the cerebral state of the patient from the first and second indications obtained at steps (c) and (d) indicative of the cerebral state of the patient, which composite indication can be updated at a repetition rate determined by the shorter sample length of the EMG signal data to rapidly indicate changes in the cerebral state of the patient. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39, 40, 41, 42, 43, 44, 45)
-
-
46. Apparatus for ascertaining the cerebral state of a patient, including a state resulting from the administration of a drug, said apparatus comprising:
-
(a) means for obtaining biopotential signals from the patient, the biopotential signals containing EEG signal data and EMG signal data; (b) means analyzing a sample of sequential EEG signal data to obtain a first indicator indicative of the cerebral state of the patient and analyzing a sample of sequential EMG signal data temporally related to the EEG signal data sample to obtain a second indicator indicative of electromyographic activity in the patient, said analyzing means using a length of an EEG signal data sample to determine the first indicator and using an EMG signal data sample of shorter length than the EEG signal data sample to determine said second indicator, said analyzing means updating said second indicator more frequently than said first indicator; and (c) means producing a composite indicator from the first and second indicators indicative of the cerebral state of the patient. - View Dependent Claims (47, 48, 49, 50, 51, 52, 53, 54, 55, 56, 57)
-
Specification