Patent ID: 6731975
Filing Date: 2004-05-04
Classification: A61B,G06K

Abstract:
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, the EMG signal data being primarily of a higher frequency than the EEG signal data which is primarily of a lower frequency; (b) means for analyzing a sample of sequential signal data over a frequency range that is sufficiently wide to include both the EEG and EMG signal data to obtain a measure of the complexity of the signal data, said analyzing means using a length of EEG signal data and effectively using a EMG signal data sample of shorter length than the EEG signal data sample; and (c) means providing the complexity measure as an indicator of the cerebral state of the patient, said providing means updating said indicator at a repetition rate allowed by a shorter sample length of the EMG signal data to indicate changes in the cerebral state of the patient.