METHOD AND APPARATUS FOR THE ESTIMATION OF THE ANESTHETIC DEPTH USING WAVELET ANALYSIS OF THE ELECTROENCEPHALOGRAM SIGNALS

摘要

The preferred embodiments proposes a method and apparatus to monitor the hypnotic state of a patient under- going general anesthesia. The methodology of the present invention may also be used to discriminate between different sleep stages, predict the duration of ECT induced seizures, and awareness levels in subjects performing safety critical activities. It can also be used to monitor the changes in th e cerebral metabolic rate. The index of hypnosis disclosed herewith (i.e. the WAVelet index) has the advantage of reacting within one second to changes in the patients hypnotic state. Based on wavelet decomposition and statistical analysis, the computa- tional complexity of the algorithm is low, making it implementable on a microprocessor. The proposed method is a single descriptor of the activity of the EEG signal within the gamma frequency band. Neither a large subject pool nor extensive database of clinical EEG data are needed for tuni ng the index.