Neuro-fuzzy closed-loop control of depth of anaesthesia

The utility of the auditory evoked potential (AEP) is under investigation as a feedback signal for the automatic closed-loop control of general anaesthesia using neural networks and fuzzy logic. The AEP is a signal derived from the electroencephalogram (EEG) in response to auditory stimulation, which may be useful as an index of the ‘depth’ of anaesthesia. A simple back-propagation neural network can learn the AEP and provides a satisfactory input to a fuzzy logic infusion controller for the administration of anaesthetic drugs, but the problem remains that of reliable signal acquisition.