Patent No. 6868345 Monitoring auditory evoked potentials
  Patent No. 6868345    Monitoring auditory evoked potentials     (Jensen, Mar 15, 2005)    Abstract   A method and an apparatus for extracting     signals which are indicative of the level of consciousness of a patient comprises     subjecting the patient to a repetitive audio stimulus, monitoring AEP produced     by the patient using an autoregressive model with exogenous input, and then     calculating an index (AAI), which is displayed or used otherwise,indicative     of the anaesthetic depth.       Notes:    BACKGROUND     OF THE INVENTION         The present invention relates to an apparatus for extracting signals which are     indicative of the level of consciousness of a patient comprising means for monitoring     auditory evoked potentials (AEP) produced by the patient as a response to a     repetitive acoustic click stimulus, means for extracting an AEP within a few     repetitions, preferably more than 10 and less than 50 of the audio stimulus,     means for using a...