| abstract |
An electroencephalographic (EEG) system includes an electroencephalographic instrument comprising a plurality of electrodes adapted to be removably connected to the patient's head to detect brain waves; a plurality of amplifiers, with each amplifier connected to a pair of electrodes; an output multiplexer and a multi-line electrographic recording device, such as a matrix printer, whose display is an on-line display of multi-channel simultaneous wavy lines on a recording medium, such as a strip chart. A digital signal conditioning system is connected between the outputs of the amplifiers and the input of the recording device and functions to minimize misleading effects of muscular artifacts, to detect epileptiform spikes and sharp waves, and to perform quantitative analysis of the EEG signals. This signal conditioning system includes a comparison means which compares analytical features of the patient's brain waves on a statistical basis, with norms stored in a digital storage means. These features are extracted from the EEG by spectral analysis, coherence analysis and symmetry analysis. Other modular digital systems and software may be added to compute cortical and brainstem average evoked potentials using multimodal sensory stimuli, to extract diagnostic features from the average evoked potentials (EP's) by computing algorithms, to construct graphic and alphanumeric displays, or to write an analytic diagnostic report. |