The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Oct. 17, 1995
Filed:
Jun. 09, 1994
Nassib G Chamoun, Dedham, MA (US);
Jeffrey C Sigl, Ashland, MA (US);
Charles P Smith, Framingham, MA (US);
Aspect Medical Systems, Inc., Natick, MA (US);
Abstract
Disclosed is a system and method to derive a diagnostic index indicative of a selected cerebral phenomena which obtains 19 unipolar EEG signals from regions of interest on both the left and right hemispheres of a subject's brain. The system uses high-gain, low-noise amplifiers to maximize the dynamic range for low energy wave components of the signals. Band-pass filtering is used to reduce noise and to avoid aliasing. The system applies commonly used digital signal processing (DSP) techniques to digitize, to low-pass filter (100 Hz), and to decimate the signals. Power spectral, bispectral, and higher-order spectral processing is then performed. In a preferred embodiment, the system divides the most recent 63 seconds of digitized EEG data from each lead into 60 4-second intervals, each with 3 seconds of overlap with the previous interval. For a selected set of derived leads, the system produces auto power spectrum, autobispectrum, and auto higher-order spectrum variables, by using either a Fast Fourier Transform (FFT) based approach or a parametric approach. Any pair of leads can be combined to compute cross power spectrum, cross bispectrum, and cross higher-order spectrum variables. The spectral values are separated into bins and a value representative of the bin is selected or computed and then each value is multiplied by a predetermined coefficient. The resulting products are summed to arrive at the diagnostic index.