Method for analyzing electroencephalogram using correlation dimension

• US 5,857,979 A
• Filed: 07/15/1997
• Issued: 01/12/1999
• Est. Priority Date: 12/09/1996
• Status: Expired due to Term

• Current Assignee: Electronics and Telecommunications Research Institute
• Original Assignee: Electronics and Telecommunications Research Institute
• Inventors: Park, Seon-Hee, Kim, Seung-Hwan, Ryu, Chang-Su
• Primary Examiner(s): Kamm, William E.
• Assistant Examiner(s): SCHAETZLE, KENNEDY
• Application Number:
  US08/892,940
• Time in Patent Office: 546 Days
• Field of Search: 600/544, 128/920, 128/923
• US Class Current: 600/544
• CPC Class Codes: A61B 5/369 Electroencephalography [EEG] devices for psychotechnics A61B5/16
• CPC Class Codes: A61B 5/372 Analysis of electroencephalograms

Abstract

This invention provides a method for analyzing an electroencephalogram(EEG) using the correlation dimension by which the brain states can be discriminated. The method uses a time-delay determining method necessary for reconstructing vectors from the EEG time series, and a relative ratio of a correlation exponent.

Claims

1. A method for analyzing an electroencephalogram (EEG) using a correlation dimension, the method comprising the steps of:

reconstructing vectors in an embedding dimension by using a time delay from an EEG time series;

calculating a correlation integral from said vectors in the embedding dimension;

obtaining correlation exponents from said correlation integral;

obtaining the relative ratios between said correlation exponents obtained at different brain states for each subject;

taking an average of said relative ratios over subjects; and

discriminating said different brain states by using said average of relative ratios.

2. The method as defined in claim 1, wherein an optimal time-delay is determined as maximizing a plateau region on a local slope of the correlation integral calculated from EEG time series.