Method and apparatus for extraction of low-frequency artifacts from brain waves for alertness detection

• US 5,626,145 A
• Filed: 03/20/1996
• Issued: 05/06/1997
• Est. Priority Date: 03/20/1996
• Status: Expired due to Term

• Current Assignee: Lockheed Martin Energy Systems, Inc. (French Alternative Energies and Atomic Energy Commission)
• Original Assignee: Lockheed Martin Energy Systems, Inc. (French Alternative Energies and Atomic Energy Commission)
• Inventors: Hively, Lee M., Clapp, Ned E.
• Primary Examiner(s): Cohen, Lee S.
• Assistant Examiner(s): Huang, Stephen D.
• Application Number:
  US08/619,031
• Time in Patent Office: 412 Days
• Field of Search: 128/731, 128/732
• US Class Current: 600/544
• CPC Class Codes: A61B 5/18 for vehicle drivers or machine operators
• CPC Class Codes: A61B 5/245 specially adapted for magnetoencephalographic [MEG] signals
• CPC Class Codes: A61B 5/316 Modalities, i.e. specific diagnostic methods
• CPC Class Codes: A61B 5/369 Electroencephalography [EEG] devices for psychotechnics A61B5/16
• CPC Class Codes: A61B 5/372 Analysis of electroencephalograms
• CPC Class Codes: A61B 5/4094 Diagnosing or monitoring seizure diseases, e.g. epilepsy

Abstract

Methods and apparatus automatically detect alertness in humans by monitoring and analyzing brain wave signals. Steps include: acquiring the brain wave (EEG or MEG) data from the subject, digitizing the data, separating artifact data from raw data, and comparing trends in f-data to alertness indicators, providing notification of inadequate alertness.

Claims

1. A method for automatically extracting low-frequency artifact data from brain wave data comprising the steps of:

(a) utilizing a standard method selected from the group of methods consisting of electroencephalogram method and magnetoencephalogram method to provide at least one channel of raw brain wave data, called e-data, selected from the group consisting of electroencephalogram data and magnetoencephalogram data; and

(b) separating artifact data, called f-data, from the e-data while preventing phase distortions in the data, by passing the e-data through a zero-phase filter means for providing an output of f-data, whereby the f-data may be further analyzed to detect alertness.

2. The method as described in claim 1 wherein said zero-phase filter means comprises an integrated circuit chip zero-phase filter.

3. The method described in claim 2 wherein recursions are used with the f-data from the zero-phase filter means described in claim 2 to yield artifact data.

4. Apparatus for automatically extracting low-frequency artifact data from brain wave data comprising:

(a) data provision means selected from the group of means consisting of electroencephalogram means and magnetoencephalogram means for providing at least one channel of raw brain wave data, called e-data, selected from the group consisting of electroencephalogram data and magnetoencephalogram data; and

(b) separation means for separating artifact data, called f-data, from the e-data while preventing phase distortions in the data, said separation means comprising a zero-phase filter means for providing an output of f-data, said separation means communicably connected to said data provision means, whereby the f-data may be further analyzed to detect alertness.

5. The apparatus as described in claim 4 wherein said zero-phase filter means comprises an integrated circuit chip zero-phase filter.

6. The apparatus described in claim 5 wherein recursions are used with the f-data from the zero-phase filter means described in claim 5 to yield artifact data.

7. A zero-phase filter for separating artifact brain wave data, called f-data, from raw brain wave data, called e-data, selected from the group consisting of electroencephalogram data and magnetoencephalogram data, said zero-phase filter comprising an integrated circuit chip zero-phase filter for separating artifact brain wave data from raw brain wave data while preventing phase distortions in the data.

8. The integrated circuit chip zero-phase filter described in claim 7 wherein recursions are used with the f-data from the zero-phase filter means described in claim 7 to yield artifact data.

9. A method for automatically detecting a subject'"'"'s state of alertness from the subject'"'"'s brain wave data comprising the steps of:

(A) utilizing a standard method selected from the group of methods consisting of electroencephalogram method and magnetoencephalogram method to provide at least one channel of raw brain wave data, called e-data, selected from the group consisting of electroencephalogram data and magnetoencephalogram data;

(B) separating artifact data, called f-data, from the e-data while preventing phase distortions in the data, by passing the e-data through a zero-phase filter means for providing an output of f-data;

(C) analyzing the f-data to detect indications of fatigue or drowsiness, thereby detecting a lack of alertness; and

(D) providing an indication of the lack of alertness.

10. The method as described in claim 9 wherein said zero-phase filter means comprises an integrated circuit chip zero-phase filter.

11. The method described in claim 10 wherein recursions are used with the f-data from the zero-phase filter means described in claim 10 to yield artifact data.

12. Apparatus for automatically detecting a subject'"'"'s state of alertness from the subject'"'"'s brain wave data comprising:

(A) data provision means selected from the group of means consisting of electroencephalogram means and magnetoencelaphogram means for providing at least one channel of raw brain wave data, called e-data, selected from the group consisting of electroencephalogram data and magnetoencephalogram data;

(B) separation means for separating artifact data, called f-data, from the e-data while preventing phase distortions in the data, said separation means comprising a zero-phase filter means for providing an output of f-data, said separation means communicably connected to said data provision means;

(C) analysis means for analyzing the f-data to detect indications of fatigue or drowsiness, thereby detecting a lack of alertness, said analysis means communicably connected to said separation means; and

(D) indication means for providing an indication of the lack of alertness, said indicator means communicably connected to said analysis means.

13. The apparatus as described in claim 12 wherein said zero-phase filter means comprises an integrated circuit chip zero-phase filter.

14. The apparatus described in claim 13 wherein recursions are used with the f-data from the zero-phase filter means described in claim 13 to yield artifact data.