Electroencephalogram diagnosis apparatus and method

• US 20040077966A1
• Filed: 04/18/2003
• Published: 04/22/2004
• Est. Priority Date: 10/17/2002
• Status: Abandoned Application

• Current Assignee: Fuji Xerox Company Limited (Xerox Holdings Corp.)
• Original Assignee: Fuji Xerox Company Limited (Xerox Holdings Corp.)
• Inventors: Ichikawa, Kazuhisa, Yamaguchi, Isao
• Application Number:
  US10/418,222
• Publication Number:
  US 20040077966A1
• Time in Patent Office: Days
• US Class Current: 600/544
• CPC Class Codes: A61B 5/369 Electroencephalography [EEG] devices for psychotechnics A61B5/16
• CPC Class Codes: A61B 5/4094 Diagnosing or monitoring seizure diseases, e.g. epilepsy

Abstract

Measuring electrodes are disposed in positions T5 and T6 according to the international 10-20 system. Electroencephalographic data obtained from these measuring electrodes is received in an input portion, and converted into phase analysis data on a phase plane V-dV/dt by a phase analysis portion. By use of a set of feature parameters selected from an aspect ratio, a V-axis maximum value, a sub/total revolution number ratio and an RL/UB distribution ratio in a feature parameter calculating portion, a Mahalanobis distance is calculated in a Mahalanobis distance calculating portion. The abnormality of the electroencephalogram is judged on the basis of the Mahalanobis distance, and a result of the judgment is outputted.

Claims

1. An electroencephalogram diagnosis apparatus comprising:

an input unit for inputting time-series electroencephalographic data;

a phase analysis unit for plotting a time derivative dV/dt of cerebral evoked potential V with respect to the cerebral evoked potential V based on the time-series electroencephalographic data to form an electroencephalographic locus on a phase plane V-dV/dt;

a feature parameter calculating unit for calculating feature parameters on the phase plane V-dV/dt formed by the phase analysis unit;

a reference space forming unit for forming a reference space using reference learning data concerning the feature parameters;

a separation index calculating unit for calculating a separation index between the calculated feature parameters and the reference space;

a judgment unit for judging existence/absence of disease including neurological disease based on the calculated separation index;

an output unit for outputting existence/absence of disease of a subject based on a judgment result of the judgment unit; and

inspection electrodes for measuring electroencephalogram of the subject number of which is less than ten.

2. The electroencephalogram diagnosis apparatus according to claim 1, wherein the inspection electrodes are disposed at least at T5 and T6 in international 10-20 system.

3. The electroencephalogram diagnosis apparatus according to claim 1, wherein the number of the inspection electrodes is two.

4. The electroencephalogram diagnosis apparatus according to claim 3, wherein the inspection electrodes are disposed at T5 and T6 in international 10-20 system.

5. The electroencephalogram diagnosis apparatus according to claim 3, wherein the feature parameter calculating unit calculates an aspect ratio of an electroencephalographic locus on the phase plane V-dV/dt as the feature parameters.

6. The electroencephalogram diagnosis apparatus according to claim 3, wherein the feature parameter calculating unit calculates a maximum value of absolute values of V on a V-axis on the phase plane V-dV/dt as the feature parameters.

7. The electroencephalogram diagnosis apparatus according to claim 3, wherein the feature parameter calculating unit calculates a ratio of number of sub-revolutions to total number of revolutions on the phase plane V-dV/dt as the feature parameters.

8. The electroencephalogram diagnosis apparatus according to claim 3, wherein the feature parameter calculating unit calculates an RL/UB distribution ratio on the phase plane V-dV/dt as the feature parameters.

9. The electroencephalogram diagnosis apparatus according to claim 3, wherein the feature parameter calculating unit calculates a maximum value of absolute values of values V on a V-axis on the phase plane V-dV/dt, a ratio of number of sub-revolutions to total number of revolutions on the phase plane V-dV/dt, and an RL/UB distribution ratio on the phase plane V-dV/dt as the feature parameters.

10. The electroencephalogram diagnosis apparatus according to claim 5, wherein the aspect ratio is a ratio of a maximum value of absolute values in a first histogram of intersection points between a V-axis of the phase plane V-dV/dt and the electroencephalographic locus, to a maximum value of absolute values in a second histogram of intersection points between a dV/dt-axis of the phase plane V-dV/dt and the electroencephalographic locus.

11. The electroencephalogram diagnosis apparatus according to claim 5, wherein the aspect ratio is a ratio of a mean vale of absolute values in a first histogram of intersection points between a V-axis of the phase plane V-dV/dt and the electroencephalographic locus, to a mean value of absolute values in a second histogram of intersection points between a dV/dt-axis of the phase plane V-dV/dt and the electroencephalographic locus.

12. The electroencephalogram diagnosis apparatus according to claim 5, wherein the aspect ratio is a ratio of a variance of absolute values in a first histogram of intersection points between a V-axis of the phase plane V-dV/dt and the electroencephalographic locus, to a variance of absolute values in a second histogram of intersection points between a dV/dt-axis of the phase plane V-dV/dt and the electroencephalographic locus.

13. The electroencephalogram diagnosis apparatus according to claim 3, wherein a variance, a mean and an inverse matrix of a correlation matrix of the feature parameters in the reference learning data are used as the reference space.

14. The electroencephalogram diagnosis apparatus according to claim 3, wherein a Mahalanobis distance is used as the separation index between the feature parameters and the reference space.

15. An electroencephalogram diagnosis method comprising:

measuring electroencephalographic data of a subject with less than ten inspection electrodes;

inputting time-series electroencephalographic data;

plotting a time derivative dV/dt of cerebral evoked potential V with respect to the cerebral evoked potential V based on the time-series electroencephalographic data to form an electroencephalographic locus on a phase plane V-dV/dt;

calculating feature parameters on the phase plane V-dV/dt formed by the plotting step;

forming a reference space using reference learning data concerning the feature parameters;

calculating a separation index between the calculated feature parameters and the reference space;

judging existence/absence of disease including neurological disease based on the calculated separation index; and

outputting existence/absence of disease of the subject based on a judgment result of the judging step.

16. The electroencephalogram diagnosis method according to claim 15, wherein the inspection electrodes are disposed at least at T5 and T6 in international 10-20 system.

17. The electroencephalogram diagnosis method according to claim 15, wherein the number of the inspection electrodes is two.

18. A recording medium readable by a computer and recording an electroencephalogram computer diagnosis program making the computer execute:

inputting time-series electroencephalographic data using less than ten inspection electrodes;

plotting a time derivative dV/dt of cerebral evoked potential V with respect to the cerebral evoked potential V based on the time-series electroencephalographic data to form an electroencephalographic locus on a phase plane V-dV/dt;

calculating feature parameters on the phase plane V-dV/dt formed by the plotting step;

forming a reference space using reference learning data concerning the feature parameters;

calculating a separation index between the calculated feature parameters and the reference space;

judging existence/absence of disease including neurological disease based on the calculated separation index; and

outputting existence/absence of disease of the subject based on a judgment result of the judging step.

19. The recording medium according to claim 18, wherein the inspection electrodes are disposed at least at T5 and T6 in international 10-20 system.

20. The recording medium according to claim 18, wherein the number of the inspection electrodes is two.