METHOD AND DEVICE FOR REMOVING EEG ARTIFACTS

• US 20110224569A1
• Filed: 03/10/2010
• Published: 09/15/2011
• Est. Priority Date: 03/10/2010
• Status: Active Grant

• Current Assignee: Brainscope SPV LLC
• Original Assignee: New York University
• Inventors: Jacquin, Arnaud, Prichep, Leslie, Isenhart, Robert
• Granted Patent: US 8,364,255 B2
• Time in Patent Office: Days
• US Class Current: 600/544
• CPC Class Codes: A61B 5/291 for electroencephalography [EEG]
• 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 5/6831 Straps, bands or harnesses
• CPC Class Codes: A61B 5/7207 of noise induced by motion artifacts

Abstract

Systems and methods for automatically identifying segments of EEG signals or other brain electrical activity signals that contain artifacts, and/or editing the signals to remove segments that include artifacts

Claims

1. A method for automatically editing brain electrical activity data, comprising:

positioning at least two frontal EEG electrodes on a patient;

obtaining a signal representing brain electrical activity in each of the electrodes;

analyzing the signal to determine if temporal segments of the signal include artifacts due to of any of eye movements, cable or electrode movements, impulse artifacts, and muscle activity, and if any segment does include artifacts identifying the segment as including artifacts; and

editing the signal to remove segments that include artifacts.

2. The method of claim 1, wherein the at least two frontal EEG electrodes are positioned at FP1 and FP2 positions based on the expanded international 10/20 placement system.

3. The method of claim 1, wherein the at least two frontal EEG electrodes are positioned at F7 and F8 positions based on the expanded international 10/20 placement system.

4. The method of claim 1, wherein the at least two frontal EEG electrodes are positioned at FP1 and FP2 positions based on the expanded international 10/20 placement system.

5. The method of claim 1, wherein the electrodes include at least five electrodes positioned at FP1, FP2, F7, F8, and AFz positions based on the expanded international 10/20 placement system.

6. The method of claim 1, further including analyzing the signal to determine if temporal segments of the signal include artifacts due to of any significantly low amplitude signal and atypical electrical activity.

7. The method of claim 6, wherein the electrodes include at least five electrodes positioned at FP1, FP2, F7, F8, and AFz positions based on the expanded international 10/20 placement system.

8. The method of claim 7, wherein determining if temporal segments of the signal include artifacts due to eye movements includes filtering signals obtained from electrodes positioned at F7 and F8 positions and determining if the difference between the filtered signals exceeds a threshold.

9. The method of claim 7, wherein determining if temporal segments of the signal include artifacts due to eye movements includes filtering signals obtained from electrodes positioned at the Fp1 and Fp2 positions, comparing each signal to an average signal from the same electrode, determining if the signals exceed a threshold, and if the signal exceeds a threshold, determining if changes in the Fp1 and Fp2 signals occur concurrently, and if the changes do occur concurrently, identifying the segment as including artifacts.

10. The method of claim 1, wherein determining if temporal segments of the signal include artifacts due to cable or electrode movement includes identifying a signal amplitude greater than a predetermined threshold, and if any segment includes an amplitude greater than the threshold identifying that segment as including cable or electrode movement artifacts.

11. The method of claim 10, wherein the threshold is between 50 and 250 μ

V.

12. The method of claim 7, wherein determining if temporal segments of the signal include impulse artifacts includes high pass filtering a signal from at least one electrode to remove the alpha component of the signal and determining if successive 100 ms segments include signal variations greater than a predetermined threshold, and if is successive 100 ms segments include signal variations of greater than the threshold, identifying the segments as containing impulse artifacts.

13. The method of claim 12, wherein the threshold is between 25 and 250 μ

V.

14. The method of claim 7, wherein determining if temporal segments of the signal include muscle movement artifacts includes band pass filtering a signal from at least one electrode in the range of the EEG β

1 band to produce signal E1 and band pass filtering the same signal in the range of the β

2 band to produce signal E2, and if relative energy of E2 relative to E1 exceeds a threshold, identifying the segment as containing muscle movement artifacts.

15. The method of claim 7, wherein determining if temporal segments of the signal include significantly low amplitude signal includes determining if the mean square energy of a segment is below a threshold, and if the mean square energy is below a threshold, identifying the segment as including significantly low amplitude signal.

16-28. -28. (canceled)

29. A device for automatically editing brain electrical activity data signals, comprising:

at least two electrodes;

a circuit for measuring electrical potential signals from the electrodes;

a memory unit configured to store data related to the electrical potential;

an analysis unit configured to analyze the signal to determine if temporal segments of the signal include artifacts due to of any of eye movements, cable or electrode movements, impulse artifacts, and muscle activity, and if any segment does include artifacts identifying the segment as including artifacts; and

editing the data in the analysis unit to remove segments that include artifacts.

30. The device of claim 29, wherein the at least two EEG electrodes are positioned at FP1 and FP2 positions based on the expanded international 10/20 placement system.

31. The device of claim 29, wherein the at least two EEG electrodes are positioned at F7 and F8 positions based on the expanded international 10/20 placement system.

32. The device of claim 29, wherein the at least two EEG electrodes are positioned at FP1 and FP2 positions based on the expanded international 10/20 placement system.

33. The device of claim 29, wherein the electrodes include at least five electrodes positioned at FP1, FP2, F7, F8, and AFz positions based on the expanded international 10/20 placement system.

34. The device of claim 29, wherein the analysis unit is configured to analyze the signal to determine if temporal segments of the signal include artifacts due to of any significantly low amplitude signal and atypical electrical activity.

35. The device of claim 34, wherein the electrodes include at least five electrodes positioned at FP1, FP2, F7, F8, and AFz positions based on the expanded international 10/20 placement system.

36. The device of claim 35, wherein determining if temporal segments of the signal include artifacts due to eye movements includes filtering signals obtained from electrodes positioned at F7 and F8 positions and determining if the difference between the filtered signals exceeds a threshold.

37. The device of claim 35, wherein determining if temporal segments of the signal include artifacts due to eye movements includes filtering signals obtained from electrodes positioned at the Fp1 and Fp2 positions, comparing each signal to an average signal from the same electrode, determining if the signals exceed a threshold, and if the signal exceeds a threshold, determining if changes in the Fp1 and Fp2 signals occur concurrently, and if the changes do occur concurrently, identifying the segment as including artifacts.

38. The device of claim 29, wherein determining if temporal segments of the signal include artifacts due to cable or electrode movement includes identifying a signal amplitude greater than a predetermined threshold, and if any segment includes an amplitude greater than the threshold, identifying that segment as including cable or electrode movement artifacts.

39. The device of claim 35, wherein determining if temporal segments of the signal include impulse artifacts includes high pass filtering a signal from at least one electrode to remove the alpha component of the signal and determining if successive 100 ms segments include signal variations of greater than a predetermined threshold, and if is successive 100 ms segments include signal variations of greater than the threshold, identifying the segments as containing impulse artifacts.

40. The device of claim 35, wherein determining if temporal segments of the signal include muscle movement artifacts includes band pass filtering a signal from at least one electrode in the range of the EEG β

1 band to produce signal E1 and band pass filtering the same signal in the range of the β

2 band to produce signal E2, and if relative energy of E2 relative to E1 exceeds a threshold, identifying the segment as containing muscle movement artifacts.

41. The device of claim 35, wherein determining if temporal segments of the signal include significantly low amplitude signal includes determining if the mean square energy of a segment is below a threshold, and if the mean square energy is below a threshold, identifying the segment as including significantly low amplitude signal.