Multi-channel brain or cortical activity monitoring and method

• US 8,838,226 B2
• Filed: 12/01/2009
• Issued: 09/16/2014
• Est. Priority Date: 12/01/2009
• Status: Active Grant

• Current Assignee: NeuroWave Systems Inc.
• Original Assignee: NeuroWave Systems Inc.
• Inventors: Bibian, Stphane, Zikov, Tatjana
• Primary Examiner(s): Mallari, Patricia
• Assistant Examiner(s): CATINA, MICHAEL ANTHONY
• Application Number:
  US12/628,568
• Publication Number:
  US 20110130675A1
• Time in Patent Office: 1,750 Days
• Field of Search: 600/544, 600/545
• US Class Current: 600/544
• CPC Class Codes: A61B 5/369 Electroencephalography [EEG] devices for psychotechnics A61B5/16
• CPC Class Codes: A61B 5/4064 Evaluating the brain A61B5/031, A61B5/369, A61B5/14553 take precedence
• CPC Class Codes: A61B 5/4082 Diagnosing or monitoring movement diseases, e.g. Parkinson, Huntington or Tourette
• CPC Class Codes: A61B 5/4821 Determining level or depth of anaesthesia A61B5/1106 takes precedence
• CPC Class Codes: A61B 5/6843 Monitoring or controlling sensor contact pressure
• CPC Class Codes: A61B 5/7203 for noise prevention, reduction or removal
• CPC Class Codes: A61B 5/7221 Determining signal validity, reliability or quality A61B5/7207 and A61B5/7217 take precedence
• CPC Class Codes: A61B 5/7225 Details of analog processing, e.g. isolation amplifier, gain or sensitivity adjustment, filtering, baseline or drift compensation A61B5/30, A61B5/316 take precedence; transformers for specific applications H01F38/00; amplifiers H03F
• CPC Class Codes: A61B 5/7257 using Fourier transforms
• CPC Class Codes: A61B 5/726 using Wavelet transforms
• CPC Class Codes: A61M 5/1723 using feedback of body parameters, e.g. blood-sugar, pressure measurement of body parameters A61B5/00

Abstract

The present invention relates to a quantitative electroencephalogram (QEEG) monitor and system capable of monitoring and displaying simultaneously neuropathological characteristic and activity of both sides of a subject'"'"'s brain. The methods include various indices and examination of differences in these indices by which neurophysiological conditions or problems can be identified and treated. These methods, and the systems and devices using these methods preferably can be used for identifying these neurophysiological conditions or brain dysfunction with monitors and methods for seizure detection, for sedation monitoring, for anesthesia monitoring, and the like. These bilateral brain monitoring methods and systems, and the devices using these methods can be used by individuals or clinicians with little or no training in signal analysis or processing. These bilateral monitoring methods can also be used in a range of applications.

Claims

1. A method of determining electroencephalogram (EEG) signal quality in a device for quantifying brain or cortical activity as a function of depth of sedation or anesthesia comprising steps of:

a. anesthetizing or sedating a subject;

b. monitoring the subject with a brain having a left hemisphere and a right hemisphere under anesthesia or sedation device for quantifying brain or cortical activity as a function of depth of sedation or anesthesia, the device with at least two measurement electrodes, and at least one reference electrode, the at least two measurement electrodes comprising at least one electroencephalogram (EEG) electrode, having a signal, positioned to monitor left hemisphere brain or cortical activity and at least one EEG electrode, having a signal, positioned to monitor right hemisphere brain or cortical activity of the subject'"'"'s brain, the reference electrode comprising at least one EEG electrode, each electrode providing an EEG analog signal which is subsequently converted to a digital signal;

c. measuring the brain or cortical activity of both the subject'"'"'s left and right brain hemispheres essentially simultaneously over a period of time part of the period of time over which the subject is under sedation or anesthesia;

d. calculating based in part on the digital signals with the processor at least one numerical quantitative electroencephalogram (QEEG) time-series index corresponding to the brain or cortical activity as a function of depth of anesthesia or sedation of each of the left and right hemispheres of the subject'"'"'s brain over the period of time part of the period of time over which the subject is under sedation or anesthesia;

e. displaying the at least two numerical time-series indices, with at least one numerical time-series index corresponding to the brain or cortical activity of each of the left and the right hemispheres over the period of time, part of the period of time over which the subject is under sedation or anesthesia, on a monitor simultaneously;

f. comparing the numerical time-series indices of each hemisphere'"'"'s cortical or brain activity as a function of depth of anesthesia or sedation; and

g. determining, based at least in part on differences between the at least two numerical QEEG time-series indices corresponding to the brain or cortical activity as a function of depth of anesthesia or sedation, whether the signal of at least one of the EEG electrodes has poor quality.

2. The method of claim 1 wherein an additional step is comparing the calculated numerical brain or cortical activity time-series indices corresponding to the brain or cortical activity as a function of depth of anesthesia or sedation for each of the subject'"'"'s brain hemispheres and determining based on differences between these indices whether the subject has suffered, or is suffering some neuropathological activity.

3. The method of claim 1 wherein an additional step is comparing the calculated numerical brain or cortical activity time-series indices for each of the subject'"'"'s brain hemispheres and determining if the subject'"'"'s status has suddenly changed indicating wakefulness or awareness in at least one hemisphere of the subject'"'"'s brain.

4. The method of claim 1 wherein indices are calculated using a wavelet transform or a Fast Fourier transform.

5. The method of claim 1 where the numerical time-series indices are displayed on a monitor in color, that color corresponding to the color of an EEG electrode lead connector, an EEG electrode label, or an EEG electrode lead wire used to attach the processor to the given side of the subject'"'"'s head where the EEG electrode is placed.

6. A method of detecting neuropathological activity with a device for quantifying brain or cortical activity in a subject as a function of depth of sedation or anesthesia comprising the steps of:

a. anesthetizing or sedating a subject;

b. monitoring the subject with a brain having a left hemisphere and a right hemisphere under anesthesia or sedation device for quantifying brain or cortical activity as a function of depth of sedation or anesthesia, the device with at least two measurement electrodes, and at least one reference electrode, the at least two measurement electrodes comprising at least one electroencephalogram (EEG) electrode, having a signal, positioned to monitor left hemisphere brain or cortical activity and at least one EEG electrode, having a signal, positioned to monitor right hemisphere brain or cortical activity of the subject'"'"'s brain, the reference electrode comprising at least one EEG electrode, each electrode providing an EEG analog signal which is subsequently converted to a digital signal;

c. measuring the brain or cortical activity of both the subject'"'"'s left and right brain hemispheres essentially simultaneously over a period of time part of the period of time over which the subject is under sedation or anesthesia;

d. calculating based in part on the digital signals with the processor at least one numerical quantitative electroencephalogram (QEEG) time-series index corresponding to the brain or cortical activity as a function of depth of anesthesia or sedation of each of the left and right hemispheres of the subject'"'"'s brain over the period of time part of the period of time which the subject is under sedation or anesthesia;

e. displaying the at least two numerical time-series indices, with at least one numerical time-series index corresponding to the brain or cortical activity of each of the left and the right hemispheres over the period of time part of the period of time which the subject is under sedation or anesthesia on a monitor simultaneously;

f. comparing the numerical time-series indices of each hemisphere'"'"'s cortical or brain activity as a function of depth of anesthesia or sedation; and

g. determining based at least in part on differences between the calculated indices for each hemisphere whether the brain or cortical activity of one hemisphere of the brain is indicative of a neuropathological condition when compared to the brain or cortical activity of the other hemisphere of the brain of the subject.

7. The method of claim 6 wherein an additional step is comparing the calculated brain or cortical activity numerical time-series indices for each of the subject'"'"'s brain hemispheres and determining, based at least in part on differences between the at least two numerical QEEG time-series indices, whether the signal of one or more of the EEG electrodes has poor signal quality.

8. The method of claim 6 wherein an additional step is comparing the calculated numerical brain or cortical activity time-series indices for each of the subject'"'"'s brain hemispheres and determining if the subject'"'"'s status has changed suddenly indicating wakefulness or awareness in at least one hemisphere of the subject'"'"'s brain.

9. The method of claim 6 wherein indices are calculated using a wavelet transform or a Fast Fourier transform.

10. The method of claim 6 where the numerical time-series indices are displayed on a monitor in color, that color corresponding to the color of an EEG electrode lead connector, an EEG electrode label, or an EEG electrode lead wire used to attach the processor to the given side of the subject'"'"'s head where the EEG electrode is placed.

11. A method of detecting a sudden change in subject status with a device for quantifying brain or cortical activity in the subject as a function of depth of sedation or anesthesia comprising the steps of:

a. anesthetizing or sedating a subject;

b. monitoring the subject with a brain having a left hemisphere and a right hemisphere under anesthesia or sedation device for quantifying brain or cortical activity as a function of depth of sedation or anesthesia, the device with at least two measurement electrodes, and at least one reference electrode, the at least two measurement electrodes comprising at least one electroencephalogram (EEG) electrode, having a signal, positioned to monitor left hemisphere brain or cortical activity and at least one EEG electrode, having a signal, positioned to monitor right hemisphere brain or cortical activity of the subject'"'"'s brain, the reference electrode comprising at least one EEG electrode, each electrode providing an EEG analog signal which is subsequently converted to a digital signal;

c. measuring the brain or cortical activity of both the subject'"'"'s left and right brain hemispheres essentially simultaneously over a period of time part of the period of time over which the subject is under sedation or anesthesia;

d. calculating based in part on the digital signals with the processor at least one numerical quantitative electroencephalogram (QEEG) time-series index corresponding to the brain or cortical activity as a function of depth of anesthesia or sedation of each of the left and right hemispheres of the subject'"'"'s brain over the period of time part of the period of time which the subject is under sedation or anesthesia;

e. displaying the at least two numerical time-series indices, with at least one numerical time-series index corresponding to the brain or cortical activity of each of the left and the right hemispheres over the period of time part of the period of time which the subject is under sedation or anesthesia on a monitor simultaneously;

f. comparing the numerical time-series indices of each hemisphere'"'"'s cortical activity as a function of depth of anesthesia or sedation; and

g. determining based on the calculated indices for each hemisphere whether differences between the brain or cortical activity of one hemisphere of the brain is indicative of a change in subject status when compared to the brain or cortical activity of the other hemisphere of the brain of the subject.

12. The method of claim 11 wherein the change in subject status corresponds to a reaction of the subject following noxious stimulation.

13. The method of claim 11 wherein an additional step is comparing the calculated numerical brain or cortical activity indices for each of the subject'"'"'s brain hemispheres and determining, based at least in part on the differences between the at least two numerical QEEG time-series indices, whether the signal of one or more of the EEG electrodes has poor signal quality.

14. The method of claim 11 wherein an additional step is comparing the calculated numerical brain or cortical activity time-series indices for each of the subject'"'"'s brain hemispheres and determining whether the subject has suffered, or is suffering some neuropathological activity based on differences between the indices.

15. The method of claim 11 wherein the indices are calculated using a wavelet transform or a Fast Fourier transform.

16. The method of claim 11 where the numerical time-series indices are displayed on a monitor in color, that color corresponding to the color of an EEG electrode lead connector, an ERG electrode label, or an EEG electrode lead wire used to attach the processor to the given side of the subject'"'"'s head where the EEC electrode is placed.

17. A method of closed-loop or semi-automatic anesthesia or sedative drug delivery to a subject with a device for quantifying brain or cortical activity as a function of depth of sedation or anesthesia comprising the steps of:

a. anesthetizing or sedating a subject;

b. monitoring the subject with a brain having a left hemisphere and a right hemisphere under anesthesia or sedation device for quantifying brain or cortical activity as a function of depth of sedation or anesthesia, the device with at least two measurement electrodes, and at least one reference electrode, the at least two measurement electrodes comprising at least one electroencephalogram (EEG) electrode, having a signal, positioned to monitor left hemisphere brain or cortical activity and at least one EEG electrode, having a signal, positioned to monitor right hemisphere brain or cortical activity of the subject'"'"'s brain, the reference electrode comprising at least one EEG electrode, each electrode providing an EEG analog signal which is subsequently converted to a digital signal;

c. measuring the brain or cortical activity of both the subject'"'"'s left and right brain hemispheres essentially simultaneously over a period of time part of the period of time over which the subject is under sedation or anesthesia;

d. calculating based in part on the digital signals with the processor at least one numerical quantitative electroencephalogram (QEEG) time-series index corresponding to the brain or cortical activity as a function of depth of anesthesia or sedation of each of the left and right hemispheres of the subject'"'"'s brain over the period, of time part of the period of time which the subject is under sedation or anesthesia;

e. displaying the at least two numerical time-series indices, with at least one numerical time-series index corresponding to the brain or cortical activity of each of the left and the right hemispheres over the period of time part of period of time which the subject is under sedation or anesthesia on a monitor simultaneously;

f. comparing the numerical time-series indices of each hemisphere'"'"'s cortical activity as a function of depth of anesthesia or sedation; and

g. determining the subject'"'"'s need for additional anesthesia or sedation based on a least risk approach calculated by comparing the numerical time-series indices of each hemisphere'"'"'s cortical activity where the least risk approach minimizes risk to the subject.

18. The method of claim 17 where the indices are calculated using a wavelet transform or a Fast Fourier transform.

19. The method of claim 17 where the numerical time-series indices are displayed on a monitor in color, that color corresponding to the color of an EEG electrode lead connector, an EEG electrode label, or an EEG electrode lead wire used to attach the processor to the given side of the subject'"'"'s head where the EEG electrode is placed.

20. A method of providing a message to the user of a device for quantifying brain or cortical activity as a function of depth of sedation or anesthesia comprising steps of:

a. anesthetizing or sedating a subject;

b. monitoring the subject with a brain having a left hemisphere and a right hemisphere under anesthesia or sedation device for quantifying brain or cortical activity as a function of depth of sedation or anesthesia, the device with at least two measurement electrodes, and at least one reference electrode, the at least two measurement electrodes comprising at least one electroencephalogram (EEG) electrode, having a signal, positioned to monitor left hemisphere brain or brain or cortical activity and at least one EEG electrode, having a signal, positioned to monitor right hemisphere brain or cortical activity of the subject'"'"'s brain, the reference electrode comprising at least one EEG electrode, each electrode providing an EEG analog signal which is converted subsequently to a digital signal;

c. measuring the brain or cortical activity of both the subject'"'"'s left and right brain hemispheres essentially simultaneously over a period of time part of the period of time over which the subject is under sedation or anesthesia;

d. calculating based in part on the digital signals and using a wavelet transform or Fast Fourier transform with a processor at least one numerical quantitative electroencephalogram (QEEG) time-series index corresponding to the brain or cortical activity as a function of depth of anesthesia or sedation of each of the left and right hemispheres of the subject'"'"'s brain over the period of time part of period of time which the subject is under sedation or anesthesia;

e. comparing the numerical indices of each hemisphere'"'"'s cortical activity as a function of depth of anesthesia or sedation; and

f. displaying a message, either audible or visual, or a combination thereof, notifying a caregiver when signal quality is low in a given electrode, some neuropathological activity is detected, or the subject'"'"'s status changes suddenly, as determined based at least in part on the at least two calculated numerical time-series indices as a function of depth of anesthesia or sedation.

21. A method for comparative electroencephalography in monitoring brain function as a function of anesthesia or sedation in a plurality of distinct brain regions of the same subject on a continuous and substantially concurrent basis, comprising the steps of:

a. applying at least one electroencephalographic measurement electrode at each of said plurality of brain regions, and applying at least one reference electrode, and coupling each measurement and reference electrode to a control and processing system;

b. continuously acquiring an analog electroencephalographic signal from each of said electroencephalographic measurement electrodes;

c. converting the analog electroencephalographic signal from each of said electroencephalographic measurement electrodes to a digital signal;

d. separately and concurrently calculating for each said digital electroencephalographic signal at least one numerical quantitative electroencephalographic time-series index representative of the brain activity as a function of depth of anesthesia or sedation of the brain region corresponding to the measurement electrode;

e. concurrently visually displaying on a monitor at least one numerical quantitative electroencephalographic time-series index for each of at least two distinct brain regions; and

f. administrating a drug or therapeutics to said subject based on a comparison of at the least two quantitative electroencephalographic time-series indices corresponding to the brain activity as a function of depth of anesthesia or sedation of the brain region.

22. The method of claim 21 where the EEG signals obtained from said distinct brain regions are displayed concurrently with the corresponding numerical quantitative electroencephalographic time-series index.

23. The method of claim 22 where at least three numerical quantitative electroencephalographic time-series indices corresponding to distinct brain regions are displayed in a spider graph.