Conformable actively multiplexed high-density surface electrode array for brain interfacing

• US 8,934,965 B2
• Filed: 06/01/2012
• Issued: 01/13/2015
• Est. Priority Date: 06/03/2011
• Status: Active Grant

• Current Assignee: Board of Trustees of The University of Illinois
• Original Assignee: Board of Trustees of The University of Illinois, Trustees Of The University Of Pennsylvania (University of Pennsylvania)
• Inventors: Rogers, John, Litt, Brian, Viventi, Jonathan, Kim, Dae-Hyeong
• Primary Examiner(s): Dvorak, Linda
• Assistant Examiner(s): ANTISKAY, BRIAN MICHAEL
• Application Number:
  US13/486,726
• Publication Number:
  US 20130072775A1
• Time in Patent Office: 956 Days
• Field of Search: 600372-373, 600377-378, 600/393, 600544-545, 607115-118
• US Class Current: 600/544
• CPC Class Codes: A61B 2562/046 in a matrix array
• CPC Class Codes: A61B 2562/125 characterised by the manufacture of electrodes
• CPC Class Codes: A61B 2562/164 the sensor is mounted in or on a conformable substrate or carrier
• CPC Class Codes: A61B 5/0036 including treatment, e.g., using an implantable medical device, ablating, ventilating
• CPC Class Codes: A61B 5/24 Detecting, measuring or recording bioelectric or biomagnetic signals of the body or parts thereof
• CPC Class Codes: A61B 5/291 for electroencephalography [EEG]
• CPC Class Codes: A61B 5/4094 Diagnosing or monitoring seizure diseases, e.g. epilepsy
• CPC Class Codes: A61B 5/6868 Brain
• CPC Class Codes: A61B 5/7246 using correlation, e.g. template matching or determination of similarity
• CPC Class Codes: A61B 5/7267 involving training the classification device
• CPC Class Codes: A61B 5/7282 Event detection, e.g. detecting unique waveforms indicative of a medical condition A61B5/4094, A61B5/4818, A61B5/349, A61B5/0823 take precedence
• CPC Class Codes: A61F 2/72 Bioelectric control, e.g. myoelectric
• CPC Class Codes: A61M 5/20 Automatic syringes, e.g. with automatically actuated piston rod, with automatic needle injection, filling automatically A61M5/142 , A61M5/46 take precedence; hypodermic projectiles F42B12/54
• CPC Class Codes: A61M 5/31 Details
• CPC Class Codes: A61N 1/0529 Electrodes for brain stimulation
• CPC Class Codes: A61N 1/0531 Brain cortex electrodes
• CPC Class Codes: A61N 1/36017 with leads or electrodes penetrating the skin
• CPC Class Codes: A61N 1/36025 for treating a mental or cerebral condition
• CPC Class Codes: A61N 2005/063 comprising light transmitting means, e.g. optical fibres
• CPC Class Codes: A61N 5/0601 Apparatus for use inside the body
• CPC Class Codes: G16H 50/70 : for mining of medical data, e.g. analysing previous cases of other patients

Abstract

Provided are methods and devices for interfacing with brain tissue, specifically for monitoring and/or actuation of spatio-temporal electrical waveforms. The device is conformable having a high electrode density and high spatial and temporal resolution. A conformable substrate supports a conformable electronic circuit and a barrier layer. Electrodes are positioned to provide electrical contact with a brain tissue. A controller monitors or actuates the electrodes, thereby interfacing with the brain tissue. In an aspect, methods are provided to monitor or actuate spatio-temporal electrical waveform over large brain surface areas by any of the devices disclosed herein.

Claims

1. A method for spatio-temporally electrically interfacing with a brain tissue, the method comprising the steps of:

providing a conformable device for interfacing with brain tissue in a biological environment, the device comprising;

a deformable substrate;

a deformable array of electrodes comprising a plurality of electrodes in electrical communication with a plurality of deformable electrical interconnects; and

a barrier layer encapsulating at least a portion of the deformable electrical interconnects, wherein the deformable substrate, deformable array of electrodes and the barrier layer provide a net bending stiffness of the device low enough that the device is capable of establishing conformal contact with the brain tissue in the biological environment, wherein the deformable array of electrodes is supported by the barrier layer;

electrically contacting at least a portion of the plurality of electrodes with the brain tissue in the biological environment by conformally contacting the conformable device with a surface of the brain tissue in the biological environment;

spatio-temporally interfacing the brain tissue with the conformable device to monitor or actuate a spatio-temporal profile over the surface of the brain tissue in electrical contact with the plurality of electrodes;

monitoring the spatio-temporal electrical brain profile with the device in conformal and electrical contact with a brain surface of a subject, wherein the monitoring comprises detecting an electric potential of a plurality of individual brain surface locations beneath each electrode of the array of electrodes at a plurality of different time points;

encoding the detected electric potential to obtain an encoded spatio-temporal brain waveform; and

analyzing the encoded spatio-temporal brain waveform to identify an abnormal spatio-temporal brain waveform, wherein the identified abnormal spatio-temporal brain waveform is a spiral waveform and actuating electrical activity over the brain surface with an output spatio-temporal profile from the deformable array of electrodes to disrupt or terminate the spiral waveform.

2. The method of claim 1, wherein the interfacing step further comprises:

actuating the electric potential of the brain tissue at a plurality of individual brain surface locations over a plurality of different time points.

3. The method of claim 1, wherein temporally adjacent time points are separated by a time period that is greater than or equal to 30 μ

s and less than or equal to 1 second.

4. The method of claim 1, wherein the plurality of different time points span a total time period selected from a range that is greater than or equal to 1 second.

5. The method of claim 1, wherein the number of individual brain surface locations is selected from a range that is greater than or equal to 200 and less than or equal to 10,000.

6. The method of claim 5, wherein adjacent individual brain surface locations are separated from each other by a range that is greater than or equal to 50 μ

m and less than or equal to 5 mm.

7. The method of claim 1, further comprising:

analyzing the monitored electric potential spatio-temporal profile to identify an electrical waveform.

8. The method of claim 7, wherein the analyzing step comprises pattern recognition, a clustering algorithm;

machine learning, data compression, or a combination thereof.

9. The method of claim 7, wherein the analyzing step comprises monitoring the magnitude of electric potential at each brain surface location, a time course of electric potential change at each brain surface location, or both.

21. The method of claim 1, wherein the spatio-temporal profile corresponds to an interictal or an ictal state.

22. The method of claim 1, wherein the spatio-temporal profile corresponds to a cluster of spikes.

23. The method of claim 1, wherein the spatio-temporal profile comprises a spindle oscillation that is punctate and temporally coherent.

24. The method of claim 1, wherein the spatio-temporal profile comprises a waveform that is at least partially a substantially planar wave having a preferential propagation direction.

25. The method of claim 1, wherein the spatio-temporal profile comprises a waveform that is a spiral wave.

26. The method of claim 25, wherein the spiral wave waveform indicates ictal onset.

29. The method of claim 1, further comprising implanting the conformable device in a patient.

30. The method of claim 29, wherein at least a portion of the conformable device is inserted into a sulcus or a groove of the brain tissue without penetrating through brain tissue.

31. The method of claim 30, wherein the conformable device is two-sided to monitor or actuate two spatio-temporal profiles, a first spatio-temporal profile from one side of the sulcus or groove, and a second spatio-temporal profile from a second side of the sulcus or groove.

32. The method of claim 31, further comprising folding the conformable device to provide the two-sides from a single deformable device.

33. The method of claim 1, wherein the electrical contact is provided by conformal contact with at least a portion of a sulcus or groove of the brain tissue and at least a portion of a gyrus of the brain tissue.

34. The method of claim 1, further comprising both monitoring and actuating brain tissue.

35. The method of claim 34, further comprising connecting the conformable device to a neuroprosthetic device.

36. The method of claim 1, wherein conformal contact comprises physical contact with a surface of the brain tissue, without penetrating the brain tissue.

37. The method of claim 1, wherein the conformable device is bendable.

38. The method of claim 1, wherein the conformable device is stretchable.

39. The method of claim 1, wherein the conformable device has:

a spatial resolution selected from a range that is greater than or equal to 50 μ

m and less than or equal to 5 mm; and

a temporal resolution selected from a range that is greater than or equal to 0.5 ms and less than or equal to 1 second.

40. The method of claim 1, wherein the conformable device has a conformable contact area footprint with the brain surface selected from a range that is greater than or equal to 10 mm² and less than or equal to 100 cm².

41. The method of claim 1, wherein the barrier layer limits a net leakage current from the deformable array of electrodes to the tissue to an amount that does not adversely affect the tissue.

42. The method of claim 1, wherein the interfacing step has a data transfer rate that is greater than or equal to 90,000 samples per second.

43. The method of claim 1, wherein the abnormal spatio-temporal brain waveform is identified from a waveform that is a spiral waveform.

44. The method of claim 1, further comprising:

actuating the array of electrodes with a spatio-temporal electric potential profile; and

generating a waveform of electric potential to the brain surface from the actuated array of electrodes to disrupt or terminate the abnormal spatio-temporal brain waveform.

45. The method of claim 44, wherein the abnormal spatio-temporal brain waveform comprises a spiral waveform.

46. The method of claim 1, further comprising the step of implanting the device in the subject by conformally contacting the device with the brain surface without physical penetration of brain tissue.

47. The method of claim 46, wherein the device is implanted endoscopically.

48. The method of claim 1 wherein the monitoring is acute monitoring during an operative procedure.

49. The method of claim 1, wherein the monitoring is chronic over a time period that is greater than or equal to 12 hours.

10. A method for spatio-temporally electrically interfacing with a brain tissue, the method comprising the steps of:

providing a conformable device for interfacing with brain tissue in a biological environment, the device comprising;

a deformable substrate;

a deformable array of electrodes comprising a plurality of electrodes in electrical communication with a plurality of deformable electrical interconnects; and

a barrier layer encapsulating at least a portion of the deformable electrical interconnects, wherein the deformable substrate, deformable array of electrodes and the barrier layer provide a net bending stiffness of the device low enough that the device is capable of establishing conformal contact with the brain tissue in the biological environment, wherein the deformable array of electrodes is supported by the barrier layer;

electrically contacting at least a portion of the plurality of electrodes with the brain tissue in the biological environment by conformally contacting the conformable device with a surface of the brain tissue in the biological environment;

spatio-temporally interfacing the brain tissue with the conformable device to monitor or actuate a spatio-temporal profile over the surface of the brain tissue in electrical contact with the plurality of electrodes;

wherein the interfacing step further comprises;

monitoring or actuating the electric potential of the brain tissue at a plurality of

individual brain surface locations over a plurality of different time points;

analyzing the monitored electric potential spatio-temporal profile to identify an electrical waveform wherein the analyzing step comprises;

monitoring the magnitude of electric potential at each brain surface location, a time course of electric potential change at each brain surface location, or both; and

calculating the relative delay of a spike in electrical potential at a brain surface location, wherein a spike is identified for any brain surface location having an electric potential that is greater than 50% of a peak root-mean-square value over all brain surface locations.

11. The method of claim 10, further comprising encoding a speed and direction of the waveform from the relative delay and electric potential at each brain surface location.

12. The method of claim 11, further comprising analyzing the encoded waveform and identifying the waveform as abnormal or normal.

13. The method of claim 12, wherein the analyzing step further comprises principal components analysis (PCA) to reduce the computational requirement of the analyzing step.

14. The method of claim 12, further comprising the step of actuating a spatio-temporal electrical profile over the surface of the brain tissue to disrupt the abnormal waveform.

15. The method of claim 14, wherein the actuating step comprises energizing the plurality of electrodes with a pattern of electric potential having:

a polarity profile that is opposite the abnormal waveform polarity to at least partially electrically cancel the abnormal waveform;

a region of high polarity sufficient to at least partially terminate propagation the abnormal waveform;

or

a polarity profile corresponding to a waveform of normal brain activity.

16. The method of claim 15, further comprising activating a therapeutic device when an abnormal waveform is identified, wherein the therapeutic device applies a therapeutic intervention to the brain.

17. The method of claim 16, wherein the therapeutic device and therapeutic intervention is selected from the group consisting of:

a penetrating electrode to provide electrical stimulation;

a micro-syringe to inject a chemical compound onto or into the brain; and

an optical fiber to optically stimulate the brain surface or brain interior.

18. The method of claim 12, wherein the waveform is identified as abnormal for a waveform comprising:

a plane wave propagating in a first direction that bends and subsequently propagates in a reentrant spiral loop having a preferential direction that is clockwise or counter-clockwise.

19. The method of claim 18, further comprising a second plane wave that changes the direction of the reentrant spiral loop.

20. The method of claim 18, further comprising:

spatio-temporally energizing the plurality of electrodes to actuate the brain tissue surface with a traveling wave of electric potential to terminate the reentrant spiral loop.

27. A method for spatio-temporally electrically interfacing with a brain tissue, the method comprising the steps of:

providing a conformable device for interfacing with brain tissue in a biological environment, the device comprising;

a deformable substrate;

a deformable array of electrodes comprising a plurality of electrodes in electrical communication with a plurality of deformable electrical interconnects; and

a barrier layer encapsulating at least a portion of the deformable electrical interconnects, wherein the deformable substrate, deformable array of electrodes and the barrier layer provide a net bending stiffness of the device low enough that the device is capable of establishing conformal contact with the brain tissue in the biological environment, wherein the deformable array of electrodes is supported by the barrier layer;

electrically contacting at least a portion of the plurality of electrodes with the brain tissue in the biological environment by conformally contacting the conformable device with a surface of the brain tissue in the biological environment;

spatio-temporally interfacing the brain tissue with the conformable device to monitor or actuate a spatio-temporal profile over the surface of the brain tissue in electrical contact with the plurality of electrodes, wherein the interfacing step further comprises identifying the spatio-temporal profile as a spiral waveform and actuating electrical activity over the brain surface with an output spatio-temporal profile from the deformable array of electrodes to disrupt or terminate the spiral waveform.

28. The method of claim 27, wherein the spiral waveform disruption prevents, attenuates, or stops a seizure.