Fitting a Neural Prosthesis Using Impedance and Electrode Height

• US 20080294223A1
• Filed: 10/26/2007
• Published: 11/27/2008
• Est. Priority Date: 12/01/2005
• Status: Active Grant

• Current Assignee: Cortigent Incorporated, Doheny Eye Institute
• Original Assignee: Doheny Eye Institute
• Inventors: Greenberg, Robert J., Roy, Arup, Zhou, Dao Min, McMahon, Matthew J., Humayun, Mark S., Fine, Ione, Yadav, Sumit, Hines, Amy, Dai, Rongqing, Horsager, Alan M., Weiland, James David
• Granted Patent: US 8,190,267 B2
• Time in Patent Office: Days
• US Class Current: 607/54
• CPC Class Codes: A61N 1/0543 Retinal electrodes
• CPC Class Codes: A61N 1/36046 of the eye
• CPC Class Codes: A61N 1/37247 User interfaces, e.g. input or presentation means

Abstract

The invention is a method of automatically adjusting an electrode array to the neural characteristics of an individual subject. The response to electrical neural stimulation varies from subject to subject. Measure of impedance may be used to predict the electrode height from the neural tissue and, thereby, predict the threshold of perception. Alternatively, electrode height may be measured directly to predict the threshold of perception. Also, impedance measurement may be used to quickly identify defective electrodes and proper electrode placement.

Claims

1. A method of determining proper placement of a neural stimulation electrode array comprising:

placing an electrode array in proximity of neural tissue;

measuring impedance across the electrode array; and

determining, by the impedance, the proper placement of the electrode array.

2. The method according to claim 1, further comprising:

placing said electrode array in a plurality of locations;

measuring impedance across the electrode array in each location; and

determining, by the impedances, the best placement of the electrode array.

5. The method according to claim 1, further comprising:

measuring electrode height; and

estimating a threshold of perception based on said impedance and said electrode height.

6. The method according to claim 5, further comprising measuring retinal thickness;

and

estimating a threshold of perception based on said impedance, said electrode height and said retinal thickness.

7. The method according to claim 6, further comprising estimating a brightness response curve based on said impedance, said electrode height and said retinal thickness.

3. A method of fitting a neural stimulation device comprising:

providing a plurality of electrodes suitable to stimulate neural tissue;

measuring impedance of at least one of said plurality of electrodes; and

estimating a threshold of perception based on said impedance.

4. The method according to claim 3, further comprising communicating said impedance to a clinician.

8. The method according to claim 3, further comprising estimating threshold of perception, based on said impedance for other geographically related electrodes.

9. A method of fitting a neural stimulation system comprising:

proving a plurality of electrodes suitable to stimulate neural tissue;

measuring electrode height of at least one of said plurality of electrodes; and

estimating a threshold of perception based on said electrode height.

10. The method according to claim 9, further comprising communicating said electrode height to a clinician.

11. The method according to claim 10, further comprising:

measuring impedance between at least one electrode; and

estimating a threshold of perception based on said impedance and said electrode height.

12. The method according to claim 11, further comprising:

measuring retinal thickness; and

estimating a threshold of perception based on said impedance, said electrode height and said retinal thickness.

13. The method according to claim 12, further comprising estimating a brightness response curve based on said impedance, said electrode height and said retinal thickness.

14. The method according to claim 9, wherein measuring electrode height is by OCT.

15. The method according to claim 9, wherein said measuring electrode height is by ultrasound.

16. A method of fitting and adjusting a neural stimulation device comprising:

providing a plurality of electrodes suitable to stimulate neural tissue;

measuring impedance of at least one of said plurality of electrodes;

communicating said impedance to an external device; and

displaying said impedance to a user.

17. The method according to claim 16, wherein displaying said impedance to a user is by graphical representation of said plurality of electrodes.

18. The method according to claim 16, wherein displaying said impedance to a user is a graphical representation of said plurality of electrodes.

19. The method according to claim 16, wherein displaying said impedance to a user is by color.

20. The method according to claim 16, wherein displaying said impedance to a user is by graphical symbol.