Method of measuring neural responses

• US 7,283,877 B1
• Filed: 12/19/2003
• Issued: 10/16/2007
• Est. Priority Date: 12/20/2002
• Status: Active Grant

• Current Assignee: Advanced Bionics AG (Sonova Holding AG)
• Original Assignee: Advanced Bionics Corporation (Sonova Holding AG)
• Inventors: Litvak, Leonid M, Overstreet, Edward H
• Primary Examiner(s): Jackson; Gary
• Assistant Examiner(s): Patton; Amanda
• Application Number:
  US10/741,409
• Time in Patent Office: 1,397 Days
• Field of Search: 607/48, 607/55, 607/56, 607/57, 607/62, 607/67, 607/46, 607/70, 600/544, 600/559
• US Class Current: 607/67
• CPC Class Codes: A61B 5/24 Detecting, measuring or recording bioelectric or biomagnetic signals of the body or parts thereof
• CPC Class Codes: A61N 1/3605 Implantable neurostimulators for stimulating central or peripheral nerve system
• CPC Class Codes: A61N 1/36071 Pain

Abstract

A new method of recording and processing neural responses (“NR”) is provided, wherein the method does not assume a linear system response and does not assume a linear response at the interface between electrodes and tissue. The method of the present invention cancels out non-linearities and/or system hysteresis. Other artifacts such as system cross-talk between stimulation and recording circuits are also canceled out. The method provided uses at least two stimulating electrodes simultaneously in one recording step.

Claims

1. A method of recording and processing neural response (NR), the method comprising:

(a) providing a stimulating electrode, E1, and a stimulating electrode, E2, and a recording electrode ER;

(b) recording RC, in response to a combination of a first, sub-threshold stimulus pulse, S1 at E1, having amplitude A and a second, sub-threshold stimulus pulse, S2 at E2, having amplitude B, wherein S1 and S2 are applied simultaneously and, when added together, provide a supra-threshold stimulus amplitude C;

(c) recording R1, in response to a sub-threshold stimulus pulse, S1 delivered through electrode E1;

(d) recording R2, in response to a sub-threshold stimulus pulse, S2 delivered through electrode E2;

(e) recording R0, in response to no stimulation at any stimulating electrodes; and

(f) processing the recordings to yield an estimated NR in accordance with the relation;

NR=RC−

(R1+R2)+R0, wherein the steps (b), (c), (d) and (e) may be performed in any order.

2. The method of claim 1, wherein the duration of each of the recordings RC, R1, R2 and R0 is approximately the same, thereby making subtraction and addition of recording data RC, R1, R2 or R0 easier by having the same number of data points in each recording.

3. The method of claim 1, wherein S1 and S2 are essentially identical stimulus with respect to shape, pulsewidth and amplitude.

4. The method of claim 1, wherein the at least two stimulating electrodes E1 and E2 stimulate a cochlear nerve.

5. The method of claim 1, wherein the at least two stimulating electrodes E1 and E2 stimulate a spinal cord nerve.

6. The method of claim 1, wherein S1 and S2 are charged-balance stimuli.

7. The method of claim 1, wherein at least one of the recordings, RC, R1, R2 or R0 is performed at least twice and then averaged to provide an averaged response recording that is more accurate than a single recording.

8. The method of claim 1, wherein each step (b), (c), (d) and (e) are performed twice in two separate runs, but with stimulus S1 and S2 applied having opposite polarities during the two runs, and the final NR estimate an average of the two NR estimates obtained from the two runs.

9. The method of claim 8, wherein at least one of the recordings, RC, R1, R2 or R0 is performed at least twice, using the same polarity stimulus, and then averaged to provide an averaged response recording that is more accurate than a single recording.

10. A method of recording and processing NR, the method comprising:

(a) providing Z stimulating electrodes E1, . . . , EZ, and one recording electrode ER, wherein Z is at least three stimulating electrodes;

(b) obtaining a recording, RC, using the recording electrode, ER, the RC recording a response to a combination of a simultaneously delivered sub-threshold stimulus pulses, S1 . . . SZ, which applied simultaneously together, provide a supra-threshold stimulus amplitude;

(c) obtaining separate recordings, R1 . . . RZ for each stimulating electrode E1 . . . EZ, using substantially identical stimuli, S1 . . . SZ, respectively, as used in step (b), but with each stimuli applied separately to obtain each recording, R1 . . . RZ;

(d) recording at least one R0 recording to no stimulation; and

(e) processing the obtained recordings to yield an estimated NR in accordance with the relation;

NR=RC−

(R1+ . . . +RZ)+R0*(Z−

1),

wherein Z is at least three and represents the number of stimulating electrodes used, and R0 is a recording run in which no stimulation is applied.

11. The method of claim 10, in which R0 is an averaged value from at least two separate runs.

12. The method of claim 10, wherein S1, . . . SZ, are essentially identical stimulus with respect to shape, pulsewidth and amplitude.

13. The method of claim 10, wherein the stimulating electrodes E1 through EZ stimulate a cochlear nerve.

14. The method of claim 10, wherein the stimulating electrodes E1 through EZ stimulate a spinal cord nerve.

15. the method of claim 10, wherein all stimuli presented S1 . . . SZ are charged-balance stimuli.

16. The method of claim 10, wherein at least one of the recordings, R0, RC, and R1 through RZ, is performed at least twice and then averaged to provide an averaged response recording.

17. The method of claim 10, wherein each steps (b), (c), (d) and (e) are performed twice in two separate runs, but with stimuli S1 . . . SZ applied having opposite polarities in the two runs and the final NR estimate is an average of the NR estimates obtained from the two runs, wherein the stimulus amplitudes, S1 . . . SZ, in the two runs may be identical or different between the two runs.

18. The method of claim 17, wherein at least one of the recordings, RC, R0 or R1 . . . RZ is performed at least twice, using the same polarity stimulus, and then averaged to provide an averaged response recording that is more accurate than a single recording.