Integrity evaluation system in an implantable hearing prosthesis

1. A method performed at a hearing prosthesis, comprising:

performing a plurality of bipolar measurements on a plurality of electrodes configurable as bipolar electrode pairs, wherein at least one or more of the electrodes are implanted in a recipient's cochlea;

determining, based on the bipolar measurements, a bipolar impedance value for each of a plurality of the bipolar electrode pairs;

performing one or more common ground measurements at each of the plurality of bipolar electrode pairs;

resolving, using the one or more common ground measurements and a model of the implanted cochlea behavior, each of the bipolar impedance values into a perilymph impedance component and an electrode-tissue impedance component;

analyzing the perilymph impedance components and the electrode-tissue impedance components; and

initiating, at the hearing prosthesis, one or more diagnostic operations based on the analysis of the perilymph impedance components and the electrode-tissue impedance components.

2. The method of claim 1 , wherein analyzing the perilymph impedance components and the electrode-tissue impedance components, comprises:

determining, based on the bipolar impedance values, the one or more common ground measurements, and the model of the implanted cochlea behavior, the presence of abnormal current flow between two or more of the implanted electrodes.

3. The method of claim 2 , further comprising:

classifying the degree of the abnormal current flow between the two or more of the implanted electrodes.

4. The method of claim 3 , wherein initiating the one or more diagnostic operations, comprises:

initiating a diagnostic operation based on the degree of the abnormal current flow between the two or more of the implanted electrodes.

5. The method of claim 1 , wherein analyzing the perilymph impedance components and the electrode-tissue impedance components, comprises:

detecting, based on the bipolar impedance values, the one or more common ground measurements, and the model of the implanted cochlea behavior, a change in a behavior of current flow through the perilymph of the cochlea.

6. The method of claim 5 , wherein detecting a change in the behavior of current flow through the perilymph of the cochlea comprises:

detecting a deviation from expected behavior of current flow through the perilymph of the cochlea.

7. The method of claim 5 , wherein detecting a change in the behavior of the current flow through the perilymph of the cochlea comprises:

detecting an increase in the perilymph impedance component of one or more bipolar impedance values.

8. The method of claim 5 , wherein detecting a change in the behavior of the current flow through the perilymph of the cochlea comprises:

detecting a non-linearity between perilymph impedance components associated with two or more bipolar impedance values.

9. The method of claim 5 , wherein detecting a change in the behavior of the current flow through the perilymph of the cochlea comprises:

detecting a larger than expected difference between perilymph impedance components associated with bipolar impedance values determined for successive electrodes.

10. The method of claim 1 , wherein analyzing the perilymph impedance components and the electrode-tissue impedance components, comprises:

detecting, based on the bipolar impedance values, the one or more common ground measurements, and the model of the implanted cochlea behavior, a change in an electrode-tissue impedance component of one or more bipolar impedance values.

11. The method of claim 10 , wherein detecting a change in the electrode-tissue impedance component of one or more bipolar impedance values comprises:

detecting an increase in the electrode-tissue impedance component of the one or more bipolar impedance values.

12. The method of claim 10 , wherein detecting a change in the electrode-tissue impedance component of one or more bipolar impedance values comprises:

detecting a non-linearity in electrode-tissue impedance components associated with two or more bipolar impedance values.

13. The method of claim 10 , wherein detecting a change in the electrode-tissue impedance component of the bipolar impedance values comprises:

detecting a larger than expected difference between electrode-tissue impedance components associated with bipolar impedance values determined for successive electrodes.

14. A method performed at a hearing prosthesis, comprising:

performing a plurality of bipolar measurements on a plurality of electrodes configurable as bipolar electrode pairs, wherein one or more of the electrodes are implanted in a recipient's cochlea;

determining, based on the bipolar measurements, a bipolar impedance value for each of a plurality of the bipolar electrode pairs,

performing one or more common ground measurements at each of the plurality of bipolar electrode pairs;

detecting, based on the bipolar impedance values, the one or more common ground measurements, and a model of the implanted cochlea behavior, a change in at least one of the behavior of the current flow through perilymph of the cochlea or a change in an electrode impedance of the cochlea;

initiating, at the hearing prosthesis, at least one diagnostic operation based on the detected change in at least one of the behavior of the current flow through perilymph of the cochlea or a change in an electrode impedance of the cochlea analysis of the perilymph.

15. The method of claim 14 , wherein detecting a change in at least one of the behavior of the current flow through the perilymph of the cochlea or in an electrode impedance of the cochlea comprises:

resolving the bipolar impedance values into perilymph impedance components and electrode-tissue impedance components.

16. The method of claim 15 , further comprising:

determining, based on the bipolar impedance values, the one or more common ground measurements, and the model of the implanted cochlea behavior, the presence of abnormal current flow between two of the implanted electrodes.

17. The method of claim 15 , wherein detecting a change in the behavior of the current flow through the perilymph of the cochlea comprises:

detecting an increase in the perilymph impedance component of one or more bipolar impedance values.

18. The method of claim 15 , wherein detecting a change in the behavior of the current flow through the perilymph of the cochlea comprises:

detecting a non-linearity between perilymph impedance components associated with two or more bipolar impedance values.

19. The method of claim 15 , wherein detecting a change in the behavior of the current flow through the perilymph of the cochlea comprises:

detecting a larger than expected difference between perilymph impedance components associated with bipolar impedance values determined for successive electrodes.

20. The method of claim 15 , wherein detecting a change in an electrode impedance of the cochlea comprises:

detecting an increase in electrode-tissue impedance components of one or more bipolar impedance values.

21. The method of claim 15 , wherein detecting a change in an electrode impedance of the cochlea comprises:

detecting a non-linearity in electrode-tissue impedance components associated with two or more bipolar impedance values.

22. The method of claim 15 , wherein detecting a change in an electrode impedance of the cochlea comprises:

detecting a larger than expected difference between electrode-tissue impedance components associated with bipolar impedance values determined for successive electrodes.

23. The method of claim 14 , wherein initiating the at least one diagnostic operation comprises:

adjusting one or more of settings in the hearing prosthesis, wherein the one or more of settings are selected from the group consisting of: a set of electrodes in use, distribution of the acoustic sound spectrum across the electrodes in use, acoustic threshold levels, maximum comfort level, and power supplied for implant operations.