Evoked Response to Stimulation

• US 20070244407A1
• Filed: 01/18/2007
• Published: 10/18/2007
• Est. Priority Date: 03/10/2006
• Status: Abandoned Application

• Current Assignee: Medtronic Incorporated (Medtronic Plc)
• Original Assignee: Medtronic Incorporated (Medtronic Plc)
• Inventors: Osorio, Ivan
• Application Number:
  US11/624,590
• Publication Number:
  US 20070244407A1
• Time in Patent Office: Days
• US Class Current: 600/544
• CPC Class Codes: A61B 5/0006 ECG or EEG signals
• CPC Class Codes: A61B 5/369 Electroencephalography [EEG] devices for psychotechnics A61B5/16
• CPC Class Codes: A61B 5/4094 Diagnosing or monitoring seizure diseases, e.g. epilepsy
• CPC Class Codes: A61N 1/36082 Cognitive or psychiatric applications, e.g. dementia or Alzheimer's disease
• CPC Class Codes: A61N 1/361 Phantom sensations, e.g. tinnitus
• CPC Class Codes: G16H 20/70 relating to mental therapies, e.g. psychological therapy or autogenous training
• CPC Class Codes: G16H 50/20 for computer-aided diagnosis, e.g. based on medical expert systems

Abstract

In an embodiment, an evoked response of an electrode may be determined. The evoked response may be compared to other evoked responses to determine the location of the electrode. The evoked response may be measured during electrode implantation so that desired changes can be made and if electrodes are being implanted in both the right and left hemisphere, it can be determined that both electrodes are positioned in the same target in both the right and left hemisphere. The evoked responses may be used to determine if the stimulation target has functional connectivity with the treatment areas. Stimulation parameters for the electrodes may be determined in a closed-loop configuration and used to stimulation the electrodes in an open-loop configuration designed to reduce the probability of neurological events such as seizures.

Claims

1. A method of treating a patient with a neurological disorder, comprising:

(a) implanting a first electrode approximate a first target site in a first hemisphere of the patient'"'"'s brain;

(b) determining an evoked response of the first electrode;

(c) implanting a second electrode in a location approximate a second target site in a second hemisphere of the patient'"'"'s brain; and

(d) verifying the location of the second electrode corresponds to the location of the first electrode by using an evoked response of the second electrode.

2. The method of claim 1, wherein the verify in (d) comprises

(i) determining the evoked response of the second electrode;

and

(ii) in response to the evoked response of the second electrode not corresponding to the evoked response of the first electrode, adjusting the position of the second electrode until the evoked response of the second electrode does correspond to the evoked response of the first electrode.

3. The method of claim 1, further comprising:

(e) adjusting a position of the first electrode in response to the evoked response.

4. The method of claim 1, wherein the first target site is a region.

5. The method of claim 1, wherein the evoked response comprises parameters associated with amplitude, latency, conduction velocity, number of peaks, polarity and shape.

6. The method of claim 1, wherein the first target site is comprises a location selected from a list consisting of anterior thalamic nuclei, nucleus Reticulatus polaris, nucleus Latero-polaris, nucleus Antero-medialis, nucleus Ventro-oralis Internus, nucleus Antero-principalis, nucleus Lateropolaris and Campus Forelli Pars H2.

7. The method of claim 1, further comprising:

(e) verifying a location of the first electrode corresponds a desired location associated with a treatment area.

8. The method of claim 7, wherein the verifying in (e) comprises:

(i) obtaining a reproducible evoked response with well defined latency, amplitudes and morphology in at least two separate stimulation trials;

(ii) comparing the evoked response to an expected evoked response; and

(iii) in response to a determination that the evoked response does not correspond to the expected evoked response, adjusting the position of the first electrode until the evoked response of the first electrode does correspond to the expected evoked response.

9. The method of claim 1, further comprising:

(e) implanting an implantable medical device in the patient; and

(f) applying a closed-loop stimulation pattern to the first and second electrodes.

10. The method of claim 9, wherein the applying open-loop stimulation pattern in (f) comprises:

(i) configuring the first and second electrode as a cathode; and

(ii) configuring a case of the implantable medical device as an anode.

11. The method of claim 10, wherein the applying of open-loop stimulation in (f) comprises:

(iii) providing stimulation at between 145 Hz and 200 Hz in a repeating pattern that includes one minute of stimulation followed by five minutes of no stimulation.

12. The method of claim 11, wherein the stimulation is applied at 175 Hz at an intensity of 5 volts.

13. A method of treating a patient with a neurological disorder, comprising:

(a) implanting a plurality of electrodes approximate a target region of the patient'"'"'s brain;

(b) verifying the location of at least one of the plurality of electrodes using an evoked response;

(c) determining stimulation parameters using the implanted electrodes and a closed-loop detection algorithm;

(d) coupling the plurality of electrodes to an implantable medical device; and

(e) applying open-loop stimulation to the plurality of electrodes with the implanted medical device based on the determined stimulation parameters.

14. The method of claim 13, wherein the verifying of the location in (b) comprises comparing the morphology, latency and polarity of the evoked response to determine the location of the implanted electrode.

15. The method of claim 13, wherein the applying of open-loop stimulation comprises:

(i) configuring the plurality of electrodes as a cathode; and

(ii) configuring a case of the implantable medical device as an anode.

16. The method of claim 13, wherein the evoked response is done while implanting the plurality of electrodes.

17. The method of claim 16, wherein the evoked response is measured using scalp electrodes.

18. The method of claim 16, wherein the evoked response is measured using intracranial electrodes.

19. The method of claim 13, wherein the verifying the location of the at least one electrode includes a determination of functionality connectivity between a structure being stimulated by the electrode and one of an ipsilateral and a contralateral structure, and wherein the applying of the open-loop stimulation stimulates a single side.

20. The method of claim 13, wherein the verifying the location of the at least one electrode includes a determination of functionality connectivity between a structure being stimulated by the electrode and one of an ipsilateral and a contralateral structure, and wherein the applying of the open-loop stimulation alternates stimulation between sides.

21. A computer readable medium comprising computer readable instructions, comprising:

(a) receiving an evoked response generated by applying a stimulation pulse applied to an implanted electrode;

(b) determining that the evoked response matches an known evoked response; and

(c) providing an indication that the evoked response matches the known evoked response.

22. The computer readable medium of claim 21, wherein the indication is rendered on a display.

23. The method of claim 22, wherein the indication provides information regarding a location of the implanted electrode.

24. A method of determining the existence of functional connectivity between a stimulation target and a treatment area, comprising:

(a) implanting a first electrode in the stimulation target;

(b) implanting a second electrode in the treatment area;

(c) stimulating the first electrode with an electrical pulse;

(d) obtaining an evoked response from the second electrode; and

(e) if the evoked response is not reproducible, repositioning the first electrode and repeating (c)-(d) until a reproducible evoked response is obtained from the second electrode.

25. The method of claim 24, wherein the treatment area comprises an abnormal brain area.