Phase shifting of neurological signals in a medical device system

• US 7,976,465 B2
• Filed: 10/17/2006
• Issued: 07/12/2011
• Est. Priority Date: 10/15/2002
• Status: Expired due to Fees

• Current Assignee: Medtronic Incorporated (Medtronic Plc)
• Original Assignee: Medtronic Incorporated (Medtronic Plc)
• Inventors: Werder, Jonathan C., Frei, Mark G., Carlson, David L.
• Primary Examiner(s): Getzow; Scott M
• Assistant Examiner(s): PATTON, AMANDA K
• Application Number:
  US11/550,294
• Publication Number:
  US 20070066915A1
• Time in Patent Office: 1,729 Days
• Field of Search: 607 2- 5, 600300-301, 600508-510
• US Class Current: 600/301
• CPC Class Codes: A61B 5/374 Detecting the frequency distribution of signals, e.g. detecting delta, theta, alpha, beta or gamma waves
• CPC Class Codes: A61B 5/4094 Diagnosing or monitoring seizure diseases, e.g. epilepsy
• CPC Class Codes: A61M 5/14276 specially adapted for implantation
• CPC Class Codes: A61M 5/1723 using feedback of body parameters, e.g. blood-sugar, pressure measurement of body parameters A61B5/00
• CPC Class Codes: A61N 1/36082 Cognitive or psychiatric applications, e.g. dementia or Alzheimer's disease
• CPC Class Codes: A61N 1/3614 based on impedance measurement
• CPC Class Codes: A61N 1/37229 Shape or location of the implanted or external antenna
• CPC Class Codes: A61N 2/006 for magnetic stimulation of nerve tissue

Abstract

Method and apparatus for phase shifting neurological signals received from monitoring elements of a medical device. The medical device comprises a plurality of monitoring elements each receiving a neurological signal. The device processes the neurological signals and identifies a time shift of the neurological signal relative to each other. The neurological signals are then time shifted according to the time shift upon which the signals are utilized to provide closed-loop feedback control of a treatment therapy.

Claims

1. In a medical device system having a plurality of monitoring elements, a method for detecting poor signal quality and for phase shifting neurological signals received from the plurality of monitoring elements, comprising the steps of:

(a) receiving a first neurological signal from a first monitoring element and a second neurological signal from a second monitoring element adjacent to the first monitoring element;

(b) processing the first neurological signal and the second neurological signal;

(c) detecting whether the first neurological signal has poor signal quality by determining either that the first signal exceeds a predetermined boundary for what is expected for the signal from the second monitoring element and other monitoring elements adjacent the first monitoring element, or determining an absolute value of a correlation coefficient between the first and second neurological signals is lower than a predetermined amount;

(d) if the first neurological signal has poor signal quality, ignoring the first neurological signal experiencing poor signal quality in signal processing; and

(e) if the first neurological signal does not have poor signal quality, performing (i) sampling the first and second neurological signals at different time instances resulting in a time shift between the first and second neurological signal samples; and

(ii) time shifting signal samples of the second neurological signal to correct for the time shift so the second neurological signal is synchronized with the first neurological signal.

2. The method of claim 1, further comprising the step of (f) delivering a notification that the signal from one of the monitoring elements is experiencing poor signal quality.

3. The method of claim 1, wherein the step of ignoring comprises the step of ignoring the received signal experiencing poor signal quality in a closed-loop feedback control of a treatment therapy.

4. The method of claim 1, wherein the step of time shifting comprises the step of computing the time shift by solving a polynomial curve fit equation based on the signal samples.

5. The method of claim 4, wherein the step of computing comprises the step of solving a polynomial curve fit equation selected from the group consisting of a parabolic equation, a linear equation, and a cubic equation.

6. The method of claim 1, wherein the step of receiving comprises the step of receiving the first neurological signal selected from the group consisting of an electrical signal, a chemical signal, a biological signal, a temperature signal, a pressure signal, a respiration signal, a heart rate signal, a ph-level signal, and a peripheral nerve signal.

7. The method of claim 1, wherein the step of receiving comprises the step of receiving the first neurological signal from the first monitoring element selected from the group consisting of an electrode and a sensor.

8. The method of claim 1, wherein the step of processing comprises the step of identifying a value of at least one variable quantifying signal quality.

9. In a medical device system having a plurality of monitoring elements, a method for detecting poor signal quality and for phase shifting neurological signals received from the plurality of monitoring elements, comprising the steps of:

(a) receiving a first neurological signal from a first monitoring element and a second neurological signal from a second monitoring element adjacent to the first monitoring element;

(b) processing the first neurological signal and the second neurological signal;

(c) detecting whether the first neurological signal has poor signal quality by determining either that the first signal exceeds a predetermined boundary for what is expected for the signal from the second monitoring element and other monitoring elements adjacent the first monitoring element, or determining an absolute value of a correlation coefficient between the first and second neurological signals is lower than a predetermined amount;

(d) if the first neurological signal has poor signal quality, ignoring the first neurological signal experiencing poor signal quality in signal processing; and

(e) if the first neurological signal does not have poor signal quality, performing (i) sampling the first and second neurological signals at different time instances resulting in a time shift between the first and second neurological signal samples; and

(ii) time shifting signal samples of the first neurological signal to correct for the time shift so the first neurological signal is synchronized with the second neurological signal.