Signal quality monitoring and control for a medical device system

• US 7,917,206 B2
• Filed: 11/07/2006
• Issued: 03/29/2011
• Est. Priority Date: 10/15/2002
• Status: Active Grant

• Current Assignee: Medtronic Incorporated (Medtronic Plc)
• Original Assignee: Medtronic Incorporated (Medtronic Plc)
• Inventors: Frei, Mark G., Osorio, Ivan
• Primary Examiner(s): MANUEL, GEORGE C
• Application Number:
  US11/557,433
• Publication Number:
  US 20070100278A1
• Time in Patent Office: 1,603 Days
• Field of Search: 607/2, 607 39- 46, 600/544, 600/545, 128/901
• US Class Current: 607/2
• CPC Class Codes: A61B 5/316 Modalities, i.e. specific diagnostic methods
• 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: A61B 5/7203 for noise prevention, reduction or removal
• CPC Class Codes: A61B 5/7217 of noise originating from a therapeutic or surgical apparatus, e.g. from a pacemaker
• CPC Class Codes: A61B 5/7221 Determining signal validity, reliability or quality A61B5/7207 and A61B5/7217 take precedence
• CPC Class Codes: A61N 1/36031 using physiological parameters for adjustment
• CPC Class Codes: A61N 1/36064 Epilepsy
• CPC Class Codes: A61N 1/36082 Cognitive or psychiatric applications, e.g. dementia or Alzheimer's disease
• CPC Class Codes: A61N 1/36135 using physiological parameters
• CPC Class Codes: A61N 1/3702 Physiological parameters A61N1/365 takes precedence; evoked response A61N1/371
• CPC Class Codes: A61N 1/37229 Shape or location of the implanted or external antenna

Abstract

Method and apparatus for detecting possible interference in a neurological signal received from a monitoring element of a medical device system. The monitoring element monitors a condition or a symptom of a nervous system disorder being treated and provides a neurological signal to the medical device system for purposes of providing closed-loop feedback control. The system analyzes various parameters of the received signal by taking instantaneous measurements of data points in moving window and thereby determining whether the signal is of poor quality. If the signal is of determined poor quality, it is removed from consideration in the closed-loop feedback control system until it is determined that the signal quality has sufficiently been restored.

Claims

1. In a medical device system having a plurality of monitoring elements providing signals, a method for detecting poor signal quality comprising:

(a) receiving a neurological signal from one of the plurality of monitoring elements;

(b) determining a plurality of data points for a first variable associated with the signal quality of the neurological signal;

(c) determining a plurality of data points for a second variable associated with the signal quality of the neurological signal;

(d) detecting that the received neurological signal has poor signal quality by determining that an amount of the data points from the first variable has exceeded a predetermined threshold; and

(e) signal processing the signals from the plurality of monitoring elements, the signal processing ignoring the received neurological signal experiencing poor signal quality;

wherein the detecting in (d) comprises determining that a percentage of the data points exhibiting poor signal quality within a moving time window has exceeded a predetermined threshold percentage.

2. The method of claim 1, further comprising:

(f) delivering a notification that a neurological signal from one of the plurality of monitoring elements is experiencing poor signal quality.

3. The method of claim 1, further comprising:

(f) providing a substituted signal for the received neurological signal experiencing poor signal quality.

4. The method of claim 1, wherein the receiving in (a) comprises receiving a neurological signal from one of the plurality of monitoring elements, the 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.

5. The method of claim 1, wherein the receiving in (a) comprises receiving a neurological signal from one of the plurality of monitoring elements, the one of the plurality of monitoring elements selected from the group consisting of an electrode and a sensor.

6. The method of claim 1, wherein the the detecting that the received neurological signal has poor signal quality in (d) is based on a shape of the data points for the first variable.

7. The method of claim 1, wherein the first variable and the second variables are determined independently of each other.

8. In a medical device system having a plurality of monitoring elements providing signals, a method for detecting poor signal quality comprising:

(a) receiving a neurological signal from one of the plurality of monitoring elements;

(b) determining a plurality of data points for a first variable associated with the signal quality of the neurological signal;

(c) determining a plurality of data points for a second variable associated with the signal quality of the neurological signal;

(d) detecting that the received neurological signal has poor signal quality by determining that an amount of the data points from the first variable has exceeded a predetermined threshold;

(e) signal processing the signals from the plurality of monitoring elements, the signal processing ignoring the received neurological signal experiencing poor signal quality in a closed-loop feedback control of a treatment therapy.

9. In a medical device system having a plurality of monitoring elements providing signals, a method for detecting poor signal quality comprising:

(a) receiving a neurological signal from one of the plurality of monitoring elements;

(b) determining a plurality of data points for a first variable associated with the signal quality of the neurological signal;

(c) determining a plurality of data points for a second variable associated with the signal quality of the neurological signal;

(d) detecting that the received neurological signal has poor signal quality by determining that an amount of the data points from the first variable has exceeded a predetermined first threshold;

(e) signal processing the signals from the plurality of monitoring elements, the signal processing ignoring the received neurological signal experiencing poor signal quality, and

wherein the determining in (d) comprises;

identifying a value of the first variable, the value corresponding to a clipping percentage.

10. The method of claim 9, wherein the detecting in (d) further comprises determining that an amount of the data points from the second variable has exceeded a predetermined second threshold.

11. The method of claim 10, wherein the detecting in (d) further comprises determining that adjacent data points for the first variable and the second variable are within a predetermined value of each other.

12. In a medical device system having a plurality of monitoring elements providing signals, a method for detecting poor signal quality comprising:

(a) receiving a neurological signal from one of the plurality of monitoring elements, the receiving for providing closed-loop feedback control of a treatment therapy;

(b) determining a plurality of data points for a first variable associated with the signal quality of the neurological signal;

(c) determining a plurality of data points for a second variable associated with the signal quality of the neurological signal;

(d) detecting that the received neurological signal has poor signal quality by determining that an amount of the data points from the first variable has exceeded a predetermined threshold;

(e) signal processing the signals from the plurality of monitoring elements, the signal processing ignoring the received neurological signal experiencing poor signal quality;

(f) determining that an amount of the data points from the first variable exhibiting poor signal quality within the time window has fallen below a second threshold; and

(g) resuming consideration of the received signal in the closed-loop feedback control.

13. A medical device system for managing a nervous system disorder and capable of detecting poor signal quality comprising in combination:

a first monitoring element for generating a signal and a second monitoring element for generating a neurological signal of a sensed neurological condition;

an analog to digital converter for converting the generated neurological signal;

a processor in communication with the analog to digital converter; and

a memory including a first software module for monitoring a first quality variable of the neurological signal and a second software module for monitoring a second quality variable of the neurological signal, the memory including computer executable instructions for causing the processor to;

(a) determine a plurality of instantaneous data points of the generated neurological signal for both of the first and the second quality variable;

(b) detect that the received signal has poor signal quality by determining that an amount of the data points from the first quality variable has exceeded a predetermined threshold;

(c) ignore the generated neurological signal from the second monitoring element experiencing poor signal quality in signal processing,

(d) use results of the signal processing in a closed-loop feedback control of a treatment therapy.

14. The medical device system of claim 13, wherein the treatment therapy is selected from the group consisting of electrical stimulation, magnetic stimulation, drug infusion, and brain cooling.

15. The medical device system of claim 13, wherein the nervous system disorder is selected from the group consisting of a disorder of a central nervous system, a disorder of a peripheral nervous system, a mental health disorder, and a psychiatric disorder.

16. The medical device system of claim 15, wherein the disorder of the central nervous system is selected from the group consisting of epilepsy, Parkinson'"'"'s disease, essential tremor, dystonia, multiple sclerosis (MS), anxiety, a mood disorder, a sleep disorder, obesity, and anorexia.

17. The medical device system of claim 13, wherein the medical device system is selected from the group consisting of an external system, a hybrid system, and an implanted system.

18. The medical device system of claim 13, wherein the first software module and second software module are configured to monitor independently.

19. The medical device system of claim 13, wherein the first and second monitoring elements are adjacent electrodes on a lead and the memory includes computer executable instructions for causing the processor to detect in (b) to:

(i) determine that the amount of the data points from the first quality variable has exceeded a predetermined bound as compared to the signal from the first monitoring element.

20. A medical device system for managing a nervous system disorder and capable of detecting poor signal quality comprising in combination:

a first monitoring element for generating a signal and a second monitoring element for generating a neurological signal of a sensed neurological condition;

an analog to digital converter for converting the generated neurological signal;

a processor in communication with the analog to digital converter; and

a memory including a first software module for monitoring a first quality variable of the neurological signal and a second software module for monitoring a second quality variable of the neurological signal, the memory including computer executable instructions for causing the processor to;

(a) determine a plurality of instantaneous data points of the generated neurological signal for both of the first and the second quality variable;

(b) detect that the received signal has poor signal quality by determining that an amount of the data points from the first quality variable has exceeded a predetermined threshold;

(c) ignore the generated neurological signal from the second monitoring element experiencing poor signal quality in signal processing, and

(d) use results of the signal processing in a closed-loop feedback control of a treatment therapy

(e) determine that the amount of data points from the first quality variable exhibiting poor signal quality within the time window has fallen below a second threshold; and

(f) resume consideration of the neurological signal from the first monitoring element in the closed-loop feedback control.