Probabilistic entropy for detection of periodic signal artifacts

Patent metadata

Field	Value
Publication number	US-11033742-B2
Application number	US-201916392129-A
Country	US
Kind code	B2
Filing date	Apr 23, 2019
Priority date	Apr 23, 2019
Publication date	Jun 15, 2021
Grant date	Jun 15, 2021

Abstract

Techniques are disclosed for using probabilistic entropy to select electrodes with fewer artifacts for controlling adaptive electrical neurostimulation. In one example, a plurality of electrodes sense bioelectrical signals of a brain of a patient. Processing circuitry determines, for each bioelectrical signal sensed at a respective electrode of the plurality of electrodes, a probabilistic entropy value of the bioelectrical signal. The processing circuitry compares each of the respective probabilistic entropy values of the bioelectrical signal to respective entropy threshold values and selects, based on the comparisons, a subset of electrodes of the plurality of electrodes. The processing circuitry controls, based on the bioelectrical signals sensed via respective electrodes of the subset of electrodes and excluding the bioelectrical signals of the plurality of bioelectrical signals sensed via respective electrodes not in the subset of electrodes, delivery of electrical stimulation therapy to the patient.

First claim

What is claimed is:

1. A method comprising:
sensing, via a plurality of electrodes, a plurality of bioelectrical signals of a brain of a patient;
determining, by processing circuitry and for each bioelectrical signal of the plurality of bioelectrical signals sensed at a respective electrode of the plurality of electrodes, a probabilistic entropy value of the bioelectrical signal;
comparing, by the processing circuitry, each of the respective probabilistic entropy values of the bioelectrical signal to respective entropy threshold values; and
selecting, by the processing circuitry and based on the comparisons, a subset of electrodes of the plurality of electrodes by:
including, in the subset, at least one electrode of the plurality of electrodes for which the comparison of the probabilistic entropy value of the bioelectrical signal sensed via the at least one electrode to the respective entropy threshold value is indicative that the bioelectrical signal exhibits high entropy; and
excluding, from the subset, each electrode of the plurality of electrodes for which the comparison of the probabilistic entropy value of the bioelectrical signal sensed via the electrode to the respective entropy threshold value is indicative that the bioelectrical signal exhibits low entropy; and

controlling, by the processing circuitry and based on the bioelectrical signals of the plurality of bioelectrical signals sensed via respective electrodes of the subset of electrodes and excluding the bioelectrical signals of the plurality of bioelectrical signals sensed via respective electrodes not in the subset of electrodes, delivery of electrical stimulation therapy to the patient via at least one of the plurality of electrodes.

2. The method of claim 1 ,
wherein determining, for each bioelectrical signal, the probabilistic entropy value comprises determining, for each bioelectrical signal, a probability distribution of entropy of the bioelectrical signal over a period of time,
wherein signal components of the bioelectrical signal that have periodic behavior indicate reduced entropy, and
wherein signal components of the bioelectrical signal that have no periodic behavior indicate increased entropy.

3. The method of claim 1 , wherein determining, for each bioelectrical signal, the probabilistic entropy value comprises:
determining that one or more signal components of a first bioelectrical signal of the plurality of bioelectrical signals demonstrate periodic behavior;
in response to determining that the one or more signal components of the first bioelectrical signal demonstrate periodic behavior, determining a first probabilistic entropy value for the first bioelectrical signal;
determining that one or more signal components of a second bioelectrical signal of the plurality of bioelectrical signals demonstrate aperiodic behavior; and
in response to determining that the one or more signal components of the second bioelectrical signal demonstrate aperiodic, determining a second probabilistic entropy value for the second bioelectrical signal,
wherein the first probabilistic entropy value is indicative of entropy in the first bioelectrical signal and the second probabilistic entropy value is indicative of entropy in the second bioelectrical signal, and
wherein the first probabilistic entropy value and the second probabilistic entropy value indicate that the first bioelectrical signal demonstrates less entropy than the second bioelectrical signal.

4. The method of claim 1 , wherein determining, for each bioelectrical signal, the probabilistic entropy value comprises determining, for each bioelectrical signal, a statistical measure of randomness over a period of time.

5. The method of claim 4 ,
wherein determining, for each bioelectrical signal, the statistical measure of randomness comprises determining a statistical measure of randomness of spectral power across a plurality of frequency bands of the bioelectrical signal,
wherein comparing each of the respective probabilistic entropy values of the bioelectrical signal to respective entropy threshold values comprises comparing each statistical measure of randomness of spectral power across the plurality of frequency bands of the bioelectrical signal to an entropy threshold value,
wherein including, in the subset, comprises including, in the subset, at least one electrode of the plurality of electrodes for which the statistical measure of randomness of spectral power across the plurality of frequency bands of a respective bioelectrical signal sensed via the electrode is greater than the respective entropy threshold value, and
wherein excluding, form the subset, comprises excluding, from the subset, each electrode of the plurality of electrodes for which the statistical measure of randomness of spectral power across the plurality of frequency bands of a respective bioelectrical signal sensed via the electrode is less than or equal to the respective entropy threshold value.

6. The method of claim 1 ,
wherein comparing each of the respective probabilistic entropy values of the bioelectrical signal to respective entropy threshold values comprises:
determining a rate at which an amplitude of each bioelectrical signal exceeds a threshold limit; and
comparing the rate at which the amplitude of the bioelectrical signal exceeds the threshold limit to a respective rate threshold,

wherein including, in the subset, comprises including, in the subset, at least one electrode of the plurality of electrodes for which a rate at which an amplitude of a respective bioelectrical signal sensed via the electrode exceeds the threshold limit is less than the respective rate threshold; and
wherein excluding, from the subset, comprises excluding, from the subset, each electrode of the plurality of electrodes for which a rate at which an amplitude of a respective bioelectrical signal sensed via the electrode exceeds the threshold limit is greater than or equal to the respective rate threshold.

7. The method of claim 6 , wherein each threshold limit is an interquartile range of sensed amplitudes of a respective bioelectrical signal.

8. The method of claim 1 ,
wherein comparing each of the respective probabilistic entropy values of the bioelectrical signal to respective entropy threshold values comprises:
determining an entropy of intervals of time between instances at which an amplitude of the bioelectrical signal exceeds a threshold limit; and
comparing the entropy of the intervals of time to the respective entropy threshold value,

wherein including, in the subset, comprises including, in the subset, at least one electrode of the plurality of electrodes for which the entropy of the intervals of time is greater than the respective entropy threshold value, and
wherein excluding, form the subset, comprises excluding, from the subset, each electrode of the plurality of electrodes for which the entropy of the intervals of time is less than or equal to the respective entropy threshold value.

9. The method of claim 8 , wherein each threshold limit is a first interquartile range of sensed amplitudes of a respective bioelectrical signal.

10. The method of claim 8 , wherein determining the interval of time comprises determining a Shannon entropy of the intervals of time.

11. The method of claim 1 ,
wherein comparing each of the respective probabilistic entropy values of the bioelectrical signal to respective entropy threshold values comprises:
determining a statistical measure of randomness of spectral power across a plurality of frequency bands of each bioelectrical signal;
comparing the statistical measures of randomness of spectral power across the plurality of frequency bands

Assignees

• Medtronic Inc

Inventors

• Panken Eric J
• Jackson Jadin C
• Xiao Yizi
• Pulliam Christopher L

Classifications

• A61B5/37

  Intracranial electroencephalography [IC-EEG], e.g. electrocorticography [ECoG] · CPC title

• A61B5/291

  for electroencephalography [EEG] · CPC title

• A61N1/0551

  Spinal or peripheral nerve electrodes · CPC title

• A61N1/0534

  Electrodes for deep brain stimulation · CPC title

• A61B5/7221

  Determining signal validity, reliability or quality (preventing, reducing or removing noise induced by motion artefacts A61B5/7207; noise originating from a therapeutic or surgical apparatus A61B5/7217) · CPC title