Seizure onset classification and stimulation parameter selection

Patent metadata

Field	Value
Publication number	US-2016228705-A1
Application number	US-201615040932-A
Country	US
Kind code	A1
Filing date	Feb 10, 2016
Priority date	Feb 10, 2015
Publication date	Aug 11, 2016
Grant date	—

Abstract

A neurostimulation system senses electrographic signals from the brain of a patient, extracts features from the electrographic signals, and when the extracted features satisfy certain criteria, detects a neurological event type. A mapping function relates the detected neurological event type to a stimulation parameter subspace and a default stimulation parameter set where the values of the stimulation parameters define an instance of stimulation therapy for the patient. The decision whether to implement a stimulation parameter subspace or a default stimulation parameter set may be informed by integrating other information about a state of the patient. A stimulation parameter subspace or stimulation parameter set may optimized by testing it against various thresholds until certain effectiveness criteria is satisfied. The neurological event type may be one of several electrographic seizure onset types.

First claim

What is claimed is:

1 . A processing system configured to define the values of the parameters used by a neurostimulator to generate an instance of stimulation therapy for delivery to a patient to treat a neurological condition, wherein the defining is performed by a mapping function module of the processing system, the mapping function module comprising:
a table stored in a memory, which table correlates each of a plurality of neurological event types to a stimulation parameter subspace; an analyzer configured to compare a neurological event detected by the neurostimulator to the plurality of neurological event types in the table and to determine a ranking for the detected neurological event corresponding to a probability that the detected neurological event is a particular one of the plurality of neurological event types; and an output configured to provide an output signal to a control module of the neurostimulator, the output signal comprising a recommended stimulation parameter subspace, which recommended stimulation parameter subspace corresponds to the stimulation parameter subspace correlated in the table with the ranking for the detected neurological event.

2 . The processing system of claim 1 , further comprising an integration module configured to determine whether the neurostimulator should (a) ignore the output signal of the mapping function module, or (b) receive the output signal of the mapping function module as a recommendation, the integration module comprising:
an integrator configured to establish a state of a patient based on one or more physiological metrics, a comparator configured to compare the state of the patient to a threshold corresponding to one or more undesirable patient states, and to:
if the patient is in one of the one or more undesirable patient states, establish the recommended stimulation parameter subspace as the stimulation parameter subspace for the neurostimulator; and
if the patient is not in one of the one or more undesirable patient states, ignore the output of the mapping function module.

3 . The processing system of claim 2 , wherein the one or more physiological metrics may be selected from a group of metrics including: a pH level of neural tissue, an oxygenation level of neural tissue, and a neurotransmitter level of neural tissue.

4 . The processing system of claim 2 , wherein the one or more physiological metrics may be selected from a group of metrics including: a rate at which the neurostimulator detects a particular neurological event type, a rate at which the patient reports the neurological condition being treated, or a symptom thereof, and a duration of a particular neurological event type.

5 . The processing system of claim 1 , further comprising an optimization module configured to test a present stimulation parameter set against a criterion related to an effectiveness of the present stimulation parameter set, and if the criterion is not met, cause the neurostimulator to generate instances of stimulation therapy in accordance with a new stimulation parameter set until the criterion is met.

6 . The processing system of claim 5 , wherein the criterion is related to at least one of: a change in the rate at which the neurostimulator detects a particular neurological event type, a change in the rate at which the patient reports the neurological condition being treated, or a symptom thereof, and a change in a duration of a particular neurological event type.

7 . The processing system of claim 1 , wherein the plurality of neurological event types are seizure onset neurological event types.

8 . The processing system of claim 1 , wherein the processing system is configured in an external component of an implantable neurostimulation system, and further comprises:
a communications module configured to establish a communications link with the neurostimulator, wherein the output provided by the mapping function module is transmitted to the neurostimulator over the communications link.

9 . The processing system of claim 8 , further comprising in the external component, a user interface configured to allow a user to select one or more stimulation parameter sets from within the recommended stimulation parameter subspace, wherein the communications module is configured to transmit instructions to the neurostimulator comprising the selected one or more selected stimulation parameter sets.

10 . The processing system of claim 1 , wherein the neurostimulator is configured as an implantable neurostimulator and the processing system is configured as a component of the implantable neurostimulator.

11 . A method of defining the values of the parameters used by a neurostimulator to generate an instance of stimulation therapy for delivery to a patient to treat a neurological condition, wherein the defining is performed by a mapping function module of a processing system, the method comprising:
correlating each of a plurality of neurological event types to a stimulation parameter sub space; comparing a neurological event detected by the neurostimulator to the correlated plurality of neurological event types; determining a ranking for the detected neurological event corresponding to a probability that the detected neurological event is a particular one of the plurality of neurological event types; and providing an output signal to a control module of the neurostimulator, the output signal comprising a recommended stimulation parameter subspace, which recommended stimulation parameter subspace corresponds to the stimulation parameter subspace correlated in the table with the ranking for the detected neurological event.

12 . The method of claim 11 , further comprising determining whether the neurostimulator should (a) ignore the output signal of the mapping function module, or (b) receive the output signal of the mapping function module as a recommendation.

13 . The method of claim 12 , wherein determining comprises:
establishing a state of a patient based on one or more physiological metrics; comparing the state of the patient to a threshold corresponding to one or more undesirable patient states; if the patient is in one of the one or more undesirable patient states, establishing the recommended stimulation parameter subspace as the stimulation parameter subspace for the neurostimulator; and if the patient is not in one of the one or more undesirable patient states, ignoring the output signal of the mapping function module.

14 . The method of claim 13 , further comprising:
testing a present stimulation parameter set against a criterion related to an effectiveness of the present stimulation parameter set; and if the criterion is not met, causing the neurostimulator to generate instances of stimulation therapy in accordance with a new stimulation parameter set until the criterion is met.

15 . An implantable neurostimulation system configured to optimize the values of the parameters which define the electrical stimulation delivered to a brain of a patient as a form of neural modulation therapy based on a classification of a sensed brain signal into a neurological event type, the implantable neurostimulation system comprising:
at least one lead provided with, at or near a distal end thereof, a plurality of sensors and a plurality of stimulators, the at least one lead configured to be implanted at least partially in the patient so that the plurality of sensors and the plurality of stimulators are in or on the brain; an implantable neurostimulator coupled to the at least one lead and configured to, with each of the plurality of sensors, selectively

Assignees

• Neuropace Inc

Inventors

• Crowder Tara Leigh
• Arcot Desai Sharanya
• Morrell Martha Jo
• TCHENG Thomas Kim
• KAPUR Ritu

Classifications

• A61B5/7264

  Classification of physiological signals or data, e.g. using neural networks, statistical classifiers, expert systems or fuzzy systems · CPC title

• A61N1/37241

  providing test stimulations · CPC title

• A61B5/4094

  Diagnosing or monitoring seizure diseases, e.g. epilepsy · CPC title

• A61B5/7282

  Event detection, e.g. detecting unique waveforms indicative of a medical condition (cough events A61B5/0823; seizures A61B5/4094; sleep apnoea A61B5/4818) · CPC title

• A61N1/36139

  with automatic adjustment · CPC title