Methods and Systems for Measuring a Subject's Susceptibility to a Seizure

Abstract

Systems and methods for monitoring physiological signals from a subject to determine the subject's susceptibility for having a seizure. Also includes are systems and methods for activating an alert when there is a communication error between an implanted device and the external assembly. Additionally included are systems and method for long-term substantially continuous physiological signal data collection. At least a portion of the systems of the present invention may be implanted within the subject. In some embodiments, brain activity signals are sampled from the subject with implanted electrodes and are communicated to an external assembly where the brain activity signals are analyzed to determine the subject's susceptibility for having a seizure.

Description

CROSS-REFERENCE TO RELATED APPLICATIONS[0001]The present application claims benefit of U.S. Provisional Patent Application No. 60 / 897,551, filed Jan. 25, 2007, to Leyde et al., entitled “Methods and Systems for Measuring a Patient's Susceptibility to a Seizure,” the disclosure of which is incorporated by reference herein in its entirety.BACKGROUND OF THE INVENTION[0002]The present invention relates generally to systems and methods for sampling and processing one or more physiological signals from a subject. More specifically, the present invention relates to monitoring of one or more neurological signals from a subject to determine a subject's susceptibility to a neurological event, communicating the subject's susceptibility to the subject, reducing a severity of seizures and / or preventing seizures. The invention also relates to continuously storing neurological signals from a subject to train algorithms to determine a subject's susceptibility for having a seizure.[0003]Epilepsy is ...

AI Technical Summary

Benefits of technology

[0037]Unlike conventional anti-epileptic drug treatments, which provide for an “open loop” chronic regimen of pharmacological agents, the present invention is able to manage seizures acutely while substantially optimizing the intake of the pharmacological agent by having the subject to take a pharmacological agent only when it is determined that the subject has transitioned to a higher susceptibility to a seizure, e.g., to a pro-ictal condition. Furthermore, with this new paradigm of seizure prevention, the present invention provides a new indication for pharmacotherapy. This new indication is served by several existing medications, including AEDs, given at doses which are sub-therapeutic to their previously known indications, such as acute AED administration for seizure termination or status epilepticus. Since this new indication is served by a new and much lower dosing regimen and consequently a new therapeutic window, the present invention is able to provide a correspondingly new and substantially reduced side effect profile and may reduce or eliminate tolerance effects of the AED. For example, the present invention allows the use of dosages that are lower than FDA-approved dosages for the various anti-epileptic agents. This dosing may be about 5% to about 95% lower than the FDA-recommended dose for the drug, and preferably at or below 90% of the FDA-recommended dose, and most preferably below about 50% of the FDA-recommended dose. But as can be appreciated, if the measured signals indicate a high susceptibility for a seizure, the methods and systems of the present invention may recommend taking an FDA or a higher than FDA approved dose of the AED to prevent the seizure. Such a paradigm has valuable application for subjects in which side effects of AEDs are problematic, particular sedation in general and teratogenicity in pregnant women or risk of teratogenicity in all women of child bearing age. A more complete description of using acute dosages of AEDs with a seizure advisory system is described in commonly owned U.S. patent application Ser. Nos. 11/321,897, 11/321,898, and 11/322,150 (all filed Dec. 28, 2005), the complete disclosures of which are incorporated herein by reference.

[0038]In another embodiment, the present invention pr

Problems solved by technology

A seizure typically manifests itself as sudden, involuntary, disruptive, and often destructive sensory, motor, and cognitive phenomena.

Seizures are frequently associated with physical harm to the body (e.g., tongue biting, limb breakage, and burns), a complete loss of consciousness, and incontinence.

A single seizure most often does not cause significant morbidity or mortality, but severe or recurring seizures (epilepsy) results in major medical, social, and economic consequences.

Epilepsy is most often diagnosed in children and young adults, making the long-term medical and societal burden severe for this population of subjects.

People with uncontrolled epilepsy are often significantly limited in their ability to work in many industries and usually cannot legally drive an automobile.

This continuous seizure activity may lead to permanent brain damage, and can be lethal if untreated.

The anticonvulsant and antiepileptic medications do not actually correct the underlying conditions that cause seizures.

These desired therapeutic effects are often accompanied by the undesired side effect of sedation, nausea, dizziness, etc.

Furthermore, some AED are inappropriate for women of child bearing age due to the potential for causing severe birth defects.

However, for the remaining 30% of the subjects, their first AED will fail to fully control their seizures and they will be prescribed a second AED—often in addition to the first—even if the first AED does not stop or change a pattern or frequency of the subject's seizures.

A major challenge for physicians treating epileptic subjects is gaining a clear view of the effect of a me

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