METHOD AND APPARATUS FOR DETECTION OF NERVOUS SYSTEM DISORDERS
First Claim
1. A method of detecting a precursor to a second neurological event following a first neurological event, the method comprising:
- acquiring EEG signal data following the first neurological event, the EEG signal data comprising a stream of data values;
determining a short-term representation of the EEG signal data based on data values acquired over a first sample interval, the first sample interval occurring after a predetermined lock-out period following the first neurological event, the first sample interval including relatively recently acquired data values;
determining a long-term representation of the EEG signal data based on data values acquired over a second sample interval, the second sample interval being longer than the first sample interval;
determining an event monitoring parameter which approximates a ratio of the short-term representation to the long-term representation;
comparing the event monitoring parameter to a low level threshold, the low level threshold having a value of less than about 0.5; and
detecting a precursor to a neurological event when the event monitoring parameter decreases below the low level threshold.
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Abstract
Systems and methods for detecting and/or treating nervous system disorders, such as seizures, are disclosed. Certain embodiments of the invention relate generally to implantable medical devices (IMDs) adapted to detect and treat nervous system disorders in patients with an IMD. Certain embodiments of the invention include detection of seizures based upon comparisons of long-term and short-term representations of physiological signals. Other embodiments include prediction of seizure activity based upon analysis of physiological signal levels. An embodiment of the invention monitors the quality of physiological signals, and may be able to compensate for signals of low signal quality. A further embodiment of the invention includes detection of seizure activity following the delivery of therapy.
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Citations
30 Claims
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1. A method of detecting a precursor to a second neurological event following a first neurological event, the method comprising:
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acquiring EEG signal data following the first neurological event, the EEG signal data comprising a stream of data values; determining a short-term representation of the EEG signal data based on data values acquired over a first sample interval, the first sample interval occurring after a predetermined lock-out period following the first neurological event, the first sample interval including relatively recently acquired data values; determining a long-term representation of the EEG signal data based on data values acquired over a second sample interval, the second sample interval being longer than the first sample interval; determining an event monitoring parameter which approximates a ratio of the short-term representation to the long-term representation; comparing the event monitoring parameter to a low level threshold, the low level threshold having a value of less than about 0.5; and detecting a precursor to a neurological event when the event monitoring parameter decreases below the low level threshold. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28)
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29. A computer-readable medium programmed with instructions for performing a method of detecting a precursor to a second neurological event following a first neurological event, the medium comprising instructions for causing a programmable processor to:
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acquire EEG signal data following the first neurological event, the EEG signal data comprising a stream of data values; determine a short-term representation of the EEG signal data based on data values acquired over a first sample interval, the first sample interval occurring after a predetermined lock-out period following the first neurological event, the first sample interval including relatively recently acquired data values; determine a long-term representation of the EEG signal data based on data values acquired over a second sample interval, the second sample interval being longer than the first sample interval; determine an event monitoring parameter which approximates a ratio of the short-term representation to the long-term representation; compare the event monitoring parameter to a low level threshold, the low level threshold having a value of less than about 0.5; and detect a precursor to a neurological event when the event monitoring parameter decreases below the low level threshold.
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30. A system for detecting a precursor to a neurological event, the system comprising:
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an implantable medical device; and an electrode adapted to sense EEG signals from a brain of a patient and communicate EEG signals to the device, wherein the device is adapted to acquire EEG signal data following the first neurological event, the EEG signal data comprising a stream of data values; determine a short-term representation of the EEG signal data based on data values acquired over a first sample interval, the first sample interval occurring after a predetermined lock-out period following the first neurological event, the first sample interval including relatively recently acquired data values; determine a long-term representation of the EEG signal data based on data values acquired over a second sample interval, the second sample interval being longer than the first sample interval; determine an event monitoring parameter which approximates a ratio of the short-term representation to the long-term representation; compare the event monitoring parameter to a low level threshold, the low level threshold having a value of less than about 0.5; and detect a precursor to a neurological event when the event monitoring parameter decreases below the low level threshold.
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Specification