US5311876A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Automatic detection of seizures using electroencephalographic signals
Assignee: Johns Hopkins University
•
Filing: 1992-11-18
•
Granted: 1994-05-17
•
Expires: 2012-11-18
Abstract
Abstract A patient monitoring system and a method of operating same, including automatically detecting a seizure in the patient, by detecting an electrical discharge in the patient's brain; converting the detected electrical discharge into a digital signal; inputting the digital signal into a microprocessor; detecting a seizure by dividing the digital signals into time segments, preprocessing each time segment including standardizing the signal, reducing the signal in each time segment to a feature, the feature providing information about whether a seizure is occurring using the feature from each time segment; and indicating that a seizure is occurring.
Inventors
- 👤 Dale E. Olsen
- 👤 Ronald P. Lesser
- 👤 John C. Harris
- 👤 W. Robert S. Webber
- 👤 John A. Cristion
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-23 03:47
CPC Classifications
A; A61; A61B; A61B5/00; A61B5/40; A61B5/4076; A61B5/4094; A61B5/24; A61B5/316; A61B5/369; A61B5/372; Y; Y10; Y10S; Y10S128/00; Y10S128/92; Y10S128/925
Claims Analysis
Total Claims: 47
Claim 1
Independent Claim
144 words
A method of operating a patient monitoring system wherein a seizure in the patient is automatically detected comprising the steps of: detecting an electrical discharge in the patient's brain; converting the detected electrical discharge into a digital signal; inputting the digital signal into a microprocessor; detecting automatically a seizure using the microprocessor and the digital signal comprising the steps of: dividing the digital signal into a plurality of time segments; standardizing the digital signal in each time segment; processing the standardized digital signal in each time segment to form at least one additional signal in each time segment; reducing each signal in each time segment to a feature, the feature providing information about whether a seizure is occurring ; standardizing each feature; and determining whether a seizure is occurring using the standardized features from each time segment; and indicating that a seizure is occurring.
Claim 2
Independent Claim
144 words
A method of operating a patient monitoring system wherein a seizure in the patient is automatically detected comprising the steps of: detecting an electrical discharge in the patient's brain; converting the detected electrical discharge into a digital signal; inputting the digital signal into a microprocessor; detecting automatically a seizure using the microprocessor and the digital signal comprising the steps of: dividing the digital signal into a plurality of time segments; standardizing the digital signal in each time segment; processing the standardized digital signal in each time segment to form at least one additional signal in each time segment; reducing each signal in each time segment to a feature, the feature providing information about whether a seizure is occurring ; standardizing each feature; and determining whether a seizure is occurring using the standardized features from each time segment; and indicating that a seizure is occurring.
Claim 3
Dependent Claim
16 words
The method as recited in claim 1, wherein each time segment is three seconds in length.
Claim 4
Dependent Claim
30 words
The method of operating a patient monitoring system as recited in claim 1, the electrical discharge detecting step comprising the step of attaching a plurality of electrodes to the patient.
Claim 5
Dependent Claim
31 words
The method as recited in claim 3, wherein the determining step comprises the step of converting the standardized features from each time segment into a probability that a seizure is occurring.
Claim 6
Dependent Claim
33 words
The method as recited in claim 4, wherein the standardized features converting step comprises the step of using logistic regression to convert the standardized features into a probability that a seizure is occurring.
Claim 7
Dependent Claim
31 words
The method as recited in claim 5, wherein the determining step further comprises the step of converting the probabilities for adjacent time segments into a determination that a seizure is occurring.
Claim 8
Dependent Claim
55 words
The method as recited in claim 6, wherein the determining step further comprises the step of deciding whether the probabilities for adjacent time segments from an electrode exceed a threshold value and a probability for a time segment from a second electrode also exceeds the threshold value during either of the two adjacent time segments.
Claim 9
Dependent Claim
33 words
The method of operating a patient monitoring system as recited in claim 4, the determining step further comprising the step of comparing the probability that a seizure is occurring to a threshold value.
Claim 10
Dependent Claim
18 words
The method as recited in claim 1, the processing step comprising the step of filtering the digital signal.
Claim 11
Dependent Claim
43 words
The method as recited in claim 9, wherein the processing step further comprises: subtracting the filtered digital signal from the standardized digital signal to obtain a residual digital signal; and differencing successive standardized digital signal points to obtain a first difference digital signal.
Claim 12
Dependent Claim
38 words
The method as recited in claim 1, wherein the reducing step comprises the step of counting in a signal of the time segment, the signal containing a plurality of extrema, the number of the extrema in the signal.
Claim 13
Dependent Claim
29 words
The method as recited in claim 1, wherein the reducing step comprises the step of calculating a percentile of an absolute value of a signal in the time segment.
Claim 14
Dependent Claim
29 words
The method as recited in claim 1, wherein the reducing step comprises the step of computing an average of the absolute value of a signal in the time segment.
Claim 15
Dependent Claim
31 words
The method as recited in claim 1, wherein the reducing step comprises the step of calculating a coefficient for an autoregressive time series model of a signal in the time segment.
Claim 16
Dependent Claim
25 words
The method as recited in claim 1, wherein the reducing step comprises the step of computing a moment for a signal in the time segment.
Claim 17
Dependent Claim
29 words
The method as recited in claim 1, wherein the reducing step comprises the step of summing an absolute change in an amplitude of a signal in the time segment.
Claim 18
Dependent Claim
28 words
The method of operating a patient monitoring system as recited in claim 1, the detected electrical discharge converting step further comprising the step of amplifying the digital signal.
Claim 19
Dependent Claim
38 words
The method of operating a patient monitoring system as recited in claim 1, wherein the determining step comprises the step of using a neural network to convert the standardized features into a determination that a seizure is occurring.
Claim 20
Dependent Claim
27 words
The method of operating a patient monitoring system as recited in claim 1, the indicating step comprising the step of displaying the signals from each time segment.
Claim 21
Dependent Claim
31 words
The method of operating a patient monitoring system as recited in claim 1, the indicating step comprising the step of sounding an alarm when a seizure is determined to be occurring.
Claim 22
Dependent Claim
31 words
The method of operating a patient monitoring system as recited in claim 1, further comprising the step of providing treatment to the patient when a seizure is determined to be occurring.
Claim 23
Dependent Claim
29 words
The method of operating a patient monitoring system as recited in claim 21, the treatment providing step comprising the step of electrically stimulating the patient to control the seizure.
Claim 24
Dependent Claim
31 words
The method of operating a patient monitoring system as recited in claim 21, the treatment providing step comprising the step of dispensing a drug to the patient to control the seizure.
Claim 25
Dependent Claim
166 words
A patient monitoring system for automatically detecting a seizure, the monitoring system comprising: means for detecting an electrical discharge in the patient's brain; means for converting the detected electrical discharge into a digital signal; a microprocessor for receiving the digital signal; means for automatically detecting a seizure using the microprocessor and the digital signal, the automatic detection means comprising: means for dividing the digital signal into a plurality of time segments; means for standardizing the digital signal in each time segment; means for processing the standardized digital signal in each time segment to form at least one additional signal in each time segment; means for reducing each signal in each time segment to a feature, the feature providing information about whether a seizure is occurring; means for standardizing each feature; and means for determining whether a seizure is occurring using the standardized features from each time segment; and means for indicating that a seizure is occurring, the indicating means being connected to the automatic detection means.
Claim 26
Dependent Claim
166 words
A patient monitoring system for automatically detecting a seizure, the monitoring system comprising: means for detecting an electrical discharge in the patient's brain; means for converting the detected electrical discharge into a digital signal; a microprocessor for receiving the digital signal; means for automatically detecting a seizure using the microprocessor and the digital signal, the automatic detection means comprising: means for dividing the digital signal into a plurality of time segments; means for standardizing the digital signal in each time segment; means for processing the standardized digital signal in each time segment to form at least one additional signal in each time segment; means for reducing each signal in each time segment to a feature, the feature providing information about whether a seizure is occurring; means for standardizing each feature; and means for determining whether a seizure is occurring using the standardized features from each time segment; and means for indicating that a seizure is occurring, the indicating means being connected to the automatic detection means.
Claim 27
Dependent Claim
19 words
The patient monitoring system as recited in claim 24, the electrical discharge detecting means comprising a plurality of electrodes.
Claim 28
Dependent Claim
38 words
The patient monitoring system as recited in claim 25, the means for determining whether a seizure is occurring comprising a means for converting the standardized features from each time segment into a probability that a seizure is occurring.
Claim 29
Dependent Claim
35 words
The patient monitoring system as recited in claim 26, the means for determining whether a seizure is occurring further comprising a means for comparing the probability that a seizure is occurring to a threshold value.
Claim 30
Dependent Claim
32 words
The patient monitoring system as recited in claim 26, the feature converting means comprising means for using logistic regression to convert the standardized features into a probability that a seizure is occurring.
Claim 31
Dependent Claim
38 words
The patient monitoring system as recited in claim 28, the means for determining whether a seizure is occurring further comprising a means for converting the probabilities for adjacent time segments into a determination that a seizure is occurring.
Claim 32
Dependent Claim
62 words
The patient monitoring system as recited in claim 29, the means for determining whether a seizure is occurring further comprising a means for deciding whether the probabilities for adjacent time segments from an electrode exceed a threshold value and a probability for a time segment from a second electrode also exceeds the threshold value during either of the two adjacent time segments.
Claim 33
Dependent Claim
24 words
The patient monitoring system as recited in claim 24, the detected electrical discharge converting means further comprising an amplifier for amplifying the digital signal.
Claim 34
Dependent Claim
17 words
The patient monitoring system as recited in claim 24, the digital signal processing means comprising a filter.
Claim 35
Dependent Claim
50 words
The patient monitoring system as recited in claim 32, the digital signal processing means further comprising: means for subtracting the filtered digital signal from the standardized digital signal to obtain a residual digital signal; and means for differencing successive standardized digital signal points to obtain a first difference digital signal.
Claim 36
Dependent Claim
30 words
The patient monitoring system as recited in claim 24, the determining means comprising a neural network means to convert the standardized features into a determination that a seizure is occurring.
Claim 37
Dependent Claim
39 words
The patient monitoring system as recited in claim 24, the reducing means comprising a means for counting in a signal of the time segment, the signal containing a plurality of extrema, the number of the extrema in the signal.
Claim 38
Dependent Claim
30 words
The patient monitoring system as recited in claim 24, the reducing means comprising a means for calculating a percentile of an absolute value of a signal in the time segment.
Claim 39
Dependent Claim
30 words
The patient monitoring system as recited in claim 24, the reducing means comprising a means for computing an average of the absolute value of a signal in the time segment.
Claim 40
Dependent Claim
32 words
The patient monitoring system as recited in claim 24, the reducing means comprising a means for calculating a coefficient for an autoregressive time series model of a signal in the time segment.
Claim 41
Dependent Claim
26 words
The patient monitoring system as recited in claim 24, the reducing means comprising a means for computing a moment for a signal in the time segment.
Claim 42
Dependent Claim
30 words
The patient monitoring system as recited in claim 24, the reducing means comprising a means for summing an absolute change in an amplitude of a signal in the time segment.
Claim 43
Dependent Claim
22 words
The patient monitoring system as recited in claim 24, the indicating means comprising means for displaying the signals from each time segment.
Claim 44
Dependent Claim
15 words
The patient monitoring system as recited in claim 24, the indicating means comprising alarm means.
Claim 45
Dependent Claim
26 words
The patient monitoring system as recited in claim 24, further comprising a therapeutic means connected to the automatic detection means for providing treatment to the patient.
Claim 46
Dependent Claim
24 words
The patient monitoring system as recited in claim 43, the therapeutic means comprising a means for electrically stimulating the patient to control the seizure.
Claim 47
Dependent Claim
26 words
The patient monitoring system as recited in claim 43, the therapeutic means comprising a means for dispensing a drug to the patient to control the seizure.
References Cited (Backward Citations)
US3498287A
Cited
US3850161A
Cited
US4214591A
Cited
US4201224A
Cited
US4566464A
Cited
SU1074484A1
Cited
US4545388A
Cited
US4579125A
Cited
US5010891A
Cited
US5181520A
Cited
US4873981A
Cited
US4878498A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1997-05-16 | 1997-11-15 | 1998-05-17 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2001-05-16 | 2001-11-15 | 2002-05-17 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2005-05-16 | 2005-11-15 | 2006-05-17 | $7700.00 | Window Closed / Lapsed |