Adaptive Time-Frequency Windows for iEEG Seizure Onset Zone Localization

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Solution Overview

Problem

Current methods for identifying the seizure onset zone (SOZ) in epilepsy are challenging due to the complex localization of the SOZ, variable seizure patterns, and the need for invasive recording techniques. Existing biomarkers often rely on predefined frequency bands and do not adapt to patient-specific patterns, lacking a fully unsupervised algorithm for SOZ localization.

Innovation Solution

A computer-implemented method that identifies time-frequency features of physiological events by filtering and analyzing intracranial electroencephalography (iEEG) signals within defined time-frequency windows. This method calculates feature values and quantifiers, such as global activation and activation entropy, to select relevant time-frequency windows and identify the seizure focus.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Device complexity

If predefined frequency bands are used for biomarker quantification, then the analysis framework is simplified, but patient-specific seizure patterns cannot be adequately captured

Engineering Contradiction:
Improveanalysis frameworkVSAvoidpatient-specific pattern detection
Core Design Contradiction:
Device complexityVSAdaptability or versatility

Solution Approach 1:

The patent transitions from static predefined frequency bands to dynamic adaptive time-frequency windows. The system automatically adjusts the time-frequency regions of interest based on detected seizure patterns, allowing the analysis framework to adapt to patient-specific characteristics while maintaining computational feasibility through algorithmic automation.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The invention changes the parameters of frequency analysis by moving from fixed frequency bands to variable time-frequency windows. The system identifies and analyzes specific time-frequency regions where seizure-related power changes occur, adapting the frequency and temporal parameters to match actual seizure patterns rather than forcing data into predetermined categories.

Inventive Principle:
Principle #35Parameter changes

2Extent of automation

If fully unsupervised algorithms are implemented for SOZ localization, then automation is improved, but reliability of detection decreases due to lack of expert validation

Engineering Contradiction:
ImproveSOZ localizationVSAvoiddetection accuracy
Core Design Contradiction:
Extent of automationVSReliability

Solution Approach 1:

The system incorporates feedback mechanisms where detection results inform subsequent analysis. The automated algorithm uses detected power changes and time-frequency patterns to refine its own detection criteria, and the system provides feedback to clinicians through visualizations that can be validated against expert knowledge, creating a loop that improves both automation and reliability.

Inventive Principle:
Principle #23Feedback

Solution Approach 2:

The patent implements self-service through automated detection algorithms that independently identify seizure patterns and localize SOZ without requiring continuous expert intervention. The system serves itself by automatically adjusting analysis parameters, selecting time-frequency windows, and generating localization results, reducing dependency on manual expert validation while maintaining reliability through multiple detection criteria.

Inventive Principle:
Principle #25Self-service

3Measurement precision

If multiple time-frequency windows are analyzed, then detection sensitivity is improved, but computational complexity increases

Engineering Contradiction:
Improveseizure detection sensitivityVSAvoidcomputational processing
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent segments the frequency spectrum into multiple time-frequency windows that can be analyzed independently. Each window focuses on specific frequency ranges and time periods where seizure-related activity is most likely to occur, allowing detailed analysis without requiring exhaustive processing of the entire signal spectrum simultaneously.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The system applies partial action by concentrating computational resources on only those time-frequency windows that show power changes consistent with seizure activity. Rather than uniformly analyzing all possible time-frequency combinations, the algorithm identifies and focuses on the most relevant windows, reducing overall computational complexity while maintaining high detection sensitivity.

Inventive Principle:
Principle #16Partial or excessive action

Data Source

PatentEP3977478B1A computer implemented method and computer program products for identifying time-frequency features of physiological events
Publication Date: 2025.02.19 UNIV POMPEU FABRA
  • EP3977478B1 patent drawingFigure 1
  • EP3977478B1 patent drawingFigure 2A~2B
  • EP3977478B1 patent drawingFigure 2C(A)~2C(D)

AI summary

A method and computer programs for identifying time-frequency features of physiological events are disclosed. A computer system comprises filtering a set of physiological signals within each one of a plurality of time-frequency windows, obtaining a filtered set for each time-frequency window; calculating, for each time- frequency window, a given feature for the filtered set, each one of the signals of the filtered set having a given feature value, providing for each time-frequency window a set of feature values; and calculating, for each time-frequency window a first quantifier defined as a function of said set of features values and/or a second quantifier defined as a function of an empirical distribution of said set of feature values. The first quantifier can be compared with a first threshold and the second quantifier can be compared with a second threshold. The computing system can further select the time-frequency windows satisfying the first threshold and/or the second threshold.