F-wave Latency Detection Using Morphological Segmentation

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Solution Overview

Problem

Current nerve conduction studies face challenges in accurately detecting and analyzing F-wave latency due to the highly variable morphology and low amplitude of F-waves, which are often obscured by noise, power-line frequency interference, and baseline disturbances, leading to errors in automated latency calculations.

Innovation Solution

A method and apparatus that preprocess signals to attenuate noise and interference, segment and classify time segments as quiet, A-wave, Repeater, or F-wave segments, and accurately determine F-wave latency by limiting the search to specific intervals and using differential features to differentiate between A-waves and F-waves.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If automated latency calculation is performed on F-waves, then productivity is improved, but measurement precision deteriorates due to variable morphology and low amplitude

Engineering Contradiction:
Improveautomated latency calculationVSAvoidF-wave latency measurement
Core Design Contradiction:
ProductivityVSMeasurement precision

Solution Approach 1:

The patent segments the neural response into distinct components (M-wave, A-waves, F-waves) based on temporal characteristics and morphology. By dividing the complex response waveform into separable segments, the system can apply different analysis methods to each segment, improving both automation capability and measurement precision for F-wave latency detection.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent performs preliminary classification and identification of wave components before conducting latency measurement. By pre-segmenting the response and identifying candidate F-wave regions based on temporal windows and morphological features, the system prepares the data structure in advance to enable accurate automated latency calculation without confusion from other wave components.

Inventive Principle:
Principle #10Preliminary action

2Measurement precision

If the entire trace is searched for F-wave latency, then measurement completeness is improved, but reliability deteriorates due to noise and interference

Engineering Contradiction:
ImproveF-wave latency detection completenessVSAvoidlatency calculation accuracy
Core Design Contradiction:
Measurement precisionVSReliability

Solution Approach 1:

The patent applies local quality by restricting the F-wave latency search to a specific temporal window and morphological criteria rather than searching the entire trace. This localized approach focuses computational resources on the region where F-waves are expected to occur, improving reliability by avoiding false detections from noise and interference in other time regions while maintaining measurement completeness within the defined search space.

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The patent performs preliminary identification of F-wave candidate regions based on temporal windows and morphological features before conducting latency measurement. This pre-filtering step prepares the data by marking likely F-wave segments, enabling the subsequent latency calculation to focus only on reliable regions and avoid noise-contaminated areas.

Inventive Principle:
Principle #10Preliminary action

3Loss of information

If A-waves are present in the trace, then information completeness is improved, but measurement precision deteriorates due to masking of F-wave onsets

Engineering Contradiction:
Improvelate wave component informationVSAvoidF-wave latency measurement
Core Design Contradiction:
Loss of informationVSMeasurement precision

Solution Approach 1:

The patent segments the late wave components into A-waves and F-waves based on their distinct temporal and morphological characteristics. By separating these overlapping components through classification algorithms that consider waveform shape, amplitude, and timing patterns, the system can identify F-wave onsets even when A-waves are present, maintaining measurement precision while preserving information about both wave types.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent performs preliminary classification of wave components to distinguish A-waves from F-waves before conducting latency measurement. By pre-identifying and separating A-wave segments from F-wave segments based on morphological features, the system prepares the data to enable accurate F-wave latency detection without confusion from A-wave masking.

Inventive Principle:
Principle #10Preliminary action

Data Source

PatentUS8078273B2Detection and classification of neuromuscular late wave activity for the assessment of neuromuscular function
Publication Date: 2011.12.13 NEUROMETRIX INC
  • US8078273B2 patent drawing
  • US8078273B2 patent drawing
  • US8078273B2 patent drawing

AI summary

A method for the assessment of neuromuscular function by the detection and classification of late wave activity, comprising: (i) pre-processing an ensemble of traces so as to attenuate noise, PFI and baseline disturbances; (ii) identifying time segments of late wave activity in the ensemble of traces; (iii) classifying the time segments of late wave activity into F-wave, A-wave and Repeater segments by exploiting the variable morphology of F-waves across the traces and the fixed morphology of A-waves and Repeater waves across the traces; and (iv) searching the traces in the vicinity of the F-wave trace segments on a trace-by-trace basis so as to identify the F-wave onset latency.