Glymphatic Activity Measurement Using NIRS During Sleep Transitions

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Solution Overview

Problem

Existing methods for measuring the activity of the human glymphatic system are invasive, difficult to implement in real-time, and cannot track dynamic changes during wake-sleep transitions or in various pathological conditions, limiting the understanding and management of neurodegenerative diseases associated with glymphatic dysfunction.

Innovation Solution

A method and apparatus using near-infrared spectroscopy (NIRS) to analyze brainwave indices and brain water content changes, combined with polysomnography indices, to non-invasively measure and quantify the activity of the glymphatic system, providing activity information and indices related to its determinants.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If two-photon microscopy is used to measure glymphatic system activity, then measurement precision is improved, but the method becomes highly invasive and cannot be applied to human body

Engineering Contradiction:
Improvemeasurement precisionVSAvoidinvasiveness
Core Design Contradiction:
Measurement precisionVSObject-affected harmful factors

Solution Approach 1:

The patent replaces the mechanical/invasive two-photon microscopy method with a non-invasive optical method using near-infrared spectroscopy (NIRS). The NIRS system uses near-infrared light to measure brain water content changes through the scalp, eliminating the need for surgical implantation of probes or catheters while still enabling quantitative measurement of glymphatic system activity through water content changes in the brain parenchyma.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent uses brain water content as an intermediary parameter to indirectly measure glymphatic system activity. Instead of directly observing CSF flow or metabolite removal, the method measures changes in brain water content using NIRS, which correlates with glymphatic system function. This intermediary approach enables non-invasive measurement while maintaining measurement precision.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Measurement precision

If gadobutrol injection and repeated MRI scans are used to measure glymphatic system activity, then measurement capability is improved, but real-time continuous measurement and tracking of dynamic changes become extremely difficult

Engineering Contradiction:
Improvemeasurement capabilityVSAvoidreal-time continuous measurement capability
Core Design Contradiction:
Measurement precisionVSProductivity

Solution Approach 1:

The patent enables continuous real-time measurement of glymphatic system activity by using NIRS to continuously monitor brain water content changes. Unlike discrete MRI scans, the NIRS system provides continuous data streams that capture dynamic changes during wake-sleep transitions and sleep stages, allowing for uninterrupted observation of glymphatic system function over extended periods.

Inventive Principle:
Principle #20Continuity of useful action

Solution Approach 2:

The patent replaces the discrete, time-consuming MRI scanning process with continuous optical monitoring using NIRS. The NIRS system uses near-infrared light to continuously measure brain water content without requiring repeated subject positioning, scanning sequences, or post-processing reconstruction, thereby enabling real-time measurement of glymphatic activity.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

3Measurement precision

If repeated MRI scans are performed to track dynamic changes during wake-sleep transitions, then measurement capability is improved, but natural sleep is interfered with and measurement of pathological conditions is impossible

Engineering Contradiction:
Improvemeasurement capabilityVSAvoidnatural sleep preservation
Core Design Contradiction:
Measurement precisionVSEase of operation

Solution Approach 1:

The patent replaces the cumbersome MRI scanning process with a simple, portable NIRS measurement system that can be applied to the subject's scalp without restricting movement or requiring specialized imaging facilities. This substitution allows subjects to sleep naturally while being continuously monitored, preserving natural sleep architecture and enabling measurement of glymphatic activity during genuine wake-sleep transitions and sleep stages.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The NIRS system allows subjects to maintain their natural sleep patterns and physiological states without requiring external intervention or positioning adjustments. The measurement device passively monitors brain water content changes while the subject sleeps naturally, eliminating the need for repeated awakening or repositioning that would interfere with sleep quality and natural glymphatic system function.

Inventive Principle:
Principle #25Self-service

4Measurement precision

If intrathecal injection of gadobutrol is used to measure glymphatic system activity, then measurement precision is improved, but the method is not approved by FDA and cannot be applied clinically

Engineering Contradiction:
Improvemeasurement precisionVSAvoidclinical applicability
Core Design Contradiction:
Measurement precisionVSAdaptability or versatility

Solution Approach 1:

The patent replaces the intrathecal injection method with a non-invasive NIRS measurement approach that does not require breaking the blood-brain barrier or introducing contrast agents into the CSF space. This substitution eliminates FDA approval barriers and enables broad clinical application for monitoring glymphatic system activity in various neurological conditions, including Alzheimer's disease, Parkinson's disease, and other neurodegenerative disorders.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent uses brain water content as an intermediary parameter that can be measured non-invasively using NIRS, replacing the need for intrathecal contrast agent injection. This intermediary approach maintains measurement precision while eliminating the safety concerns and regulatory barriers associated with intrathecal gadobutrol injection, thereby enabling widespread clinical use.

Inventive Principle:
Principle #24Intermediary (Mediator)

Applied Scientific Principles

This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.

Function Achieved in This Case

Enables accurate, non-invasive measurement of the glymphatic system activity, allowing for the identification of physiological mechanisms and biomarkers that regulate its function, and aiding in the diagnosis and management of neurodegenerative diseases.

Implementation Method 1

the present inventors have developed a method for accurately measuring the brain water content in real time and non-invasively, using near-infrared spectroscopy (NIRS)

Methodology Applied
Scientific EffectNear-infrared spectroscopy: Absorption Spectroscopy

Data Source

PatentEP4721646A1Method and apparatus for providing activity information of cerebral glymphatic system
Publication Date: 2026.04.08 SEOUL NAT UNIV HOSPITAL
  • EP4721646A1 patent drawingFigure 1
  • EP4721646A1 patent drawingFigure 2A
  • EP4721646A1 patent drawingFigure 2B

AI summary

Disclosed in the present specification are a novel and effective method and apparatus for measuring the activity level of the cerebral glymphatic system and a method and apparatus for screening a glymphatic system activity index. In one aspect, the method and apparatus of the present invention enable measurement of the activity of the glymphatic system with high predictive value and accuracy, and the method and apparatus of the present invention enable the discovery of polysomnography, brainwaves, and near-infrared spectroscopy indices for determining the activity of the glymphatic system.