Biomarker of the colour perception of a mammal subject based on pupil frequency tagging
Inventors
Pouget, Pierre • DAYE, PIERRE • Lorenceau, Jean
Assignees
Centre National de la Recherche Scientifique CNRS • Assistance Publique Hopitaux de Paris APHP • Institut National de la Sante et de la Recherche Medicale INSERM • Sorbonne Universite • Institut du Cerveau et de La Moelle Epiniere ICM
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Publication Number
US-11229356-B2
Publication Date
2022-01-25
Expiration Date
Abstract
Evaluation of the perception of colors by mammals with a view to obtaining a characteristic biomarker of each tested subject takes advantage of the slow pupillary oscillatory response to generate an objective neurological signature of this perception of colors. A method based on pupil frequency tagging is used at a tagging frequency Ftag adapted to the pupil response speed. A dynamic two-color stimulus is displayed, this stimulus comprising a two-color pattern the colors of which are inverted at the frequency Ftag, one of the colors gradually varying in a range of possible values. From the pupillary response, a signal representative of the oscillation power of the pupil is generated. The minimum of this signal corresponds to the relative iso-luminance of the tested pair of colors.
Core Innovation
The invention generates an indicator or biomarker (SIGpower, APPROXpower) of the perception of colors by a mammal subject by subjecting the mammal subject to at least one dynamic multi-color stimulus. The stimulus displays, on a display peripheral, a multi-color pattern in which at least two colors are periodically inverted at a tagging frequency (Ftag), and at least one color’s luminance is modified over time by controlling a modification over time of at least one (C2) of the two colors of the multi-color pattern.
While the dynamic multi-color stimulus is displayed, an image-acquiring device acquires an oscillatory response (SIGresp) of at least one pupil of the mammal subject. From the acquired pupil oscillatory response, the invention generates a signal (SIGpower, APPROXpower) representative of the power of the oscillatory response as a function of the luminance modification over time of at least one of the two colors, and the generated power signal serves as a pupil-as-function-of-color-modification representation.
A configuration of chromatic iso-luminance is determined from the minimum of the generated signal power. The iso-luminance configuration corresponds to relative iso-luminance of the color pair, and the invention defines a modification indicator by comparing iso-luminance values determined at two times (t1, t2). The modification indicator is used for pathology-related diagnosis or progression tracking based on changes in the perception-related indicator, including multiple sclerosis and intoxications related to hepatitis treatment.
Claims Coverage
The partial content identifies two independent claims. Each independent claim centers on generating a color-perception indicator or biomarker from periodically inverted dynamic multi-color stimulation and a pupil oscillatory response, using a power-representative signal as a function of color luminance modification over time.
Power signal from pupil oscillatory response as a function of luminance modification
Generating an indicator or biomarker (SIGpower, APPROXpower) of the perception of colors by subjecting a mammal subject to a dynamic multi-color stimulus with a multi-color pattern at least two colors periodically inverted at a tagging frequency (Ftag), controlling a modification over time of at least one (C2) of the two colors to make the displayed luminance of this color vary, acquiring with an image-acquiring device an oscillatory response (SIGresp) of at least one pupil during the display, and generating from the acquired response a signal representative of the power of the oscillatory response as a function of the modification over time.
System with display stimulation, pupil acquisition, and power-based indicator generation
Providing a system for generating an indicator or biomarker (SIGpower, APPROXpower) comprising a display peripheral, a computational system controlling the display of a dynamic multi-color stimulus with a multi-color pattern at least two colors periodically inverted at a tagging frequency (Ftag), a color controller configured to modify over time at least one (C2) of the two colors to vary luminance, an image-acquiring device acquiring an oscillatory response (SIGresp) of at least one pupil during the stimulus, and an indicator or biomarker generator configured to generate, from the acquired response, a signal representative of the power of the oscillatory response as a function of the luminance modification over time.
Across both independent claims, the core inventive concept is generating a color-perception indicator or biomarker by displaying a dynamically stimulated multi-color pattern with periodic inversion at Ftag, varying luminance of at least one color over time, acquiring a pupil oscillatory response during the display, and generating a power-representative signal (SIGpower/APPROXpower) as a function of luminance modification over time.
Stated Advantages
Low tagging frequency (Ftag) enables use of off-the-shelf ~25 fps video cameras.
Reduces noise/contamination.
Avoids calibration burden.
Documented Applications
Diagnosis/progression tracking for multiple sclerosis.
Diagnosis/progression tracking for intoxications related to hepatitis treatment.
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