Optical Taxonomic Signal and the Diagnosis of Alzheimer's Disease

• Published in: IEEE open journal of engineering in medicine and biology Vol. 6; pp. 107 - 112
• Main Authors: Greco, Frank A., Schell, Brent R., Hanlon, Eugene B.
• Format: Journal Article
• Language: English
• Published: United States IEEE 01.01.2025; The Institute of Electrical and Electronics Engineers, Inc. (IEEE)
• Subjects: Alzheimer's disease; amyloid; Biomedical optical imaging; cerebral amyloid angiopathy; Cerebral cortex; Cognitive ability; Detectors; Disease control; Feature extraction; feature selection; Indexes; Infrared spectra; Infrared spectroscopy; Meninges; Near infrared radiation; near-infrared spectroscopy; Neurodegenerative diseases; Optical detectors; Optical fibers; Optical scattering; Photonics; Taxonomy; Ultraviolet sources; near-infrared spectroscopy; amyloid; cerebral amyloid angiopathy; Alzheimer's disease; feature selection
• ISSN: 2644-1276; 2644-1276
• DOI: 10.1109/OJEMB.2024.3477449

Goal: We previously demonstrated that near-infrared spectroscopy in vivo presents spectral features at 895 and 861 nm that accurately classify Alzheimer's disease, mild cognitive impairment, and age-matched control subjects. Our purpose here is to associate the 895 nm signal with <inline-formula><tex-math notation="LaTeX">\beta</tex-math></inline-formula>-amyloid. Methods: We applied our feature selection technique to subjects with and without leptomeningeal amyloid. We developed a novel concept, optical taxonomic signal, to determine the dependence of signal on source-detector distance. Results: Features at 891 and 768 nm discriminate between subjects with and without leptomeningeal <inline-formula><tex-math notation="LaTeX">\beta</tex-math></inline-formula>-amyloid. The variation of optical taxonomic signal with source-detector distance indicates that both signals come from the leptomeninges and not cerebral cortex. The two features are highly correlated and likely result from the same cellular material. Conclusions: The discovery of an 891 nm feature that clearly depends upon the presence of <inline-formula><tex-math notation="LaTeX">\beta</tex-math></inline-formula>-amyloid supports our hypothesis that the 895 nm feature previously discovered also reports <inline-formula><tex-math notation="LaTeX">\beta</tex-math></inline-formula>-amyloid.