Near-Infrared Optical Spectroscopy In Vivo Distinguishes Subjects with Alzheimer's Disease from Age-Matched Controls

Area of Science:

• Biomedical optics
• Neuroimaging
• Spectroscopy

Background:

• Current Alzheimer's disease (AD) diagnosis relies on expensive and complex imaging like PET and MRI.
• There is a need for more accessible, cost-effective, and widely deployable technologies for AD screening and monitoring.
• Previous in vitro near-infrared (NIR) spectroscopy studies indicated potential for brain tissue analysis.

Purpose of the Study:

• To evaluate the efficacy of non-invasive, in vivo clinical NIR spectroscopy in differentiating AD patients from age-matched controls.
• To assess the potential of NIR as a tool for clinical screening and monitoring therapeutic efficacy in AD.
• To investigate NIR spectral features for classifying AD and mild cognitive impairment (MCI).

Main Methods:

• Acquisition of in vivo NIR spectra from three groups: autopsy-confirmed AD, controls, and MCI patients.
• Utilized a feature selection approach on the first derivative of intensity-normalized spectra.
• Identified spectral regions that best distinguish AD from controls and differentiate MCI subjects.

Main Results:

• Two specific spectral regions (around 860 nm and 895 nm) effectively separated AD patients from controls.
• The 895 nm feature was crucial for differentiating MCI from controls, while the 860 nm feature was more important for distinguishing MCI from AD.
• Results demonstrated the ability of NIR to classify diseased and normal human brain tissue in vivo.

Conclusions:

• Near-infrared spectroscopy (NIR) provides a proof-of-concept for in vivo detection and classification of diseased and normal brain tissue.
• The identified spectral features show potential for clinical screening of Alzheimer's disease and mild cognitive impairment.
• Further clinical trials are necessary to validate NIR's ability to track disease progression and monitor therapeutic interventions.