Kernel flow and the eye‐ brain connectome: Study design and objectives

Abstract

AbstractBackgroundMore evidence suggests how the eye health may be crucial in older adults at risk of developing cognitive impairment (CI) and Alzheimer’s disease (AD). Ocular conditions and AD share several common factors, including older age behavioral and cardiometabolic disease. Poor vision can lead to reduced activation of central sensory pathways, which is associated with higher cognitive load and brain structure damage. We showed that CI is not limited to the brain but also affects the retina. However, despite recent advances in neuroimaging biomarkers (e.g., PET diagnostics), there remains a need for more readily available and affordable diagnostic testing for AD risk. While blood flow within the optic nerve head can be quantified using advanced optical imaging technologies, it is essential to measure what is going on in the brain at the same time.MethodWe propose a cross‐sectional and longitudinal, observational study evaluating structural and functional biomarkers of the retina and brain associated with AD disease risk and/or progression. The study objective is to collect structural and functional data of the retina and brain to facilitate the discovery of reliable and sensitive multimodal biomarkers of AD disease risk and/or progression. We will examine participants (N = 200) aged 55‐80; 50 cognitively healthy (CH), 50 with preclinical AD, 50 with mild CI (MCI), and 50 with mild AD. Assessments will include neuropsychological testing, medical/functional assessment, retinal imaging, brain activity, electroretinography, pupillometry, and contrast sensitivity. We will use a wearable, whole‐head coverage time‐domain functional near‐infrared spectroscopy system (Kernel Inc) to measure local changes in blood oxygenation and electroencephalography.ResultThe eye‐brain connectome is integral in understanding pathology in neurodegenerative diseases. We aim to use the eye‐brain data to develop screening and monitoring tools to identify and track AD risk and severity.ConclusionThis study will overcome limitations for performing functional brain imaging due to the lack of portability and user‐friendliness of neuroimaging devices. Our eye‐brain multimodal biomarker study could also facilitate a novel application for diagnostic assessment and therapeutic intervention to target neuroanatomical sites compromised early in AD, leading to a more robust technique to identify high‐risk individuals before cognitive decline with sufficient sensitivity and specificity.