How the Eyes Might Be Windows to the Risk of Alzheimer's Disease

A study in Neurobiology of Aging suggests the possibility of screening individuals at increased genetic risk for Alzheimer's disease (AD) before onset of cognitive decline by measuring pupil dilation during cognitive testing, reports Medical Xpress . The pupillary response the researchers explored is triggered by the locus coeruleus (LC), a cluster of neurons in the brainstem, which is involved in regulating arousal and modulates cognitive function. The tau protein — the earliest occurring known biomarker for AD — first manifests in the LC, and has a stronger association with cognition than amyloid-beta. Earlier research demonstrated that adults with mild cognitive impairment exhibited greater pupil dilation and cognitive effort than cognitively normal individuals, and the latest study connects pupillary dilation responses with identified AD risk genes. "These results are proof-of-concept that measuring pupillary response during cognitive tasks could be another screening tool to detect Alzheimer's before symptoms appear," said University of California, San Diego Professor William S. Kremen.