This open enrollment, choose a plan that includes access to our world-class providers. Get better care now

Menu
Search

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

Researchers say how quickly a person’s pupil dilates while taking cognitive tests

September 10, 2019  |  

Alzheimer’s disease (AD) begins to alter and damage the brain years — even decades — before symptoms appear, making early identification of AD risk paramount to slowing its progression.

In a new study published online in the September 9, 2019 issue of the Neurobiology of Aging, scientists at University of California San Diego School of Medicine say that, with further developments, measuring how quickly a person’s pupil dilates while they are taking cognitive tests may be a low-cost, low-invasive method to aid in screening individuals at increased genetic risk for AD before cognitive decline begins.

face of an elderly man

How quickly a person’s pupils dilate while doing mental tasks may be an indicator of increased genetic risk for Alzheimer’s disease. Image: Pixabay

In recent years, researchers investigating the pathology of AD have primarily directed their attention at two causative or contributory factors: the accumulation of protein plaques in the brain called amyloid-beta and tangles of a protein called tau. Both have been linked to damaging and killing neurons, resulting in progressive cognitive dysfunction.

The new study focuses on pupillary responses which are driven by the locus coeruleus (LC), a cluster of neurons in the brainstem involved in regulating arousal and also modulating cognitive function. Tau is the earliest occurring known biomarker for AD; it first appears in the LC; and it is more strongly associated with cognition than amyloid-beta. The study was led by first author William S. Kremen, PhD, and senior author Carol E. Franz, PhD, both professors of psychiatry and co-directors of the Center for Behavior Genetics of Aging at UC San Diego School of Medicine.

The LC drives pupillary response — the changing diameter of the eyes’ pupils — during cognitive tasks. (Pupils get bigger the more difficult the brain task.) In previously published work, the researchers had reported that adults with mild cognitive impairment, often a precursor to AD, displayed greater pupil dilation and cognitive effort than cognitively normal individuals, even if both groups produced equivalent results. Critically, in the latest paper, the scientists link pupillary dilation responses with identified AD risk genes.

“Given the evidence linking pupillary responses, LC and tau and the association between pupillary response and AD polygenic risk scores (an aggregate accounting of factors to determine an individual’s inherited AD risk), these results are proof-of-concept that measuring pupillary response during cognitive tasks could be another screening tool to detect Alzheimer’s before symptom appear,” said Kremen.

Co-authors include: Matthew S. Panizzon, Jeremy A. Elman, Anders M. Dale, Daniel E. Gustavson and Nathan Whitsel, UC San Diego; Eric L. Granholm, UC San Diego and Veterans Affairs San Diego Healthcare System; Ole A. Andreassen, Oslo University Hospital; Nathan A. Gillespie and Michael C. Neale, Virginia Commonwealth University; Mark W. Logue, VA Boston Healthcare System and Boston University; Michael J. Lyons, Boston University; and Chandra A. Reynolds, UC Riverside.

Funding for this research came, in part, from the National Institute on Aging (grants R01AG050595, R01AG022381, P01AG055367, R01AG059329, K08AG047903, AG054509), the Research Council of Norway and Stiftelsen KG Jebsen. Additional support from the CA San Diego Center of Excellence for Stress and Mental Health and the Cooperative Studies Program of the U.S. Department of Veterans Affairs.

Disclosure: Anders Dale is founder and holds equity in CorTech Labs, Inc. and serves on its scientific advisory board. He also has equity interest in and is a member of the scientific advisory board of Human Longevity, Inc., and receives funding through research agreements with General Electric Healthcare and Medtronic, Inc.


​Care at UC San Diego Health

Memory Disorders



Media Contact

Scott LaFee
858-249-0456
slafee@ucsd.edu

Share This Article


Related News

11/14/2019
Researchers identified non-coding regions of the human genome that control the development and function of four brain cell types and mapped genetic risk variants for psychiatric diseases. They found t ...
10/9/2019
Study finds when verbal memory test cut-offs were tailored to patient sex, more female patients and fewer male patients were considered to have amnesic mild cognitive impairment. This could change the ...
7/8/2019
UC San Diego will launch a payload of stem cell-derived human brain organoids to the International Space Station. Researchers will document how these “mini brains” organize into the beginnings of a fu ...
3/21/2017
An international team of scientists, led by researchers at University of California San Diego School of Medicine and University of California San Francisco, has developed a novel genetic score that al ...



Follow Us