MAR 15, 2022 3:00 AM PDT

Can an Eye Scan Help with Early Detection of Alzheimer's Disease?

WRITTEN BY: Katie Kokolus

According to Alzheimer's Association, one in nine people over 65 are currently living with Alzheimer's disease (AD). The condition impacts over six million Americans, and sadly, due to the rapid expansion of diagnoses, experts expect this figure to more than double over the next thirty years. Last year, treatment related to dementia care cost approximately $355 billion, and costs are expected to surpass $1.1 trillion by 2050.  

Early AD diagnosis is essential for optimal disease management, therapy, and patient care. However, methods to differentiate pathological changes from normal aging remain limited. As AD is typically diagnosed at an advanced stage when symptoms arise, investigational therapeutic approaches have failed. Thus, investigators have focused their research on improving diagnostics to identify AD at the preclinical stage, where treatment may be feasible.

Prior studies suggest that the retina, tissue in the back of the eye that recognizes light and transmits images to the brain, could serve as a biomarker for AD due to its proximity to the brain. Doctors can image the retina with a non-invasive procedure called optical coherence tomography (OCT). Recent studies have demonstrated a correlation between AD and thinness in two components of the retina: the retinal nerve fiber layer (RNFL) and ganglion cell layer (GCL). However, research on RNFL/GCL thinning and AD remain inconsistent.  

A study recently published in JAMA Opthamology examined whether RNFL and GCL thinning correlate to cognitive impairment at various ages. Researchers conducted the study within the Dunedin Multidisciplinary Health and Development Study, a large behavioral study in New Zealand following over 1000 individuals born in 1972 and 1973 from birth onward.  

Investigators accessed cognitive performance based on IQ, processing speed (how fast a person can react to information), perceptual reasoning, and verbal comprehension at ages 7, 9, 11, and 45.  Additionally, the researchers measured RNFL and GCL thickness with OCT when participants reached 45 years old.  At the time of analysis, 865 enrollees were included in the present study. 

Analysis revealed thin RNFL and GCL in participants with low IQ in childhood and at age 45 years.  Reduced processing speed from childhood to adulthood was also associated with thin RNFL. 

The authors conclude that their data highlights the potential use of OCT for measuring biomarkers of cognitive function.  While this study does not confirm that RNFL and GCL thinning can predict AD, it does make a significant advancement in accessing and analyzing these potential biomarkers.  Additional large-scale studies could establish the timeframe between retinal thinning and cognitive decline to conclude the feasibility of these measures as early diagnostic markers. 

 

Sources: Nat Rev Neurol, Invest Ophthalmol Vis Sci, Front Aging Neurosci, Medicina, JAMA Ophthalmol

About the Author
PhD
PhD in Tumor Immunology. I am interested in developing novel strategies to improve the efficacy of immunotherapies used to extend cancer survivorship.
You May Also Like
JUN 13, 2022
Technology
New Technology Allows for Quick Ebola Diagnosis
JUN 13, 2022
New Technology Allows for Quick Ebola Diagnosis
Ebola is a deadly disease that can spread easily through bodily fluids. Several outbreaks have occurred over the years, ...
JUN 21, 2022
Cancer
Advanced Lung Cancer Diagnosis Linked to Socioeconomic Status
JUN 21, 2022
Advanced Lung Cancer Diagnosis Linked to Socioeconomic Status
Lung cancer remains the leading cause of cancer-related deaths for both males and females, and an estimated 120,000 peop ...
JUN 27, 2022
Genetics & Genomics
A Genetic Score Can Determine Who Needs Surgery for Varicose Veins
JUN 27, 2022
A Genetic Score Can Determine Who Needs Surgery for Varicose Veins
It's thought that about 30% of people in Western countries develop varicose veins, which are caused by chronic venous di ...
JUL 21, 2022
Immunology
For the First Time, Microscopy Catches Antibodies Attacking a Receptor
JUL 21, 2022
For the First Time, Microscopy Catches Antibodies Attacking a Receptor
Using cryo-electron microscopy, researchers captured images of a molecule called an autoantibody as it attached to a rec ...
JUL 30, 2022
Health & Medicine
Large-Scale Study Suggests Link Between Temporary Menstrual Changes and Covid-19 Vaccine
JUL 30, 2022
Large-Scale Study Suggests Link Between Temporary Menstrual Changes and Covid-19 Vaccine
The most comprehensive analysis of menstrual changes following a Covid-19 vaccination has revealed that its recipients e ...
AUG 02, 2022
Cardiology
Exercising 150-600 Minutes Per Week Leads to Lowest Death Risk
AUG 02, 2022
Exercising 150-600 Minutes Per Week Leads to Lowest Death Risk
People who exercise for two to four times the recommended amount per week see major reductions in all-cause mortality.
Loading Comments...