Study Says Loss of Visual Sensitivity Can Predict Dementia 12 Years Before It Is Diagnosed

Your brain's health can be read through the windows of our souls: the eyes.

Problems with vision often surface as one of the earliest indicators of cognitive decline. Recent research shows that a loss of visual sensitivity can predict dementia up to 12 years before a formal diagnosis.

Researchers conducted a study involving 8,623 healthy individuals in Norfolk, England, monitored over several years. By the end of the study, 537 participants had developed dementia, allowing researchers to identify potential early indicators of the disease.

Visual Sensitivity Test: A Predictive Tool

At the beginning of the study, participants underwent a visual sensitivity test, where they pressed a button upon seeing a triangle in a field of moving dots.

According to Science Alert, adults showed that individuals who later developed dementia were significantly slower in detecting the triangle than those who did not develop the condition.

The Underlying Cause: Toxic Amyloid Plaques

Visual issues may serve as an early sign of cognitive decline due to the toxic amyloid plaques associated with Alzheimer's disease, which initially affect brain areas related to vision.

As the disease progresses, it damages regions associated with memory, suggesting that vision tests might detect deficits earlier than memory tests.

Broader Visual Processing Issues in Alzheimer's

Alzheimer's disease affects several aspects of visual processing, such as contrast sensitivity (the ability to see object outlines) and color discernment, particularly in the blue-green spectrum. These deficits can impact daily life without immediate awareness.

Inhibitory Control and Eye Movements

Another early sign of Alzheimer's is impaired "inhibitory control" of eye movements, where distracting stimuli capture attention more readily. Individuals with Alzheimer's struggle to ignore distractions, leading to eye-movement control issues. This difficulty can increase the risk of driving accidents, a subject currently under investigation at Loughborough University.

Recognizing Faces: A Cognitive Challenge

Evidence suggests that people with dementia process new faces inefficiently, not following the usual eye movement pattern from eyes to nose to mouth. This inefficient scanning makes it harder to imprint and remember faces, leading to recognition difficulties.

Healthcare professionals often notice this when interacting with dementia patients, who may seem lost due to ineffective environmental scanning.

Improving Memory Through Eye Movements

Given the link between visual sensitivity and memory performance, researchers are exploring whether encouraging eye movements can enhance memory.

While previous research shows mixed results, some studies indicate that eye movement can boost memory. This could explain why those who watch TV and read more have better memory and a lower risk of dementia.

Educational Impact on Memory and Dementia Risk

Reading frequently often correlates with higher education levels, which builds brain reserve capacity. This reserve helps mitigate the negative effects of brain damage. Additionally, quick left-to-right and right-to-left eye movements have been found to improve autobiographical memory, though this benefit appears more pronounced in right-handed individuals for reasons not yet understood.

Eye Movements in Memory Treatment

Despite promising findings, using deliberate eye movements as a treatment for memory issues in older adults is still not widespread. Eye movement deficits are not regularly used as a diagnostic tool, partly due to the high cost and complexity of eye-tracking technologies.

Until these technologies become more affordable and user-friendly, using eye movements for early-stage Alzheimer's diagnosis remains limited to laboratory settings.

Early detection of dementia through eye health assessment holds significant potential. With advancements in eye-tracking technology, these diagnostic methods could become more accessible, offering a non-invasive way to identify and address cognitive decline early.

Access the full study here.

Back in June, Tech Times reported that a unique brain scan model can predict dementia up to nine years in advance. What's more, it has 80% accuracy of working so you can avoid brain cell death early on.