Correct interpretation is essential when evaluating brain function and behavior. Unfortunately, other issues associated with aging, such as poor vision, often get overlooked, resulting in the possible misdiagnosis of older adults with undiagnosed eye problems like cataracts and age-related macular degeneration (AMD). For people with AMD, difficulty reading or recognizing faces may cause low scores on cognition tests dependent on visual tasks. According to a study by the University of Australia, millions of people over age 50 could be diagnosed with mild cognitive impairment when they actually have poor vision.*

What the researchers did

In the study, published in Scientific Reports, researchers set out to demonstrate how visual deficiencies from AMD can affect cognitive test performance.

• 24 participants with normal vision completed one cognitive test involving visual tasks and a second test on verbal fluency.
• The participants completed each test with and without special goggles that simulated the effects of AMD.

What they found

The participants scored much lower on the visual-based cognitive test when they wore the goggles than when they did not wear them. The goggles had no impact on the verbal fluency test, a short screening of cognitive function that does not involve reading.

With over 200 million people living with visual impairment worldwide, the risk of misdiagnosis of mild cognitive impairment is high with tests involving visual ability. Such misdiagnoses could have “devastating ramifications,” said Anne Macnamara, a Ph.D. candidate at the University of Australia, “leading to unnecessary changes to a person’s living, working, financial or social circumstances,” and could further lead to mental health issues like anxiety and depression. 

Researchers Must Take Notice

The researchers estimate that up to half of older adults with visual impairment could be misdiagnosed by neuro-degenerative scientists. As the population ages, it’s critical that these impairments are accounted for when evaluating brain function.

The study authors note that mobile apps simulating vision impairment are now available for researchers to use when developing cognitive tests. Simple visual screening could also be used before engaging in cognitive testing.

“Verbal tests should always be part of the assessment, too” they added, to help ensure accurate results.

*University of Australia. (2022, May 10). Poor eyesight unfairly mistaken for brain decline. MDLinx. https://www.mdlinx.com/news/poor-eyesight-unfairly-mistaken-for-brain-decline