Poor Vision is Usually Mistaken for Brain Cognition

Millions of aged people with poor vision are at risk of being misdiagnosed as having mild cognitive impairments, according to a new study from the University of South Australia (UniSA).

Cognitive tests rely on vision-dependent tasks that could lead to skewed results in up to a quarter of people over the age of 50 who have undiagnosed visual problems, such as cataracts or age-related macular degeneration (AMD).

‘AMD is one of the leading causes of vision loss for aged people. It doesn't cause total vision loss, but it severely affects people's ability to read, drive, cook and even recognize faces.’

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AMD is one of the leading causes of vision loss for aged people. It doesn't cause total vision loss, but it severely affects people's ability to read, drive, cook and even recognize faces. It has nothing to do with cognition. The study has been published in Scientific Reports.

Experimental Tests and Results

UniSA researchers recruited 24 participants with normal vision to complete two cognitive tests, one involving vision-dependent reactive tasks and the other based on verbal fluency.

Using a set of glasses to simulate AMD, the participants scored much lower on the cognitive test involving reaction time tasks than without the glasses. There was no statistical difference with the verbal fluency tests when wearing the glasses.

UniSA doctoral candidate Anne Macnamara, who led the study, says that the results are a stark reminder that visual impairments, which affect an estimated 200 million people worldwide over the age of 50, unfairly affect cognitive scores when tests involve visual skills.

“A mistaken score in cognitive tests could have devastating ramifications, leading to unnecessary changes to a person’s living, working, financial or social circumstances,” Macnamara says.

“For example, if a mistaken score contributed to a diagnosis of mild cognitive impairment, it could trigger psychological problems including depression and anxiety."

“People with AMD are already experiencing multiple issues due to vision loss and an inaccurate cognitive assessment is an additional burden they don’t need.”

UniSA researchers say that visual impairments are often overlooked in clinical and research settings, and this reduced vision was underestimated in up to 50% of older adults.

And since this figure is expected to increase as the population ages, it is critical that neurodegenerative researchers monitor vision when assessing people's cognition.

“Mobile apps can now be used to overlay simulated visual impairments onto test materials when piloting their stimuli,” Macnamara says.

“Also, researchers can incorporate quick and simple screening tasks before getting people to do cognitive tests. Verbal tasks should always be part of the assessment, too.”

Source-Medindia