Cognitive tests are crucial for identifying and managing dementia. Despite the fact that visual impairment is common among older adults, there is little research on the influence of visual impairment on cognitive test performance, and the most commonly used screening tests for dementia include items that rely on vision. A study published in Age and Ageing compared the performance of older adults with and without visual impairments on two commonly used dementia screening tools, highlighting the importance of vision-independent cognitive testing.
The study included 74 older adults with visual impairment, and 76 without any visual impairment. Participants were administered a set of three cognitive tests that were vision-independent (i.e., did not require any visual skills), and two vision-dependent tests, including the widely used dementia screening test, the Mini Mental State Examination (MMSE). The two groups of participants were also assessed on whether they had any functional impairment (as measured by difficulty in activities of daily living [ADL]), and completed a brief demographic questionnaire.
The group consisting of participants with visual impairments was slightly older (by about two years), and had a higher number of ADL difficulties. There were no significant test score differences across the two groups in the vision-independent tests; however, on the vision-dependent tests, the participants without visual impairment scored higher. When the vision-dependent items on these tests were replaced with vision-independent items, there were no significant differences between the scores of the two groups. These findings show that clinicians and researchers need to consider the visual demands of the cognitive tests used in clinical and research settings.
Killen A, Firbank MJ, Collerton D, et al. The assessment of cognition in visually impaired older adults. Age and Ageing; (2013). 42:98-102.