Effects of low visual acuity on neuropsychological assessment

Background and aimsNorm data of most neuropsychological tests do not correct for the potential influence of visual disorders. Therefore, current neuropsychological assessment for elderly with visual disorders, which is a relatively large population, is non-optimal quality. For a number of commonly used neuropsychological tests, it is examined to what extent low vision influences test performance.MethodIn 241 healthy elderly without visual or neurological disorders, simulation glasses were used to simulate low visual acuity. Participants in group A (n=119, average age 65) performed the MMSE, Balloons Test and Complex Figure of Rey with simulation glasses, and the Trailmaking Test and VOSP with normal vision. Participants in group B (n=122, average age 65) performed the Trailmaking Test and VOSP with simulation glasses and the other tests with normal vision. ResultsLow visual acuity had a negative impact on the Trailmaking Test, Complex Figure of Rey (copy score) and VOSP subtest 3, but not on the MMSE and Balloons Test. For some tests, the negative impact of low visual acuity increased with age.ConclusionsWhen administering the Trailmaking Test, Complex Figure of Rey (copy score) and VOSP subtest 3 to older people with low visual acuity, low test scores should be interpreted with great caution. Low test scores on the MMSE and Balloons Test are not likely to be caused by low visual acuity and are more likely to reflect actual cognitive impairment. These results have important implications for the use of neuropsychological tests in the visually impaired population.