Visual determinants of reduced performance on the stroop color-word test in normal aging individuals

It is unknown to what extent the performance on the Stroop color-word test is affected by reduced visual function in older individuals. We tested the impact of common deficiencies in visual function (reduced distant and close acuity, reduced contrast sensitivity, and color weakness) on Stroop perfor mance among 821 normal individuals aged 53 and older. After adjustment for age, sex, and educational level, low contrast sensitivity was associated wi th more time needed on card 1 (word naming), red/green color weakness with slower card 2 performance (color naming), and reduced distant acuity with s lower performance on card 3 (interference). Half of the age-related varianc e in speed performance was shared with visual function. The actual impact o f reduced visual function may be underestimated in this study when some of this age-related variance in Stroop performance is mediated by visual funct ion decrements. It is suggested that reduced visual function has differenti al effects on Stroop performance which need to be accounted for when the St roop test is used both in research and in clinical settings. Stroop perform ance measured from older individuals with unknown visual status should be i nterpreted with caution.