PREVALENCE OF VISUAL DEFICITS IN ALZHEIMERS-DISEASE

This study addressed the issue of prevalence and pattern of visual def icits in 77 subjects with Alzheimer's disease (AD) and 111 healthy con trol subjects. We defined cutoff scores that would be expected from on ly 1 control subject of 100 (p = 0.01). The percentage of AD subjects who performed at or worse than this level varied across the 16 visual tests from a high of 58% to a low of 0%. The distribution of impairmen t across tests suggests a high vulnerability in AD of pattern vision, moderate vulnerability of spatial vision, and low vulnerability of mot ion and flicker perception. We found evidence for heterogeneity in the AD subject group: a subgroup (N = 14) emerged that was characterized by poor performance on the Backward Pattern Masking test, relatively y oung age, and relatively short duration of AD. Overall, the results in dicate that visual dysfunction, especially on Backward Masking, is a c ommon sign of AD.