Simulated cataract and low contrast stimuli impair cognitive performance in older adults: implications for neuropsychological assessment and everyday function.
OBJECTIVE
To investigate how age-related declines in vision (particularly contrast sensitivity), simulated using cataract-goggles and low-contrast stimuli, influence the accuracy and speed of cognitive test performance in older adults. An additional aim was to investigate whether declines in vision differentially affect secondary more than primary memory.


METHODS
Using a fully within-subjects design, 50 older drivers aged 66-87 years completed two tests of cognitive performance--letter matching (perceptual speed) and symbol recall (short-term memory)--under different viewing conditions that degraded visual input (low-contrast stimuli, cataract-goggles, and low-contrast stimuli combined with cataract-goggles, compared with normal viewing). However, presentation time was also manipulated for letter matching. Visual function, as measured using standard charts, was taken into account in statistical analyses.


RESULTS
Accuracy and speed for cognitive tasks were significantly impaired when visual input was degraded. Furthermore, cognitive performance was positively associated with contrast sensitivity. Presentation time did not influence cognitive performance, and visual gradation did not differentially influence primary and secondary memory.


CONCLUSIONS
Age-related declines in visual function can impact on the accuracy and speed of cognitive performance, and therefore the cognitive abilities of older adults may be underestimated in neuropsychological testing. It is thus critical that visual function be assessed prior to testing, and that stimuli be adapted to older adults' sensory capabilities (e.g., by maximising stimuli contrast).
See
Amy Y
AY
Centre for Mental Health Research, Australian National University, Canberra, Australia.
Anstey
Kaarin J
KJ
Wood
Joanne M
JM
D000368:Aged; D000369:Aged, 80 and over; D000375:Aging / Q000502:physiology*; D002386:Cataract / Q000503:physiopathology*; D003072:Cognition Disorders / Q000209:etiology*; D015350:Contrast Sensitivity / Q000502:physiology*; D005135:Eye Protective Devices / Q000009:adverse effects*; D005260:Female; D006801:Humans; D008297:Male; D011939:Mental Recall / Q000502:physiology; D009483:Neuropsychological Tests; D010775:Photic Stimulation; D011930:Reaction Time; D014792:Visual Acuity / Q000502:physiology