The sensitivity of dual-task performance to cognitive status in aging

The present study examined dual-task performance in elders with cognitive impairments and normal controls. The participants (N = 60; M age = 84.6) were recruited from residential facilities and the community. They were assigned to one of three groups: (1) cognitive impairment; (2) residential facility control; (3) community control. Two different dual-task conditions were comprised of simple tests that are presumably processed via separate perceptual modalities: 1 visual-manual and 1 auditory-verbal. The first condition consisted of a visual cancellation test and an auditory digit span. The second condition was comprised of an alternate form of the visual cancellation test and letter fluency. NIANOVA examined the effect of cognitive status (3-level independent variable) on 3 indices of dual-task performance (letter fluency, digit span, visual cancellation). Analyses controlled for age, education and performance on each test when performed alone. The results revealed that the cognitive impairment group incurred significantly greater dual-task costs compared to both control groups. Furthermore, as was evident from discriminant function analyses, the dual-task measures were very accurate and better than the traditional neuropsychological measures at discriminating elders with cognitive impairments from normal controls.