Dual-task performance in early stage dementia: differential effects for automatized and effortful processing.
Attentional functions of individuals with early stage Alzheimer's disease (AD) and normal older adults (NC) were studied using a concurrent-task paradigm. Fourteen patients (5 men, 9 women) and 14 age- and sex-matched normal adults engaged in speeded unimanual tapping and speaking tasks during single- and dual-task trials. Speaking tasks were either relatively automatized (Speech Repetition) or relatively effortful (Speech Fluency). As single-task tapping rates were slower for the AD participants than for the NC participants, a proportional decrement score was used as an index of interference in the dual-task conditions. Interference during concurrent-task performance was greater when the cognitive task was effortful for both the NC and the AD groups. Although AD patients suffered higher levels of interference than NC participants while performing the effortful speech task, the two groups showed equivalent small changes in tapping speed while combining the automatized speaking and tapping tasks. Results suggest that a general-purpose attentional processing resource declines in the early stages of AD but dual-task performance is well-maintained when the component tasks are relatively automatized.
Crossley
Margaret
M
Department of Psychology, University of Saskatchewan, 9 Campus Drive, Saskatoon, Sask., Canada S7N 5A5. crossley@sask.usask.ca
Hiscock
Merrill
M
Foreman
Jeanette Beckie
JB
D000203:Activities of Daily Living; D000339:Affect / Q000502:physiology; D000368:Aged; D000544:Alzheimer Disease / Q000503:physiopathology*; D000704:Analysis of Variance; D001288:Attention / Q000502:physiology*; D016022:Case-Control Studies; D005260:Female; D007839:Functional Laterality / Q000502:physiology; D006801:Humans; D008297:Male; D008568:Memory / Q000502:physiology; D008875:Middle Aged; D009483:Neuropsychological Tests; D011340:Problem Solving / Q000502:physiology; D011597:Psychomotor Performance / Q000502:physiology*; D011930:Reaction Time / Q000502:physiology; D012647:Self-Assessment; D013647:Task Performance and Analysis; D014705:Verbal Behavior / Q000502:physiology