OBJECTIVE: The characteristics of response time (RT) distributions beyond measures of central tendency were explored in 3 attention tasks across groups of young adults, healthy older adults, and individuals with very mild dementia of the Alzheimer's type (DAT). METHOD: Participants were administered computerized Stroop, Simon, and switching tasks, along with psychometric tasks that tap various cognitive abilities and a standard personality inventory (NEO-FFI). Ex-Gaussian (and Vincentile) analyses were used to capture the characteristics of the RT distributions for each participant across the 3 tasks, which afforded 3 components: mu and sigma (mean and standard deviation of the modal portion of the distribution) and tau (the positive tail of the distribution). RESULTS: The results indicated that across all 3 attention tasks, healthy aging produced large changes in the central tendency mu parameter of the distribution along with some change in sigma and tau (mean etap(2) = .17, .08, and .04, respectively). In contrast, early stage DAT primarily produced an increase in the tau component (mean etap(2) = .06). tau was also correlated with the psychometric measures of episodic/semantic memory, working memory, and processing speed, and with the personality traits of neuroticism and conscientiousness. Structural equation modeling indicated a unique relation between a latent tau construct (-.90), as opposed to sigma (-.09) and mu constructs (.24), with working memory measures. CONCLUSIONS: The results suggest a critical role of attentional control systems in discriminating healthy aging from early stage DAT and the utility of RT distribution analyses to better specify the nature of such change.
OBJECTIVE: The characteristics of response time (RT) distributions beyond measures of central tendency were explored in 3 attention tasks across groups of young adults, healthy older adults, and individuals with very mild dementia of the Alzheimer's type (DAT). METHOD:Participants were administered computerized Stroop, Simon, and switching tasks, along with psychometric tasks that tap various cognitive abilities and a standard personality inventory (NEO-FFI). Ex-Gaussian (and Vincentile) analyses were used to capture the characteristics of the RT distributions for each participant across the 3 tasks, which afforded 3 components: mu and sigma (mean and standard deviation of the modal portion of the distribution) and tau (the positive tail of the distribution). RESULTS: The results indicated that across all 3 attention tasks, healthy aging produced large changes in the central tendency mu parameter of the distribution along with some change in sigma and tau (mean etap(2) = .17, .08, and .04, respectively). In contrast, early stage DAT primarily produced an increase in the tau component (mean etap(2) = .06). tau was also correlated with the psychometric measures of episodic/semantic memory, working memory, and processing speed, and with the personality traits of neuroticism and conscientiousness. Structural equation modeling indicated a unique relation between a latent tau construct (-.90), as opposed to sigma (-.09) and mu constructs (.24), with working memory measures. CONCLUSIONS: The results suggest a critical role of attentional control systems in discriminating healthy aging from early stage DAT and the utility of RT distribution analyses to better specify the nature of such change.
Authors: Andrew J Aschenbrenner; David A Balota; Anne M Fagan; Janet M Duchek; Tammie L S Benzinger; John C Morris Journal: J Int Neuropsychol Soc Date: 2015-09 Impact factor: 2.892
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Authors: Karin L Meeker; Beau M Ances; Brian A Gordon; Cort W Rudolph; Patrick Luckett; David A Balota; John C Morris; Anne M Fagan; Tammie L Benzinger; Jill D Waring Journal: Neurobiol Aging Date: 2020-11-02 Impact factor: 4.673
Authors: Janet M Duchek; David A Balota; Jewell B Thomas; Abraham Z Snyder; Patrick Rich; Tammie L Benzinger; Anne M Fagan; David M Holtzman; John C Morris; Beau M Ances Journal: Neuropsychology Date: 2013-09 Impact factor: 3.295