title: Delay and probability discounting as candidate markers for dementia: an initial investigation.
abstract: The present study investigated delay discounting and probability discounting-behavioral economic indices of impulsivity and risk proneness, respectively-in 39 healthy older adults and 25 older adults with mild cognitive impairment (MCI). Relative to the healthy group, it was hypothesized that older adults with MCI would display greater levels of impulsivity, risk proneness, and response inconsistency. The MCI group was found to display a unique delay discounting profile characterized by increasing impulsivity with decreasing reward magnitude, such that cognitively impaired older adults were significantly more impulsive than healthy controls at the small reward magnitude. The two groups exhibited similar levels of probability discounting, though older adults with MCI were significantly less consistent in their risk preferences. The present findings shed light onto decision-making in pre-dementia disease stages and suggest that discounting performance holds potential to complement early diagnostic instruments, likely due to pathophysiological processes in relevant brain regions.
authors.affiliation: Department of Psychology, University of Georgia, Athens, GA 30602, USA cal@uga.edu.
authors.forename: Cutter A
authors.initials: CA
authors.lastname: Lindbergh
authors.affiliation: Department of Psychology, University of Georgia, Athens, GA 30602, USA.
authors.forename: Antonio N
authors.initials: AN
authors.lastname: Puente
authors.affiliation: Department of Psychology, University of Georgia, Athens, GA 30602, USA.
authors.forename: Joshua C
authors.initials: JC
authors.lastname: Gray
authors.affiliation: Department of Psychology, University of Georgia, Athens, GA 30602, USA.
authors.forename: James
authors.initials: J
authors.lastname: Mackillop
authors.affiliation: Department of Psychology, University of Georgia, Athens, GA 30602, USA Bio-Imaging Research Center, Paul D. Coverdell Center, University of Georgia, Athens, GA 30602, USA.
authors.forename: L Stephen
authors.initials: LS
authors.lastname: Miller
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D015415:Biomarkers; D060825:Cognitive Dysfunction / Q000175:diagnosis / Q000503:physiopathology*; D065786:Delay Discounting / Q000502:physiology*; D003704:Dementia / Q000175:diagnosis / Q000503:physiopathology*; D005260:Female; D006801:Humans; D007175:Impulsive Behavior / Q000502:physiology*; D008297:Male; D011336:Probability; D012201:Reward
chemical_list: D015415:Biomarkers
keywords: Aging; Behavioral economics; Cognition; Delay discounting; Mild cognitive impairment; Probability discounting