The Study Of Intertemporal Decision-making Of Alzheimer's Disease And Mild Cognitive Impairment Patients

BackgroundIntertemporal decision-making is an important part of social cognition and is very common in daily life.Intertemporal decision-making refers to selection among options with distinct consequences over time.There are many factors affecting intertemporal decision-making,including cognitive functions,such as executive functions and working memory,but at the same time the aging process itself can influence the choice of intertemporal decision-making.Patients with Alzheimer's disease(AD)and mild cognitive impairment(MCI)are common age-related neurodegenerative diseases,with cognitive impairment as the core feature which including executive functions and working memory.With the progression of AD and MCI,patients will gradually lose their cognitive function and may further influence the ability of intertemporal decision-making.In the preclinical stage,patients with AD and MCI often have brain dysfunction and some of them may appear decreased self-control.The ability of self-control is important component of intertemporal decision-making and patients with AD or MCI may appear changes of intertemporal decision-making.This study is to explore the changes of intertemporal decision-making in patients with AD and MCI and further research on the relationship between intertemporal decision disorder and related cognitive functions.ObjectiveWe recruited AD and MCI patients and age,sex and education-matched controls and to evaluate intertemporal preferences in AD and MCI patients compared to healthy matched controls.MethodAD patients(N=22),MCI patients(N=37)and healthy controls(N=51)patients participated in a computerized,Chinese version of the Intertemporal Choice Task in which they were asked to choose between sooner-smaller(SS)and later-larger(LL)options in now-trials and not-now-trials.All participants completed a series of standardized neuropsychological tests to investigate cognitive function.The main evaluation parameter was the percentage of choices for delayed rewards(%LL)in different amount levels.ResultsAD or MCI patients tended to choose SS options in now-trials and not now-trials with greater frequency compared to HC patients.Additionally,AD and MCI patients demonstrated significantly poorer performance in several cognitive tests compared to healthy groups,including the Mini Mental State Exam(MMSE)and other tests of memory and executive function.Correlational analysis revealed that poor intertemporal decision-making was associated with executive function deficits in MCI patients.ConclusionsThe present study demonstrates that AD and MCI patients all have impairments in intertemporal decision-making function.Reduced intertemporal decision-making capacity in MCI may stem from impaired executive function,possibly due to frontalparietal circuit degeneration.Intertemporal decision-making disfunction may be a potential behavioral marker of AD.