The Effects of rs405509 on APOEε4 Non-carriers in Non-demented Aging

BackgroundThere is evidence that the T allele of rs405509 located in the apolipoprotein E (APOE) promotor region is a risk factor for Alzheimer’s disease (AD). However, the effect of the T/T allele on brain function in non-demented aging is still unclear.MethodsWe analyzed the effects of the rs405509 T/T allele on cognitive performances using multiple neuropsychological tests and local brain function using resting-state functional magnetic resonance imaging (rs-fMRI).ResultsSignificant differences were found between T/T carriers and G allele carriers on general cognitive status, memory, and attention (p < 0.05). Rs-fMRI analyses demonstrated decreased amplitude of low frequency fluctuation (ALFF) in the right middle frontal gyrus, decreased percent amplitude of fluctuation (PerAF) in the right middle frontal gyrus, increased regional homogeneity (ReHo) in the right cerebellar tonsil and decreased ReHo in the right putamen, and decreased degree centrality (DC) in the left middle frontal gyrus (p < 0.05, corrected). Furthermore, significant correlations were found between cognitive performance and these neuroimaging changes (p < 0.05).ConclusionThese findings suggest that T/T allele may serve as an independent risk factor that can influence brain function in different regions in non-demented aging.

A Virtual Reality-Based Screening Test for Cognitive Impairment in Small Vessel Disease

Background: There is a need for new practical tools to assess the cognitive impairment of small vessel disease (SVD) patients in the clinic. Objective: This study aimed to examine cognitive functioning by administering the Virtual Supermarket (VST) in patients with SVD with cognitive impairment (SVD-CI, N = 32), cognitively normal SVD (SVD-CN, N = 37), and age-and education-matched healthy controls (HC, N = 30). Methods: The tablet-based VST application and comprehensive traditional pencil-and-paper neuropsychological tests assessing memory, attention, executive function, visuospatial function, and language were administered to all participants. Results: A moderate correlation was found between the “Duration” and “Correct Quantities” variables of VST and visuospatial function and general cognitive status composite Z scores across SVD-CI patients. “Duration” and “Correct Money” variables were moderately related to memory, executive functions, and visuospatial function composite Z scores across SVD-CN patients. A combination of all VST variables discriminated SVD-CI and HC with a correct classification rate of 81%, a sensitivity of 78%, and a specificity of 84%. Conclusion: This study is the first to evaluate cognitive functions employing the VST in SVD with and without cognitive impairment. It provides encouraging preliminary findings of the utility of the VST as a screening tool in the assessment of cognitive impairment and the differentiation of SVD patients from HC. In the future, validation studies of the VST with larger samples are needed.

Branching Condition of the Color-Word Interference Test Enhances Prediction of Meta-Tasking in Community-Dwelling Older Adults

Objectives: Meta-tasking (MT) is an aspect of executive functioning (EF) that involves the ability to branch (i.e., to apply “if-then” rules) and to effectively interleave sub-goals of one task with sub-goals of another task. As such, MT is crucial for successful planning, coordination, and execution of multiple complex tasks in daily life. Traditional tests of EF fail to adequately measure MT. This study examined whether Condition 4 of the Color-Word Interference Test (CWIT-4; the inhibition/switching condition that requires branching) predicted MT beyond Condition 3 (CWIT-3; inhibition-only condition) and beyond other subtests from the Delis–Kaplan Executive Function System (D-KEFS) that have a switching condition. Method: Ninety-eight non-Hispanic white community-dwelling older adults completed the first four subtests of the D-KEFS and an ecologically valid measure of MT. Results: Time to completion and total errors on CWIT-4 accounted for variance in MT above and beyond CWIT-3 and beyond the switching conditions of other D-KEFS subtests. Results remained virtually unchanged when controlling for demographics and general cognitive status. Conclusions: Among older adults, CWIT-4 is more strongly associated with MT than other D-KFES tasks. Future research should examine whether CWIT-4 relates to lapses in instrumental activities of daily living among older adults above and beyond other EF tests.

Relational binding and holistic retrieval in aging

Episodic memory binds together diverse elements of an event into a cohesive unit. This property enables the reconstruction of multidimensional experiences when triggered by a cue related to a past event via pattern completion processes. Such holistic retrieval is evident in young adults, as shown by dependency in the retrieval success for different associations from the same event (Horner & Burgess, 2013, 2014). Aspects of episodic memory capacity are vulnerable to aging processes, as shown by reduced abilities to form linkages within an event through relational binding (associative deficit hypothesis: Naveh-Benjamin, 2002). However, prior work has not examined whether this reduction affects holistic retrieval in typical aging. Here, we leveraged dependency analyses to examine whether older adults remember or forget events holistically, and whether the degree of holistic retrieval declines with old age. We found evidence for continued holistic retrieval, because accuracy for one aspect of an event predicted accuracy for other aspects of the same event. Younger and older adults did not differ in the degree of holistic recollection, despite robust age-related differences in relational binding. However, within the group of older adults, holistic recollection showed a significant decline with advancing age, controlling for pairwise relational binding performance, verbal IQ, and general cognitive status. These results suggest that a decline in holistic retrieval is an aspect of episodic memory decrements later in cognitive aging.

Characteristics of neurocognitive functions in mild cognitive impairment with depression

ABSTRACTBackground:Previous studies suggest that there is a strong association between depression and cognitive decline, and that concurrent depressive symptoms in MCI patients could contribute to a difference in neurocognitive characteristics compared to MCI patients without depression. The authors tried to compare neurocognitive functions between MCI patients with and without depression by analyzing the results of neuropsychological tests.Methods:Participants included 153 MCI patients. Based on the diagnosis of major depressive disorder, the participants were divided into two groups: depressed MCI (MCI/D+) versus non-depressed MCI (MCI/D−). The general cognitive and functional statuses of participants were evaluated. And a subset of various neuropsychological tests was presented to participants. Demographic and clinical data were analyzed using Student t-test or χ2 test.Results:A total of 153 participants were divided into two groups: 94 MCI/D+ patients and 59 MCI/D− patients. Age, sex, and years of education were not significantly different between the two groups. There were no significant differences in general cognitive status between MCI/D+ and MCI/D− patients, but MCI/D+ participants showed significantly reduced performance in the six subtests (Contrasting Program, Go-no-go task, Fist-edge-palm task, Constructional Praxis, Memory Recall, TMT-A) compared with MCI/D− patients.Conclusions:There were significantly greater deficits in neurocognitive functions including verbal memory, executive function, attention/processing speed, and visual memory in MCI/D+ participants compared to MCI/D−. Once the biological mechanism is identified, distinct approaches in treatment or prevention will be determined.