Detecting subtle changes in visuospatial executive function and learning in the amnestic variant of mild cognitive impairment

Measuring Cognitive Abilities in the Wild: Validating a Population-Scale Game-Based Cognitive Assessment

Rapid individual cognitive phenotyping holds the potential to revolutionize domains as wide-ranging as personalized learning, employment practices, and precision psychiatry. Going beyond limitations imposed by traditional lab-based experiments, new efforts have been underway toward greater ecological validity and participant diversity to capture the full range of individual differences in cognitive abilities and behaviors across the general population. Building on this, we developed Skill Lab, a novel game-based tool that simultaneously assesses a broad suite of cognitive abilities while providing an engaging narrative. Skill Lab consists of six mini-games as well as 14 established cognitive ability tasks. Using a popular citizen science platform (N = 10,725), we conducted a comprehensive validation in the wild of a game-based cognitive assessment suite. Based on the game and validation task data, we constructed reliable models to simultaneously predict eight cognitive abilities based on the users' in-game behavior. Follow-up validation tests revealed that the models can discriminate nuances contained within each separate cognitive ability as well as capture a shared main factor of generalized cognitive ability. Our game-based measures are five times faster to complete than the equivalent task-based measures and replicate previous findings on the decline of certain cognitive abilities with age in our large cross-sectional population sample (N = 6369). Taken together, our results demonstrate the feasibility of rapid in-the-wild systematic assessment of cognitive abilities as a promising first step toward population-scale benchmarking and individualized mental health diagnostics.

Using shoe-mounted inertial sensors and stepping exergames to assess the motor-cognitive status of older adults: A correlational study

Objective

Stepping exergames designed to stimulate physical and cognitive skills can provide important information concerning individuals’ performance. In this study, we investigated the potential of stepping and gameplay metrics to assess the motor-cognitive status of older adults.

Methods

Stepping and gameplay metrics were recorded in a longitudinal study involving 13 older adults with mobility limitations. Game parameters included games’ scores and reaction times. Stepping parameters included length, height, speed, and duration, measured by inertial sensors placed on the shoes while interacting with the exergames. Parameters measured on the first gameplay were correlated against standard cognitive and mobility assessments, including the Montreal Cognitive Assessment (MoCA), gait speed, and the Short Physical Performance Battery. Based on MoCA scores, patients were then stratified into two groups: cognitively impaired and healthy controls. The differences between the two groups were visually inspected, considering their within-game progression over the training period.

Results

Stepping and gameplay metrics had moderate-to-strong correlations with cognitive and mobility performance indicators: faster, longer, and higher steps were associated with better mobility scores; better cognitive games’ scores and reaction times, and longer and faster steps were associated with better cognitive performance. The preliminary visual analysis revealed that the group with cognitive impairment required more time to advance to the next difficulty level, also presenting slower reaction times and stepping speeds when compared to the healthy control group.

Conclusion

Stepping exergames may be useful for assessing the cognitive and motor status of older adults, potentially allowing assessments to be more frequent, affordable, and enjoyable. Further research is required to confirm results in the long term using a larger and more diverse sample.

Higher-Level Executive Functions in Healthy Elderly and Mild Cognitive Impairment: A Systematic Review

Mild Cognitive Impairment (MCI) is a clinical syndrome characterized by a moderate decline in one or more cognitive functions with a preserved autonomy in daily life activities. MCI exhibits cognitive, behavioral, psychological symptoms. The executive functions (EFs) are key functions for everyday life and physical and mental health and allow for the behavior to adapt to external changes. Higher-level executive functions develop from basic EFs (inhibition, working memory, attentional control, and cognitive flexibility). They are planning, reasoning, problem solving, and fluid intelligence (Gf). This systematic review investigates the relationship between higher-level executive functions and healthy and pathological aging, assuming the role of executive functions deficits as a predictor of cognitive decline. The systematic review was conducted according to the PRISMA Statement. A total of 73 studies were identified. The results indicate that 65.8% of the studies confirm significant EFs alterations in MCI (56.8% planning, 50% reasoning, 100% problem solving, 71.4% fluid intelligence). These results seem to highlight a strong prevalence of higher-level executive functions deficits in MCI elderly than in healthy elderly.

Apolipoprotein E ε4 Allele Is Associated with Reduced Retention of the "Where" Memory Component in Cognitively Intact Older Adults

OBJECTIVE

The present study investigated the effect of the apolipoprotein E (ApoE) ε4 allele on the four memory components (i.e., who, when, where, and what) among cognitively intact older adults.

METHODS

Participants comprised 47 cognitively intact older adults, who were classified into 2 groups based on the presence or absence of at least 1 ApoE ε4 allele. All participants completed standardized neuropsychological tests, including the Logical Memory subtest of the Wechsler Memory Scale-III with a revised scoring method.

RESULTS

The results revealed that recollection for each component followed a pattern of who > what > when = where. Furthermore, a significant group-by-component-by-condition interaction indicated that the presence of the ApoE ε4 allele resulted in a disproportionately detrimental effect on the where component retention in the verbal episodic memory task; this finding was significantly correlated with hippocampal volumes.

CONCLUSION

These results highlighted the importance of evaluating the subcomponents of verbal episodic memory to detect subtle cognitive differences related to ApoE ε4 status, which could help elucidate the mechanism behind the cascades caused by ApoE ε4 in the trajectories of cognitive aging.

Lorazepam Challenge for Individuals at Varying Genetic Risk for Alzheimer Disease

INTRODUCTION

This study set out to clarify the differential acute cognitive impact of lorazepam based on varying genetic risk for Alzheimer disease.

METHODS

Fifty-seven cognitively unimpaired individuals aged 51 to 88, genotyped according to apolipoprotein E (APOE) and translocase of outer mitochondrial membrane (40 homolog) poly-T lengths, completed cognitive testing before, 2.5 and 5 hours after receiving a 1 mg dose of lorazepam.

RESULTS

Post-lorazepam, there were significant (P<0.05) declines from baseline in memory, psychomotor processing speed, and executive function. At 2.5 hours, the magnitude of this lorazepam-induced cognitive change was significantly greater in the APOE3/4 group than in the APOE3/3 group for tests of working memory and visuospatial memory/executive function. At 5 hours postchallenge, verbal memory and working memory deficits persisted in the APOE3/4 group compared with the APOE3/3 group. At 5 hours after lorazepam challenge, as compared with the very long/very long group, the short/short group performed slightly worse on a test of working memory (P<0.05), but no other differences were observed among translocase of the outer mitochondrial membrane 40 homolog poly-T variant groups.

DISCUSSION

The lorazepam challenge may be unmasking presymptomatic cognitive dysfunction associated with APOE4 carriage.

Change in retinal structural anatomy during the preclinical stage of Alzheimer's disease

INTRODUCTION

We conducted a 27-month longitudinal study of mid-life adults with preclinical Alzheimer's disease (AD), using spectral domain optical coherence tomography to compare changes in volume and thickness in all retinal neuronal layers to those of age-matched healthy control subjects.

METHODS

Fifty-six older adults (mean age = 65.36 years) with multiple risk factors for AD completed spectral domain optical coherence tomography retinal imaging and cognitive testing at baseline. Twenty-seven months later, they completed the same examinations and an 18F-florbetapir positron emission tomography imaging study.

RESULTS

Compared to healthy control subjects, those in the preclinical stage of AD showed a significant decrease in macular retinal nerve fiber layer (mRNFL) volume, over a 27-month follow-up interval period, as well as a decrease in outer nuclear layer and inner plexiform layer volumes and thickness in the inferior quadrant. However, only the mRNFL volume was linearly related to neocortical positron emission tomography amyloid standardized uptake value ratio after controlling for any main effects of age (R2 = 0.103; ρ = 0.017). Furthermore, the magnitude of mRNFL volume reduction was significantly correlated with performance on a task of participants' abilities to efficiently integrate visual and auditory speech information (McGurk effect).

DISCUSSION

We observed a decrease in mRNFL, outer nuclear layer, and inner plexiform layer volumes, in preclinical AD relative to controls. Moreover, the largely myelinated axonal loss in the RNFL is related to increased neocortical amyloid-β accumulation after controlling for age. Volume loss in the RNFL, during the preclinical stage, is not related to performance on measures of episodic memory or problem solving. However, this retinal change does appear to be modestly related to relative decrements in performance on a measure of audiovisual integration efficiency that has been recently advanced as a possible early cognitive marker of mild cognitive impairment.

WITHDRAWN: Revisiting the cholinergic hypothesis in Alzheimer's disease: Emerging evidence from translational and clinical research

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Resting-State Cardiac Workload is Related to Both Increased Neocortical Aggregation of Amyloid-β and Relative Impairments in Spatial Working Memory in Pre-Clinical Alzheimer's Disease

We sought to determine whether there is any association between a cardiac workload marker, rate pressure product (RPP), working memory, and cortical amyloid-β (Aβ) burden in 63 cognitively normal midlife adults (Mage = 62.8 years; range = 55 to 75 years) at risk for Alzheimer's disease (AD). The results show a small-to-moderate relationship between increasing cardiac workload (at rest) and neocortical amyloidosis in individuals at the preclinical stage of AD. Moreover, increasing RPP was linearly related to increasing relative impairments on a spatial working memory task (R2 = 0.30), but only for those individuals with neuroimaging evidence suggestive of preclinical AD. These results support a relationship between the aggregation of Aβ protein plaques in the neocortex, increased cognitive impairment, and more inefficient myocardial oxygen use in the absence of significant metabolic demands.

Rule induction performance in amnestic mild cognitive impairment and Alzheimer's dementia: examining the role of simple and biconditional rule learning processes

INTRODUCTION

Rule induction tests such as the Wisconsin Card Sorting Test require executive control processes, but also the learning and memorization of simple stimulus-response rules. In this study, we examined the contribution of diminished learning and memorization of simple rules to complex rule induction test performance in patients with amnestic mild cognitive impairment (aMCI) or Alzheimer's dementia (AD).

METHOD

Twenty-six aMCI patients, 39 AD patients, and 32 control participants were included. A task was used in which the memory load and the complexity of the rules were independently manipulated. This task consisted of three conditions: a simple two-rule learning condition (Condition 1), a simple four-rule learning condition (inducing an increase in memory load, Condition 2), and a complex biconditional four-rule learning condition-inducing an increase in complexity and, hence, executive control load (Condition 3).

RESULTS

Performance of AD patients declined disproportionately when the number of simple rules that had to be memorized increased (from Condition 1 to 2). An additional increment in complexity (from Condition 2 to 3) did not, however, disproportionately affect performance of the patients. Performance of the aMCI patients did not differ from that of the control participants. In the patient group, correlation analysis showed that memory performance correlated with Condition 1 performance, whereas executive task performance correlated with Condition 2 performance.

CONCLUSIONS

These results indicate that the reduced learning and memorization of underlying task rules explains a significant part of the diminished complex rule induction performance commonly reported in AD, although results from the correlation analysis suggest involvement of executive control functions as well. Taken together, these findings suggest that care is needed when interpreting rule induction task performance in terms of executive function deficits in these patients.

Hierarchical Mazes in Psychological Research

Hierarchical mazes have been used in psychology for more than 100 years. During this time many different maze tasks have been created and used to test.cognitive processes and distinguish personality traits. Some of these mazes seem better than others to test different abilities. This article describes the most important mazes used in psychological research and the most important procedures used with these mazes. More than 20 different hierarchical mazes (including maze sets with more than 1 maze, e.g., those of Porteus and Elithorn) were analyzed and classified to different categories.

Exercise, sedentary pastimes, and cognitive performance in healthy older adults

BACKGROUND

Moderately vigorous physical activity (MVPA) provides a protective affect against cognitive decline and cardiovascular risk factors. Less is known about sedentary pastimes or non exercise physical activity (NEPA) and cognitive performance.

METHOD

125 healthy adults 65 or older with no clinical evidence of cognitive impairment were enrolled. The CogState computerized neurocognitive battery was administered. Leisure activities were measured using the Community Health Activity Program for Seniors (CHAMPS).

RESULTS

Sedentary pastimes were associated with executive dysfunction (P = 0.01); MVPA with high memory scores (P = 0.05) and NEPA with improved working memory (P = 0.05). Only sedentary pastimes and executive dysfunction retained significance after correction for multiple comparisons. Smoking and alcohol confounded the association of memory with sedentary pastimes and MVPA.

CONCLUSIONS

Study highlights: negative impact of sedentary pastimes on executive function, need for additional investigation of sedentary behavior, NEPA, the impact of addictions upon activity in late life.

Performance of the CogState computerized battery in the Mayo Clinic Study on Aging

INTRODUCTION

The feasibility and validity of brief computerized cognitive batteries at the population-level are unknown.

METHODS

Nondemented participants (n = 1660, age 50-97 years) in the Mayo Clinic Study on Aging completed the computerized CogState battery and standard neuropsychological battery. The correlation between tests was examined and comparisons between CogState performance on the personal computer (PC) and iPad (n = 331), and in the clinic vs. at home (n = 194), were assessed.

RESULTS

We obtained valid data on greater than 97% of participants on each test. Correlations between the CogState and neuropsychological tests ranged from -0.462 to 0.531. Although absolute differences between the PC and iPad were small and participants preferred the iPad, performance on the PC was faster. Participants performed faster on Detection, One Card Learning, and One Back at home compared with the clinic.

DISCUSSION

The computerized CogState battery, especially the iPad, was feasible, acceptable, and valid in the population.

A two years longitudinal study of a transgenic Huntington disease monkey

Background

A two-year longitudinal study composed of morphometric MRI measures and cognitive behavioral evaluation was performed on a transgenic Huntington’s disease (HD) monkey. rHD1, a transgenic HD monkey expressing exon 1 of the human gene encoding huntingtin (HTT) with 29 CAG repeats regulated by a human polyubiquitin C promoter was used together with four age-matched wild-type control monkeys. This is the first study on a primate model of human HD based on longitudinal clinical measurements.

Results

Changes in striatal and hippocampal volumes in rHD1 were observed with progressive impairment in motor functions and cognitive decline, including deficits in learning stimulus-reward associations, recognition memory and spatial memory. The results demonstrate a progressive cognitive decline and morphometric changes in the striatum and hippocampus in a transgenic HD monkey.

Conclusions

This is the first study on a primate model of human HD based on longitudinal clinical measurements. While this study is based a single HD monkey, an ongoing longitudinal study with additional HD monkeys will be important for the confirmation of our findings. A nonhuman primate model of HD could complement other animal models of HD to better understand the pathogenesis of HD and future development of diagnostics and therapeutics through longitudinal assessment.

Mild cognitive impairment in adult: A neuropsychological review

Mild cognitive impairment (MCI) is associated with an increased risk of developing dementia. This is clinically relevant overt dementia can be prevented if treatment strategies are devised for MCI. Neuropsychological deficits in this condition are very common and are important clinically for treatment and outcomes. We aimed to review various neuropsychological deficits in MCI. Further, we have presented the current evidence for nosological status, neuroanatomical basis, and clinical outcome of this heterogeneous construct. All published papers on the topic of neuropsychological deficits in MCI on Medline and other databases were reviewed. A wide range of memory and executive function deficits are common in MCI patients. However, several studies are limited by either improper designs or inadequate sample sizes. Several neuropsychological impairments like memory function and executive functions can be diagnosed in MCI. The evidence base for the exact neuroanatomical basis of MCI is not robust yet. However, given the wide range of outcomes, controversies and debates exist regarding the nosological significance of the deficits. Hence, more studies are needed to specifically locate the impairments and further delineate the construct of MCI.

Subjective memory complaints, cognitive performance, and psychological factors in healthy older adults

OBJECTIVE

To determine whether subjective memory complaints (SMCs) are associated with performance on objective cognitive measures and psychological factors in healthy, community-dwelling older adults.

METHOD

The cohort was composed of adults, 65 years and older with no clinical evidence of cognitive impairment (n = 125). Participants were administered: CogState computerized neurocognitive battery, Prospective Retrospective Memory Questionnaire, personality and meaning-in-life measures.

RESULTS

SMCs were associated with poorer performance on measures of executive function (p = 0.001). SMCs were also associated with impaired delayed recall (p = 0.006) but this did not remain significant after statistical adjustment for multiple comparisons. SMCs were inversely associated with conscientiousness (p = 0.004) and directly associated with neuroticism (p < 0.001). Higher scores on SMCs were associated with higher perceived stress (p = 0.001), and ineffective coping styles (p = 0.001). Factors contributing to meaning-in-life were associated with fewer SMCs (p < 0.05).

CONCLUSIONS

SMCs may reflect early, subtle cognitive changes and are associated with personality traits and meaning-in-life in healthy, older adults.

Early brain injury alters the blood-brain barrier phenotype in parallel with β-amyloid and cognitive changes in adulthood

Clinical studies suggest that traumatic brain injury (TBI) hastens cognitive decline and development of neuropathology resembling brain aging. Blood-brain barrier (BBB) disruption following TBI may contribute to the aging process by deregulating substance exchange between the brain and blood. We evaluated the effect of juvenile TBI (jTBI) on these processes by examining long-term alterations of BBB proteins, β-amyloid (Aβ) neuropathology, and cognitive changes. A controlled cortical impact was delivered to the parietal cortex of male rats at postnatal day 17, with behavioral studies and brain tissue evaluation at 60 days post-injury (dpi). Immunoglobulin G extravasation was unchanged, and jTBI animals had higher levels of tight-junction protein claudin 5 versus shams, suggesting the absence of BBB disruption. However, decreased P-glycoprotein (P-gp) on cortical blood vessels indicates modifications of BBB properties. In parallel, we observed higher levels of endogenous rodent Aβ in several brain regions of the jTBI group versus shams. In addition at 60 dpi, jTBI animals displayed systematic search strategies rather than relying on spatial memory during the water maze. Together, these alterations to the BBB phenotype after jTBI may contribute to the accumulation of toxic products, which in turn may induce cognitive differences and ultimately accelerate brain aging.