Relationship between activities of daily living and cognitive ability in a sample of older adults with heterogeneous educational level

Functional social isolation mediates the association between depression and executive function in older women: findings from the Canadian Longitudinal Study on Aging Comprehensive cohort

Depression and social isolation increase risk for executive function declines and are among the top five modifiable risk factors for dementia. However, the interrelationships between depression, social isolation and executive function are not well established. Further evidence is needed to inform strategies to promote executive function and independence in older age. We examined whether social isolation mediated the association between depression and executive function in community-dwelling middle-aged and older adults and whether this association was modified by age and sex. Adults aged 45 to 85 years from the Canadian Longitudinal Study on Aging (CLSA) Comprehensive cohort were followed over three years (complete case analysis, n = 14,133). Baseline depressive symptoms, a history of clinical depression, and functional social isolation (perceived lack of social support) were self-reported. Executive function at follow-up was a composite measure of five cognitive tests. Conditional process analysis assessed the mediating effects of functional social isolation across age group and sex, adjusted for sociodemographic and health covariates. Functional social isolation significantly mediated the association of depressive symptoms (proportion mediated [PM] = 8.0%) or clinical depression (PM = 17.5%) with executive function only among women aged 75+ years. Functional social isolation explains a proportion of the total effect of depressive symptoms or clinical depression on executive function in women aged 75 and older. Although reverse causation cannot be ruled out, our findings suggest that interventions that reduce functional social isolation or depression in older women may promote executive function.

The relation between cognitive functioning and activities of daily living in normal aging, mild cognitive impairment, and dementia: a meta-analysis

Literature suggests that dementia and, more generally, cognitive impairment affect the capacity to carry out activities of daily living (ADL) in aging. However, it is important to decipher the weight of specific cognitive domains and neurodegenerative profiles mainly related to ADL difficulties. A meta-analysis was conducted to investigate the nature and strength of the association between cognitive functioning and ADL in healthy older adults, mild cognitive impairment (MCI), and dementia. A comprehensive search of the PubMed, PsycINFO (PROQUEST), and Scopus databases for cross-sectional or longitudinal studies up until December 2022. Our meta-analytic results revealed that: overall, instrumental ADL (IADL) showed a significant association with executive functioning, in particular, abstraction ability/concept formation, set-shifting, and processing speed/complex attention/working memory, regardless of type of participants (i.e., healthy older adults, MCI, and dementia); whereas ADL (both basic ADL, BADL, and IADL) significantly correlated with global cognitive functioning and long-term verbal memory, with a moderator effect of clinical condition (e.g., increasing ES based on the level of cognitive impairment). Moreover, visuospatial and language abilities significantly correlated with ADL, mainly when performance-based tasks were used for ADL assessment. These findings emphasize the importance of neuropsychological assessment in aging to early identify people most at risk of functional decline and shed light on the need to consider specific cognitive abilities in rehabilitation programs.

A Novel Dual-Language Touch-Screen Intervention to Slow Down Cognitive Decline in Older Adults: A Randomized Controlled Trial

Background and Objectives

Bilingualism has been suggested to protect older adults from cognitive aging and delay the onset of dementia. However, no studies have systematically explored bilingual usage as a tool to mitigate age-related cognitive decline. We developed the Dual-Language Intervention in Semantic memory-Computerized (DISC), a novel cognitive training program with three training tasks (object categorization, verbal fluency, and utility of things) designed specifically for older adults that featured two modes: single-language (SL) exposure mode and dual-language (DL) exposure mode.

Research Design and Methods

The final sample included 50 cognitively healthy (CH; 33 female, M age = 72.93 years, range = 53.08-87.43 years) and 48 cognitively impaired (CI; 35 female, M age = 80.93 years, range = 62.31-96.67 years) older adults, randomly assigned them into one of three groups: SL group, DL group, and control group (no training). Participants in SL and DL groups used DISC in either SL mode (i.e., training instructions were spoken in only one language throughout the entire training) or DL mode (i.e., training instructions alternated between two languages), respectively, for 24 sessions. Participants in the control group were asked to continue with their normal daily activities (e.g., playing bingo and reading newspapers).

Results

For CH older adults, we found significant improvements in the Rey Auditory Verbal Learning Test (RAVLT) Trial 5 score and the Clock Drawing Test score in the DL group but not in the SL and control groups posttraining compared with pretraining. For CI older adults, there was a delayed improvement in the RAVLT Trial 1, six months later.

Discussion and Implications

Our findings provided novel evidence that implementing DL cognitive training benefits CH older adult's late verbal learning and visuospatial construction skills, and a delayed improvement in CI older adults' early verbal learning abilities.

Effects of virtual reality-based cognitive interventions on cognitive function and activity of daily living among stroke patients: Systematic review and meta-analysis

AIMS

To examine the effects of virtual reality-based cognitive interventions on cognitive function and activities of daily living among stroke patients, and to identify the optimal design for such intervention.

DESIGN

Systematic review and meta-analysis.

DATA SOURCES

Medline, EMBASE, Cochrane, CINANL, JBI-EBP and Web of Science from inception to October 2023.

METHODS

Methodological quality was assessed by Risk of Bias Tool. Meta-analyses were assessed by Review Manager 5.4. Subgroup analyses were conducted to explore the influence of study design. Grading of Recommendations Assessment, Development and Evaluation approach was adopted to assess the certainty of evidence.

RESULTS

Twenty-five randomized controlled trials (1178 participants) were included. Virtual reality-based cognitive interventions demonstrated moderate-to-large effects in improving global cognitive function (SMD = 0.43; 95% CI [0.01, 0.85]), executive function (SMD = 0.84; 95% CI [0.25, 1.43]) and memory (SMD = 0.65; 95% CI [0.15, 1.16]) compared to control treatments. No significant effects were found on language, visuospatial ability and activities of daily living. Subgroup analyses indicated one-on-one coaching, individualized design and dynamic difficulty adjustment, and interventions lasting ≥ 6 weeks had particularly enhanced effects, especially for executive function.

CONCLUSIONS

Virtual reality-based cognitive interventions improve global cognitive function, executive function and memory among stroke patients.

IMPLICATIONS FOR THE PATIENT CARE

This review underscores the broad cognitive advantages offered by virtual technology, suggesting its potential integration into standard stroke rehabilitation protocols for enhanced cognitive recovery.

IMPACT

The study identifies key factors in virtual technology interventions that effectively improve cognitive function among stroke patients, offering healthcare providers a framework for leveraging such technology to optimize cognitive outcomes in stroke rehabilitation.

REPORTING METHOD

PRISMA 2020 statement.

PROSPERO REGISTRATION NUMBER

CRD42022342668.

An Exploratory Analysis of Contributors to Cognitive Functioning Among Sexual and Gender Minority Individuals Who Had COVID-19

Sexual and gender minority (SGM) individuals face mental health disparities. However, research analyzing SGM people's mental health after a COVID-19 diagnosis is scarce. In this secondary analysis of a remote study, we 1) examined associations between cognitive and psychosocial health and 2) explored differences between these health outcomes among SGM (n = 14) and heterosexual cisgender (n = 64) U.S. adults who had COVID-19. We used the Patient Reported Outcome Measures Information System (PROMIS) v2.0 to assess subjective cognition and the BrainCheck cognitive test to analyze objective cognition. We administered the Perceived Stress Scale and PROMIS 57 Profile V.2.0 to measure psychosocial health. SGM COVID-19 survivors had worse scores in depression, anxiety, sleep disturbance, pain, stress, and objective cognition than heterosexual cisgender participants (p-values < .05). Objective cognition was associated with age, SGM classification, racial or ethnic minority classification, income, comorbidities, COVID-19 severity, number of symptoms, and pain (|0.137| < r < |0.373|, p-values < .05). Subjective cognition was associated with comorbidities, number of symptoms, depression, anxiety, sleep disturbance, pain, and stress (|0.158| < r < |0.537|, p-values < .05). Additional studies are needed to expand what is known about post-COVID-19 health disparities and to guide policies and interventions that promote cognitive functioning.

Association Between Body Mass Index and Cognitive Function Among Older Adults in India: Findings from a Cross-Sectional Study

OBJECTIVE

The study aimed to explore the association between body mass index (BMI) and cognitive function among older adults in India.

METHODS

Cross-sectional data on 21,000 older adults aged 60 years and older from the first wave of the Longitudinal Ageing Study of India (LASI), conducted in India during 2017-18, were used. Bivariate analysis and multivariate linear regression models were applied. The cognition tests include memory, orientation, arithmetic function, executive function, and object naming.

RESULTS

The mean overall cognition score was 24.6 in the study population. Further, BMI status showed a significant and positive association with cognition. The association of underweight with poor cognition (β=-0.72; 95% CI = -0.89, -0.54) whereas overweight (β = 0.57; 95% CI = 0.39, 0.75) and obese (β = 0.97; 95% CI = 0.68, 1.26) with better cognition remained statistically significant after adjusting for sociodemographic, health-related behavior, and health covariates. The mean cognition score of female older adults was always lower than male older adults with normal BMI, irrespective of their BMI categories.

CONCLUSIONS

This study shows that an underweight BMI is associated with poor cognition in both male and female older adults. In the context of providing health care for older individuals, underweight individuals should be given more attention in India.

Determinants of semantic and episodic memory decline among older adults in Ghana: Evidence from the WHO study on global AGEing and adult health Ghana wave 2

Objective

Determined factors associated with semantic (SM) and episodic memory (EM) among older adults aged 50 years and older in Ghana.

Methods

Data from WHO Study on Global AGEing and Adult Health (SAGE) Ghana Wave 2 was used for this study. Semantic memory (SM) and Episodic memory (EM) were the main study outcomes separately. The study employed Nested Ordinary Least Square regression analysis by sequentially adding 6 blocks of variables and comparison tests between the nested models.

Results

The study involved 3575 adult Ghanaians aged 50 years and older with a mean ± standard deviation of 62.6 ± 18.4 years. The overall mean ± SD of EM and SM were 5.86 ± 2.51 and 11.69 ± 8.59 respectively. Overall, analysis from block 6 showed a significant variation in SM by approximately 16.9%(ΔR2 = 1.17%) where increasing age, never married (β = -1.55; 95% CI = -2.41-0.69), being resident in Greater Accra (regional disparity) (β = -3.45; 95% CI = -4.73-2.20), underweight (β = -0.81;95% CI = -1.34-0.27), and moderate self-rated health (SRH) (β = -0.98; 95% CI = -1.52-0.45) significantly decreased SM. Similarly, increasing age, separated/divorced (β = -0.22; 95% CI = -0.35-0.87), being resident in Greater Accra (β = -0.53; 95% CI = -0.80-0.26), and moderate SRH (β = -0.20; 95% CI = -0.36--0.04) significantly decrease EM with an overall significant variation of approximately 22.9%(ΔR2 = 2.7%).

Conclusions

Increasing age, sex, marital status, regional disparity, and poor SRH significantly decreased both Semantic memory and Episodic memory. Higher educational attainment and life satisfaction significantly influenced SM and EM. These provide pointers to important socio-demographic determinants of SM and EM with implications for the implementation of the Ghana national ageing policy 2010, 'ageing with security and dignity', and as a key consideration for healthy ageing towards 2030.

Food insecurity and cognitive function in older adults: findings from the longitudinal aging study in India

BACKGROUND

As we grow older, food insecurity (FI) may have an impact on our cognitive abilities. The study examines the association of FI with the cognitive function of older adults in India.

METHODS

We have used the data from the first wave of the Longitudinal Ageing Study of India (LASI), with a sample of 27,032 older adults aged 60 years and older. Bivariate analysis and linear regression models with clusters were applied to show the association. The cognitive performance tests include episodic memory, orientation, arithmetic function, executive function, and object naming.

RESULTS

The mean cognition was 24.2 (range 0-43), while 36.4%, 2.1%, and 6.4% experienced mild, moderate, and severe FI, respectively. After adjustment for potential confounders, mild (β = -0.18, 95% CI: -0.32, - 0.04) and severe (β = -0.52, 95% CI: -0.82, - 0.22) food insecurity was associated with poor overall cognitive performance. Domain-specific differences in cognition, such as memory, orientation, arithmetic function, executive function, and object naming, were also validated by the level of FI.

CONCLUSION

The finding suggests that FI is associated with a poor level of cognition among older adults, highlighting the need for increasing the coverage and intervention strategies to address FI in India.

Efficacy of Transcranial Alternating Current Stimulation in the Enhancement of Working Memory Performance in Healthy Adults: A Systematic Meta-Analysis

BACKGROUND

Transcranial alternating current stimulation (tACS)-a noninvasive brain stimulation technique that modulates cortical oscillations in the brain-has shown the capacity to enhance working memory (WM) abilities in healthy individuals. The efficacy of tACS in the improvement of WM performance in healthy individuals is not yet fully understood.

OBJECTIVE/HYPOTHESIS

This meta-analysis aimed to systematically evaluate the efficacy of tACS in the enhancement of WM in healthy individuals and to assess moderators of response to stimulation. We hypothesized that active tACS would significantly enhance WM compared with sham. We further hypothesized that it would do so in a task-dependent manner and that differing stimulation parameters would affect response to tACS.

MATERIALS AND METHODS

Ten tACS studies met the inclusion criteria and provided 32 effects in the overall analysis. Random-effect models assessed mean change scores on WM tasks from baseline to poststimulation. The included studies involved varied in stimulation parameters, between-subject and within-subject study designs, and online vs offline tACS.

RESULTS

We observed a significant, heterogeneous, and moderate effect size for active tACS in the enhancement of WM performance over sham (Cohen's d = 0.5). Cognitive load, task domain, session number, and stimulation region showed a significant relationship between active tACS and enhanced WM behavior over sham.

CONCLUSIONS

Our findings indicate that active tACS enhances WM performance in healthy individuals compared with sham. Future randomized controlled trials are needed to further explore key parameters, including personalized stimulation vs standardized electroencephalography frequencies and maintenance of tACS effects, and whether tACS-induced effects translate to populations with WM impairments.

Working memory ımprovement after transcranial direct current stimulation paired with working memory training ın diabetic peripheral neuropathy

Association of cognitive deficits and diabetic peripheral neuropathy (DPN) is frequent. Working memory (WM) deficits result in impairment of daily activities, diminished functionality, and treatment compliance. Mounting evidence suggests that transcranial Direct Current Stimulation (tDCS) with concurrent working memory training (WMT) ameliorates cognitive deficits. Emboldening results of tDCS were shown in DPN. The study aimed to evaluate the efficacy of anodal tDCS over the left dorsolateral prefrontal cortex (DLPFC) coupled with cathodal right DLPFC with concurrent WMT in DPN for the first time. The present randomized triple-blind parallel-group sham-controlled study evaluated the efficacy of 5 sessions of tDCS over the DLPFC concurrent with WMT in 28 individuals with painful DPN on cognitive (primary) and pain-related, psychiatric outcome measures before, immediately after, and 1-month after treatment protocol. tDCS enhanced the efficacy of WMT on working memory and yielded lower anxiety levels than sham tDCS but efficacy was not superior to sham on other cognitive domains, pain severity, quality of life, and depression. tDCS with concurrent WMT enhanced WM and ameliorated anxiety in DPN without affecting other cognitive and pain-related outcomes. Further research scrutinizing the short/long-term efficacy with larger samples is accredited.

The Moderating Role of Race and Ethnicity in the Association Between Cognitive Performance and Functional Abilities in Later Life

This study examined ethnic/racial influences on the relationship of cognitive performance and functional abilities of 2,713 older individuals from the National Health and Nutrition Examination Survey (NHANES). Functional domains included activities of daily living (ADL), instrumental ADL, and leisure and social activities. In adjusted logistic regression models, low cognitive performance as assessed by the Digit Symbol Substitution Test was found significantly associated with functional limitation in each domain. However, moderation analysis revealed that being Hispanic and non-Hispanic Black may weaken this association demonstrating protective effects of underrepresented ethnic/racial status. Future studies should investigate perceived discrimination and resilience.

Factors associated with verbal fluency in older adults living with HIV in West Africa: A longitudinal study

OBJECTIVE

Verbal fluency decline, observed both in aging and HIV infection, has been related to lower quality of life. This study aimed to evaluate the factors associated with categorical fluency in people living with HIV (PLHIV) aged ≥60 years living in West Africa.

METHODS

In this longitudinal study, PLHIV aged ≥60 years, on antiretroviral therapy (ART) for ≥6 months were included in three clinics (two in Côte d'Ivoire, one in Senegal) participating in the West Africa International epidemiological Databases to Evaluate AIDS (IeDEA) collaboration. Categorical fluency was evaluated with the Isaacs Set Test at 60 s at baseline and 2 years later. Factors associated with verbal fluency baseline performance and annual rates of changes were evaluated using multivariate linear regression models.

RESULTS

Ninety-seven PLHIV were included with 41 of them (42%) having a 2-year follow-up visit. The median age was 64 (62-67), 45.4% were female, and 89.7% had an undetectable viral load. The median annual change in categorical fluency scores was -0.9 (IQR: -2.7 to 1.8). Low baseline categorical fluency performance and its decline were associated with older age and being a female. Low educational level was associated with low baseline categorical fluency performance but not with its decline. Categorical fluency decline was also associated with marital status and hypertension.

CONCLUSIONS

Among older West African PLHIV, usual socio-demographic variables and hypertension were the main factors associated with low categorical fluency performance and/or its decline. Interventions that focus on supporting cardiometabolic health are highly recommended to prevent cognitive disorders in PLHIV.

Relationships of Low Cognitive Performance and Sleep Disorder With Functional Disabilities Among Older Adults

Objectives

This study examined the relationships of low cognitive performance and sleep disorder with functional disabilities among older adults. Methods: NHANES 2011–2014 data on 3179 individuals [Mage=69.71] were analyzed. Functional domains included: activities of daily living (ADL), instrumental ADL (IADL) and leisure and social activities (LSA). Animal Fluency Test and the Digit Symbol Substitution Test assessed cognitive performance. Participants self-reported having physician-diagnosed sleep disorder. Results: Participants with both low cognitive performance and sleep disorder had 4- to 10-times greater odds for ADL, IADL, and LSA difficulties compared to the participants with no low cognitive performance/sleep disorder. Participants with only low cognitive performance and those with only sleep disorder were two to three times more likely to experience these difficulties. Discussion: Low cognitive performance and sleep disorder together or independently were associated with functional disabilities. Participants with both low cognitive performance and sleep disorder had higher odds of functional disabilities.

A 13-Year Time-Lagged Description of General Cognitive and Functional Abilities in Older Men: A Cross-Lagged Panel Model

Objectives: The purpose of this study was to evaluate a cross-lagged panel model of general cognition and functional abilities over 13 years. The goal was to determine whether general cognitive abilities predict or precede functional decline versus functional abilities predicting cognitive decline. Methods: The sample included 3508 men (71-93 years of age at baseline) of the Kuakini Honolulu-Asia Aging Study who were tested repeatedly using a global cognitive test and an assessment of functional capacity. Education and age served as covariates. Cross-lagged models were tested, assessing stationarity of stability and cross-lags. Results: The overall model fit the data well. Cognitive scores had better stability than functional abilities and predicted functional abilities more strongly than functional abilities predicted cognitive scores over time. The strength of all cross-lags increased over time. Discussion: These longitudinal data show that cognitive scores predicted functional decline in a population-based study of older men.

The efficiency of activities of daily living (ADLs) skills in late adulthood: A mediational approach

The term "Activities of Daily Living" (ADLs) refers to a set of fundamental tasks (i.e., toileting, bathing, personal care, eating, grooming, and getting dressed) considered necessary for living and being autonomous in everyday life. Although in the clinical setting ADLs efficiency is a marker to diagnose dementia, limited evidence on the mechanism implicating muscular function and cognitive alterations in ADLs skills in late adulthood exists. This study primarily intended to determine the extent to which executive functions mediate between muscular strength, as assessed through handgrip strength (HGS) measurement, and ADLs skills of older community-dwellers. A further goal was to explore the impact of gender and cognitive status on ADLs and HGS scores, using education as a covariate. Three hundred and thirty-four older participants, 199 females and 135 males (Mage = 77.5 years, SD = 5.6 years, age range = 63-93 years) completed a battery of tests assessing ADLs, HGS, and executive functions. The results showed that 34-56% of the variance in the ADLs condition was explained by HGS and executive functioning. Furthermore, cognitively healthy participants exhibited better ADLs skills, whereas cognitively impaired individuals, both males and females, exhibited poorer HGS efficiency. In conclusion, in clinical settings, the concurrent evaluation of ADLs skills, motor, and higher-order cognitive processes should be encouraged to detect individuals needing a person-tailored intervention to boost their quality of life.

Associations between social network components and cognitive domains in older adults

Previous research shows that social network components are associated with cognitive function later in life. However, fewer studies consider different cognitive domains or disaggregate the social network by relationship type. Using data from 2,553 participants aged 65 or older in the Health and Retirement Study's Harmonized Cognitive Assessment Protocol, this study examined relationships between social network structure (i.e., size, contact frequency) and quality (i.e., support, strain) and performance in five cognitive domains (i.e., episodic memory, executive function, visuoconstruction, language, and processing speed) 2-4 years later, controlling for sociodemographics and previous global cognition. Separate linear regressions were conducted for each cognitive outcome. When averaged across relationship types, network size was not associated with any domain. Contact frequency was positively associated with all domains except episodic memory. Support and strain were negatively associated with all cognitive domains. When considering individual relationship types, larger friend networks were positively associated with visuoconstruction, and greater contact frequency with friends was positively associated with all cognitive domains. Larger family networks were associated with worse executive function, visuoconstruction, and speed. Strain from friends had a negative relationship with every domain except episodic memory. Support from family was negatively associated with episodic memory, executive function, and language. These associations were equivalent to one to 3.5 years of cognitive aging. These results showed that both social network structure and quality may be consequential for cognitive functioning and that links between social relations and cognition differ across domains and as a function of relationship type. (PsycInfo Database Record (c) 2022 APA, all rights reserved).

Association Between Cognition, Health Related Quality of Life, and Costs in a Population at Risk for Cognitive Decline

Background:

The association between health-related quality of life (HRQoL) and care costs in people at risk for cognitive decline is not well understood. Studying this association could reveal the potential benefits of increasing HRQoL and reducing care costs by improving cognition.

Objective:

In this exploratory data analysis we investigated the association between cognition, HRQoL utilities and costs in a well-functioning population at risk for cognitive decline.

Methods:

An exploratory data analysis was conducted using longitudinal 2-year data from the FINGER study (n = 1,120). A change score analysis was applied using HRQoL utilities and total medical care costs as outcome. HRQoL utilities were derived from the Short Form Health Survey-36 (SF-36). Total care costs comprised visits to a general practitioner, medical specialist, nurse, and days at hospital. Analyses were adjusted for activities of daily living (ADL) and depressive symptoms.

Results:

Although univariable analysis showed an association between cognition and HRQoL utilities, multivariable analysis showed no association between cognition, HRQoL utilities and total care costs. A one-unit increase in ADL limitations was associated with a -0.006 (p < 0.001) decrease in HRQoL utilities and a one-unit increase in depressive symptoms was associated with a -0.004 (p < 0.001) decrease in HRQoL utilities.

Conclusion:

The level of cognition in people at-risk for cognitive decline does not seem to be associated with HRQoL utilities. Future research should examine the level at which cognitive decline starts to affect HRQoL and care costs. Ideally, this would be done by means of cross-validation in populations with various stages of cognitive functioning and decline.

Critical review of multisensory integration programs and proposal of a theoretical framework for its combination with neurocognitive training

INTRODUCTION

The main purpose of this manuscript is to critically review the Multisensory Integration (MI) training programs applied to older adults, their characteristics, target sensory systems, efficacy, assessment methods, and results. We also intend to propose an integrated framework to support combined interventions of neurocognitive and sensory training.

AREAS COVERED

A critical review was conducted covering the most relevant literature on the MI training programs applied to older adults. Two MI training programs applied to cognitively healthy older adults were found: (a) audio-visual temporal discrimination training and (b) simultaneity judgment training. Both led to the improvement of the MI between pre- and post-training. However, only the audio-visual temporal discrimination training led to the generalization of the improvements to another MI task.

EXPERT OPINION

Considering the relationship between sensory and cognitive functioning, this review supports the potential advantages of combining MI with neurocognitive training in the rehabilitation of older adults. We suggested that this can be achieved within the framework of Branched Programmed Neurocognitive Training (BPNT). Criteria for deciding the most suitable multisensory intervention, that is, MI or Multisensory Stimulation, and general guidelines for the development of MI intervention protocols with older adults with or without cognitive impairment are provided.

Electric Field Strength From Prefrontal Transcranial Direct Current Stimulation Determines Degree of Working Memory Response: A Potential Application of Reverse-Calculation Modeling?

BACKGROUND

Transcranial direct current stimulation (tDCS) for working memory is an enticing treatment, but there is mixed evidence to date.

OBJECTIVES

We tested the effects of electric field strength from uniform 2 mA dosing on working memory change from prestimulation to poststimulation. Second, we statistically evaluated a reverse-calculation method of individualizing tDCS dose and its effect on normalizing electric field at the cortex.

MATERIALS AND METHODS

We performed electric field modeling on a data set of 28 healthy older adults (15 women, mean age = 73.7, SD = 7.3) who received ten sessions of active 2 mA tDCS (N = 14) or sham tDCS (N = 14) applied over bilateral dorsolateral prefrontal cortices (DLPFC) in a triple-blind design. We evaluated the relationship between electric field strength and working memory change on an N-back task in conditions of above-median, high electric field from active 2 mA (N = 7), below-median, low electric field from active 2 mA (N = 7), and sham (N = 14) at regions of interest (ROI) at the left and right DLPFC. We then determined the individualized reverse-calculation dose to produce the group average electric field and measured the electric field variance between uniform 2 mA doses vs individualized reverse-calculation doses at the same ROIs.

RESULTS

Working memory improvements from pre- to post-tDCS were significant for the above-median electric field from active 2 mA condition at the left DLPFC (mixed ANOVA, p = 0.013). Furthermore, reverse-calculation modeling significantly reduced electric field variance at both ROIs (Levene's test; p < 0.001).

CONCLUSIONS

Higher electric fields at the left DLPFC from uniform 2 mA doses appear to drive working memory improvements from tDCS. Individualized doses from reverse-calculation modeling significantly reduce electric field variance at the cortex. Taken together, using reverse-calculation modeling to produce the same, high electric fields at the cortex across participants may produce more effective future tDCS treatments for working memory.

Association of Neurofilament Light With the Development and Severity of Parkinson Disease

BACKGROUND AND OBJECTIVES

Blood biomarkers may allow earlier identification of Parkinson disease (PD), parkinsonism, and poor PD-related outcomes, such as physical functioning. Neurofilament light (NfL), a neuronal cytoplasmic protein, is a biomarker of neurodegeneration measurable in biofluids. Our objective was to examine the association of serum NfL at baseline with clinically diagnosed PD, parkinsonian signs, and physical functioning change over 16 years in a population-based sample of older adults.

METHODS

Data came from 1,327 older participants from the Chicago Health and Aging Project, a longitudinal population-based study. Clinical evaluations included assessing parkinsonian signs in 4 domains-bradykinesia, parkinsonian gait, rigidity, and tremors-using a structured version of the Unified Parkinson's Disease Rating Scale. Board-certified neurologists diagnosed PD. Physical functioning was assessed using chair stands, tandem walk, and timed walk. An ultrasensitive immunoassay was used to measure the concentration of NfL in blood.

RESULTS

Of the 1,254 participants examined for clinical PD, 77 (6.1%) developed clinical PD and parkinsonian signs were on average 9.5 (range 0-66.0). After adjusting for demographic characteristics, APOE ε4 allele, and global cognition, a 2-fold higher concentration of serum NfL was associated with incident clinical PD (odds ratio [OR] 2.54, 95% CI 1.70, 3.81) and global parkinsonian signs (OR 2.44, 95% CI 1.94, 2.94). This association was significant >5 years before diagnosis. Compared with participants with levels below 18.5 pg/mL of serum NfL at baseline, participants with levels between 18.5 and 25.4 pg/mL, between 25.4 and 37.3 pg/mL, and above 37.3 pg/mL had a higher OR of clinical PD at all time intervals from the time of diagnosis to >5 years before diagnosis. A higher concentration of serum NfL was associated with a faster rate of physical functioning decline. In participants with 2-fold higher concentrations of serum NfL, the annual rate of decline in physical functioning increased by 0.15 units (95% CI 0.21, 0.08).

DICUSSION

Serum NfL was associated with incident clinical PD, parkinsonian signs, and physical functioning decline in a population-based sample. Our findings suggest that NfL may serve as a potential biomarker for neurodegeneration, including PD outcomes.

CLASSIFICATION OF EVIDENCE

This study provides Class II evidence that serum NfL levels are associated with incident PD, parkinsonian signs, and physical functioning decline.

Association between physical activity and physical and functional performance in non-institutionalized Mexican older adults: a cohort study

BACKGROUND

Aging is an independent risk factor for deterioration in functional capacity. Some studies have reported that physical activity (PA) improves functional capacity and physical performance among older adults (OA). Thus the objective of the present study was to assess the longitudinal association between PA and functional and physical performance in non-institutionalized OA.

METHODS

A longitudinal analysis using data from the Frailty, Dynapenia and Sarcopenia in Mexican adults (FRADYSMEX, by its Spanish acronym) cohort study was conducted. PA was assessed through the Community Healthy Activities Model Program for Seniors (CHAMPS) instrument. Functionality was measured with the Barthel index and the Lawton and Brody scale, while physical performance was measured with the Short Physical Performance Battery (SPPB). To evaluate the association between the level of PA and physical and functional performance as a continuous variable, a linear regression of mixed effects was performed. To assess PA and dependence in basic activities of the daily life (BADL), instrumental activities of the daily life (IADL), and low physical performance (PP), generalized estimation equation models [to compute odds ratios (OR) and 95% confidence intervals (95%CI)] were computed.

RESULTS

Older people who performed moderate to vigorous-intensity PA had a lower risk of dependence in IADL (OR = 0.17; 95%CI: 0.10, 0.80) and lower risk of low PP (OR = 0.18; 95%CI: 0.11, 0.58) compared to those in lower categories of PA.

CONCLUSIONS

Older adults living in the community who perform PA of moderate to vigorous intensity have a lower risk of dependence in BADL and IADL and have a lower risk of low PP.

Individualized tDCS modeling predicts functional connectivity changes within the working memory network in older adults

BACKGROUND

Working memory decline has been associated with normal aging. The frontal brain structure responsible for this decline is primarily located in the prefrontal cortex (PFC). Our previous neuroimaging study demonstrated a significant change in functional connectivity between the left dorsolateral PFC (DLPFC) and left ventrolateral PFC (VLPFC) when applying 2 mA tDCS in MRI scanner during an N-Back task. These regions were part of the working memory network. The present study is the first study that utilizes individualized finite element models derived from older adults' MRI to predict significant changes of functional connectivity observed from an acute tDCS application.

METHODS

Individualized head models from 15 healthy older adults (mean age = 71.3 years) were constructed to create current density maps. Each head model was segmented into 11 tissue types: white matter, gray matter, CSF, muscle, blood vessels, fat, eyes, air, skin, cancellous, and cortical bone. Electrodes were segmented from T1-weighted images and added to the models. Computed median and maximum current density values in the left DLPFC and left VLPFC regions of interest (ROIs) were correlated with beta values as functional connectivity metrics measured in different timepoint (baseline, during stimulation) and stimulation condition (active and sham).

MAIN RESULTS

Positive significant correlations (R2 = 0.523 for max J, R2 = 0.367 for median J, p < 0.05) were found between the beta values and computed current densities in the left DLPFC ROIs for active stimulation, but no significant correlation was found during sham stimulation. We found no significant correlation between connectivity and current densities computed in the left VLPFC for both active and sham stimulation.

CONCLUSIONS

The amount of current within the left DLPFC ROIs was found positively correlated with changes in functional connectivity between left DLPFC and left VLPFC during active 2 mA stimulation. Future work may include expansion of number of participants to further test the accuracy of tDCS models used to predict tDCS-induced functional connectivity changes within the working memory network.

Educational level as a protective factor against the influence of depressive symptoms on cognition in older adults: implications for functional independence during a 10-year follow-up

OBJECTIVES

To examine whether the educational level moderates the relationship between baseline depressive symptoms and cognitive functioning at 5- and 10-year follow-ups in older adults, considering the association between cognitive functioning and difficulty with activities of daily living (ADL).

DESIGN

Using a prospective design, a path analysis was performed.

SETTING

In-home, face-to-face interviews and self-administered questionnaires, within the National Social Life, Health, and Aging Project.

PARTICIPANTS

In total, 1,461 participants (mean age = 66.62) were followed up from Wave 1 (baseline) to Wave 2 (at 5 years) and Wave 3 (at 10 years).

MEASUREMENTS

Depressive symptoms were assessed at baseline. Cognitive functioning and difficulty with ADL were assessed at baseline and at 5 and 10 years.

RESULTS

Educational level moderates the relationship between depressive symptoms and cognitive functioning at 5 years (β = 0.07, SE = 0.03, p = 0.04, Cohen's f2 = 0.02), being depressive symptoms related to poor cognitive functioning only at low educational levels. Cognitive functioning predicts difficulty with ADL at 5 and 10 years (β = -0.08, SE = 0.03, p = 0.008, Cohen's f2 = 0.01; β = -0.09, SE = 0.03, p = 0.006, Cohen's f2 = 0.02). The proposed model yielded excellent fit (CFI = 1.00, RMSEA = 0.0001, 90% CI 0.0001-0.03, SRMR = 0.004, and χ2(8) = 7.16, p = 0.52).

CONCLUSIONS

Cognitive reserve may act as a protective factor against the effect of depressive symptoms on cognition in older adults, which, in turn, is relevant to their functional independence.

Association of life course socioeconomic status and adult height with cognitive functioning of older adults in India and China

BACKGROUND

Cognitive functioning is an important measure of intrinsic capacity. In this study, we examine the association of life course socioeconomic status (SES) and height with cognitive functioning among older adults (50+) in India and China. The age pattern of cognitive functioning with measures of life course socioeconomic status has also been examined.

METHODS

Cross-sectional comparative analysis was conducted using the WHO's Study on global AGEing and adult health (SAGE) data for India and China. Multilevel mixed-effect linear regression analysis was used to examine the association of life course socioeconomic status and adult height with cognitive functioning.

RESULTS

In both India and China, parental education as a measure of childhood socioeconomic status was positively associated with cognitive functioning. The association between adult socioeconomic status and cognitive functioning was positive and significant. Height was significantly and positively associated with improved cognitive functioning of older adults in India and China. Furthermore, the age-related decline in cognitive functioning score was higher among older adults whose parents had no schooling, particularly in China. The cognitive functioning score with age was much lower among less-educated older adults than those with higher levels of education in China. Wealthier older adults in India had higher cognitive functioning in middle ages, however, wealth differences narrowed with age.

CONCLUSIONS

The results of this study suggest a significant association of lifetime socioeconomic status and cumulative net nutrition on later-life cognitive functioning in middle-income settings.

The utility and cultural specificity of cognitive-based interventions in preventing cognitive decline among healthy older adults in Asia: A systematic review

BACKGROUND

The effects of aging and its associated cognitive decline is particularly acute in Asia given the exponential growth of older adults as a proportion of the population as a whole. Many structured cognitive interventions have been proposed to prevent the cognitive decline typically seen in older age, but their utility as a viable means of achieving these goals is questionable.

OBJECTIVES

To summarize and synthesize evidence on the utility and methodological quality of cognitive-based interventions on cognitive performance and associated secondary outcomes among healthy older adults in Asia, as well as novel, culture-specific components of cognitive interventions across the region.

DATA SOURCES

The PubMed/Medline, Web of Science, Scopus, and ScienceDirect databases were searched through May 2020.

ELIGIBILITY

Studies including individuals aged 60 years and above, who had no previous history of physical and/or mental illness. Few restrictions placed on intervention design, duration and mode of delivery, provided that participants were randomized to study conditions, and intervention included components addressing at least one cognitive domain.

RESULTS

A total of 17 studies from six countries met the eligibility criteria and were included in the final review. Evidence from those studies indicated that cognitive interventions may be most effective when the design and aims were directed towards improvement in specific cognitive domains, but evidence regarding long-term effectiveness in preventing progression to clinical-level cognitive deficits is still unclear. Several studies highlighted culture-specific activities as components of their interventions, though these will need to be further outlined and standardized clearly in future research.

Increasing autonomy through improved care: effects of a professional care-giver training programme on the functional status of older adults

The aim of the present research was to evaluate the effectiveness of a care-giver training programme that trains professional care-givers in cognitive stimulation strategies for functional maintenance in care-dependent older adults. The sample contained 69 older adults (37 in the treatment group, 32 control group) assessed with the Barthel Index, the Mini-Mental State Examination and the Clifton Assessment Procedure for the Elderly (Cognitive Scale). Participants in the treatment group were treated by professional care-givers who were trained with the programme CUIDA-2 in communication and cognitive stimulation strategies. The results from the Barthel Index showed significant differences in the post-intervention assessment and in the follow-up assessment, where the treatment group obtained higher scores, and there were significant differences within the treatment group between the initial assessment and the post-treatment assessment, as well as between the initial assessment and the follow-up. The data obtained reflect that a training programme to train professional care-givers produced functional benefits in the older adults, and these improvements persisted over time. Moreover, the care-givers saw themselves as more competent and more satisfied with their work.

Narrative review of the multisensory integration tasks used with older adults: inclusion of multisensory integration tasks into neuropsychological assessment

Introduction: Age-related changes in sensory functioning impact the activities of daily living and interact with cognitive decline. Given the interactions between sensory and cognitive functioning, combining multisensory integration (MI) assessment with the neuropsychological assessment of older adults seems promising. This review aims to examine the characteristics and utility of MI tasks in functional and cognitive assessment of older adults, with or without neurocognitive impairment.Areas covered: A literature search was conducted following the quality assessment of narrative review criteria. Results focused on tasks of detection, discrimination, sensory illusion, temporal judgment, and sensory conflict. Studies were not consensual regarding the enhancement of MI with age, but most studies showed that older adults had an expanded time window of integration. In older adults with mild cognitive impairment or major neurocognitive disorder it was a mediating role of the magnitude of visual-somatosensory integration between neurocognitive impairment and spatial aspects of gait.Expert opinion: Recently, some concerns have been raised about how to maximize the ecological validity of the neuropsychological assessment. Since most of our activities of daily living are multisensory and older adults benefit from multisensory information, MI assessment has the potential to improve the ecological validity of the neuropsychological assessment.

Daily functioning and dementia

Dementia is characterized by a decline in memory, language, problem-solving and in other cognitive domains that affect a person's ability to perform everyday activities and social functioning. It is consistently agreed that cognitive impairment is an important risk factor for developing functional disabilities in patients with dementia. Functional status can be conceptualized as the ability to perform self-care, self- maintenance and physical activity. A person with dementia usually requires help with more complex tasks, such as managing bills and finances, or simply maintaining a household. Good functional performance is fundamental for elderly people to maintain independency and avoid institutionalization. The purpose of this review is to describe functional changes in demented patients, evaluating the variability in subgroups of dementias.

Effects of Transcranial Direct Current Stimulation Paired With Cognitive Training on Functional Connectivity of the Working Memory Network in Older Adults

Background

Working memory, a fundamental short-term cognitive process, is known to decline with advanced age even in healthy older adults. Normal age-related declines in working memory can cause loss of independence and decreased quality of life. Cognitive training has shown some potential at enhancing certain cognitive processes, although, enhancements are variable. Transcranial direct current stimulation (tDCS), a form of non-invasive brain stimulation, has shown promise at enhancing working memory abilities, and may further the benefits from cognitive training interventions. However, the neural mechanisms underlying tDCS brain-based enhancements remain unknown.

Objective/Hypothesis

Assess the effects of a 2-week intervention of active-tDCS vs. sham paired with cognitive training on functional connectivity of the working memory network during an N-Back working memory task.

Methods

Healthy older adults (N = 28; mean age = 74 ± 7.3) completed 10-sessions of cognitive training paired with active or sham-tDCS. Functional connectivity was evaluated at baseline and post-intervention during an N-Back task (2-Back vs. 0-Back).

Results

Active-tDCS vs. sham demonstrated a significant increase in connectivity between the left dorsolateral prefrontal cortex and right inferior parietal lobule at post-intervention during 2-Back. Target accuracy on 2-Back was significantly improved for active vs. sham at post-intervention.

Conclusion

These results suggest pairing tDCS with cognitive training enhances functional connectivity and working memory performance in older adults, and thus may hold promise as a method for remediating age-related cognitive decline. Future studies evaluating optimal dose and long-term effects of tDCS on brain function will help to maximize potential clinical impacts of tDCS paired with cognitive training in older adults.

Clinical Trial Registration:

www.ClinicalTrials.gov, identifier NCT02137122.

Test-retest reliability and minimal detectable change of the Cognitive Abilities Screening Instrument in patients with dementia

Background

The Cognitive Abilities Screening Instrument (CASI) is widely used to assess global cognitive function in patients with dementia. It contains nine cognitive domains, namely long-term memory, short-term memory, attention, mental manipulation, orientation, abstraction and judgment, language, visual construction, and list-generating fluency. However, test-retest reliability and minimal detectable change (MDC) of the CASI are largely unknown in patients with dementia, which limits its utility and the explanation of a score change.

Purpose

The purpose of this study was to examine test-retest reliability and calculate MDC of the CASI in patients with dementia.

Methods

Fifty-two patients with dementia completed the CASI twice with a two-week interval. The frequencies of the scores in the Clinical Dementia Rating (0.5, 1, and ≥ 2) were 38.5, 36.5, and 25.0, respectively. Test-retest reliability was examined using intraclass correlation coefficient (ICC) for the total score and nine domains of the CASI. The MDC was calculated based on standard error of measurement.

Results

The ICC value of the CASI total score was 0.97 while the ICC value for the nine domains were 0.65–0.92. The MDC values (MDC%) were 11.6 (12.9%), 2.8 (23.2%), 4.5 (41.2%), 3.4 (42.1%), 4.9 (49.2%), 5.3 (29.2%), 3.4 (28.8%), 2.2 (22.3%), 3.2 (32.1%), and 3.1 (30.7%) for CASI total score, long-term memory, short-term memory, attention, mental manipulation, orientation, abstraction and judgment, language, visual construction, and list-generating fluency, respectively.

Conclusion

Our results revealed that the CASI has sufficient test-retest reliability. The MDC values are useful in determining a real change (i.e., improvement or deterioration) between two assessments of an individual patient. However, four domains (i.e., short-term memory, attention, mental manipulation, and list-generating fluency) demonstrated lower ICC values and substantial random measurement errors. Clinicians and researchers should be cautious while using these four domains to explain score changes between repeated assessments of patients with dementia.

Effects of in-Scanner Bilateral Frontal tDCS on Functional Connectivity of the Working Memory Network in Older Adults

Working memory is an executive memory process essential for everyday decision-making and problem solving that declines with advanced age. Transcranial direct current stimulation (tDCS) is a non-invasive form of brain stimulation that has demonstrated potential for improving working memory performance in older adults. However, the neural mechanisms underlying effects of tDCS on working memory are not well understood. This mechanistic study investigated the acute and after-effects of bilateral frontal (F3/F4) tDCS at 2 mA for 12-min on functional connectivity of the working memory network in older adults. We hypothesized active tDCS over sham would increase frontal connectivity during working memory performance. The study used a double-blind within-subject 2 session crossover design. Participants performed an functional magnetic resonance imaging (fMRI) N-Back working memory task before, during, and after active or sham stimulation. Functional connectivity of the working memory network was assessed within and between stimulation conditions (FDR < 0.05). Active tDCS produced a significant increase in functional connectivity between left ventrolateral prefrontal cortex (VLPFC) and left dorsolateral PFC (DLPFC) during stimulation, but not after stimulation. Connectivity did not significantly increase with sham stimulation. In addition, our data demonstrated both state-dependent and time-dependent effects of tDCS working memory network connectivity in older adults. tDCS during working memory performance produces a selective change in functional connectivity of the working memory network in older adults. These data provide important mechanistic insight into the effects of tDCS on brain connectivity in older adults, as well as key methodological considerations for tDCS-working memory studies.

Self-Reported Sensory Impairments and Changes in Cognitive Performance: A Longitudinal 6-Year Follow-Up Study of English Community-Dwelling Adults Aged ⩾50 Years

Objective: To investigate the influence of single and dual sensory impairments prospectively on cognition in adults aged ⩾50 years. Method: Community-dwelling English adults (n = 4,621) were followed up from 2008 to 2014. Self-reported hearing and vision were collected in 2008. Change in cognitive performance on working memory and executive function between 2008 and 2014 was evaluated. Results: Compared with good hearing and good vision, respectively, poor hearing and poor vision were associated with worse cognitive function (hearing: unstandardized coefficient B = 0.83, 95% Confidence Interval [CI] = [0.29, 1.37]; vision: B = 1.61, 95% CI = [0.92, 2.29] adjusted for age, sex, baseline cognition). Compared with no sensory impairment, dual sensory impairment was associated with worse cognition (B = 2.30, 95% CI = [1.21, 3.39] adjusted for age, sex, baseline cognition). All associations remained after further adjustment for sociodemographic characteristics, lifestyle factors, chronic conditions, falls, mobility, depression, and lack of companionship. Discussion: The findings are important as age-related sensory impairments are often preventable or modifiable, which may prevent or delay cognitive impairment.

Correlates of cognitive impairment in patients with chronic kidney failure on haemodialysis: Systematic review and meta-analysis

AIM

To review and identify correlates of cognitive impairment in patients with chronic kidney failure (CKF) on haemodialysis.

BACKGROUND

The literature is consistent with regard to the high prevalence of cognitive impairment among patients with CKF on haemodialysis and its dependence on multidimensional risk factors.

DESIGN

Systematic review and meta-analysis based on Cochrane Handbook and PRISMA.

DATA SOURCES

Electronic searches of the MEDLINE, EMBASE, Cochrane Library databases and major Korean databases were used. Only original research that assessed correlates of cognitive impairment in patients with CKF on haemodialysis and published between 2004-2016 in English or Korean were included.

REVIEW METHODS

Studies were selected according to the PICOS: Population (chronic kidney failure patients with cognitive impairment on haemodialysis); Intervention (not applicable); Comparison (healthy controls or patients with chronic kidney failure on haemodialysis without cognitive impairment); Outcome (cognitive impairment); and Study design (primarily nonexperimental correlational studies and studies with experimental, quasi-experimental, or pre-post cohort designs). Q-test and I² index were used to examine study homogeneity.

RESULTS

A total of 39 studies were finally included. Age, gender, stroke history, difficulties in activities of daily life, haemoglobin levels, pain, sleep difficulties, and depression were found to be significant correlates of cognitive impairment.

CONCLUSIONS

Nurses should be aware that the risk of cognitive impairment in patients with CKF on haemodialysis can be significantly higher for elders, women and in patients with a stroke, greater difficulties in activities of daily living, lower haemoglobin concentrations, higher pain levels, sleep difficulties, or depression.

Investigating the Usability and Acute Effects of a Bedside Video Console to Prefrontal Cortical Activity Alterations: A Preclinical Study in Healthy Elderly

Elderly people at risk of developing cognitive decline; e.g., following surgery, may benefit from structured, challenging, and repetitive cognitive video training. This study assessed usability and acute effects of a newly developed bedside console (COPHYCON). Fifteen healthy elderly individuals performed a one-time 80-min intervention, including cognitive video games aimed at improving awareness and selective attention. Perceived usefulness and perceived ease of use (Technology Acceptance Model) were assessed together with measures of the achieved game level, reaction times, (in-) correct responses during ALERT and SELECT game play. Further, prefrontal cortical involvement of the regional cerebral hemoglobin saturation (rS02%) assessed with functional near infrared spectroscopy (fNIRS) (n = 5) and EEG power (n = 10) was analyzed. All participants completed the study without any adverse events. Perceived usefulness and perceived ease of use (TAM scores range 1-7) of the system varied between 3.9 and 6.3. The game levels reached for awareness varied between 9 and 11 (initial score 8-10), for reaction speed between 439 and 469 ms, and for correct responses between 74.1 and 78.8%. The highest level for the selective attention games was 2 (initial score 1), where reaction speed varied between 439 and 469 ms, correct responses between 96.2 and 98.5%, respectively. The decrease of rS02% in the right prefrontal cortex during gameplay was significantly (p < 0.001) lower, compared to the left prefrontal cortex. Four participants yielded significant lower rS02% measures after exergaming with the ALERT games (p < 0.000), but not with the SELECT games. EEG recordings of theta power significantly decreased in the averaged ~0.25-0.75 time interval for the left prefrontal cortex sensor across the cognitive game levels between the ALERT 1 and SELECT 1, as well as between SELECT 1 and 2 games. Participants rated the usability of the COPHYCON training positively. Further results indicate that video gaming may be an effective measure to affect prefrontal cortical functioning in elderly. The results warrant a clinical explorative study investigating the feasibility of the COPHYCON in a clinical setting.

The Relationship Between Mobility Dysfunction Staging and Global Cognitive Performance

OBJECTIVES

To assess the relationship and the directionality between mobility and cognitive performance.

METHOD

A cross-sectional analysis of a racially/ethnically diverse sample of 327 community-dwelling adults (mean age=68.9±9.9 y; range, 40 to 100 y) categorized as having no mobility dysfunction, upper-extremity (UE) impairment, lower-extremity (LE) impairment, or mobility limitation (both UE and LE impairments), and compared by global cognition with multiple hierarchical linear regression adjusted for sociodemographic, health, and mood factors. A bootstrapping mediation analysis investigated the directionality of the mobility-cognition association.

RESULTS

LE (Est.=-2.95±0.77, P=0.001) but not UE impairment (Est.=-1.43±1.05, P=0.175) was associated with a poorer global cognitive performance/impairment. The presence of mobility limitation had the strongest effect on cognition (Est.=-3.78±1.09, P<0.001) adjusting for sociodemographic factors, body composition, comorbidities, and mood. Mediation analysis indicated that the relationship between cognition and mobility likely operates in both directions.

DISCUSSION

The association between cognitive function and mobility follows a dose-response pattern in which the likelihood of poor global cognition increases with the progression of mobility dysfunction, with evidence that LE impairments may be better indicators of an impaired cognitive status than UE impairments. Using brief, valid tools to screen older patients for early signs of mobility dysfunction, especially when the LE is affected, is feasible, and may provide the first detectable stage of future cognitive impairment and provide actionable steps for interventions to improve performance, reduce burden, and prevent the development of physical disability and loss of independence.

Frontal Structural Neural Correlates of Working Memory Performance in Older Adults

Working memory is an executive memory process that allows transitional information to be held and manipulated temporarily in memory stores before being forgotten or encoded into long-term memory. Working memory is necessary for everyday decision-making and problem solving, making it a fundamental process in the daily lives of older adults. Working memory relies heavily on frontal lobe structures and is known to decline with age. The current study aimed to determine the neural correlates of decreased working memory performance in the frontal lobes by comparing cortical thickness and cortical surface area from two demographically matched groups of healthy older adults, free from cognitive impairment, with high versus low N-Back working memory performance (N = 56; average age = 70.29 ± 10.64). High-resolution structural T1-weighted images (1 mm isotropic voxels) were obtained on a 3T Philips MRI scanner. When compared to high performers, low performers exhibited significantly decreased cortical surface area in three frontal lobe regions lateralized to the right hemisphere: medial orbital frontal gyrus, inferior frontal gyrus, and superior frontal gyrus (FDR p < 0.05). There were no significant differences in cortical thickness between groups, a proxy for neurodegenerative tissue loss. Our results suggest that decreases in cortical surface area (a proxy for brain structural integrity) in right frontal regions may underlie age-related decline of working memory function.

Verbal Memory Impairment in Polydrug Ecstasy Users: A Clinical Perspective

Background

Ecstasy use has been associated with short-term and long-term memory deficits on a standard Word Learning Task (WLT). The clinical relevance of this has been debated and is currently unknown. The present study aimed at evaluating the clinical relevance of verbal memory impairment in Ecstasy users. To that end, clinical memory impairment was defined as decrement in memory performance that exceeded the cut-off value of 1.5 times the standard deviation of the average score in the healthy control sample. The primary question was whether being an Ecstasy user (E-user) was predictive of having clinically deficient memory performance compared to a healthy control group.

Methods

WLT data were pooled from four experimental MDMA studies that compared memory performance during placebo and MDMA intoxication. Control data were taken from healthy volunteers with no drug use history who completed the WLT as part of a placebo-controlled clinical trial. This resulted in a sample size of 65 E-users and 65 age- and gender-matched healthy drug-naïve controls. All participants were recruited by similar means and were tested at the same testing facilities using identical standard operating procedures. Data were analyzed using linear mixed-effects models, Bayes factor, and logistic regressions.

Results

Findings were that verbal memory performance of placebo-treated E-users did not differ from that of controls, and there was substantial evidence in favor of the null hypothesis. History of use was not predictive of memory impairment. During MDMA intoxication of E-users, verbal memory was impaired.

Conclusion

The combination of the acute and long-term findings demonstrates that, while clinically relevant memory impairment is present during intoxication, it is absent during abstinence. This suggests that use of Ecstasy/MDMA does not lead to clinically deficient memory performance in the long term. Additionally, it has to be investigated whether the current findings apply to more complex cognitive measures in diverse ‘user categories’ using a combination of genetics, imaging techniques and neuropsychological assessments.

The most frequently used tests for assessing executive functions in aging

There are numerous neuropsychological tests for assessing executive functions in aging, which vary according to the different domains assessed.

OBJECTIVE

To present a systematic review of the most frequently used instruments for assessing executive functions in older adults with different educational levels in clinical and experimental research.

METHODS

We searched for articles published in the last five years, using the PubMed database with the following terms: "neuropsychological tests", "executive functions", and "mild cognitive impairment". There was no language restriction.

RESULTS

25 articles fulfilled all the inclusion criteria. The seven neuropsychological tests most frequently used to evaluate executive functions in aging were:[1] Trail Making Test (TMT) Form B;[2] Verbal Fluency Test (VFT) - F, A and S;[3] VFT Animals category;[4] Clock Drawing Test (CDT);[5] Digits Forward and Backward subtests (WAIS-R or WAIS-III);[6] Stroop Test; and[7] Wisconsin Card Sorting Test (WCST) and its variants. The domains of executive functions most frequently assessed were: mental flexibility, verbal fluency, planning, working memory, and inhibitory control.

CONCLUSION

The study identified the tests and domains of executive functions most frequently used in the last five years by research groups worldwide to evaluate older adults. These results can direct future research and help build evaluation protocols for assessing executive functions, taking into account the different educational levels and socio-demographic profiles of older adults in Brazil.