Impaired perceptual discrimination of complex objects in older adults at risk for dementia

Tau pathology accumulates in the perirhinal cortex (PRC) of the medial temporal lobe (MTL) during the earliest stages of the Alzheimer's disease (AD), appearing decades before clinical diagnosis. Here, we leveraged perceptual discrimination tasks that target PRC function to detect subtle cognitive impairment even in nominally healthy older adults. Older adults who did not have a clinical diagnosis or subjective memory complaints were categorized into "at-risk" (score <26; n = 15) and "healthy" (score ≥26; n = 23) groups based on their performance on the Montreal Cognitive Assessment. The task included two conditions known to recruit the PRC: faces and complex objects (greebles). A scene condition, known to recruit the hippocampus, and a size control condition that does not rely on the MTL were also included. Individuals in the at-risk group were less accurate than those in the healthy group for discriminating greebles. Performance on either the face or size control condition did not predict group status above and beyond that of the greeble condition. Visual discrimination tasks that are sensitive to PRC function may detect early cognitive decline associated with AD.

Strategy-training post-stroke via tele-rehabilitation: a pilot randomized controlled trial

PURPOSE

Long-term limitations in social participation are common after stroke. Whether these can be attenuated through a tele-rehabilitation approach is unknown. We were particularly interested in examining transfer of learning effects which could result in broader improvements in social participation.

METHODS

We adapted a strategy training rehabilitation approach (tele-CO-OP) for remote delivery. Participants with chronic stroke were randomized to receive the intervention (EXPT) or to a wait list (Control). Feasibility and acceptability were measured via attendance scores, satisfaction with the training and therapist evaluation of engagement with the training. The primary outcome measure was the Canadian Occupational Performance Measure (COPM), a standardized semi-structured interview which elicits difficulties in day-to-day life.

RESULTS

Seventeen participants were randomized. Tele-CO-OP was found to be feasible and acceptable: participants reported high satisfaction and engagement, and missed few sessions. Large effect sizes for transfer of learning effects were observed in favor of receiving tele-CO-OP vs being waitlisted. Significant benefits were also conferred to the Control group following receipt of tele-CO-OP. The intervention also appeared to improve mood.

CONCLUSIONS

This exploratory study demonstrates the feasibility and acceptability of tele-CO-OP and provides preliminary evidence for transfer of learning effects to untrained everyday social participation activities. Trial registration number: NCT02724813.

Nutrition risk and cognitive performance in community-living older adults without cognitive impairment: a cross-sectional analysis of the Canadian Longitudinal Study on Aging

Malnutrition is correlated with poor cognition; however, an understanding of the association between nutrition risk, which precedes malnutrition, and cognition is lacking. This study aimed to determine if nutrition risk measured with the SCREEN-8 tool is associated with cognitive performance among cognitively healthy adults aged 55+, after adjusting for demographic and lifestyle covariates. Sex- and age-stratified analyses were also explored. Baseline data from the Canadian Longitudinal Study on Aging was used. Cognition was determined using a 6-measure composite score based on four executive functions and two memory tasks, taking into account age, sex, and education. Multivariable linear regression was performed while adjusting for body mass index (BMI), lifestyle, and health covariates in the entire sample (n = 11 378) and then stratified by sex and age. Approximately half of participants were female (54.5%) aged 65+ (54.1%). Greater nutrition risk was associated with poorer cognitive performance in the entire sample (F[1, 11 368] = 5.36, p = 0.021) and among participants aged 55-64 (n = 5227; F[1, 5217] = 5.45, p = 0.020). Sex differences in lifestyle and health factors associated with cognition were apparent, but nutrition risk was not associated with cognition in sex-stratified models. Based on this analysis, there may be an association between nutrition risk and cognitive performance in older adults. When screening for either cognitive impairment or nutrition risk, complementary assessments for these conditions is warranted, as early intervention may provide benefit.

Effect of High-Intensity Interval Training and Moderate-Intensity Continuous Training in People With Poststroke Gait Dysfunction: A Randomized Clinical Trial

Background The exercise strategy that yields the greatest improvement in both cardiorespiratory fitness (V ̇ O 2 peak $$ \dot{\mathrm{V}}{\mathrm{O}}_{2\mathrm{peak}} $$ ) and walking capacity poststroke has not been determined. This study aimed to determine whether conventional moderate-intensity continuous training (MICT) or high-intensity interval training (HIIT) have different effects on V ̇ O 2 peak $$ \dot{\mathrm{V}}{\mathrm{O}}_{2\mathrm{peak}} $$ and 6-minute walk distance (6MWD). Methods and Results In this 24-week superiority trial, people with poststroke gait dysfunction were randomized to MICT (5 days/week) or HIIT (3 days/week with 2 days/week of MICT). MICT trained to target intensity at the ventilatory anaerobic threshold. HIIT trained at the maximal tolerable treadmill speed/grade using a novel program of 2 work-to-recovery protocols: 30:60 and 120:180 seconds. V̇O2 and heart rate was measured during performance of the exercise that was prescribed at 8 and 24 weeks for treatment fidelity. Main outcomes were change in V ̇ O 2 peak $$ \dot{\mathrm{V}}{\mathrm{O}}_{2\mathrm{peak}} $$ and 6MWD. Assessors were blinded to the treatment group for V ̇ O 2 peak $$ \dot{\mathrm{V}}{\mathrm{O}}_{2\mathrm{peak}} $$ but not 6MWD. Secondary outcomes were change in ventilatory anaerobic threshold, cognition, gait-economy, 10-meter gait-velocity, balance, stair-climb performance, strength, and quality-of-life. Among 47 participants randomized to either MICT (n=23) or HIIT (n=24) (mean age, 62±11 years; 81% men), 96% completed training. In intention-to-treat analysis, change in V ̇ O 2 peak $$ \dot{\mathrm{V}}{\mathrm{O}}_{2\mathrm{peak}} $$ for MICT versus HIIT was 2.4±2.7 versus 5.7±3.1 mL·kg-1·min-1 (mean difference, 3.2 [95% CI, 1.5-4.8]; P<0.001), and change in 6MWD was 70.9±44.3 versus 83.4±53.6 m (mean difference, 12.5 [95% CI, -17 to 42]; P=0.401). HIIT had greater improvement in ventilatory anaerobic threshold (mean difference, 2.07 mL·kg-1·min-1 [95% CI, 0.59-3.6]; P=0.008). No other between-group differences were observed. During V̇O2 monitoring at 8 and 24 weeks, MICT reached 84±14% to 87±18% of V ̇ O 2 peak $$ \dot{\mathrm{V}}{\mathrm{O}}_{2\mathrm{peak}} $$ while HIIT reached 101±22% to 112±14% of V ̇ O 2 peak $$ \dot{\mathrm{V}}{\mathrm{O}}_{2\mathrm{peak}} $$ (during peak bouts). Conclusions HIIT resulted in more than a 2-fold greater and clinically important change in V ̇ O 2 peak $$ \dot{\mathrm{V}}{\mathrm{O}}_{2\mathrm{peak}} $$ than MICT. Training to target (ventilatory anaerobic threshold) during MICT resulted in ~3 times the minimal clinically important difference in 6MWD, which was similar to HIIT. These findings show proof of concept that HIIT yields greater improvements in cardiorespiratory fitness than conventional MICT in appropriately screened individuals. Registration URL: https://www.clinicaltrials.gov; Unique identifier: NCT03006731.

Using co-creation focus groups to customise a remote multidomain programme designed to increase dementia literacy

OBJECTIVES

To adapt the content and functionalities of Brain Health PRO, a web-based multidomain program designed to increase dementia literacy, to the context and needs of users, providers and community organisations across Québec, Canada.

DESIGN

Five consecutive qualitative co-creation focus group sessions 30-90 min in duration each, exploring potential barriers and facilitators to usability, accessibility, comprehensibility, participant recruitment and retention.

SETTING

Virtual meetings.

PARTICIPANTS

A 15-member team based in Québec and Ontario, Canada, consisting of 9 researchers (including a graduate student and the project coordinator), representing occupational therapy, sensory rehabilitation, neuropsychology, psychology, health science and research methods, 3 informal caregivers of older adults living with cognitive decline and 3 members of the Federation of Quebec Alzheimer Societies.

DATA ANALYSIS

Session recordings were summarised through both qualitative description and thematic analysis.

RESULTS

The synthesised recommendations included adjustments around diversity, the complexity and presentation styles of the materials, suggestions on refining the web interface and the measurement approaches; it influenced aspects of participant recruitment, retention efforts and engagement with the content of Brain Health PRO.

CONCLUSIONS

Co-creation in dementia prevention research is important because it involves collaboration between researchers, community support and service providers, and persons with lived experience as care providers, in the design and implementation of clinical studies. This approach helps to ensure that the content and presentation of educational material is relevant and meaningful to the target population and those involved in its delivery, and it leads to a greater understanding of their needs and perspectives.

Effect of sex on the APOE4-aging interaction in the white matter microstructure of cognitively normal older adults using diffusion-tensor MRI with orthogonal-tensor decomposition (DT-DOME)

The influence of the apolipoprotein E ε4 allele (APOE4) on brain microstructure of cognitively normal older adults remains incompletely understood, in part due to heterogeneity within study populations. In this study, we examined white-matter microstructural integrity in cognitively normal older adults as a function of APOE4 carrier status using conventional diffusion-tensor imaging (DTI) and the novel orthogonal-tensor decomposition (DT-DOME), accounting for the effects of age and sex. Age associations with white-matter microstructure did not significantly depend on APOE4 status, but did differ between sexes, emphasizing the importance of accounting for sex differences in APOE research. Moreover, we found the DT-DOME to be more sensitive than conventional DTI metrics to such age-related and sex effects, especially in crossing WM fiber regions, and suggest their use in further investigation of white matter microstructure across the life span in health and disease.

Protocol for the Brain Health Support Program Study of the Canadian Therapeutic Platform Trial for Multidomain Interventions to Prevent Dementia (CAN-THUMBS UP): A Prospective 12-Month Intervention Study

BACKGROUND/OBJECTIVES

CAN-THUMBS UP is designed as a comprehensive and innovative fully remote program to 1) develop an interactive and compelling online Brain Health Support Program intervention, with potential to positively influence dementia literacy, self-efficacy and lifestyle risk factors; 2) enroll and retain a community-dwelling Platform Trial Cohort of individuals at risk of dementia who will participate in the intervention; 3) support an open platform trial to test a variety of multidomain interventions that might further benefit individuals at risk of dementia. This manuscript presents the Brain Health Support Program Study protocol.

DESIGN/SETTING

Twelve-month prospective multi-center longitudinal study to evaluate a fully remote web-based educational intervention. Participants will subsequently be part of a Platform Trial Cohort and may be eligible to participate in further dementia prevention clinical trials.

PARTICIPANTS

Three hundred fifty older adults who are cognitively unimpaired or have mild cognitive impairment, with at least 1 well established dementia risk factor.

INTERVENTION

Participants engage in the Brain Health Support Program intervention for 45-weeks and complete pre/post intervention measures. This intervention is designed to convey best available evidence for dementia prevention, consists of 181 chapters within 8 modules that are progressively delivered, and is available online in English and French. The program has been developed as a collaborative effort by investigators with recognized expertise in the program's content areas, along with input from older-adult citizen advisors.

MEASUREMENTS

This study utilizes adapted remote assessments with accessible technologies (e.g. videoconferencing, cognitive testing via computer and mobile phone, wearable devices to track physical activity and sleep, self-administered saliva sample collection). The primary outcome is change in dementia literacy, as measured by the Alzheimer's Disease Knowledge Scale. Secondary outcomes include change in self-efficacy; engagement using the online program; user satisfaction ratings; and evaluation of usability and acceptance. Exploratory outcomes include changes in attitudes toward dementia, modifiable risk factors, performance on the Neuropsychological Test Battery, performance on self-administered online cognitive assessments, and levels of physical activity and sleep; success of the national recruitment plan; and the distribution of age adjusted polygenic hazard scores.

CONCLUSIONS

This fully remote study provides an accessible approach to research with all study activities being completed in the participants' home environment. This approach may reduce barriers to participation, provide an easier and less demanding participant experience, and reach a broader geography with recruitment from all regions of Canada. CAN-THUMBS UP represents a Canadian contribution to the global World-Wide FINGERS program (alz.org/wwfingers).

Familiarity Deficits for Words and Objects in Amnestic Mild Cognitive Impairment in a Context Minimizing the Role of Recollection

OBJECTIVES

Amnestic mild cognitive impairment (aMCI) is associated with cortical thinning in perirhinal and entorhinal cortices, key regions of the brain supporting familiarity. Individuals with aMCI demonstrate familiarity deficits in their behavior, often repeating questions in the same conversation. While familiarity deficits in healthy aging are minimal, past studies measuring familiarity in aMCI have mixed results, perhaps due to the influence of recollection. We therefore used a paradigm that minimized the influence of recollection, and hypothesized that familiarity would be impaired in aMCI relative to age-matched controls, but not in healthy older adults relative to younger adults. We also hypothesized that familiarity deficits in aMCI would be greater for objects than words because the perirhinal cortex plays a significant role in visual discrimination.

METHODS

A sample of 36 younger adults, 38 cognitively intact older adults, and 30 older adults with aMCI made absolute frequency judgments for words and objects seen a variable number of times in an incidental encoding task. Estimates of familiarity were derived from correlating participants' frequency judgments with the actual frequency of presentation.

RESULTS

Familiarity was largely spared in healthy aging, with minor deficits in familiarity for words. Familiarity deficits were evident in aMCI comparably for words and objects.

DISCUSSION

The present research underscores the need to study familiarity in contexts minimizing recollection, particularly when comparing groups with different levels of recollection, and adds to our understanding of the phenomenology of aMCI. Familiarity deficits may provide an early biomarker of dementia risk.

Time of Day Effects on Inhibitory Functioning: Cognitive and Neural Evidence of Sundowning in Amnestic Mild Cognitive Impairment

Background: Amnestic mild cognitive impairment (aMCI), a prodromal phase of Alzheimer’s disease (AD), is characterized by episodic memory dysfunction, but inhibitory deficits have also been commonly reported. Time of day (TOD) effects have been confirmed in 1) healthy aging on cognitive processes such as inhibitory control, and 2) on behavior in AD (termed the sundowning effect), but no such research has addressed aMCI. Objective: The present study examined the impact of TOD on the behavioral and electrophysiological correlates of inhibition in 54 individuals with aMCI and 52 healthy controls (HCs), all of morning chronotype. Methods: Participants were randomly assigned to complete two inhibition tasks (Go-NoGo and Flanker) during their optimal (morning) or non-optimal (evening) TOD, while electroencephalography was recorded. Results: Both tasks elicited changes in N2 and P3 event-related potential (ERP) components, which commonly index inhibitory functioning. Analyses showed that the Go-NoGo difference in P3 amplitude was reduced in individuals with aMCI relative to HCs. Compared to HCs, the Flanker difference in P3 amplitude was also reduced and coincided with more errors in the aMCI group. Notably, these behavioral and ERP differences were exaggerated in the non-optimal TOD relative to the optimal TOD. Conclusion: Findings confirm the presence of inhibition deficits in aMCI and provide novel evidence of sundowning effects on inhibitory control in aMCI. Results reinforce the need to consider the influences of TOD in clinical assessments involving individuals with aMCI.

The Role of the Gut Microbiome in Diet and Exercise Effects on Cognition: A Review of the Intervention Literature

Interest in the gut-brain axis and its implications for neurodegenerative diseases, such as Alzheimer's disease and related dementias, is growing. Microbial imbalances in the gastrointestinal tract, which are associated with impaired cognition, may represent a therapeutic target for lowering dementia risk. Multicomponent lifestyle interventions are a promising dementia risk reduction strategy and most often include diet and exercise, behaviors that are also known to modulate the gut microbiome. A better understanding of the role of the gut microbiome in diet and exercise effects on cognition may help to optimize these lifestyle interventions. The purpose of this review is to summarize findings from diet and exercise interventions that have investigated cognitive changes via effects on the microbiome. We aim to discuss the underlying mechanisms, highlight current gaps in the field, and provide new research directions. There is evidence mainly from rodent studies supporting the notion that microbiota changes mediate the effects of diet and exercise on cognition, with potential mechanisms including end-product metabolites and regulation of local and systemic inflammation. The field lacks whole diet and exercise interventions, especially those involving human participants. It is further limited by heterogeneous rodent models, outcome assessments, and the absence of proper mediation analyses. Trials including older adults with dementia risk factors, factorial designs of diet and exercise, and pre and post measures of microbiota, end-product metabolites, and inflammation would help to elucidate and potentially leverage the role of the microbiome in lowering dementia risk through lifestyle modification.

The adverse effect of modifiable dementia risk factors on cognition amplifies across the adult lifespan

Background

Reversible lifestyle behaviors (modifiable risk factors) can reduce dementia risk by 40%, but their prevalence and association with cognition throughout the adult lifespan is less well understood.

Methods

The associations between the number of modifiable risk factors for dementia (low education, hypertension, hearing loss, traumatic brain injury, alcohol or substance abuse, diabetes, smoking, and depression) and cognition were examined in an online sample (N = 22,117, ages 18–89).

Findings

Older adults (ages 66–89) had more risk factors than middle‐aged (ages 45–65) and younger adults (ages 18–44). Polynomial regression revealed that each additional risk factor was associated with lower cognitive performance (equivalent to 3 years of aging), with a larger association as age increased. People with no risk factors in their forties to seventies showed similar cognitive performance to people 10 or 20 years younger with many risk factors.

Interpretation

Modifiable dementia risk factors amplify lifespan age differences in cognitive performance.

Sex differences and modifiable dementia risk factors synergistically influence memory over the adult lifespan

Introduction

More women than men develop Alzheimer's disease, yet women perform better and show less decline on episodic memory measures, a contradiction that may be accounted for by modifiable risk factors for dementia.

Methods

Associations among age, sex, modifiable dementia risk factors, and cognition were measured in a cross‐sectional online sample (n = 21,840, ages 18 to 89).

Results

Across four tests of associative memory and executive functions, only a Face‐Name Association task revealed sex differences in associative memory that varied by age. Men had worse memory than women (the equivalent of performing similar to someone 4 years older) across ages. Men had larger age differences than women (ie, worse memory in older ages) among people with no to one risk factor, but not those with multiple risk factors.

Discussion

Because the relationship between dementia risk factors and age‐related memory differences varies between men and women, sex‐specific dementia prevention approaches are warranted.

The Effects of Aging and Time of Day on Inhibitory Control: An Event-Related Potential Study

Time of day (TOD) influences on executive functions have been widely reported, with greater efficiency demonstrated at optimal relative to non-optimal TOD according to one’s chronotype (i.e., synchrony effect). Older adults (OAs) show declines in inhibitory control and are more sensitive to the effects of circadian variation on executive functioning. To date, no studies have investigated the effects of TOD and aging on executive functioning using electrophysiological measures. The present study investigated the effects of aging and TOD on the neural correlates of inhibitory processing (N2 and P3) using event-related potentials (ERPs). Go-NoGo and Flanker tasks were administered to 52 OAs of morning chronotype and 51 younger adults (YAs) of afternoon-to-evening chronotype who were randomly assigned to morning or afternoon test sessions, with the optimal TOD for OAs in the morning and for YAs in the afternoon/evening. While behavioral results demonstrated no TOD effects, ERPs indicated synchrony effects. Both YAs and OAs showed greater modulation of Go-NoGo N2 and greater P3 amplitude during the non-optimal than optimal TOD, consistent with the synchrony effect. For the Flanker task, age differences in P3 amplitude were only apparent during the non-optimal TOD. These results suggest that processes associated with inhibitory control are differentially affected by TOD and aging, with age-related reductions in inhibitory efficiency during off-peak test times on measures of interference control. These findings highlight the sensitivity of ERPs to detect TOD effects in the absence of behavioral differences, confirm more pronounced TOD effects in OAs relative to YAs on ERP measures of interference control, and reinforce the need to assess and control for circadian typology in research studies.

Feasibility and preliminary efficacy of the LEAD trial: a cluster randomized controlled lifestyle intervention to improve hippocampal volume in older adults at-risk for dementia

BACKGROUND

Healthy diet and exercise are associated with reduced risk of dementia in older adults. The impact of diet and exercise interventions on brain health is less consistent, especially with dietary interventions which rely on varying approaches. Our objective was to evaluate the feasibility and preliminary efficacy of a 6-month intervention combining exercise with a novel dietary counseling approach to improve hippocampal volume among older adults at-risk for dementia.

METHODS

Participants with vascular risk factors and subjective cognitive decline or early mild cognitive impairment were cluster randomized in groups of 3-4 to the diet intervention (DIET) or control education (ED) group. All participants engaged in 1 h of supervised exercise per week and additional exercise at home. DIET involved 1 h per week of group-based dietary counseling comprising education, goal setting, and strategy training. ED involved 1 h per week of group-based brain health education classes. Our primary outcome was change in hippocampal volume from baseline to 6 months. Secondary outcomes included changes in cognitive function, blood biomarkers, diet, and fitness. Recruitment challenges and early discontinuation of the trial due to COVID-19 necessitated a revised focus on feasibility and preliminary efficacy.

RESULTS

Of 190 older adults contacted, 14 (7%) were eligible and enrolled, constituting 21% of our recruitment target. All participants completed the intervention and attended 90% of exercise and DIET/ED sessions on average. All 6-month assessments prior to COVID-19 were completed but disruptions to in-person testing resulted in incomplete data collection. No serious adverse events occurred and all participants expressed positive feedback about the study. Preliminary findings did not identify any significant changes in hippocampal volume; however, substantial improvements in diet and HbA1c were observed with DIET compared to ED (d = 1.75 and 1.07, respectively).

CONCLUSIONS

High adherence and retention rates were observed among participants and preliminary findings illustrate improvements in diet quality and HbA1c. These results indicate that a larger trial is feasible if difficulties surrounding recruitment can be mitigated.

TRIAL REGISTRATION

ClinicalTrials.gov identifier: NCT03056508 .

Interindividual and intraindividual variability in amnestic mild cognitive impairment (aMCI) measured with an online cognitive assessment

INTRODUCTION

Mean cognitive performance is worse in amnestic mild cognitive impairment (aMCI) compared to control groups. However, studies on variability of cognitive performance in aMCI have yielded inconclusive results, with many differences in variability measures and samples from one study to another.

METHODS

We examined variability in aMCI using an existing older adult sample (n = 91; 51 with aMCI, 40 with normal cognition for age), measured with an online self-administered computerized cognitive assessment (Cogniciti's Brain Health Assessment). Our methodology extended past findings by using pure measures of variability (controlling for confounding effects of group performance or practice), and a clinically representative aMCI sample (reflecting the continuum of cognitive performance between normal cognition and aMCI).

RESULTS

Between-group t-tests showed significantly greater between-person variability (interindividual variability or diversity) in overall cognitive performance in aMCI than controls, although the effect size was with a small to moderate effect size, d = 0.44. No significant group differences were found in within-person variability (intraindividual variability) across cognitive tasks (dispersion) or across trials of a response time task (inconsistency), which may be because we used a sample measuring the continuum of cognitive performance. Exploratory correlation analyses showed that a worse overall score was associated with greater inter- and intraindividual variability, and that variability measures were correlated with each other, indicating people with worse cognitive performance were more variable.

DISCUSSION

The current study demonstrates that self-administered online tests can be used to remotely assess different types of variability in people at risk of Alzheimer`s. Our findings show small but significantly more interindividual differences in people with aMCI. This diversity is considered as "noise" in standard assessments of mean performance, but offers an interesting and cognitively informative "signal" in itself.

Occupational performance coaching for stroke survivors delivered via telerehabilitation using a single-case experimental design

INTRODUCTION

Sustaining a stroke has a devastating, long-term impact on participation in everyday life. Despite the recognition of participation as a key outcome of stroke rehabilitation, there are few effective interventions that address participation. Occupational performance coaching is a promising intervention designed to improve participation among stroke survivors. Delivery of occupational performance coaching using telerehabilitation could improve access. This study examined the feasibility, acceptability and potential efficacy of telerehabilitation occupational performance coaching.

METHOD

A single-case experimental design was used. Six community-dwelling stroke survivors received 10 sessions of telerehabilitation occupational performance coaching over 16 weeks. We examined the feasibility and acceptability of telerehabilitation occupational performance coaching, improvement in performance and satisfaction with identified goals.

RESULTS

Telerehabilitation occupational performance coaching was feasible and acceptable to deliver; participants who started the intervention completed it and reported high satisfaction and a strong therapeutic relationship. All participants experienced technological issues that required resolution. Goal-performance and/or satisfaction improved for five of six participants. Sixty-four percent of goals showed trends for improvement and 43% showed significant improvements.

CONCLUSIONS

Findings support the feasibility and acceptability of telerehabilitation occupational performance coaching, along with its efficacy for improving performance and satisfaction with performance of goals. Further research is needed to prove the effectiveness of telerehabilitation occupational performance coaching and to determine who may benefit most.

When I'm 64: Age-related variability in over 40,000 online cognitive test takers

Objectives

Age-related differences in cognition are typically assessed by comparing groups of older to younger participants, but little is known about the continuous trajectory of cognitive changes across age, or when a shift to older adulthood occurs. We examined the pattern of mean age differences and variability on episodic memory and executive function measures over the adult life span, in a more fine-grained way than past group or life-span comparisons.

Method

We used a sample of over 40,000 people aged 18–90 who completed psychometrically validated online tests measuring episodic memory and executive functions (the Cogniciti Brain Health Assessment).

Results

Cognitive performance declined gradually over adulthood, and rapidly later in life on spatial working memory, processing speed, facilitation (but not interference), associative recognition, and set shifting. Both polynomial and segmented regression fit the data well, indicating a nonlinear pattern. Segmented regression revealed a shift from gradual to rapid decline that occurred in the early 60s. Variability between people (interindividual variability or diversity) and variability within a person across tasks (intraindividual variability or dispersion) also increased gradually until the 60s, and rapidly after. Confirmatory factor analysis revealed a single general factor (of variance shared between tasks) offered a good fit for performance across tasks.

Discussion

Life-span cognitive performance shows a nonlinear pattern, with gradual decline over early and mid-adulthood, followed by a transition in the 60s to notably accelerated, but more variable, decline. Some people show less decline than others, and some cognitive abilities show less within-person decline than others.

Known-Groups and Convergent Validity of the Telephone Rey Auditory Verbal Learning Test total Learning Scores for Distinguishing Between Older Adults With Amnestic Cognitive Impairment and Subjective Cognitive Decline

OBJECTIVE

To examine known-groups validity of a telephone administration of the total learning scores of the Rey Auditory Verbal Learning Test (RAVLT) in discriminating between people with subjective cognitive decline (SCD) and amnestic mild cognitive impairment (aMCI) and convergent validity of the telephone-RAVLT.

METHOD

In total, 83 older adults (age = 71.4 ± 7.0) with SCD or aMCI completed the RAVLT learning trials over the telephone and the Hopkins Verbal Learning Test (HVLT) in-person.

RESULTS

Telephone-RAVLT total recall significantly correlated with HVLT total recall (r = .49, p < .001). Significant between group differences were found (effect size = 0.94).

CONCLUSIONS

This study provides support for known-groups and convergent validity of the telephone-RAVLT.

Occupational performance issues in older adults with subjective cognitive decline

PURPOSE

To describe and categorize difficulties in daily activities of older adults with subjective cognitive decline (SCD) compared to individuals with mild cognitive impairment (MCI).

METHODS

Deductive quantitative content analysis was used to classify reported issues in the performance of meaningful daily activities, in older adults with SCD (n = 67; age= 70 ± 6.3) or MCI (n = 42; age= 72 ± 6.6). The occupational performance issues were identified using the Canadian Occupational Performance Measure, a semi-structured interview, and categorised using the International Classification of Functioning, Disability and Health (ICF).

RESULTS

Both groups identified issues in all nine ICF "Activities and Participation" domains, with no significant group effects on seven of them. The most frequently affected "Activities and Participation" domains in both groups were "Self-care" (e.g. exercise and diet); "Community, social and civic life" (e.g. social-leisure activities); and "General tasks and demands" (e.g. time management). Over 90% of the issues in both groups were described in the context of difficulties in "Mental functions" (e.g. memory and higher-level cognitive functions).

CONCLUSIONS

Older adults with SCD, although independent, identified a variety of daily activities that they are not performing satisfactorily, remarkably similar in nature to the occupational performance issues described by older adults with MCI.Implications for RehabilitationOlder adults with SCD identified difficulties in performing social and leisure activities, maintaining healthy lifestyle behaviours, and managing multiple daily tasks.The daily challenges described by older adults with SCD are similar in nature to those identified by those with MCI.Older adults with SCD and MCI describe their daily challenges are related not only to memory problems, but also to executive dysfunction.Interventions for older adults with SCD should aim to improve self-identified problems in everyday functioning.

Reaction time intra-individual variability reveals inhibitory deficits in single- and multiple-domain amnestic mild cognitive impairment

OBJECTIVES

Amnestic mild cognitive impairment (aMCI), a prodromal stage of Alzheimer's disease and other dementias, is characterized by episodic memory impairment. Recent evidence has shown inhibitory control deficits in aMCI, but the extent of these deficits across inhibitory domains (i.e., response inhibition and interference control) and aMCI subtypes (i.e., single- versus multiple-domain) remains unclear. Few studies have included response time intra-individual variability (RT IIV) in these efforts. The aim of this study was to compare response inhibition and interference control between aMCI subtypes using measures of accuracy, mean RT, and RT IIV.

METHOD

We report data from 34 individuals with single-domain aMCI (sdaMCI, 66-86 years), 20 individuals with multiple-domain aMCI (mdaMCI, 68-88 years), and 52 healthy controls (64-88 years) who completed tasks of response inhibition (Go-NoGo) and interference control (Flanker). Group differences in accuracy, mean RT, and RT IIV were examined for both tasks.

RESULTS

Individuals with mdaMCI had higher RT IIV than the other groups on both tasks. In RT IIV, we observed an interference control deficit in mdaMCI and sdaMCI relative to healthy controls, a finding not observed through accuracy or mean RT.

DISCUSSION

RT IIV may detect subtle differences in inhibition deficits between aMCI subtypes that may not be evident with conventional behavioral measures. Findings support the supplementary use of RT IIV when assessing early executive function deficits.

The Association Between Dietary Pattern Adherence, Cognitive Stimulating Lifestyle, and Cognitive Function Among Older Adults From the Quebec Longitudinal Study on Nutrition and Successful Aging

OBJECTIVES

This study examined the effect of dietary patterns and engagement in cognitive stimulating lifestyle (CSL) behaviors on the trajectory of global cognition, executive function (EF), and verbal episodic memory (VEM).

METHODS

Western and prudent dietary patterns were empirically derived using food frequency questionnaire responses from 350 community-dwelling older adults (mean age: 73.7 years) participating in the Quebec Longitudinal Study on Nutrition and Successful Aging. CSL was represented by a binary composite indicator based on education, occupational complexity, and social engagement. Global cognition, EF, and VEM were assessed prospectively.

RESULTS

Primary effect models revealed an association between higher Western dietary pattern score and a greater rate of decline in global cognition and EF. Higher Western dietary pattern adherence was also associated with poorer baseline VEM. Primary effect models also revealed that CSL was independently associated with baseline global cognition and EF. Effect modification models suggested an interactive effect between Western dietary pattern and CLS on global cognition only. No associations were found for prudent dietary pattern score.

DISCUSSION

Contributing to existing research supporting the negative impact of consuming an unhealthy diet on cognitive function, the current study suggests increased vulnerability among older adults who do not engage in a CSL. These findings can inform the development of lifestyle intervention programs that target brain health in later adulthood.

Household physical activity is positively associated with gray matter volume in older adults

Background

Total physical activity is positively associated with brain volume and cognition in older adults. While we have ample evidence that recreational physical activity influences brain health, the contributions of other daily activities are less understood. In particular, the associations between household physical activity and brain health in older adults is underexplored. The purpose of this study was to identify associations between household physical activity, brain volume, and cognition in a sample of cognitively unimpaired older adults.

Methods

We report data from 66 cognitively unimpaired older adults (71 ± 4 years) who participated in a health evaluation, cognitive assessment, and structural brain imaging. Physical activity was assessed using the Phone-FITT questionnaire and separated into household and recreational physical activity. We quantified whole brain volume, gray matter volume, and white matter volume, and assessed cognitive performance in four domains: memory, working memory/attention, processing speed, and executive function. Associations between physical activity, brain volume, and cognition were investigated in an omnibus approach using two multivariate analysis of variance (MANOVA) models. The first model assessed the associations between physical activity and brain volume adjusting for age, sex, Framingham Risk score (FRS) and intracranial volume. The second model assessed the associations between physical activity and overall cognitive performance adjusting for age, sex, FRS and education. Post hoc regression analyses were conducted to investigate significant MANOVA results. We also conducted further regression analyses to investigate associations with hippocampal and frontal lobe volume.

Results

Household, but not recreational, physical activity was positively associated with brain volume measurements (F = 3.07, p = .035), specifically gray matter volume (t = 2.51, p = .015). Further exploratory analyses identified that household physical activity was associated with hippocampal (p = .015) and frontal lobe (p = .010) volume. No significant relationships were observed between household or recreational physical activity and cognition.

Conclusion

Time spent engaging in household physical activity was positively associated with brain volume, specifically gray matter volume, in older adults. Highlighting the benefits associated with household chores may motivate older adults to be more active by providing a more attainable, low risk form of physical activity.

Deficits in recent but not lifetime familiarity in amnestic mild cognitive impairment

People with amnestic mild cognitive impairment (aMCI) repeat questions, seemingly without any sense of familiarity (i.e., recognition of prior occurrence without recollection of episodic context). Accumulation of neurofibrillary tau in preclinical Alzheimer's disease begins in perirhinal cortex, a medial temporal lobe region linked to familiarity. Both observations would predict impaired familiarity assessment in aMCI; however, the extant evidence is mixed. To reveal familiarity impairments, it may be necessary to minimize the influence of recollection. In the current study, older adults with aMCI and healthy controls were administered two tasks on which a well-characterized patient (NB) with selective familiarity impairments due to surgical left temporal lobe excision sparing the hippocampus showed abnormal performance: frequency judgments for words exposed to in a recent study phase and judgments of cumulative lifetime familiarity for object concepts denoted by words. We also administered a process dissociation procedure (PDP) task that previously revealed spared familiarity in aMCI. We predicted that familiarity would be spared in aMCI on the PDP task, but impaired when assessed by frequency judgments for recent laboratory exposures and lifetime familiarity judgments. Familiarity was spared on the PDP task, but was impaired when probed with frequency judgments for recently exposed words in aMCI. Lifetime familiarity was also not impaired in aMCI. These results highlight the benefits of studying familiarity under conditions that minimize recollection and the value of frequency judgments in revealing familiarity deficits, and suggest that perirhinal cortex may not be necessary for accessing familiarity accumulated over a lifetime of experience.

Fornix Integrity Is Differently Associated With Cognition in Healthy Aging and Non-amnestic Mild Cognitive Impairment: A Pilot Diffusion Tensor Imaging Study in Thai Older Adults

Damage to the fornix leads to significant memory impairment and executive dysfunction and is associated with dementia risk. We sought to identify if fornix integrity and fiber length are disrupted in mild cognitive impairment (MCI) and how they associate with cognition. Data from 14 healthy older adult controls (HCs) and 17 subjects with non-amnestic MCI (n-aMCI) were analyzed. Diffusion tensor imaging (DTI) at 1.5 Tesla MRI was performed to enable manual tracing of the fornix and calculation of DTI parameters. Higher fractional anisotropy of body and column of the fornix was associated with better executive functioning and memory, more strongly in the HC than in the n-aMCI group. Fornix fiber tract length (FTL) was associated with better executive function, more strongly in the n-aMCI than in the HC group, and with better memory, more strongly in the HC than in the n-aMCI group. These results highlight a decline in the contributions of the fornix to cognition in n-aMCI and suggest that maintenance of fornix FTL is essential for sustaining executive functioning in people with n-aMCI.

Lower Thalamic Blood Flow Is Associated With Slower Stride Velocity in Older Adults

Background

Gait deficits are associated with brain atrophy and white matter hyperintensities (WMH) - both markers of underlying cerebral small vessel disease (SVD). Given reduced subcortical cerebral blood flow (CBF) is prevalent in SVD, we tested the hypothesis that regional CBF is positively associated with gait performance among older adults.

Methods

Thirty-two older adults (55-80 years) with at least one vascular risk factor were recruited. We assessed gait during 2 consecutive walking sequences using a GAITRite system: (1) at a self-selected pace, and (2) while performing a serial subtraction dual-task challenge. We quantified CBF using pseudo-continuous arterial spin labeling MRI within 4 regions of interest: putamen, pallidum, thalamus, and hippocampus. We investigated associations between gait characteristics and overall CBF adjusting for age, sex, and height in an omnibus approach using multivariate analysis of variance, followed by regression analysis with each individual region. We also conducted further regression analyses to investigate associations between gait characteristics and frontal lobe CBF. Sensitivity analyses examined how the observed associations were modified by WMH, executive function, and depressive symptoms. A change of 10% in the model's adjusted r² and effect size was considered as a threshold for confounding.

Results

Overall subcortical CBF was not associated with self-paced gait. When examining individual ROI, gait velocity was directly related to thalamic CBF (p = 0.026), and across all gait variables the largest effect sizes were observed in relation to thalamic CBF. In the dual-task condition, gait variables were not related to CBF in either the omnibus approach or individual multiple regressions. Furthermore, no significant associations were observed between frontal CBF and gait variables in either the self-paced or dual-task condition. Sensitivity analyses which were restricted to examine the association of velocity and thalamic CBF identified a cofounding effect of depressive symptoms which increased the effect size of the CBF-gait association by 12%.

Conclusion

Subcortical hypoperfusion, particularly in regions that comprise central input/output tracts to the cortical tissue, may underlie the association between gait deficits and brain aging.

Sex differences in the relationship between dietary pattern adherence and cognitive function among older adults: findings from the NuAge study

BACKGROUND

Consumption of a prudent dietary pattern rich in healthy nutrients is associated with enhanced cognitive performance in older adulthood, while a Western dietary pattern low in healthy nutrients is associated with poor age-related cognitive function. Sex differences exist in dietary intake among older adults; however, there is a paucity of research examining the relationship between sex-specific dietary patterns and cognitive function in later life.

METHODS

The current study aimed to investigate sex differences in the relationship between sex-specific dietary pattern adherence and global cognitive function at baseline and over a 3-year follow-up in 1268 community-dwelling older adults (M_age = 74 years, n = 664 women, n = 612 men) from the Quebec Longitudinal Study on Nutrition and Successful Aging (NuAge). A 78-item Food Frequency Questionnaire was used to estimate dietary intake over the previous year. Sex-specific dietary pattern scores were derived using principal component analysis. Global cognition was assessed using the Modified Mini-Mental State Examination (3MS).

RESULTS

Adjusted linear mixed effects models indicated that a healthy, prudent dietary pattern was not associated with baseline cognitive performance in men or women. No relationship was found between Western dietary pattern adherence and baseline cognitive function in women. Among men, adherence to an unhealthy, Western dietary pattern was associated with poorer baseline cognitive function (β = - 0.652, p = 0.02, 95% CI [- 1.22, - 0.65]). No association was found between prudent or Western dietary patterns and cognitive change over time in men or women.

CONCLUSIONS

These findings highlight the importance of conducting sex-based analyses in aging research and suggest that the relationship between dietary pattern adherence and cognitive function in late life may be sex-dependent.

A consensus-based transparency checklist

We present a consensus-based checklist to improve and document the transparency of research reports in social and behavioural research. An accompanying online application allows users to complete the form and generate a report that they can submit with their manuscript or post to a public repository.

When Gist and Familiarity Collide: Evidence From False Recognition in Younger and Older Adults

OBJECTIVES

Aging is associated with decreased recollection required to offset misleading effects of familiarity, as well as an increased mnemonic reliance on gist-based over detail-based information. We tested the novel hypothesis that age-related decrements in overriding familiarity can be eliminated under conditions in which gist-based information facilitates retrieval.

METHOD

Twenty-seven younger adults and 27 older adults viewed scenes from two categories in an incidental encoding phase. In a recognition phase, old scenes were intermixed with new scenes from the studied categories and an unstudied category, with each new scene reappearing after 4, 18, or 48 intervening scenes. Participants were to respond "yes" to old scenes, and "no" to new scenes, including their repetitions.

RESULTS

Despite encoding the scenes similarly, older adults made more false endorsements of new and repeated new scenes from studied categories. Both groups, however, were equally unlikely to falsely recognize new and repeated new scenes from the unstudied category.

DISCUSSION

When helpful gist and misleading familiarity collide, gist wins, and eliminates age-related increases in false recognition.

Cardiovascular risk and encoding-related hippocampal connectivity in older adults

Background

Cardiovascular conditions contribute to brain volume loss, reduced cerebrovascular health, and increased dementia risk in aging adults. Altered hippocampal connectivity has also been observed in individuals with cardiovascular conditions, yet the functional consequences of these changes remain unclear. In the present study, we collected functional magnetic resonance imaging data during memory encoding and used a psychophysiological interaction analysis to examine whether cardiovascular burden, indexed using the Framingham risk score, was associated with encoding-related hippocampal connectivity and task performance in cognitively-intact older adults between 65 and 85 years of age. Our goal was to better understand the early functional consequences of vascular and metabolic dysfunction in those at risk for cognitive decline.

Results

High Framingham risk scores were associated with lower total brain volumes. In addition, those with high Framingham risk scores showed an altered relationship between left hippocampal-medial prefrontal coupling and task performance compared to those with low Framingham risk scores. Specifically, we found a significant interaction of Framingham risk and learning on connectivity between the left hippocampus and primarily left midline prefrontal regions comprising the left ventral anterior cingulate cortex and medial prefrontal cortex. Those with lower Framingham risk scores showed a pattern of weaker connectivity between left hippocampal and medial prefrontal regions associated with better task performance. Those with higher Framingham risk scores showed the opposite pattern; stronger connectivity was associated with better performance.

Conclusions

Findings from the current study show that amongst older adults with cardiovascular conditions, higher Framingham risk is associated with lower brain volume and altered left hippocampal-medial prefrontal coupling during task performance compared to those with lower Framingham risk scores. This may reflect a compensatory mechanism in support of memory function and suggests that older adults with elevated cardiovascular risk are vulnerable to early Alzheimer disease-like dysfunction within the episodic memory system.

Rationale and protocol of the ENGAGE study: a double-blind randomized controlled preference trial using a comprehensive cohort design to measure the effect of a cognitive and leisure-based intervention in older adults with a memory complaint

BACKGROUND

Leisure activities can be both enjoyable and cognitively stimulating, and participation in such activities has been associated with reduced age-related cognitive decline. Thus, integrating stimulating leisure activities in cognitive training programs may represent a powerful and innovative approach to promote cognition in older adults at risk of dementia. The ENGAGE study is a randomized controlled, double-blind preference trial with a comprehensive cohort design that will test the efficacy and long-term impact of an intervention that combines cognitive training and cognitively stimulating leisure activities.

METHODS

One hundred and forty-four older adults with a memory complaint will be recruited in Montreal and Toronto. A particular effort will be made to reach persons with low cognitive reserve. Participants will be randomly assigned to one of two conditions: cognitive + leisure training (ENGAGE-MUSIC/SPANISH) or active control (ENGAGE-DISCOVERY). The ENGAGE-MUSIC/SPANISH training will include teaching of mnemonic and attentional control strategies, casual videogames selected to train attention, and classes in music or Spanish as a second language. The ENGAGE-DISCOVERY condition will comprise psychoeducation on cognition and the brain, low-stimulating casual videogames and documentary viewing with discussions. To retain the leisure aspect of the activities, participants will be allowed to exclude either music or Spanish at study entry if they strongly dislike one of these activities. Participants randomized to ENGAGE-MUSIC/SPANISH who did not exclude any activity will be assigned to music or Spanish based on a second random assignment. Training will be provided in 24 2-h sessions over 4 months. Outcomes will be measured at baseline, at 4-month follow-up, and at 24-month follow-up. The primary outcome will be cognitive performance on a composite measure of episodic memory (delayed recall scores for words and face-name associations) measured at baseline and at the 4-month follow-up. Secondary outcomes will include a composite measure of attention (speed of processing, inhibition, dual tasking, and shifting), psychological health, activities of daily living, and brain structure and function and long-term maintenance measured at the 24-month follow-up. Information on cognitive reserve proxies (education and lifestyle questionnaires), sex and genotype (apolipoprotein (Apo)E4, brain-derived neurotrophic factor (BDNF), and catechol-O-methyltransferase (COMT)) will be collected and considered as moderators of training efficacy.

DISCUSSION

This study will test whether a program combining cognitive training with stimulating leisure activities can increase cognition and reduce cognitive decline in persons at risk of dementia.

TRIAL REGISTRATION

NCT03271190 . Registered on 5 September 2017.

Cognitive Contributors to Multiple Errands Test (MET) Performance

OBJECTIVE

The Multiple Errands Test (MET) was designed to measure the effect of executive dysfunction on everyday life activities, but little is known about the cognitive requirements for successful performance. This study's objective was to investigate cognitive functions associated with successful MET performance, specifically, the Baycrest-MET.

METHOD

Correlation analysis examined relationships between Baycrest-MET performance and neuropsychological functioning in participants with acquired brain injury (ABI; N = 27).

RESULTS

The association of tasks omitted with executive function (EF) accounted for 15.2%-42.3% of the variance; the association of tasks omitted with attention and processing speed, for 16.8%-24.0%; and the association of tasks omitted and total rule breaks with visuospatial memory, for 18.5%-31.4%.

CONCLUSION

Poor performance on the Baycrest-MET in people with ABI is associated with impairments of EF, attention, memory, and processing speed. Different patterns of performance may arise from different constellations of impairments.

Effects of Question Framing on Self-Reported Memory Concerns across the Lifespan

Background/Study Context: Evidence regarding whether there is an age-related increase in subjective memory concerns is mixed. The goal of this study was to investigate whether calling to mind specific instances of memory failures affects the likelihood that individuals report being concerned about their memory.

METHODS

Young, middle-aged, and older individuals responded to statements that probed general memory concerns (e.g., I am concerned about my memory) before or after probing the frequency of memory difficulties in specific everyday situations (e.g., I forget appointments).

RESULTS

We found no relationship between age and memory concern, and older compared to younger adults reported having fewer everyday memory failures. Furthermore, individuals of all ages were more likely to report being concerned about their memory if asked before relative to after rating the frequency of specific everyday memory failures.

CONCLUSION

Increasing age is associated with fewer reported difficulties with specific everyday memory situations, but people of all ages display anchoring effects on memory concern based on realistic occurrences of remembering. Our findings have implications for the measurement of self-reported memory as they show that the order of questions can influence responding.

Slow and steady: Training induced improvements to response time consistency are due to overall slowing and minimized extremely slow responses

Previous studies on response time intraindividual variability (RT IIV) have focused on differences between groups, ignoring the potential for modification. The current study provides a detailed analysis of RT IIV training effects across three age groups. Healthy adults (40 young [aged 18-30], 40 young-old [aged 65-74], and 41 old-old [aged 75-85]) were assigned to feedback or no feedback (standard) conditions during a touch-screen feature integration task. In the feedback condition, participants were shown their performance on the previous block of trials and encouraged to improve going forward. Transfer was assessed by comparing pre- and posttraining performance on a 4-choice RT task. Data were analyzed with respect to RT IIV, ex-Gaussian distribution fitting, and the diffusion model of RT decision making. Significant feedback-related reductions were observed in Target RT IIV and the ex-Gaussian parameter τ, accompanied by an increase in μ. There was no significant change in σ, and no evidence of transfer to the 4-choice RT task. The diffusion model analysis indicated that feedback training promoted a reduction in response threshold for the young and young-old groups, as well as a modulation of drift rate throughout training in the young group. The findings indicate that training to improve consistency induces overall slowing, but also reduces the frequency of extremely slow responses that have been linked to brief attention lapses. The results provide evidence that RT consistency is malleable, but improvements are not necessarily transferable. (PsycINFO Database Record (c) 2018 APA, all rights reserved).

Attention-Related Brain Activation Is Altered in Older Adults With White Matter Hyperintensities Using Multi-Echo fMRI

Cognitive decline is often undetectable in the early stages of accelerated vascular aging. Attentional processes are particularly affected in older adults with white matter hyperintensities (WMH), although specific neurovascular mechanisms have not been elucidated. We aimed to identify differences in attention-related neurofunctional activation and behavior between adults with and without WMH. Older adults with moderate to severe WMH (n = 18, mean age = 70 years), age-matched adults (n = 28, mean age = 72), and healthy younger adults (n = 19, mean age = 25) performed a modified flanker task during multi-echo blood oxygenation level dependent functional magnetic resonance imaging. Task-related activation was assessed using a weighted-echo approach. Healthy older adults had more widespread response and higher amplitude of activation compared to WMH adults in fronto-temporal and parietal cortices. Activation associated with processing speed was absent in the WMH group, suggesting attention-related activation deficits that may be a consequence of cerebral small vessel disease. WMH adults had greater executive contrast activation in the precuneous and posterior cingulate gyrus compared to HYA, despite no performance benefits, reinforcing the network dysfunction theory in WMH.

Learning from your mistakes: does it matter if you're out in left foot, I mean field?

Studies have shown that generating errors prior to studying information (pencil-?) can improve target retention relative to passive (i.e., errorless) study, provided that cues and targets are semantically related (pencil-ink) and not unrelated (pencil-frog). In two experiments, we manipulated semantic proximity of errors to targets during trial-and-error to examine whether it would modulate this error generation benefit. In Experiment 1, participants were shown a cue (band-?) and asked to generate a related word (e.g., drum). Critically, they were given a target that either matched the semantic meaning of their guess (guitar) or mismatched it (rubber). In Experiment 2, participants studied Spanish words where the English translation either matched their expectations (pariente-relative) or mismatched it (carpeta-folder). Both experiments show that errors benefit memory to the extent that they overlap semantically with targets. Results are discussed in terms of the retrieval benefits of activating related concepts during learning.

Aerobic With Resistance Training or Aerobic Training Alone Poststroke: A Secondary Analysis From a Randomized Clinical Trial

BACKGROUND

Stroke is associated with muscle atrophy and weakness, mobility deficits, and cardiorespiratory deconditioning. Aerobic and resistance training (AT and RT) each have the potential to improve deficits, yet there is limited evidence on the utility of combined training.

OBJECTIVE

To examine the effects of AT+RT versus AT on physiological outcomes in chronic stroke with motor impairments.

METHODS

Participants (n = 73) were randomized to 6 months of AT (5 d/wk) or AT+RT (3 and 2 d/wk, respectively). Outcomes included those related to body composition by dual-energy X-ray absorptiometry, mobility (6-minute walk distance [6MWD], sit-to-stand, and stair climb performance), cardiorespiratory fitness (VO_2peak, oxygen uptake at the ventilatory threshold [VO_2VT]), and muscular strength.

RESULTS

A total of 68 (93.2%) participants (age, mean ± SD = 63.7 ± 11.9) completed the study. AT+RT and AT yielded similar and significant improvements in 6MWD (39.9 ± 55.6 vs 36.5 ± 63.7 m, P = .8), VO_2peak (16.4% ± 43.8% vs 15.2% ± 24.7%, P = .9), sit-to-stand time (-2.3 ± 5.1 vs 1.02 ± 9.5 s, P = .05), and stair climb performance (8.2% ± 19.6% vs 7.5% ± 23%, P = .97), respectively. AT+RT produced greater improvements than AT alone for total body lean mass (1.23 ± 2.3 vs 0.27 ± 1.6 kg, P = .039), predominantly trunk ( P = .02) and affected-side limbs ( P = .04), VO_2VT (19.1% ± 26.8% vs 10.5% ± 28.9%, P = .046), and upper- and lower-limb muscular strength ( P < .03, all except affected-side leg).

CONCLUSION

Despite being prescribed 40% less AT, AT+RT resulted in similar and significant improvement in mobility and VO_2peak, superior improvements in VO_2VT and muscular strength, and an almost 5-fold greater increase in lean mass compared with AT. RT is the most neglected exercise component following stroke but should be prescribed with AT for metabolic, cardiorespiratory, and strength recovery.

Repetition lag training eliminates age-related recollection deficits (and gains are maintained after three months) but does not transfer: Implications for the fractionation of recollection

The objectives of this study were to replicate age-related decrements in recollection and source memory, and to determine if repetition lag training improves recollection and whether these effects maintain and transfer to other tasks. Sixteen young adults and 46 healthy older adults participated, the latter of whom comprised hi-old (n = 16) and lo-old (n = 30) based on neuropsychological memory tests. All participants completed memory tests and questionnaires at baseline, and then half of the lo-old underwent nine days of repetition lag training while the other half engaged in a 9-day active control program. The memory tests and questionnaires were repeated immediately after the training or control program, and again three months later. The baseline data replicated well-established age-related decrements in recollection. Repetition lag training improved objective measures of recollection, eliminated the age-related recollection decrement, and these improvements maintained over three months. However, training did not transfer to any other objective test of memory thought to rely on recollection, or to any subjective memory measure. The results demonstrate for the first time that repetition lag training improves objective measures of recollection, eliminates recollection differences between younger and older adults, and that these gains maintain over a 3-month period posttraining. The lack of transfer to other tasks, however, indicates that training one type of recollection (for the studied modality in this case) does not affect other types of recollection (e.g., of an item's recency). We suggest that recollection can be fractionated into many distinct types. (PsycINFO Database Record

50 Years of Cognitive Aging Theory

OBJECTIVES

The objectives of this Introduction to the Journal of Gerontology: Psychological Sciences special issue on "50 Years of Cognitive Aging Theory" are to provide a brief overview of cognitive aging research prior to 1965 and to highlight significant developments in cognitive aging theory over the last 50 years.

METHOD

Historical and recent theories of cognitive aging were reviewed, with a particular focus on those not directly covered by the articles included in this special issue.

RESULTS

Prior to 1965, cognitive aging research was predominantly descriptive, identifying what aspects of intellectual functioning are affected in older compared with younger adults. Since the mid-1960s, there has been an increasing interest in how and why specific components of cognitive domains are differentially affected in aging and a growing focus on cognitive aging neuroscience.

DISCUSSION

Significant advances have taken place in our theoretical understanding of how and why certain components of cognitive functioning are or are not affected by aging. We also know much more now than we did 50 years ago about the underlying neural mechanisms of these changes. The next 50 years undoubtedly will bring new theories, as well as new tools (e.g., neuroimaging advances, neuromodulation, and technology), that will further our understanding of cognitive aging.

Twelve-Day Reinforcement-Based Memory Retention in African Cichlids (Labidochromis caeruleus)

The formation of long-term memories for food sources is essential for the survival of most animals. Long-term memory formation in mammalian species has been demonstrated through a variety of conditioning tasks, however, the nature of long-term memory in fish is less known. In the current study, we explored whether African cichlids (Labidochromis caeruleus) could form memories for food-reinforced stimuli that last for 12 days. During the training sessions, fish were reinforced for approaching an upward drifting line grating. After a rest period of 12 days, fish demonstrated a significant preference for the upward drifting grating. To determine whether this preference could also be reversed, fish were then reinforced for approaching a downward drifting line grating after a 20-day rest period. When tested 12 days later, there were no significant differences in preference for either stimulus; however, following a second training period for the downward stimulus, there was a significant preference for the downward drifting grating. This suggests that cichlids are able to form reversible discrimination-based memories for food-reinforced stimuli that remain consolidated for at least 12 days.

The benefits of errorless learning for people with amnestic mild cognitive impairment

The aim of this study was to explore whether errorless learning leads to better outcomes than errorful learning in people with amnestic mild cognitive impairment (MCI), and to examine whether accuracy in error recognition relates to any observed benefit of errorless over errorful learning. Nineteen participants with a clinical diagnosis of amnestic MCI were recruited. A word-list learning task was used and learning was assessed by free recall, cued recall and recognition tasks. Errorless learning was significantly superior to errorful learning for both free recall and cued recall. The benefits of errorless learning were less marked in participants with better error recognition ability. Errorless learning methods are likely to prove more effective than errorful methods for those people with MCI whose ability to monitor and detect their own errors is impaired.