Contemporary review 2009: cognitive aging

Deciphering the relationship between objective and subjective aspects of recollection in healthy aging

Although healthy aging has been related to a decline in recollection as indexed by objective measures, the subjective experience of recollection sometimes remains stable. To date, however, these age-related differences have only been examined using aggregated data across trials. In the current study, we investigated the relationship between subjective and objective measures of recollection on a trial-by-trial basis to determine whether the magnitude of this relationship was similar in young and older adults. Young and older participants were presented with pictures that were associated with descriptive labels at encoding. At retrieval, they were cued with the labels and were asked to rate the vividness of their memory for the associated picture and to recall as many details of the picture as possible. On average, older adults assigned higher vividness ratings but recalled fewer episodic details than young adults. Mixed-effects modelling revealed that the relationship between subjective (vividness) and objective (number of recalled details) recollection across trials was stronger in young than in older participants. These findings provide evidence that older adults not only retrieve fewer episodic details but also rely on these details to a lesser extent than young adults for judging the subjective quality of their memories.

A distributional and theoretical analysis of reaction time in the reversal task across adulthood

Reversal learning assesses components of executive function important for understanding cognitive changes with age. Extant reversal learning literature has largely assessed measures of accuracy, but reaction time (RT) has not yet been well characterized, perhaps due to the daunting task of analyzing non-normal RT distributions. The current study contributes to the literature by examining distributional and theoretical aspects of the entire RT distribution in addition to accuracy. Participant sample included young (N = 43) and community-dwelling, healthy, middle-aged (N = 139) adults. Results showed a Normal-3 Mixture distribution best fits the sample as a whole, with the ex-Gaussian distribution passing visual inspection. Age related significantly to various measures of RT (p's < 0.5); older age was associated with higher both efficient and overall RT, perhaps due to a more conservative criterion of decision-making. In a generalized adaptive elastic net regression, RT explained age-related differences in performance while accuracy did not contribute. Specifically, middle-aged adults were slower in efficient RT and had increased intra-individual variability which has been previously linked to poorer frontal lobe processes and age-related cognitive decline. Overall, these findings highlight the importance of examining the entire RT distribution and measuring RT as a fractionated construct to further explain age-related differences in reversal learning, even in middle-aged individuals.

Brain structure and cognitive ability in healthy aging: a review on longitudinal correlated change

Little is still known about the neuroanatomical substrates related to changes in specific cognitive abilities in the course of healthy aging, and the existing evidence is predominantly based on cross-sectional studies. However, to understand the intricate dynamics between developmental changes in brain structure and changes in cognitive ability, longitudinal studies are needed. In the present article, we review the current longitudinal evidence on correlated changes between magnetic resonance imaging-derived measures of brain structure (e.g. gray matter/white matter volume, cortical thickness), and laboratory-based measures of fluid cognitive ability (e.g. intelligence, memory, processing speed) in healthy older adults. To theoretically embed the discussion, we refer to the revised Scaffolding Theory of Aging and Cognition. We found 31 eligible articles, with sample sizes ranging from n = 25 to n = 731 (median n = 104), and participant age ranging from 19 to 103. Several of these studies report positive correlated changes for specific regions and specific cognitive abilities (e.g. between structures of the medial temporal lobe and episodic memory). However, the number of studies presenting converging evidence is small, and the large methodological variability between studies precludes general conclusions. Methodological and theoretical limitations are discussed. Clearly, more empirical evidence is needed to advance the field. Therefore, we provide guidance for future researchers by presenting ideas to stimulate theory and methods for development.

A Particularly Tragic Case of Possible Alzheimer's Disease, that of Marshal Pétain

After World War I and more particularly in June 1940, the prestige of French Marshal Philippe Pétain, considered as the winning general the battle of Verdun, was very high. He became President of Council while the French army was unable to stop the German offensives. But five years later he was sentenced to death for high treason. By rereading his bibliography from a medical perspective, it is possible to find multiple suggestive events and to affirm a posteriori Pétain suffered from a neurodegenerative disorder, whose first signs appeared in the 1930s, suggestive of Alzheimer's disease, which had an impact on French politics. The modern medical knowledge of this disease casts a new light on the behavior of Petain during the last war.

Operators' views of mobile equipment ingress and egress safety

A large proportion of non-fatal slips, trips, and falls (STFs) at surface mining facilities are associated with mobile equipment. Ingress and egress from mobile equipment can pose a fall risk to mobile equipment operators. The objective of this study was to determine mobile equipment operators' views of STF risks from mobile equipment, and to ascertain what factors, tasks, and conditions they perceive as contributing to these risks. A thematic analysis of 23 individual interviews and 2 group interviews was conducted, with 10 overarching themes identified from the transcripts. Mobile equipment operators indicated that being unable to see their feet or the ladder rungs during descent and the presence of contaminants on the ladders caused by normal operation make egress more dangerous than ingress. The flexible rails and high heights of the lower rungs identified over 40 years ago as issues for mobile equipment operators still pose a perceived STF risk. Further, the requirements of routine maintenance tasks such as oil and filter changes, greasing, and cleaning windows pose fall risks due to inadequate access and the need to carry supplies up and down equipment ladders. In addition to the mobile equipment, hazardous ground conditions and insufficient lighting were found to be key issues around the mobile equipment and in parking areas. The findings of this work indicate that mobile equipment operators feel at risk for STFs due to the design and condition of their equipment, and would like to see ladders replaced with safer stairways as the primary ingress/egress system.

Age-Related Atrophy and Compensatory Neural Networks in Reading Comprehension

OBJECTIVES

Despite changes to brain integrity with aging, some functions like basic language processes remain remarkably preserved. One theory for the maintenance of function in light of age-related brain atrophy is the engagement of compensatory brain networks. This study examined age-related changes in the neural networks recruited for simple language comprehension.

METHODS

Sixty-five adults (native English-speaking, right-handed, and cognitively normal) aged 17-85 years underwent a functional magnetic resonance imaging (fMRI) reading paradigm and structural scanning. The fMRI data were analyzed using independent component analysis to derive brain networks associated with reading comprehension.

RESULTS

Two typical frontotemporal language networks were identified, and these networks remained relatively stable across the wide age range. In contrast, three attention-related networks showed increased activation with increasing age. Furthermore, the increased recruitment of a dorsal attention network was negatively correlated to gray matter thickness in temporal regions, whereas an anterior frontoparietal network was positively correlated to gray matter thickness in insular regions.

CONCLUSIONS

We found evidence that older adults can exert increased effort and recruit additional attentional resources to maintain their reading abilities in light of increased cortical atrophy.

Spatial release from informational masking declines with age: Evidence from a detection task in a virtual separation paradigm

Declines in spatial release from informational masking may contribute to the speech-processing difficulties that older adults often experience within complex listening environments. The present study sought to answer two fundamental questions: (1) Does spatial release from informational masking decline with age and, if so, (2) does age predict this decline independently of age-typical hearing loss? Younger (18-34 years) and older (60-80 years) adults with age-typical hearing completed a yes/no target-detection task with low-pass filtered noise-vocoded speech designed to reduce non-spatial segregation cues and control for hearing loss. Participants detected a target voice among two-talker masking babble while a virtual spatial separation paradigm [Freyman, Helfer, McCall, and Clifton, J. Acoust. Soc. Am. 106(6), 3578-3588 (1999)] was used to isolate informational masking release. The younger and older adults both exhibited spatial release from informational masking, but masking release was reduced among the older adults. Furthermore, age predicted this decline controlling for hearing loss, while there was no indication that hearing loss played a role. These findings provide evidence that declines specific to aging limit spatial release from informational masking under challenging listening conditions.

Age-sensitive job design antecedents of innovative work behavior

Purpose

Integrating the lifespan perspectives on job design and creativity/innovation, the purpose of this paper is to examine the moderating role of chronological age in the relationship between cognitive job demands (i.e. job complexity and job innovation requirements) and individual innovative work behavior (IWB).

Design/methodology/approach

Multilevel regression analyses are employed to analyze survey data of 336 employee–supervisor dyads from 61 departments across three organizations.

Findings

Results demonstrate that age was a significant moderator of the cognitive job demands-IWB relationship. Under the condition of high job complexity, younger employees outperformed their older counterparts. Conversely, older employees attained the same level of IWB as younger colleagues when more job innovation requirements were placed upon them.

Practical implications

IWB needs to be stimulated following different paths and by making job design decisions with regards to cognitive job demands that are dependent on employee age.

Originality/value

Empirical evidence has been provided to support the lifespan perspective on job design, with a special focus given to the cognitive job demands–IWB relationship.

Evidence of stable individual differences in implicit learning

There is a fundamental psychological and neuropsychological distinction between explicit and implicit memory, and it has been proposed that whereas there are stable trait individual differences in explicit memory ability, there are not such differences across people for implicit learning. There is, however, little evidence about whether or not there are stable trait differences in implicit learning. Here we performed a test-retest reliability study with healthy young adults in which they performed four implicit learning tasks (artificial grammar learning, probabilistic classification, serial response, and implicit category learning) twice, about a week apart. We found medium (by Cohen's guidelines) test-retest reliability for three of the tasks: probabilistic classification, serial response, and implicit category learning, suggesting that differences in implicit learning ability are more stable than originally thought. In addition, implicit learning on all tasks was unrelated to explicit measures: we did not find any correlation between implicit learning measures and independent measures of IQ, working memory, or explicit learning ability. These findings indicate that implicit learning, like explicit learning, varies reliably across individuals.

P300, Gray Matter Volume and Individual Characteristics Correlates in Healthy Elderly

We investigated whether P300-ERP and cognitive test performance differ for age, sex, and education in two groups of healthy elderly, and verified whether any correlations exist between P300 amplitude and latency and gray matter volume using whole brain voxel-by-voxel-based mapping, controlling for age, education, sex and Total Intracranial Volume (TIV). We used 32 channel electroencephalograms (EEG) to record the P300 responses and 3T Magnetic Resonance Imaging (MRI) to determine gray matter volume. We recruited 36 native-Dutch speaking healthy older subjects, equally divided in two sub-groups of 52-64 and 65-76 years old, administered a battery of cognitive tests and recorded their demographics, EEGs and task performance; additionally, 16 adults from the second sub-group underwent an MRI scan. We found significant differences between age groups in their cognitive tests performance, P300 amplitudes for the frontal and parietal electrodes for the most difficult task, and P300 latencies for frontal, central and parietal electrodes for all three tasks difficulty levels. Interesting, sex and education affected cognitive and P300 results. Higher education was related to higher accuracy, and P300 amplitudes and shorter latencies. Moreover, females exhibited higher P300 amplitudes and shorter latencies, and better cognitive tasks performance compared to males. Additionally, for the 16 adults underwent to MRI scan, we found positive correlations between P300 characteristics in frontal, central and parietal areas and gray matter volume, controlling for demographic variables and TIV, but also showing that age, sex, and education correlate with gray matter volume. These findings provide support that age, sex, and education affect an individual's cognitive, neurophysiological and structural characteristics, and therefore motivate the need to further investigate these in relation to P300 responses and gray matter volume in healthy elderly.

The Altered Reconfiguration Pattern of Brain Modular Architecture Regulates Cognitive Function in Cerebral Small Vessel Disease

Background: Cerebral small vessel disease (SVD) is a common cause of cognitive dysfunction. However, little is known whether the altered reconfiguration pattern of brain modular architecture regulates cognitive dysfunction in SVD.

Methods: We recruited 25 cases of SVD without cognitive impairment (SVD-NCI) and 24 cases of SVD with mild cognitive impairment (SVD-MCI). According to the Framingham Stroke Risk Profile, healthy controls (HC) were divided into 17 subjects (HC-low risk) and 19 subjects (HC-high risk). All individuals underwent resting-state functional magnetic resonance imaging and cognitive assessments. Graph-theoretical analysis was used to explore alterations in the modular organization of functional brain networks. Multiple regression and mediation analyses were performed to investigate the relationship between MRI markers, network metrics and cognitive performance.

Results: We identified four modules corresponding to the default mode network (DMN), executive control network (ECN), sensorimotor network and visual network. With increasing vascular risk factors, the inter- and intranetwork compensation of the ECN and a relatively reserved DMN itself were observed in individuals at high risk for SVD. With declining cognitive ability, SVD-MCI showed a disrupted ECN intranetwork and increased DMN connection. Furthermore, the intermodule connectivity of the right inferior frontal gyrus of the ECN mediated the relationship between periventricular white matter hyperintensities and visuospatial processing in SVD-MCI.

Conclusions: The reconfiguration pattern of the modular architecture within/between the DMN and ECN advances our understanding of the neural underpinning in response to vascular risk and SVD burden. These observations may provide novel insight into the underlying neural mechanism of SVD-related cognitive impairment and may serve as a potential non-invasive biomarker to predict and monitor disease progression.

Do Alzheimer's Disease Patients Benefit From Prior-Knowledge in Associative Recognition Memory?

OBJECTIVES

Although the influence of prior knowledge on associative memory in healthy aging has received great attention, it has never been studied in Alzheimer's disease (AD). This study aimed at assessing whether AD patients could benefit from prior knowledge in associative memory and whether such benefit would be related to the integrity of their semantic memory.

METHODS

Twenty-one AD patients and 21 healthy older adults took part in an associative memory task using semantically related and unrelated word pairs and were also submitted to an evaluation of their semantic memory.

RESULTS

While participants of both groups benefited from semantic relatedness in associative discrimination, related pairs recognition was significantly predicted by semantic memory integrity in healthy older adults only.

CONCLUSIONS

We suggest that patients benefitted from semantic knowledge to improve their performance in the associative memory task, but that such performance is not related to semantic knowledge integrity evaluation measures because the two tasks differ in the way semantic information is accessed: in an automatic manner for the associative memory task, with automatic processes thought to be relatively preserved in AD, and in a controlled manner for the semantic knowledge evaluation, with controlled processes thought to be impaired in AD. (JINS, 2019, 25, 443-452).

Steeper aging-related declines in cognitive control processes among adults with bipolar disorders

BACKGROUND

Little is known about the specificity of executive functioning (EF) decline in older adults with bipolar disorders (OABD), or the impact of bipolar disorders (BD) on the timing and slope of age-related declines in EF processes implicated in both BD etiology and normative aging-cognitive control (CC). This cross-sectional study investigated age-related CC decline in BD.

METHODS

Participants were 43 adults with BD (M age = 61.5, SD = 15.8; 86% male) and 45 Controls (M age = 65.2, SD = 12.2; 98% male). Two-way ANOVAs examined the effects of median-age-split and diagnostic groups on cognitive processes with established BD deficits-CC processes (mental flexibility and response inhibition), verbal learning, and verbal fluency.

RESULTS

The median-split-age-by-diagnostic-group interaction was significant for mental flexibility; OABD performed significantly worse than younger adults with BD and younger and older Controls. Exploratory multivariate adaptive regression spline characterized non-linear nature of aging-slope changes in mental flexibility for each diagnostic group, yielding an inflection point at older age and steeper subsequent decline in OABD versus Controls.

LIMITATIONS

This study is limited by a small sample (particularly for select neuropsychological measures) of mostly Caucasian men and BD diagnoses based on clinical interview and medical records review.

CONCLUSIONS

Compared to healthy older adults, OABD showed steeper age-related decline in mental flexibility-select EF processes that depend on the integrity of the CC system. Preliminary evidence links CC integrity to daily functioning in OABD; accelerated aging decline in CC may pose a mechanism for high risk of functional impairment and dementia in OABD.

Identifying brain changes related to cognitive aging using VBM and visual rating scales

Aging is often associated with changes in brain structures as well as in cognitive functions. Structural changes can be visualized with Magnetic Resonance Imaging (MRI) using voxel-based grey matter morphometry (VBM) and visual rating scales to assess atrophy level. Several MRI studies have shown that possible neural correlates of cognitive changes can be seen in normal aging. It is still not fully understood how cognitive function as measured by tests and demographic factors are related to brain changes in the MRI. We recruited 55 healthy elderly subjects aged 50–79 years. A battery of cognitive tests was administered to all subjects prior to MRI scanning. Our aim was to assess correlations between age, sex, education, cognitive test performance, and the said two MRI-based measures. Our results show significant differences in VBM grey matter volume for education level (≤ 12 vs. > 12 years), with a smaller amount of grey matter volume in subjects with lower educational levels, and for age in interaction with education, indicating larger grey matter volume for young, higher educated adults. Also, grey matter volume was found to be correlated with working memory function (Digit Span Backward). Furthermore, significant positive correlations were found between visual ratings and both age and education, showing larger atrophy levels with increasing age and decreasing level of education. These findings provide supportive evidence that MRI-VBM detects structural differences for education level, and correlates with educational level and age, and working memory task performance.

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VBM grey matter volume differences were significant for the interaction of age and education level.

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Grey matter volume correlated with education level and working memory function (Digit Span Backward).

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Significant correlations were found between visual rating scales and both age and education.

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VBM is able to detect structural differences for age and education, and correlates with education and working memory.

Schizophrenia, cognition, and aging: cognitive deficits and the relationship between test performance and aging

Most measures of cognitive function decline with age during adulthood. Research indicates that people with schizophrenia experience considerable cognitive deficits. These deficits appear to become more troublesome with increasing age, but this has been debated. The aim of this research was to better understand the age related cognitive deficits of Icelandic subjects with schizophrenia in comparison to healthy individuals. Cognition of individuals 18 to 64 years of age was evaluated with 10 neuropsychological tests. People with schizophrenia performed significantly worse on all tests, as expected, indicating widespread cognitive deficits compared to healthy individuals, independent of age. Furthermore, the results suggest that people with schizophrenia follow a similar age-related trajectory of cognitive decline as healthy individuals. Overall, we conclude that the cognitive difficulties often experienced by older people with schizophrenia are better explained by lower cognitive function at the time of diagnosis than by faster cognitive decline with increasing age.

Textual cohesion in oral narrative and procedural discourse: the effects of ageing and cognitive skills

BACKGROUND

Knowledge of the discourse performance of non-brain-damaged individuals is critical not only for its differentiation from disordered expression but also for more accurate models of ageing and communication. The effect of ageing and cognitive skills on the cohesive adequacy of discourse has, until now, presented a confusing and ambiguous picture.

AIMS

To examine comprehensively the effects of both age and cognitive skills on the discourse cohesion of 32 non-brain-damaged males divided into four age groups.

METHODS & PROCEDURES

A large body of narrative and procedural samples (394 samples) was elicited from the participants. Their cognitive skills were determined using three tests, whilst their discourse cohesion was analyzed and correlated with the cognitive test results.

OUTCOMES & RESULTS

This extensive investigation of ageing effects on discourse cohesion and their relationship to cognitive behaviour did not provide neat generalizable results. It showed that ageing significantly increases the number of cohesive errors and reduces the quantity of referential ties in picture-sequence narratives. The changes with age were limited to two aspects of cohesion and not linear across age groups. The participants' cognitive skills declined with age. Correlations between some cognitive tests and certain cohesive changes suggest co-occurring deficits rather than a causal explanation of cohesive decline with age.

CONCLUSIONS & IMPLICATIONS

With ageing there are increased cohesive errors and decreased referential ties, co-occurring with declining cognitive skills. This study yields important guidance for future research, suggesting that picture-sequence narrative is the most effective tool for clinical evaluation of discourse, but also that findings from one discourse sample may be misleading.

Higher Levels of Protein Palmitoylation in the Frontal Cortex across Aging Were Associated with Reference Memory and Executive Function Declines

Cognitive decline with aging is often due to altered levels of protein expression. The NMDA receptor (NMDAR) and the complex of proteins surrounding the receptor are susceptible to age-related changes in expression. In the frontal cortex of aged mice, there is a significant loss of expression of the GluN2B subunit of the NMDAR, an increase in Fyn expression, and no change in PSD-95. Studies have also found that, in the frontal cortex, phosphorylation of GluN2B subunits and palmitoylation of GluN2 subunits and NMDAR complex proteins are affected by age. In this study, we examined some of the factors that may lead to the differences in the palmitoylation levels of NMDAR complex proteins in the frontal cortex of aged animals. The Morris water maze was used to test spatial learning in 3- and 24-month-old mice. The acyl-biotinyl exchange method was used to precipitate palmitoylated proteins from the frontal cortices and hippocampi of the mice. Additionally, brain lysates from old and young mice were probed for the expression of fatty acid transporter proteins. An age-related increase of palmitoylated GluN2A, GluN2B, Fyn, PSD-95, and APT1 (acyl protein thioesterase 1) in the frontal cortex was associated with poorer reference memory and/or executive functions. These data suggest that there may be a perturbation in the palmitoylation cycle in the frontal cortex of aged mice that contributes to age-related cognitive declines.

Age-related differences in conversational discourse abilities A comparative study

Conversational discourse (CD) is among the most complex tasks in everyday life and relies on multiple cognitive domains (communicative and executive abilities). Alterations in discourse comprehension and production are often present in pathological aging. However, there is still a need to identify changes in healthy aging.

OBJECTIVE

This study aimed to compare young and older adults for the frequency of impaired communicative behaviors on a CD task. Performance was scored according to the Complementary Procedure of Conversational Discourse Analysis (CPCDA), developed based on the CD task from the Montreal Communication Evaluation Battery.

METHODS

A total of 95 participants (54 young-adults and 41 older adults) were evaluated. The frequency of communicative behaviors was compared between groups using MANCOVA and Chi-square tests.

RESULTS

Young adults showed fewer impairments in expression, pragmatics, cohesion, coherence, comprehension and emotional prosody. Older adults showed higher levels of verbal initiative and had fewer word finding difficulties. Communicative behaviors associated with planning and self-monitoring (e.g. repetition of information and syllabic false starts) appear to be common in the speech of healthy individuals in general.

CONCLUSION

Studies which evaluate both discursive and cognitive skills are required to identify age-related changes. This would allow for the development of screening tools for CD assessment and preventive programs.

Anodal tDCS improves attentional control in older adults

Transcranial direct current stimulation (tDCS) facilitates cognitive enhancement by directly increasing neuroplasticity, and has shown promising results as an external intervention to attenuate age-related cognitive decline. However, stimulation protocols have failed to account for age-associated changes in brain structure and the present literature omits investigation of attentional control, despite the occurrence of substantial inhibitory processing deficits with age. To provide new insight into the benefits of tDCS, the objective of this study was to develop an age-optimised stimulation protocol in which key parameters (amplitude, duration, and electrode configuration) were selected in accordance with knowledge of stimulation effects, specific to the ageing brain. Participants (mean age 66.5 years) completed three sessions of double-blind, anodal or sham stimulation, in conjunction with a novel task switching paradigm, which was designed to reflect the complexities of simultaneously monitoring and updating stimulus representations. The results show that those who had anodal tDCS exhibited an acute, post-stimulation increase in task switching speed (p < .01, d = 1.36). Although the sham group was subject to the same task exposure, only the anodal stimulation group experienced a performance gain, thus emphasising the efficacy of active brain stimulation. For the first time, this study demonstrates the utility of stimulation protocols tailored specifically for use with older adults, targeted towards the modulation of attentional control. This finding has critical implications for cognitive health and encourages the use of age-optimised tDCS as a viable method for enhancing executive function in later life.

The Relationship between Age, Neural Differentiation, and Memory Performance

Healthy aging is associated with decreased neural selectivity (dedifferentiation) in category-selective cortical regions. This finding has prompted the suggestion that dedifferentiation contributes to age-related cognitive decline. Consistent with this possibility, dedifferentiation has been reported to negatively correlate with fluid intelligence in older adults. Here, we examined whether dedifferentiation is associated with performance in another cognitive domain-episodic memory-that is also highly vulnerable to aging. Given the proposed role of dedifferentiation in age-related cognitive decline, we predicted there would be a stronger link between dedifferentiation and episodic memory performance in older than in younger adults. Young (18-30 years) and older (64-75 years) male and female humans underwent fMRI scanning while viewing images of objects and scenes before a subsequent recognition memory test. We computed a differentiation index in two regions of interest (ROIs): parahippocampal place area (PPA) and lateral occipital complex (LOC). This index quantified the selectivity of the BOLD response to preferred versus nonpreferred category of an ROI (scenes for PPA, objects for LOC). The differentiation index in the PPA, but not the LOC, was lower in older than in younger adults. Additionally, the PPA differentiation index predicted recognition memory performance for the studied items. This relationship was independent of and not moderated by age. The PPA differentiation index also predicted performance on a latent "fluency" factor derived from a neuropsychological test battery; this relationship was also age invariant. These findings suggest that two independent factors, one associated with age, and the other with cognitive performance, influence neural differentiation.SIGNIFICANCE STATEMENT Aging is associated with neural dedifferentiation-reduced neural selectivity in "category-selective" cortical brain regions-which has been proposed to contribute to cognitive aging. Here, we examined whether neural differentiation is predictive of episodic memory performance, and whether the relationship is moderated by age. A neural differentiation index was estimated for scene-selective (PPA) and object-selective (LOC) cortical regions while participants studied images for a subsequent memory test. Age-related reductions were observed for the PPA, but not for the LOC, differentiation index. Importantly, the PPA differentiation index demonstrated age-invariant correlations with subsequent memory performance and a fluency factor derived from a neuropsychological battery. Together, these findings suggest that neural differentiation is associated with two independent factors: age and cognitive performance.

Reliability of retrospective reports on childhood abuse and its determinants in older adults during a 6-year follow-up

Controversy exists concerning the reliability of retrospective self-reports on childhood abuse since this method might be subject to under- or overreporting. Until now, no studies have been done in older adults, although reasons for under- or overreporting could be even more prominent in this age group. In this first study in older adults, test-retest reliability of retrospective measurements on childhood abuse and the influence of age, cognitive functioning and depression on this test-retest reliability was investigated. A longitudinal cohort study, the Netherlands Study of Depression in Older persons (NESDO), obtained information on childhood abuse at baseline and at a 6-year follow-up interview. Our sample consisted of 277 adults (mean age 68.5 years at baseline) of which 118 (42.6%) reported childhood abuse at baseline. The largest proportion of the answers was consistent (yes-yes or no-no) for every type of childhood abuse, varying from 85.2 to 93.5%. Looking more closely, 'yes' answers were more fluctuating than 'no' answers. Sexual abuse was most reliably reported in two separate interviews. There was no significant effect of age nor cognition on the test-retest reliability. Only test-retest reliability of emotional neglect was significantly associated with depression diagnosis and depression severity at baseline. In conclusion, test-retest reliability of retrospective self-reports on childhood abuse seems moderate to good, but slightly dependent on the type of abuse. The test-retest reliability was influenced neither by age nor cognition, only reporting of emotional neglect was associated with depression state.

Predicting Hepatic Encephalopathy-Related Hospitalizations Using a Composite Assessment of Cognitive Impairment and Frailty in 355 Patients With Cirrhosis

INTRODUCTION

Hepatic encephalopathy (HE) is the most common potentially modifiable reason for admission in patients with cirrhosis. Cognitive and physical components of frailty have pathophysiologic rationale as risk factors for HE. We aimed to assess the utility of a composite score (MoCA-CFS) developed using the Montreal Cognitive Assessment (MoCA) and the Clinical Frailty Scale (CFS) for predicting HE admissions within 6 months.

METHODS

Consecutive adult patients with cirrhosis were followed for 6 months or until death/transplant. Patients with overt HE and dementia were excluded. Primary outcome was the prediction of HE-related admissions at 6 months.

RESULTS

A total of 355 patients were included; mean age 55.9 ± 9.6; 62.5% male; Hepatitis C and alcohol etiology in 64%. Thirty-six percent of patients had cognitive impairment according to the MoCA (≤24) and 14% were frail on the CFS (>4). The MoCA-CFS independently predicted HE hospitalization within 6 months, a MoCA-CFS score of 1 and 2 respectively increasing the odds of hospitalization by 3.3 (95% CI:1.5-7.7) and 5.7 (95% CI:1.9-17.3). HRQoL decreased with increasing MoCA-CFS. Depression and older age were independent predictors of a low MoCA.

CONCLUSIONS

Cognitive and physical frailty are common in patients with cirrhosis. In addition to being an independent predictor of HE admissions within 6 months, the MoCA-CFS composite score predicts impaired HRQoL and all-cause admissions within 6 months. These data support the predictive value of a "multidimensional" frailty tool for the prediction of adverse clinical outcomes and highlight the potential for a multi-faceted approach to therapy targeting cognitive impairment, physical frailty and depression.

The Aging Well through Interaction and Scientific Education (AgeWISE) Program

OBJECTIVE

We conducted a randomized controlled trial of the Aging Well through Interaction and Scientific Education (AgeWISE) program, a 12-week manualized cognitive rehabilitation program designed to provide psychoeducation to older adults about the aging brain, lifestyle factors associated with successful brain aging, and strategies to compensate for age related cognitive decline.

METHODS

Forty-nine cognitively intact participants ≥ 60 years old were randomly assigned to the AgeWISE program (n = 25) or a no-treatment control group (n = 24). Questionnaire data were collected prior to group assignment and post intervention. Two-factor repeated-measures analyses of covariance (ANCOVAs) were used to compare group outcomes.

RESULTS

Upon completion, participants in the AgeWISE program reported increases in memory contentment and their sense of control in improving memory; no significant changes were observed in the control group. Surprisingly, participation in the group was not associated with significant changes in knowledge of memory aging, perception of memory ability, or greater use of strategies.

CONCLUSIONS

The AgeWISE program was successfully implemented and increased participants' memory contentment and their sense of control in improving memory in advancing age.

CLINICAL IMPLICATIONS

This study supports the use of AgeWISE to improve perspectives on healthy cognitive aging.

Age-related changes in the relationship between visual exploration and hippocampal activity

Deciphering the mechanisms underlying age-related memory declines remains an important goal in cognitive neuroscience. Recently, we observed that visual sampling behavior predicted activity within the hippocampus, a region critical for memory. In younger adults, increases in the number of gaze fixations were associated with increases in hippocampal activity (Liu et al., 2017). This finding suggests a close coupling between the oculomotor and memory system. However, the extent to which this coupling is altered with aging has not been investigated. In this study, we gave older adults the same face processing task used in Liu et al. (2017) and compared their visual exploration behavior and neural activation in the hippocampus and the fusiform face area (FFA) to those of younger adults. Compared to younger adults, older adults showed an increase in visual exploration as indexed by the number of gaze fixations. However, the relationship between visual exploration and neural responses in the hippocampus and FFA was weaker than that of younger adults. Older adults also showed weaker responses to novel faces and a smaller repetition suppression effect in the hippocampus and FFA compared to younger adults. All together, this study provides novel evidence that the capacity to bind visually sampled information, in real-time, into coherent representations along the ventral visual stream and the medial temporal lobe declines with aging.

Long-term effects of curcumin in the non-human primate brain

Curcumin has recently been shown to be a potential treatment for slowing or ameloriating cognitive decline during aging in our nonhuman primate model of normal aging. In these same monkeys, we studied for the first time the neurological impacts of long-term curcumin treatments using longitudinal magnetic resonance imaging (MRI). Sixteen rhesus monkeys received curcumin or a vehicle control for 14-18 months. We applied a combination of structural and diffusion MRI to determine whether the curcumin resulted in structural or functional changes in focal regions of the brain. The longitudinal imaging revealed decreased microscale diffusivity (mD) measurements mainly in the hippocampus and basal forebrain structures of curcumin treated animals. Changes in generalized fractional anisotropy (GFA) and grey matter density (GMd) measurements indicated an increased grey matter density in cortical ROIs with improved white matter integrity in limbic, cerebellar, and brain stem regions. These findings suggest that noticeable changes in the neuronal environment could be induced from long-term curcumin treatments. Results may provide a neurological basis on the recent findings demonstrating improved spatial working memory and motor function in nonhuman primates.

Measurement tools for assessment of older age bipolar disorder: A systematic review of the recent global literature

OBJECTIVES

More than 50% of people with bipolar disorder will be age 60 years or older by 2030. There is a need for more data to guide assessment and treatment in older age bipolar disorder (OABD); however, interpretation of findings from small, single-site studies may not be generalizable and there are few large trials. As a step in the direction of coordinated large-scale OABD data collection, it is critical to identify which measurements are currently used and identify potential gaps in domains typically assessed.

METHODS

An international group of OABD experts performed a systematic literature review to identify studies examining OABD in the past 6 years. Relevant articles were assessed to categorize the types of clinical, cognitive, biomarker, and neuroimaging OABD tools routinely used in OABD studies.

RESULTS

A total of 53 papers were identified, with a broad range of assessments. Most studies evaluated demographic and clinical domains, with fewer studies assessing cognition. There are relatively few biomarker and neuroimaging data, and data collection methods were less comprehensively covered.

CONCLUSION

Assessment tools used in the recent OABD literature may help to identify both a minimum and a comprehensive dataset that should be evaluated in OABD. Our review also highlights gaps where key clinical outcomes have not been routinely assessed. Biomarker and neuroimaging assessment could be further developed and standardized. Clinical data could be combined with neuroimaging, genetic, and other biomarkers in large-scale coordinated data collection to further improve our understanding of OABD phenomenology and biology, thereby contributing to research that advances care.

Discrepancies between crystallized and fluid ability are associated with frequency of social and physical engagement in community dwelling older adults

OBJECTIVE

Age differences have been noted in the discrepancies between crystallized and fluid ability (Gc-Gf). Larger Gc-Gf discrepancies have also been shown to be associated with Alzheimer's disease biomarkers and clinical severity. However, little is known regarding the relationship between Gc-Gf discrepancies in normal aging and functional outcomes. The aim of the present study was to examine this.

METHOD

Data from 104 adults (M_age = 71.70 years, SD = 9.016) were included in the present study. Measures from the NIH toolbox were used to form the discrepancy scores. Physical, cognitive, and social activities were identified using the Community Healthy Activities Model Program for Seniors activity questionnaire. Linear regression analyses, controlling for age, education, gender, health, and depressive symptoms, were used to examine the association between social, cognitive, and physical activities on Gc-Gf discrepancies.

RESULTS

Results showed that social and physical activity were significantly associated with greater discrepancies between crystallized and fluid ability, independent of covariates. There was no association between cognitive activity and Gc-Gf discrepancies.

CONCLUSIONS

Larger discrepancies between crystallized and fluid ability are related to frequency of social and physical activity. The findings support previous research that discrepancy scores may serve as a marker of cognitive decline. In more highly educated older individuals, Gc-Gf discrepancies may be a more accurate indicator of actual cognitive status.

The modulating effect of education on semantic interference during healthy aging

Aging has traditionally been related to impairments in name retrieval. These impairments have usually been explained by a phonological transmission deficit hypothesis or by an inhibitory deficit hypothesis. This decline can, however, be modulated by the educational level of the sample. This study analyzed the possible role of these approaches in explaining both object and face naming impairments during aging. Older adults with low and high educational level and young adults with high educational level were asked to repeatedly name objects or famous people using the semantic-blocking paradigm. We compared naming when exemplars were presented in a semantically homogeneous or in a semantically heterogeneous context. Results revealed significantly slower rates of both face and object naming in the homogeneous context (i.e., semantic interference), with a stronger effect for face naming. Interestingly, the group of older adults with a lower educational level showed an increased semantic interference effect during face naming. These findings suggest the joint work of the two mechanisms proposed to explain age-related naming difficulties, i.e., the inhibitory deficit and the transmission deficit hypothesis. Therefore, the stronger vulnerability to semantic interference in the lower educated older adult sample would possibly point to a failure in the inhibitory mechanisms in charge of interference resolution, as proposed by the inhibitory deficit hypothesis. In addition, the fact that this interference effect was mainly restricted to face naming and not to object naming would be consistent with the increased age-related difficulties during proper name retrieval, as suggested by the transmission deficit hypothesis.

Physiological Aging Influence on Brain Hemodynamic Activity during Task-Switching: A fNIRS Study

Task-switching (TS) paradigm is a well-known validated tool useful for exploring the neural substrates of cognitive control, in particular the activity of the lateral and medial prefrontal cortex. This work is aimed at investigating how physiological aging influences hemodynamic response during the execution of a color-shape TS paradigm. A multi-channel near infrared spectroscopy (fNIRS) was used to measure hemodynamic activity in 27 young (30.00 ± 7.90 years) and 11 elderly participants (57.18 ± 9.29 years) healthy volunteers (55% male, age range: (19-69) years) during the execution of a TS paradigm. Two holders were placed symmetrically over the left/right hemispheres to record cortical activity [oxy-(HbO) and deoxy-hemoglobin (HbR) concentration] of the dorso-lateral prefrontal cortex (DLPFC), the dorsal premotor cortex (PMC), and the dorso-medial part of the superior frontal gyrus (sFG). TS paradigm requires participants to repeat the same task over a variable number of trials, and then to switch to a different task during the trial sequence. A two-sample t-test was carried out to detect differences in cortical responses between groups. Multiple linear regression analysis was used to evaluate the impact of age on the prefrontal neural activity. Elderly participants were significantly slower than young participants in both color- (p < 0.01, t = -3.67) and shape-single tasks (p = 0.026, t = -2.54) as well as switching (p = 0.026, t = -2.41) and repetition trials (p = 0.012, t = -2.80). Differences in cortical activation between groups were revealed for HbO mean concentration of switching task in the PMC (p = 0.048, t = 2.94). In the whole group, significant increases of behavioral performance were detected in switching trials, which positively correlated with aging. Multivariate regression analysis revealed that the HbO mean concentration of switching task in the PMC (p = 0.01, β = -0.321) and of shape single-task in the sFG (p = 0.003, β = 0.342) were the best predictors of age effects. Our findings demonstrated that TS might be a reliable instrument to gather a measure of cognitive resources in older people. Moreover, the fNIRS-related brain activity extracted from frontoparietal cortex might become a useful indicator of aging effects.

Age effects on perceptual restoration of degraded interrupted sentences

Adult cochlear-implant (CI) users show small or non-existent perceptual restoration effects when listening to interrupted speech. Perceptual restoration is believed to be a top-down mechanism that enhances speech perception in adverse listening conditions, and appears to be particularly utilized by older normal-hearing participants. Whether older normal-hearing participants can derive any restoration benefits from degraded speech (as would be presented through a CI speech processor) is the focus of this study. Two groups of normal-hearing participants (younger: age ≤30 yrs; older: age ≥60 yrs) were tested for perceptual restoration effects in the context of interrupted sentences. Speech signal degradations were controlled by manipulating parameters of a noise vocoder and were used to analyze effects of spectral resolution and noise burst spectral content on perceptual restoration. Older normal-hearing participants generally showed larger and more consistent perceptual restoration benefits for vocoded speech than did younger normal-hearing participants, even in the lowest spectral resolution conditions. Reduced restoration in CI users thus may be caused by factors like noise reduction strategies or small dynamic ranges rather than an interaction of aging effects and low spectral resolution.

Unlocking Neurocognitive Substrates of Late-Life Affective Symptoms Using the Research Domain Criteria: Worry Is an Essential Dimension

While investigations have sought to identify the distinct and shared contributions of anxiety and depression to neurocognitive processes in late life, less is known regarding the further contribution of worry, a unique and critical dimension of affective dysregulation. Capturing the full range of symptoms, as inspired by the NIH Research Domain Criteria (RDoC), may provide finer-grained information on inter-relationships among worry, anxiety and depression on neurocognitive processing in later life. The objective of this study was to determine if the dimensional trait of worry intensifies known negative associations of dimensional measures of anxiety and depressive symptoms with neurocognitive processes, specifically cognitive control and memory processes. Using a cross-sectional and observational design, this study was conducted within a translational research center located with a Veterans medical center in Northern California. One hundred and nineteen community-residing older adults ages 65-91 years participated, and were characterized with psychiatric and neurocognitive dimensional measures. Affective symptom severity was assessed with the Penn State Worry Questionnaire, the Beck Anxiety Inventory (BAI), and the Beck Depression Inventory-II. Primary neurocognitive outcomes were inhibitory control assessed using a Stroop paradigm and delayed verbal memory assessed with the Rey Auditory Verbal Learning Test. Secondary outcomes included other less frequently examined cognitive control mechanisms (working memory, information processing, and verbal fluency) and memory processes (visual delayed memory). Contrary to prediction, the dimensional trait of worry attenuated negative associations between anxiety and depressive symptoms and inhibitory control on the one hand, and between depressive symptoms and delayed verbal memory processes on the other. In the secondary models, symptom dimensions were not associated with other cognitive control or visual delayed memory processes. Our fine-grained approach, in line with the NIMH RDoC model, suggests the neurocognitive processes associated with dimensional measures of late-life affective symptoms are dissociable. Specifically, dimensional measures of worry operate independently from other anxiety and depression symptoms to reveal differential patterns of neurocognitive processes associated with affective dysregulation.

Chronic curcumin treatment improves spatial working memory but not recognition memory in middle-aged rhesus monkeys

Studies of both humans and non-human primates have demonstrated that aging is typically characterized by a decline in cognition that can occur as early as the fifth decade of life. Age-related changes in working memory are particularly evident and mediated, in part, by the prefrontal cortex, an area known to evidence age-related changes in myelin that is attributed to inflammation. In recent years, several nutraceuticals, including curcumin, by virtue of their anti-inflammatory and antioxidant effects, have received considerable attention as potential treatments for age-related cognitive decline and inflammation. Accordingly, we assessed for the first time in a non-human primate model of normal aging the efficacy of dietary intervention using the natural phenol curcumin to ameliorate the effects of aging on spatial working and recognition memory. Results revealed that monkeys receiving daily administration of curcumin over 14-18 months demonstrated a greater improvement in performance on repeated administration of a task of spatial working memory compared to monkeys that received a control substance.

Development and Evaluation of a Cognitive Training Game for Older People: A Design-based Approach

In the research field of cognitive aging, games have gained attention as training interventions to remediate age-related deficits. Cognitive training games on computer, video and mobile platforms have shown ample and positive support. However, the generalized effects are not agreed upon unanimously, and the game tasks are usually simple and decontextualized due to the limitations of measurements. This study adopted a qualitative approach of design-based research (DBR) to systematically review and pragmatically examine the regime, presentation and feedback design of a cognitive training game for older adults. An overview of the literature of cognitive aging and training games was conducted to form the theoretical conjectures of the design, and an iterative cycle and process were employed to develop a mobile game for older adults who are homebound or receiving care in a nursing home. Stakeholders, i.e., elderly users and institutional administrators, were invited to participate in the design process. Using two cycles of design and evaluation, a working prototype of an iPad-based app that accounted for the needs of elderly adults in terms of form, appearance and working function was developed and tested in the actual contexts of the participants' homes and an assisted living facility. The results showed that the cognitive training game developed in this study was accepted by the participants, and a high degree of satisfaction was noted. Moreover, the elements of the interface, including its size, layout and control flow, were tested and found to be suitable for use. This study contributes to the literature by providing design suggestions for such games, including the designs of the cognitive training structure, interface, interaction, instructions and feedback, based on empirical evidence collected in natural settings. This study further suggests that the effectiveness of cognitive training in mobile games be evaluated through field and physical testing on a larger scale in the future.

Dynamic range of frontoparietal functional modulation is associated with working memory capacity limitations in older adults

Older adults tend to over-activate regions throughout frontoparietal cortices and exhibit a reduced range of functional modulation during WM task performance compared to younger adults. While recent evidence suggests that reduced functional modulation is associated with poorer task performance, it remains unclear whether reduced range of modulation is indicative of general WM capacity-limitations. In the current study, we examined whether the range of functional modulation observed over multiple levels of WM task difficulty (N-Back) predicts in-scanner task performance and out-of-scanner psychometric estimates of WM capacity. Within our sample (60-77years of age), age was negatively associated with frontoparietal modulation range. Individuals with greater modulation range exhibited more accurate N-Back performance. In addition, despite a lack of significant relationships between N-Back and complex span task performance, range of frontoparietal modulation during the N-Back significantly predicted domain-general estimates of WM capacity. Consistent with previous cross-sectional findings, older individuals with less modulation range exhibited greater activation at the lowest level of task difficulty but less activation at the highest levels of task difficulty. Our results are largely consistent with existing theories of neurocognitive aging (e.g. CRUNCH) but focus attention on dynamic range of functional modulation asa novel marker of WM capacity-limitations in older adults.

Is intraindividual reaction time variability an independent cognitive predictor of mortality in old age? Findings from the Sydney Memory and Ageing Study

Intraindividual variability of reaction time (IIV_RT), a proposed cognitive marker of neurobiological disturbance, increases in old age, and has been associated with dementia and mortality. The extent to which IIV_RT is an independent predictor of mortality, however, is unclear. This study investigated the association of IIV_RT and all-cause mortality while accounting for cognitive level, incident dementia and biomedical risk factors in 861 participants aged 70–90 from the Sydney Memory and Ageing Study. Participants completed two computerised reaction time (RT) tasks (76 trials in total) at baseline, and comprehensive medical and neuropsychological assessments every 2 years. Composite RT measures were derived from the two tasks—the mean RT and the IIV_RT measure computed from the intraindividual standard deviation of the RTs (with age and time-on-task effects partialled out). Consensus dementia diagnoses were made by an expert panel of clinicians using clinical criteria, and mortality data were obtained from a state registry. Cox proportional hazards models estimated the association of IIV_RT and mean RT with survival time over 8 years during which 191 (22.2%) participants died. Greater IIV_RT but not mean RT significantly predicted survival time after adjusting for age, sex, global cognition score, cardiovascular risk index and apolipoprotein ɛ4 status. After excluding incident dementia cases, the association of IIV_RT with mortality changed very little. Our findings suggest that greater IIV_RT uniquely predicts shorter time to death and that lower global cognition and prodromal dementia in older individuals do not explain this relationship.

Disentangling cognition and emotion in older adults: the role of cognitive control and mental health in emotional conflict adaptation

OBJECTIVE

Recent research suggests cognition has a bidirectional relationship with emotional processing in older adults, yet the relationship is still poorly understood. We aimed to examine a potential relationship between late-life cognitive function, mental health symptoms, and emotional conflict adaptation. We hypothesized that worse cognitive control abilities would be associated with poorer emotional conflict adaptation. We further hypothesized that a higher severity of mental health symptoms would be associated with poorer emotional conflict adaptation.

METHODS

Participants included 83 cognitively normal community-dwelling older adults who completed a targeted mental health and cognitive battery, and emotion and gender conflict-adaptation tasks.

RESULTS

Consistent with our hypothesis, poorer performance on components of cognitive control, specifically attention and working memory, was associated with poorer emotional conflict adaptation. This association with attention and working memory was not observed in the non-affective-based gender conflict adaptation task. Mental health symptoms did not predict emotional conflict adaptation, nor did performance on other cognitive measures.

CONCLUSION

Our findings suggest that emotion conflict adaptation is disrupted in older individuals who have poorer attention and working memory. Components of cognitive control may therefore be an important potential source of inter-individual differences in late-life emotion regulation and cognitive affective deficits. Copyright © 2016 John Wiley & Sons, Ltd.

Targeting Adult Neurogenesis to Optimize Hippocampal Circuits in Aging

Millions of individuals suffer from age-related cognitive decline, defined by impaired memory precision. Increased understanding of hippocampal circuit mechanisms underlying memory formation suggests a role for computational processes such as pattern separation and pattern completion in memory precision. We describe evidence implicating the dentate gyrus-CA3 circuit in pattern separation and completion, and examine alterations in dentate gyrus-CA3 circuit structure and function with aging. We discuss the role of adult hippocampal neurogenesis in memory precision in adulthood and aging, as well as the circuit mechanisms underlying the integration and encoding functions of adult-born dentate granule cells. We posit that understanding these circuit mechanisms will permit generation of circuit-based endophenotypes that will edify new therapeutic strategies to optimize hippocampal encoding during aging.

Clinically silent Alzheimer's and vascular pathologies influence brain networks supporting executive function in healthy older adults

Aging is associated with declines in executive function. We examined how executive functional brain systems are influenced by clinically silent Alzheimer's disease (AD) pathology and cerebral white-matter hyperintensities (WMHs). Twenty-nine younger adults and 34 cognitively normal older adults completed a working memory paradigm while functional magnetic resonance imaging was performed. Older adults further underwent lumbar cerebrospinal fluid draw for the assessment of AD pathology and FLAIR imaging for the assessment of WMHs. Accurate working memory performance in both age groups was associated with high fronto-visual functional connectivity (fC). However, in older adults, higher expression of fronto-visual fC was linked with lower levels of clinically silent AD pathology. In addition, AD pathology and WMHs were each independently related to increased functional magnetic resonance imaging response in the left dorsolateral prefrontal cortex, a pattern associated with slower task performance. Our results suggest that clinically silent AD pathology is related to lower expression of a fronto-visual fC pattern supporting executive task performance. Further, our findings suggest that AD pathology and WMHs appear to be linked with ineffective increases in frontal response in CN older adults.

Prioritization of Self-Relevant Perspectives in Ageing

This study investigated whether age-related sensitivity to self-relevance may benefit perspective taking, despite generally poorer perspective-taking capacity in older adults. In one perceptual matching task and two visual perspective-taking paradigms, we examined age differences in sensitivity to avatars representing self and other. In the matching task, older (60–83 years) and younger (18–20 years) adults were similarly biased toward the self- versus other-associated avatar. In the perspective-taking tasks, participants viewed these avatars within a virtual room. Task-relevant perspectives were either the same (i.e., congruent) or different (i.e., incongruent). In the 3PP–3PP task, both avatars were present, and participants adopted the perspective of one or the other. As in the matching task, young and old were similarly biased toward the self-associated avatar. However, age differences emerged in the 1PP–3PP task, which presented only one avatar per trial (varying between self and other), and participants responded based on their own first-person perspective or the avatar's. In summary, age modulated the ability to take perspectives primarily when participants’ own first-person perspective was task relevant. Relative to younger adults, older adults prioritized the self (vs. other) avatar more during initial perspective computation and the first-person (vs. third-person) perspective more when selecting between incongruent perspectives.

Gender differences in healthy aging and Alzheimer's Dementia: A 18 F-FDG-PET study of brain and cognitive reserve

Cognitive reserve (CR) and brain reserve (BR) are protective factors against age-associated cognitive decline and neurodegenerative disorders. Very limited evidence exists about gender effects on brain aging and on the effect of CR on brain modulation in healthy aging and Alzheimer's Dementia (AD). We investigated gender differences in brain metabolic activity and resting-state network connectivity, as measured by ¹⁸ F-FDG-PET, in healthy aging and AD, also considering the effects of education and occupation. The clinical and imaging data were retrieved from large datasets of healthy elderly subjects (HE) (225) and AD patients (282). In HE, males showed more extended age-related reduction of brain metabolism than females in frontal medial cortex. We also found differences in brain modulation as metabolic increases induced by education and occupation, namely in posterior associative cortices in HE males and in the anterior limbic-affective and executive networks in HE females. In AD patients, the correlations between education and occupation levels and brain hypometabolism showed gender differences, namely a posterior temporo-parietal association in males and a frontal and limbic association in females, indicating the involvement of different networks. Finally, the metabolic connectivity in both HE and AD aligned with these results, suggesting greater efficiency in the posterior default mode network for males, and in the anterior frontal executive network for females. The basis of these brain gender differences in both aging and AD, obtained exploring cerebral metabolism, metabolic connectivity and the effects of education and occupation, is likely at the intersection between biological and sociodemographic factors. Hum Brain Mapp 38:4212-4227, 2017. © 2017 Wiley Periodicals, Inc.

Processing Distracting Non-face Emotional Images: No Evidence of an Age-Related Positivity Effect

Cognitive aging may be accompanied by increased prioritization of social and emotional goals that enhance positive experiences and emotional states. The socioemotional selectivity theory suggests this may be achieved by giving preference to positive information and avoiding or suppressing negative information. Although there is some evidence of a positivity bias in controlled attention tasks, it remains unclear whether a positivity bias extends to the processing of affective stimuli presented outside focused attention. In two experiments, we investigated age-related differences in the effects of to-be-ignored non-face affective images on target processing. In Experiment 1, 27 older (64-90 years) and 25 young adults (19-29 years) made speeded valence judgments about centrally presented positive or negative target images taken from the International Affective Picture System. To-be-ignored distractor images were presented above and below the target image and were either positive, negative, or neutral in valence. The distractors were considered task relevant because they shared emotional characteristics with the target stimuli. Both older and young adults responded slower to targets when distractor valence was incongruent with target valence relative to when distractors were neutral. Older adults responded faster to positive than to negative targets but did not show increased interference effects from positive distractors. In Experiment 2, affective distractors were task irrelevant as the target was a three-digit array and did not share emotional characteristics with the distractors. Twenty-six older (63-84 years) and 30 young adults (18-30 years) gave speeded responses on a digit disparity task while ignoring the affective distractors positioned in the periphery. Task performance in either age group was not influenced by the task-irrelevant affective images. In keeping with the socioemotional selectivity theory, these findings suggest that older adults preferentially process task-relevant positive non-face images but only when presented within the main focus of attention.

Perceived stress and cognitive function in older adults: which aspect of perceived stress is important?

OBJECTIVE

Few studies examined the association between perceived stress and cognitive function in older adults. This study will examine which aspects of perceived stress especially impact cognitive function.

METHODS

Cross-sectional data of 1099 older adults between 64 and 100 years from the Longitudinal Aging Study Amsterdam were used. Perceived stress and its subscales perceived helplessness and perceived self-efficacy were measured with the Perceived Stress Scale. Cognitive function was assessed regarding memory, processing speed and executive function. Univariate and multivariate linear regression analyses were performed between the stress measures and the domains of cognitive function.

RESULTS

Perceived stress was associated with worse processing speed, direct and delayed recall, semantic fluency and digit span backwards (range β = -0.10; -0.11; p < 0.01). The subscale perceived helplessness showed negative associations only with processing speed (β = -0.06, p < 0.05) and delayed recall (β = -0.06, p < 0.05), which became nonsignificant after the adjustment for depressive symptoms or sense of mastery. The subscale perceived self-efficacy was significantly associated with better cognitive function, also after adjustment for depressive symptoms or sense of mastery (range β = 0.10; 0.18; p < 0.01).

CONCLUSIONS

In older adults, especially perceived self-efficacy showed independent associations with a broad range of cognitive functions. Perceived self-efficacy might be an important factor in reducing stress and the prevention of cognitive decline. Copyright © 2016 John Wiley & Sons, Ltd.

n-3 Fatty acids, Mediterranean diet and cognitive function in normal aging: A systematic review

BACKGROUND

Intake of n-3 fatty acids and adherence to the Mediterranean diet (MedDiet) have been shown to slow the progression of age-related cognitive decline, but the results are mixed. We summarized and evaluated the effect of n-3 fatty acids and MedDiet on cognitive outcomes in a cognitively healthy aged population.

METHODS

Relevant published studies from January 2000 to May 2015 were identified by searching three electronic databases: Pubmed, Web of Science/MEDLINE, and CINHAL. Observational studies and randomized controlled trials (RCTs) were considered.

RESULTS

Twenty-four studies were included for the systematic review. n-3 fatty acids were associated with better global cognition and some specific cognitive domains though some results were conflicting. Adherence to the MedDiet was also significantly associated with better cognitive performance and less cognitive decline. Finally, better cognitive performance was observed in men compared to women and mixed results were also found for the influence of APOE4 genotype on the association between n-3 fatty acids or MedDiet and cognition.

CONCLUSIONS

Studies suggest that n-3 fatty acids in the diet and adherence to the MedDiet are beneficial in slowing age-related cognitive decline. However, more high-quality RCTs would be useful to clarify the effect of n-3 fatty acid supplements on cognition.