Is body mass index in old age related to cognitive abilities? The Lothian Birth Cohort 1936 Study

We tested the hypothesis that the previously reported association between a higher body mass index (BMI) and poorer cognition in later adulthood is an artifact of confounding by previous cognitive ability and socioeconomic status. Participants were 1,079 adults aged about 70 years in the Lothian Birth Cohort 1936 Study, on whom there are IQ data from age 11. Cognitive outcome measures included: IQ at age 70 using the same test that was administered at age 11; composite measures of general cognitive ability (g factor), speed of information processing, and memory; and two tests of verbal ability. People classified as overweight or obese in later adulthood had significantly lower scores on tests of childhood IQ, age 70 IQ, g factor, and verbal ability. There was no significant association with processing speed or memory performance. After adjusting for childhood IQ and social class in general linear models, associations with age 70 IQ and g factor were nonsignificant or attenuated. However, throughout the models, there was a persistent (inverse) relationship between BMI and performance on the National Adult Reading Test (NART) and Wechsler Test of Adult Reading (WTAR), which remained significant after full adjustment for all sociodemographic and health covariates (for the NART, p = .025; for the WTAR, p = .011). The findings suggest that the previously reported BMI-cognition associations in later adulthood could be largely accounted for by prior ability and socioeconomic status, and by the possible influence of these factors on the adoption of health behaviors in adulthood.     

Impact of physical and psychological resources on functional autonomy in old age

Functional autonomy is a core condition of successful ageing. To maximize autonomous functioning is not only a claim of social policy but also primarily an individual need. Part of the challenge of preventing unnecessary dependence in old age is to recognize the diversity among the elderly and the different availability of their physical, psychological and social resources. The aim of this study is to examine the age- and time-related changes in functional autonomy (activities of daily living, ADL, and instrumental activities of daily living, IADL) and the psychophysical resources correlated with these changes in a sample of 441 healthy elderly persons aged 65-95. Furthermore, we are interested in the long-term predictive power of physical resources (objective and subjective health, physical strength) and psychological resources (memory) on functional autonomy. Results show significant age- and time-related deteriorations in functional autonomy and in most psychophysical resources. Structural equation model analyses were performed to test the long-term predictive power of these resources. Results suggest that ADL is better predicted by physical resources than by psychological ones, but for IADL the reverse is the case; here memory variables play a dominant role. Physical and psychological variables are thus specifically related to different components of functional autonomy. This has to be taken into account in the development of preventive and intervention programmes.     

Improving specific autobiographical memory in older adults: impacts on mood,social problem solving,and functional limitations

Older adults have difficulty recalling specific autobiographical events. This over-general memory style is a vulnerability factor for depression. Two groups receiving interventions that have previously been successful at reducing over-general memory in depressed populations were compared to a control group. Participants were healthy older adults aged ≥70 years: memory specificity training (MEST; n = 22), life review (n = 22), and control group (n = 22). There were significant improvements in autobiographical memory specificity in the MEST and life review groups at post-training, relative to the control group, suggesting that over-general memory can be reduced in older adults. Change in social problem solving ability and functional limitations were related to change in autobiographical memory specificity, supporting the suggested role of specific retrieval in generating solutions to social problems and maintaining independence. Qualitative analysis of participants’ feedback revealed that life review may be more appropriate for older adults, possibly because it involves integrating specific memories into a positive narrative.     

Memory flexibility training for autobiographical memory as an intervention for maintaining social and mental well-being in older adults

Autobiographical memory specificity (AMS) reduces with increasing age and is associated with depression, social problem-solving and functional limitations. However, ability to switch between general and specific, as well as between positive and negative retrieval, may be more important for the strategic use of autobiographical information in everyday life. Ability to switch between retrieval modes is likely to rely on aspects of executive function. We propose that age-related deficits in cognitive flexibility impair AMS, but the “positivity effect” protects positively valenced memories from impaired specificity. A training programme to improve the ability to flexibly retrieve different types of memories in depressed adults (MemFlex) was examined in non-depressed older adults to determine effects on AMS, valence and the executive functions underlying cognitive flexibility. Thirty-nine participants aged 70+ (MemFlex, n?=?20; control, n?=?19) took part. AMS and the inhibition aspect of executive function improved in both groups, suggesting these abilities are amenable to change, although not differentially affected by this type of training. Lower baseline inhibition scores correlated with increased negative, but not positive AMS, suggesting that positive AMS is an automatic process in older adults. Changes in AMS correlated with changes in social problem-solving, emphasising the usefulness of AMs in a social environment.     

Well-being affects changes in perceptual speed in advanced old age: longitudinal evidence for a dynamic link

This study examined competing hypotheses about dynamic cross-domain associations between perceptual speed and well-being in advanced old age. We applied the bivariate dual change score model (J. J. McArdle & F. Hamagami, 2001) to 13-year incomplete longitudinal data from the Berlin Aging Study (P. B. Baltes & K. U. Mayer, 1999; N=516, 70-103 years at T1, M=85 years). Reports of well-being were found to influence subsequent decline in perceptual speed (time lags of 2 years). No evidence was found for a directed effect in the other direction. None of the potential covariates examined (initial health constraints, personality, and social participation) accounted for these differential lead-lag associations. Our results suggest that well-being is not only a consequence of but also a source for successful aging. The discussion focuses on conceptual implications and methodological considerations.     

Associative learning over trials activates the hippocampus in healthy elderly but not mild cognitive impairment

The ability to form associations between choice alternatives and their contingent outcomes is an important aspect of learning that may be sensitive to hippocampal dysfunction in memory disorders of aging such as amnestic mild cognitive impairment (MCIa), or early Alzheimer disease. In this preliminary study we examined brain activation using functional magnetic resonance imaging (fMRI) in 12 healthy elderly participants and nine patients with MCIa during an associative learning task. Using a high-field 3.0-Tesla MRI scanner, we examined the dynamic neural response during associative learning over trials. The slope of signal attenuation associated with learning was analyzed for differences between groups within an a priori defined hippocampal region. Results indicated dynamic signal attenuation associated with learning in the healthy elderly sample, but not in MCIa. The absence of an associative learning effect in the MCIa sample reaffirms an important link between the learning difficulties that are commonly encountered in MCIa and the mesial temporal region.     

Correlates of subjective health in older adults: a meta-analysis

Age-associated changes of subjective health and associations of subjective health with physical health, functional health, and mental health were meta-analyzed in older adults (M age > 60 years). An age-associated decline of subjective health, which was stronger in old-old samples than in young-old samples, was found. Subjective health was correlated with the indicators of objective health, but the association with physical health was stronger than with functional health. Correlations of subjective health with physical health and functional health were lower in the old-old than in the young-old samples, whereas associations of subjective health with mental health were stronger in older samples. Furthermore, the size of the association between subjective and objective health varied by the method of assessment of objective health, showing highest associations with symptom checklists and results of medical examinations due to strict protocols.     

Global and domain-specific changes in cognition throughout adulthood

Normative adult age-related decrements are well documented for many diverse forms of effortful cognitive processing. However, it is currently unclear whether each of these decrements reflects a distinct and independent developmental phenomenon, or, in part, a more global phenomenon. A number of studies have recently been published that show moderate to large magnitudes of positive relations among individual differences in rates of changes in different cognitive variables during adulthood. This suggests that a small number of common dimensions or even a single common dimension may underlie substantial proportions of individual differences in aging-related cognitive declines. This possibility was directly examined using data from 1,281 adults 18-95 years of age who were followed longitudinally over up to 7 years on 12 different measures of effortful processing. Multivariate growth curve models were applied to examine the dimensionality of individual differences in longitudinal changes. Results supported a hierarchical structure of aging-related changes, with an average of 39% of individual differences in change in a given variable attributable to global (domain-general) developmental processes, 33% attributable to domain-specific developmental processes (abstract reasoning, spatial visualization, episodic memory, and processing speed), and 28% attributable to test-specific developmental processes. Although it is often assumed that systematic and pervasive sources of cognitive decline only emerge in later adulthood, domain-general influences on change were apparent for younger (18-49 years), middle aged (50-69 years), and older (70-95 years) adults.     

Happiness and health: environmental and genetic contributions to the relationship between subjective well-being, perceived health, and somatic illness

The aim was to identify genetic and environmental influences on the covariances between subjective well-being (SWB), perceived health, and somatic illness. Analyses were based on 6576 Norwegian twins aged 18-31. Heritabilities ranged from .24 to.66. SWB correlated .50 with perceived health, -.25 with musculoskeletal pain, and -.07 with allergy. Common genetic factors accounted for 45%-60% of associations. SWB and perceived health was to a high extent influenced by the same genes (r(g)=.72 and.82 for males and females, respectively). For SWB and musculoskeletal pain, r-sub(g) =-.29 and -.42 for males and females, respectively. Effects were partly sex specific. Environmental factors shared by twins did not affect the covariances. Results support a differentiated view of SWB-health relations, and imply that both genes and environment play important roles in the associations between well-being and health.     

Health-engagement control strategies and 2-year changes in older adults' physical health

This study examined the associations between older adults' daily physical symptoms (e.g., chest pain or difficulty breathing) and 2-year changes in chronic health problems (e.g., cardiovascular disease or cancer) and in functional problems (e.g., difficulty dressing or moving around at home). We reasoned that these associations depend on a person's active control processes aimed at counteracting physical health problems (i.e., health-engagement control strategies, or HECS). In particular, we hypothesized that high levels of HECS buffer the adverse effect of daily physical symptoms on increases in chronic and functional health problems. We found that daily physical symptoms were associated with declines in chronic and functional health among older adults who were not engaged in addressing their health problems, but not among their counterparts who reported high levels of HECS. These findings suggest that active control strategies play an important role in the maintenance of older adults' physical health.     

Health‐adjusted neuropsychological test norms based on 463 older Swedish car drivers

There is a need for improved normative information in particular for older persons. The present study provides neuropsychological test norms on seven cognitive tests used in a sample representing the general older driving population, when uncontrolled and controlled for physical health. A group of 463 healthy Swedish car drivers, aged 65 to 84 years, participated in a medical and neuropsychological examination. The latter included tests of visual scanning, mental shifting, visual spatial function, memory, reaction time, selective attention, and simultaneous capacity. Hierarchical regression analyses demonstrated that, when uncontrolled for health, old age was associated with significant impairment on all seven tests. Education was associated with a significant advantage for all tests except most reaction time subtests. Women outperformed men on selective attention. Controlling for health did not consistently change the associations with education, but generally weakened those with age, indicating rises in normative scores of up to 0.36 SD (residual). In terms of variance explained, impaired health predicted on average 2.5%, age 2.9%, education 2.1% and gender 0.1%. It was concluded (1) that individual regression‐based predictions of expected values have the advantage of allowing control for the impact of health on normative scores in addition to the adjustment for various demographic and performance‐related variables and (2) that health‐adjusted norms have the potential to classify functional status more accurately, to the extent that these norms diverge from norms uncontrolled for physical health.     

Peer victimization, depressive symptoms, and high salivary cortisol predict poorer memory in children

The predictive relations of peer victimization, depressive symptoms, and salivary cortisol on memory in 168 children aged 12 at Time 1 (T1) were examined using a longitudinal design in which data were collected on four occasions over a 2-year period. Results indicated that: (1) peer victimization, depressive symptoms, and evening cortisol were stable over time, (2) peer victimization and elevated symptoms of depression were concurrently linked at each time, (3) T1 peer victimization predicted elevated symptoms of depression at T2 which in turn predicted lower cortisol levels at T3, and (4) controlling for earlier associations, T3 peer victimization, depressive symptoms, and higher morning and evening cortisol levels uniquely predicted memory deficits at T4. The links between elevated cortisol, symptoms of depression, and poor memory are consistent with published research on depressed adults and extend the findings to children exposed to peer victimization. These findings highlight that peer abuse is harmful and may impact children's long-term mental health and memory functioning.     

Memory Functioning Questionnaire: concurrent validity with memory performance and self-reported memory failures

Concurrent validity of factor scores from the Memory Functioning Questionnaire (MFQ; Gilewski, Zelinski, & Schaie, in press) with memory performance was investigated in 2 studies. Study 1 involved 198 adults aged 55-85; Study 2, 89 adults aged 50-87. After effects of depression, education, and health were partialed out, MFQ scores predicted performance on laboratory memory tests in Study 1 and performance on clinical memory tests and diaries of memory failures over 2 weeks in Study 2. Additional variance in predicting performance and failures recorded in diaries is accounted for by MFQ scores after partialing out subjects' responses to a yes-no question about whether they have memory problems. Results suggest that the MFQ has moderate concurrent validity with memory measures and is preferable to responses to a single question about memory self-perception in assessing memory complaints in normal adults.     

Cognitive impairment and the 10-year survival probability of a normal 62-year-old population

The predictive value of cognitive impairment together with demographic and health factors on long-term survival was evaluated. The population sample comprised 389 subjects, all 62 years old. Cognitive performances were measured using verbal, visuomotor and memory tests. Cognitive impairment was determined by comparing performances with norms derived from healthy controls. Ten years after testing, the probability of survival was 89% for the cognitively preserved subjects, 80% for those with mild impairment, and 71% for those with moderate impairment (p = 0.009). Relative risk (RR) for shortened survival was 1.7 (95% CI 0.9-3.2) for the mildly, and 2.6 (95% CI 1.4-4.8) for the moderately impaired. Perceived health problems were, as expected, related to reduced survival (p < 0.001, RR 3.6, 95% CI 2.1-6.0), and there was an association between cognitive impairment and impaired perceived health (p = 0.040). Multivariate analyses with Cox's regression models showed that cognitive impairment, in particular, impaired episodic memory had an association with survival, in addition to the expected effects. Thus, memory impairment may reflect very early signs of underlying disease, and so the findings provide predictive validity for the cognitive methods used.     

Processing efficiency theory in children: working memory as a mediator between trait anxiety and academic performance

Working memory skills are positively associated with academic performance. In contrast, high levels of trait anxiety are linked with educational underachievement. Based on Eysenck and Calvo's (1992) processing efficiency theory (PET), the present study investigated whether associations between anxiety and educational achievement were mediated via poor working memory performance. Fifty children aged 11-12 years completed verbal (backwards digit span; tapping the phonological store/central executive) and spatial (Corsi blocks; tapping the visuospatial sketchpad/central executive) working memory tasks. Trait anxiety was measured using the State-Trait Anxiety Inventory for Children. Academic performance was assessed using school administered tests of reasoning (Cognitive Abilities Test) and attainment (Standard Assessment Tests). The results showed that the association between trait anxiety and academic performance was significantly mediated by verbal working memory for three of the six academic performance measures (math, quantitative and non-verbal reasoning). Spatial working memory did not significantly mediate the relationship between trait anxiety and academic performance. On average verbal working memory accounted for 51% of the association between trait anxiety and academic performance, while spatial working memory only accounted for 9%. The findings indicate that PET is a useful framework to assess the impact of children's anxiety on educational achievement.     

Social Cognition and Externalizing Psychopathology: An Investigation of the Mediating Role of Language

The present study integrates findings from three lines of research on the association of social cognition and externalizing psychopathology, language and externalizing psychopathology, and social cognition and language functioning using Structural Equation Modeling (SEM). To date these associations have been examined in pairs. A sample of 354 clinic-referred children (aged 7 to14 years) recruited from a children’s mental health centre were tested on measures of language, social cognition, working memory, and child psychopathology. We compared a hypothesized model presenting language functioning as a mediator of the association between social cognition and externalizing psychopathology to a model presenting the independent contribution of language and social cognition to externalizing psychopathology. As hypothesized, we found that the mediation model fits the data better than the alternative model. Our findings have implications for developing and modifying intervention techniques for children with dual language and externalizing psychopathology. This research was supported by a grant from Health Canada (NHRDP, 6606-4835) to the third author.     

Dynamic awareness of age-related losses predict concurrent and subsequent changes in daily inductive reasoning performance

To address gaps in previous research, we examined daily within-person associations between awareness of age-related change (AARC) and cognitive performance in older adults. One hundred twelve adults aged 60–90 participated in an online daily diary study for nine consecutive days. On Day 1, they reported demographic information. On Days 2–9, they reported daily AARC, subjective age, and stressors and completed three tasks that gauged memory (word recall), perceptual speed (number comparison), and reasoning (letter series), respectively, once per day. Unconditional multilevel models revealed significant within-person fluctuations in daily cognitive performance and daily AARC. Controlling for age, education, health, and daily stressors, daily awareness of age-related losses was negatively associated with letter series scores of the same day and changes from one day to the next. The effects held over and above AARC gains and subjective age. Dynamic, naturally occurring perceptions of ageing may influence within-person concurrent and subsequent changes in reasoning performance on a daily basis and point to a promising avenue of intervention.     

Nonlinear blood pressure effects on cognition in old age: separating between-person and within-person associations

Midlife hypertension is associated with increased risk of cognitive impairment in later life. The association between blood pressure (BP) in older ages and cognition is less clear. In this study we provide estimates of between-person and within-person associations of BP and cognition in a population-based sample (N = 382) followed from age 70 across 12 occasions over 30 years. Between-person associations refer to how individual differences in BP relates to individual differences in cognition. Within-person associations refer to how individual and time specific changes in BP relate to variation in cognition. Hierarchical linear models were fitted to data from three cognitive measurements (verbal ability, spatial ability, and perceptual speed) while accounting for demographic and health-related covariates. We found consistent nonlinear between-person associations between diastolic BP (DBP) and cognition, such that both low (<75 mmHg) and high (>95 mmHg) pressure were associated with poorer cognition. Within-person decreases in systolic BP (SBP) and DBP were associated with decreases in perceptual speed. Notably, between-person and within-person estimates did not reveal similar associations, suggesting the need to separate the two effects in the analysis of associations between BP and cognition in old age.     

Choline Uptake in the Frontal Cortex Is Proportional to the Absolute Error of a Temporal Memory Translation Constant in Mature and Aged Rats

The relationship between the magnitude of the error in the content of temporal memory and sodium-dependent high-affinity choline uptake (SDHACU) in the frontal cortex and hippocampus was examined in mature (10- to 16-month-old) and aged (24- to 30-month-old) male rats. The peak time of the response rate distribution that relates the probability of a response to signal duration in a 20-s peak-interval timing procedure was used to index the remembered time of reinforcement. Regression analyses indicated that SDHACU in the frontal cortex of both mature and aged rats and in the hippocampus of aged rats is proportional to the absolute error in the content of temporal memory. These biochemical effects of peak-interval training were also compared with biochemical measures taken from control rats that received random-interval training. This comparison indicated that the observed changes in SDHACU were dependent upon the predictability of the programmed time of reinforcement and age-related changes in memory encoding and retrieval.     

Examining dynamic links between perceived control and health: longitudinal evidence for differential effects in midlife and old age

Perceived control and health are often closely linked in adulthood and old age. Little is known, however, about their time-ordered interplay at various phases of adult life. By applying dynamic models to four waves of data over 15.5 years from the Americans' Changing Lives Study, we examined time-ordered relations between perceived control and health in midlife and old age. Results revealed that levels of perceived control predict subsequent changes in health over time in old age (65+ years of age; n = 1,238) but not in midlife (25-64 years of age; n = 2,364). No evidence was found for predictive effects of health for changes in perceived control in either age group. These age-differential findings were corroborated with nested-model comparisons. Predictive effects of perceived control for health were attenuated to the null in models covarying for sociodemographic and psychosocial factors (physical activity, memory, emotional support, and depressive symptoms), suggesting that these variables play an important role in control-health relations. Our discussion focuses on the importance of perceived control for healthy living in old age and the differential implications of perceived control for health in midlife and old age.