Stress on health-related quality of life in older adults: the protective nature of mindfulness.

OBJECTIVES: The current study examined whether the link between stress and health-related quality of life was buffered by protective factors, namely mindfulness, in a sample of middle-aged and older adults. METHODS: In this cross-sectional study, 134 healthy, community-dwelling adults (ages 50-85 years) were recruited from Dallas, TX. The participants were screened for depressive symptoms and severity (using the Patient Health Questionnaire [PHQ-9]). All participants completed measures of self-reported health status (i.e. SF36v2: mental and physical health composites), life stress (using the Elders Life Stress Inventory [ELSI]), and trait mindfulness (i.e. Mindful Attention Awareness Scale). RESULTS: Hierarchical regressions (covarying for age, gender, and education) showed that life stress was inversely related to physical and mental health. Mindfulness was positively related to mental health. The negative effect of life stress on mental health was weakened for those individuals with higher levels of trait mindfulness. CONCLUSIONS: The results suggest that mindfulness is a powerful, adaptive strategy that may protect middle-aged and older adults from the well-known harmful effects of stress on mental health.

Neurocognitive speed and inconsistency in Parkinson's disease with and without incipient dementia: an 18-month prospective cohort study.

We examined two-wave longitudinal changes in two indicators of neurocognitive speed (i.e., mean rate, intraindividual variability) using one simple and three complex reaction time tasks. Participants included idiopathic Parkinson's disease (PD) patients, with and without incipient dementia, and normal controls. At baseline, there were 45 patients (26 men, 19 women) with idiopathic PD who ranged from 65 to 84 years (M = 71.3; SD = 4.5) and 47 matched controls (27 men, 20 women) who ranged from 65 to 84 years (M = 71.4; SD = 4.9). The 18-month longitudinal sample comprised of 74 returning participants (43 controls; 31 PD patients) who had no cognitive impairment or dementia at both waves. Ten of the 31 PD patients returning for Time 3 had dementia or cognitive impairment. These constituted the PD with incipient dementia (PDID) group. Repeated measures analyses of variance showed that the PD and PDID groups were slower over time on the reaction time tasks, whereas the controls improved their performance over time on all tasks. Inconsistency distinguished the two clinical groups (i.e., the PDID group but not the PD group became more inconsistent over time). Changes in neurocognitive speed and inconsistency may be valid clinical markers of PDID.

Influence of COMT gene polymorphism on fMRI-assessed sustained and transient activity during a working memory task.

The catechol O-methyltransferase (COMT) gene--encoding an enzyme that is essential for the degradation of dopamine (DA) in prefrontal cortex (PFC)--contains a single nucleotide polymorphism (val/met) important for cognition. According to the tonic-phasic hypothesis, individuals carrying the low-enzyme-activity allele (met) are characterized by enhanced tonic DA activity in PFC, promoting sustained cognitive representations in working memory. Val carriers have reduced tonic but enhanced phasic dopaminergic activity in subcortical regions, enhancing cognitive flexibility. We tested the tonic-phasic DA hypothesis by dissociating sustained and transient brain activity during performance on a 2-back working memory test using mixed blocked/event-related functional magnetic resonance imaging. Participants were men recruited from a random sample of the population (the Betula study) and consisted of 11 met/met and 11 val/val carriers aged 50 to 65 years, matched on age, education, and cognitive performance. There were no differences in 2-back performance between genotype groups. Met carriers displayed a greater transient medial temporal lobe response in the updating phase of working memory, whereas val carriers showed a greater sustained PFC activation in the maintenance phase. These results support the tonic-phasic theory of DA function in elucidating the specific phenotypic influence of the COMT val(158)met polymorphism on different components of working memory.

Early, untreated Parkinson's disease patients show reaction time variability.

While Parkinson's disease (PD) is associated with motor slowing, less attention has been paid to variability in performance on motor and cognitive tasks. To examine reaction time latencies and intraindividual variability in untreated patients with PD compared to healthy controls. Twenty-nine (19 men/10 women) patients with untreated PD and 16 controls (8 men/8 women) were examined using measures of simple reaction time (SRT) and choice reaction time (CRT) in addition to cognitive measures of executive function (Trail Making Test; adaptive digit ordering). Latencies and intraindividual variability were compared between groups. Partial correlation coefficients, adjusting for age, sex and education were used to examine the relationship between RT measures and motor or cognitive measures. Patients and controls did not differ with respect to age or sex distribution. Education and cognitive status differed between groups, but no subject was demented or clinically depressed. After adjusting for age, sex and education, significant group differences were found in latencies (2-choice RT and 8-choice RT) and intraindividual variability scores (all CRT conditions). Latencies did not differ significantly after adjusting for finger tapping rate. In the PD group neither the motor nor the executive measures correlated significantly with any of the reaction time measures. We conclude that CRT intraindividual variability and latencies are increased in untreated PD.

Intraindividual variability in neurocognitive speed: a comparison of Parkinson's disease and normal older adults.

We examined whether intraindividual variability of neurocognitive speed, or inconsistency, is greater in stages of Parkinson's disease (PD) as compared to a matched group of normal older adults. Intraindividual variability was assessed using four reaction time (RT) (simple and complex) tasks. We examined three sets of correlates: executive functioning (Stroop (interference index), Trail Making Test (Part B), and Digit Ordering Test), finger tapping speed, and gait speed. The participants were matched on age, sex, and education, and did not differ in global cognitive functioning. There were 50 patients with a clinical diagnosis of idiopathic PD (29 men and 21 women) who ranged from 65 to 84 years (M=71.5, S.D.=4.7) and 48 matched healthy older adults who ranged from 65 to 84 years (M=71.5, S.D.=4.9). Multiple analyses of variance showed that the PD patients were slower on all three complex RT tasks, and more inconsistent than healthy older adults on the most complex (eight-choice) RT task. Individuals with advanced disease had slower neurocognitive speed and more inconsistency than patients with earlier stage PD. Poorer executive functioning was associated with slower neurocognitive performance in healthy older adults, mild PD patients, and especially severe PD patients. Greater inconsistency in speed was related to poorer executive functioning in late stage PD (for the most complex task) and in healthy older adults (for the simplest task), indicating that motor and cognitive domains have functional coupling (i.e., as one becomes compromised so does the other). Intraindividual variability was not correlated with tapping speed and gait speed in any group. Executive functioning and neurocognitive speed may be valid and distinct clinical markers of disease progression in PD.

Mild memory deficits differentially affect 6-year changes in compensatory strategy use.

The authors examined memory compensation techniques used by older adults from 2 memory status groups, not impaired control (NIC) and mild memory deficit (MMD), both at baseline and across a 6-year (3-wave) interval. The groups were derived from a parent sample of 55- to 85-year-old adults from the Victoria Longitudinal Study (NIC baseline, n = 276; memory > parent sample mean; MMD baseline, n = 79; memory > 1 standard deviation below parent sample mean). Multilevel modeling was used to test 3 research questions concerning differences in initial use of, and 6-year changes and variability in, memory compensation. Initial group differences were observed for both a memory compensation technique and a general compensation indicator. Significant differences in 6-year change patterns were observed for 2 memory compensation techniques (recruitment of human memory assistance, investment of extra effort in memory tasks). Interactions of group status and wave showed that older adults with MMD declined in their use of memory compensation strategies, whereas initially NIC older adults increased their use of compensatory techniques over the 6 years.

Cholesterol and triglycerides moderate the effect of apolipoprotein E on memory functioning in older adults.

We used data from the Betula Study to examine associations between total cholesterol, triglycerides, and apolipoprotein E on 10-year changes in cognitive performance. Tests assessing episodic memory (recall and recognition), semantic memory (knowledge and fluency), and visuospatial ability (block design) were administered to 524 nondemented adults (initial age of 55-80 years); multilevel modeling was applied to the data. Higher triglyceride levels were associated with a decline in verbal knowledge. Lipid levels moderated the influence of apolipoprotein E on episodic memory, such that among epsilon4 allele carriers, decline in recognition was noted for individuals with higher cholesterol levels. Cholesterol and triglyceride levels are pharmacologically modifiable risk factors that account for variation in normal cognitive aging.

Structure of four executive functioning tests in healthy older adults.

The authors examined the factor structure of 4 indicators of executive functioning derived from 2 new (i.e., Hayling and Brixton) and 2 traditional (i.e., Stroop and Color Trails) tests. Data were from a cross-sectional sample of 55- to 85-year-old healthy adults (N=427) from the Victoria Longitudinal Study. Confirmatory factor analysis (LISREL 8.52) tested both a 2-factor model of Inhibition (Hayling, Stroop) and Shifting (Brixton, Color Trails) and a single-factor model. The 2-factor model did not fit the data because the covariance matrix of the factors was not positive definite. The single-factor model fit the data well, chi(2)(2, N=427)=0.32, p=.85, root-mean-square error of approximation (RMSEA)=.00, comparative fit index (CFI)=1.00, goodness-of-fit index (GFI)=1.00. Moreover, the single-factor structure of executive functioning was invariant (configural and metric) across gender, and invariant (configural with limited metric) across age. Structural relations showed that poorer executive functioning performance was related to older age and lower fluid intelligence, chi(2)(11, N=418)=23.04, p=.02, RMSEA=.05, CFI=.97, GFI=.98.

Sex differences in cognition are stable over a 10-year period in adulthood and old age.

Sex differences in declarative memory and visuospatial ability are robust in cross-sectional studies. The present longitudinal study examined whether sex differences in cognition were present over a 10-year period, and whether age modified the magnitude of sex differences. Tests assessing episodic and semantic memory, and visuospatial ability were administered to 625 nondemented adults (initially aged 35-80 years), participating in the population-based Betula study at two follow-up occasions. There was stability of sex differences across five age groups and over a 10-year period. Women performed at a higher level than men on episodic recall, face and verbal recognition, and semantic fluency, whereas men performed better than women on a task-assessing, visuospatial ability. Sex differences in cognitive functions are stable over a 10-year period and from 35 to 90 years of age.

Cognitive performance differentiates selected aspects of psychosocial maturity in adolescence.

This study examined relations between adolescents' cognitive performance and psychosocial maturity. Forty-eight adolescents in Grades 9 and 12 were measured on intelligence (composite, crystallized, fluid), executive functioning (backward digit span, Color Trails 2 (CT2), Stroop, everyday problem solving), and psychosocial maturity (subjective age, problem behavior, psychological maturity). Significant relations between aspects of cognitive performance and psychosocial maturity emerged. Problem behavior was related to lower crystallized intelligence, whereas psychological maturity was related to higher crystallized intelligence and better performance on the CT2. Psychosocially mature adolescents had significantly higher composite IQ scores than did pseudomature adolescents. Mature adolescents also showed advantages in crystallized and fluid intelligence, and in performance on the CT2, compared to their less mature counterparts (the combined group of immature and pseudomature adolescents). The results suggest that cognitive abilities are related to psychosocial maturity.

Confirmatory factor structure and measurement invariance of the Memory Compensation Questionnaire.

Recent research with the Memory Compensation Questionnaire (MCQ) has examined changes, functions, and correlates of compensatory strategy use in older adults. The twofold aim of this study was to test (a) the hypothesized structure of the MCQ and (b) structural equivalence across age, gender, and time. The 7-scale MCQ was designed to measure 5 compensatory mechanisms and 2 general aspects of compensatory awareness. The authors assembled a 3-wave (6-year) sample (N = 521; age = 55-85 years) from the Victoria Longitudinal Study. The results of structural equation modeling supported (a) the a priori structure of the MCQ and (b) the inference of measurement invariance across the 3 dimensions. Accordingly, the MCQ is available for measuring self-reported efforts to compensate for everyday memory losses.

Use of memory compensation strategies is related to psychosocial and health indicators.

Research has shown that psychosocial and health characteristics may affect older adults' cognitive performance, self-referent beliefs, and general adaptive resilience. Are such characteristics related specifically to older adults' reported efforts to compensate for memory losses? The Memory Compensation Questionnaire (MCQ) measures 5 mechanisms of everyday memory compensation as well as 2 general aspects of compensatory motivation and awareness. Correlates were derived from indicators of specific health conditions, subjective health ratings, personality, well-being, and memory self-efficacy (MSE). All measures were administered to a cross-sectional sample of 528 healthy older adults between 55 and 94 years of age from the Victoria Longitudinal Study. Specific health composites (i.e., infirmities, respiratory illness), several personality dimensions (e.g., agreeableness, neuroticism), negative affect, and low MSE were associated with more frequent use of everyday memory compensation strategies. Linking healthy older adults' cognitive resilience with individual characteristics is an important contribution to emerging conceptions of adaptation and success in late life.

Memory compensation in older adults: the role of health, emotion regulation, and trait mindfulness.

OBJECTIVES: The current study examined associations between everyday memory compensation and 3 person-level resource domains (i.e., health, emotion regulation, and trait mindfulness) in older adults. METHOD: In this cross-sectional study, 89 healthy, community-dwelling older adults (ages 51-85 years) completed the multidimensional Memory Compensation Questionnaire, along with measures of self-reported health status, emotion regulation strategies, and trait mindfulness. RESULTS: Hierarchical regressions (covarying for age, gender, and education) showed that poorer mental health (especially for older adults) and physical health functioning were related to using compensatory strategies (e.g., reliance on others and investment of time and effort) more frequently. Cognitive reappraisers reported using more internal mnemonic strategies. Conversely, having a more mindful predisposition was associated with less frequent use of compensatory strategies, especially for middle-aged adults. DISCUSSION: The results suggest that health-related quality of life, adaptive strategies to regulate emotions, and trait mindfulness are additional contexts that determine the degree of engagement in everyday memory compensation and ultimately to successful aging.

Lifestyle engagement affects cognitive status differences and trajectories on executive functions in older adults.

The authors first examined the concurrent moderating role of lifestyle engagement on the relation between cognitive status (cognitively elite, cognitively normal [CN], and cognitively impaired [CI]) and executive functioning (EF) in older adults. Second, the authors examined whether baseline participation in lifestyle activities predicted differential 4.5-year stabilities and transitions in cognitive status. Participants (initial N = 501; 53-90 years) were from the Victoria Longitudinal Study. EF was represented by a 1-factor structure. Lifestyle activities were measured in multiple domains of engagement (e.g., cognitive, physical, and social). Two-wave status stability groups included sustained normal aging, transitional early impairment, and chronic impairment. Hierarchical regressions showed that baseline participation in social activities moderated cognitive status differences in EF. CI adults with high (but not low) social engagement performed equivalently to CN adults on EF. Longitudinally, logistic regressions showed that engagement in physical activities was a significant predictor of stability of cognitive status. CI adults who were more engaged in physical activities were more likely to improve in their cognitive status over time than their more sedentary peers. Participation in cognitive activities was a significant predictor of maintenance in a higher cognitive status group. Given that lifestyle engagement plays a detectable role in healthy, normal, and impaired neuropsychological aging, further research in activity-related associations and interventions is recommended.

Cognitively elite, cognitively normal, and cognitively impaired aging: neurocognitive status and stability moderate memory performance.

OBJECTIVE: Although recent theories of brain and cognitive aging distinguish between normal, exceptional, and impaired groups, further empirical evidence is required. We adapted and applied standard procedures for classifying groups of cognitively impaired (CI) and cognitively normal (CN) older adults to a third classification: cognitively healthy, exceptional, or elite (CE) aging. We then examined concurrent and two-wave longitudinal performance on composite variables of episodic, semantic, and working memory. METHOD: We began with a two-wave source sample from the Victoria Longitudinal Study (VLS; source n = 570; baseline age = 53-90 years). The goals were to: (a) apply standard and objective classification procedures to discriminate three cognitive status groups, (b) conduct baseline comparisons of memory performance, (c) develop two-wave status stability and change subgroups, and (d) compare of stability subgroup differences in memory performance and change. RESULTS: As expected, the CE group performed best on all three memory composites. Similarly, expected status stability effects were observed: (a) stable CE and CN groups performed memory tasks better than their unstable counterparts, and (b) the stable (and chronic) CI group performed worse than its unstable (variable) counterpart. These stability group differences were maintained over two waves. CONCLUSION: New data validate the expectations that (a) objective clinical classification procedures for cognitive impairment can be adapted for detecting cognitively advantaged older adults, and (b) performance in three memory systems is predictably related to the tripartite classification.

Hypertension moderates the effect of APOE on 21-year cognitive trajectories.

We examined whether hypertension moderated the effects of apolipoprotein ε4 (APOE ε4) on individual differences in level and change in cognitive functions over a 21-year period using data from the Seattle Longitudinal Study (SLS). A total of 563 nondemented adults ages 32 to 74 years in 1984 (M = 51.06, SD = 12.03) were included in the study. Cognitive performance was assessed spanning 7 domains-verbal comprehension, numeric facility, episodic memory, spatial orientation, inductive reasoning, perceptual speed, and cognitive flexibility-over 4 occasions of measurement at 7-year intervals. Multilevel modeling was used to test the cross-sectional and longitudinal effects of hypertension, APOE, and their interaction, after adjusting for age, gender, and education. APOE and hypertension had additive and interactive effects on select cognitive functions. APOE ε4 carriers had a performance advantage at baseline on reasoning ability, relative to non-ε4 carriers. The additive effect of hypertension on level of cognitive flexibility (i.e., lower performance for hypertensives) was qualified by a significant APOE × Hypertension interaction on the slope. Hypertension moderated the effects of APOE ε4 on the rate of change for cognitive flexibility, such that the presence of the APOE ε4 allele and hypertension was associated with steeper cognitive decline over a 21-year period. A double dose of genetic vascular risk factors accounted for variation in the slope in normal cognitive aging, suggesting that clinical interventions aimed at lowering vascular risk may benefit cognitive health.

Characterizing executive functioning in older special populations: from cognitively elite to cognitively impaired.

The authors examined the structure and invariance of executive functions (EF) across (a) a continuum of cognitive status in 3 groups of older adults (cognitively elite [CE], cognitively normal [CN], and cognitively impaired [CI]) and (b) a 3-year longitudinal interval. Using latent variable analyses (LISREL 8.80), the authors tested 3-factor models ("Inhibition": Hayling [Burgess & Shallice, 1997], Stroop [Regard, 1981]; "Shifting": Brixton [Burgess & Shallice, 1997], Color Trails [D'Elia et al., 1996]; and "Updating": Reading and Computational Span [Salthouse & Babcock, 1991]) and 1-factor models within each group. Participants (initial N = 570; 53-90 years) were from the Victoria Longitudinal Study (Sample 3, Waves 1 and 2). Cross-sectionally, the authors observed a 3-factor EF structure especially for the CE group and 1-factor solutions for all 3 groups. Longitudinally, temporal invariance was supported for the 3-factor model (CE and CN groups) and the 1-factor model (CI and CN groups). Subgroups with higher cognitive status and greater 3-year stability performed better on EF factors than corresponding groups with lower cognitive status and less stability. Studies of EF structure, performance, dedifferentiation, and dysfunction will benefit from considering initial cognitive status and longitudinal stability.

Short-term longitudinal trends in cognitive performance in older adults with type 2 diabetes.

Type 2 diabetes is associated with cognitive deficits, although inconsistently across neuropsychological domains. We examined 3-year longitudinal data from the Victoria Longitudinal Study, comparing diabetes (n = 28) and control (n = 272) older adults on a comprehensive neuropsychological battery. Assessing potential change and stability, we found that (a) baseline diabetes group deficits in semantic speed and speed-intensive executive function were preserved, (b) new average deficits for reaction time and nonspeeded executive function appeared, and (c) no differential short-term change was observed. It is clinically and theoretically important to examine sequential change in multiple domains over time.

Exploring cognitive effects of self reported mild stroke in older adults: selective but robust effects on story memory.

Relatively little systematic information is available regarding patterns of cognitive effects of mild stroke in older adults. We explored this problem with a series of two independent samples from the Victoria Longitudinal Study data archives. In Study 1, self-reported mild stroke and neurologically intact matched controls were (a) confirmed as similar on a set of neurocognitive speed, basic cognition, and awareness indicators, and (b) compared for differences on a set of episodic, semantic, and working memory tasks. The mild stroke group was selectively worse on the language intensive story memory task. This effect was partially attributable to a deficit in remembering the most thematic information. Study 2 closely replicated these procedures and results. In addition, Study 2 follow-up analyses, comparing provisional right-hemisphere damaged and left-hemisphere damaged (LHD) participants, revealed that the thematic story memory deficit for mild stroke participants could be due to the selective impairment of LHD participants.

Catechol O-methyltransferase Val158Met polymorphism is associated with cognitive performance in nondemented adults.

The catechol O-methyltransferase (COMT) gene is essential in the metabolic degradation of dopamine in the prefrontal cortex. In the present study, we examined the effect of a Val158Met polymorphism in the COMT gene on individual differences and changes in cognition (executive functions and visuospatial ability) in adulthood and old age. The participants were 292 nondemented men (initially aged 35-85 years) from a random sample of the population (i.e., the Betula study) tested at two occasions with a 5-year interval. Confirmatory factor analyses were used to test the underlying structure of three indicators of executive functions (verbal fluency, working memory, and Tower of Hanoi). Associations between COMT, age, executive functioning, and visuospatial (block design) tasks were examined using repeated-measures analyses of variance. Carriers of the Val allele (with higher enzyme activity) compared with carriers of the Met/Met genotype (with low enzyme activity) performed worse on executive functioning and visuospatial tasks. Individuals with the Val/Val genotype declined in executive functioning over the 5-year period, whereas carriers of the Met allele remained stable in performance. An Age x COMT interaction for visuospatial ability located the effect for middle-aged men only. This COMT polymorphism is a plausible candidate gene for executive functioning and fluid intelligence in nondemented middle-aged and older adults.