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.

Depressive symptoms and inductive reasoning performance: findings from the ACTIVE reasoning training intervention

Within the context of the Advanced Cognitive Training for Independent and Vital Elderly study (ACTIVE; Ball et al., 2002; Jobe et al., 2001; Willis et al., 2006), we examined the longitudinal association of baseline depressive symptoms on inductive reasoning performance over a 10-year period between the reasoning training and control conditions (N = 1,375). At baseline, 322 participants (23%) reported elevated depressive symptoms, defined by a score ≥9 on the 12-item version of the Center for Epidemiological Studies Depression Scale (CES-D; Mirowsky & Ross, 2003; Radloff, 1977). Differences in baseline depressive status were not associated with immediate posttraining gains or with subsequent annual change in reasoning performance, suggesting that the presence of elevated baseline depressive symptoms does not impact the ability to benefit from reasoning training.

Reasoning training in the ACTIVE study: how much is needed and who benefits?

OBJECTIVE

To characterize change through 5-year follow-up, associated with training, booster, adherence, and other characteristics.

METHODS

Sample included all individuals randomly assigned to reasoning training (N = 699). Piecewise latent growth modeling was used to examine trajectory of performance on outcome measures.

RESULTS

Training resulted in improved reasoning performance through Year 5. A significant third annual booster effect was one-half the size of the training effect. Training adherence resulted in greater training effects. Higher education, Mini-Mental State Exam (MMSE), better health, and younger age related to higher baseline performance. Higher MMSE was related to larger training effects, larger linear slopes, and smaller booster effects. Significant functional outcomes included a training effect for complex reaction time (CRT), and first annual booster effects for the CRT and observed tasks of daily living.

DISCUSSION

Initial training gain was comparable with magnitude of age-related cognitive decline over 5 years with no training. Neither age nor gender predicted training or booster effects, indicating the generality of training effects across age (65-90 years).

Ten-year effects of the advanced cognitive training for independent and vital elderly cognitive training trial on cognition and everyday functioning in older adults

OBJECTIVES

To determine the effects of cognitive training on cognitive abilities and everyday function over 10 years.

DESIGN

Ten-year follow-up of a randomized, controlled single-blind trial (Advanced Cognitive Training for Independent and Vital Elderly (ACTIVE)) with three intervention groups and a no-contact control group.

SETTING

Six U.S. cities.

PARTICIPANTS

A volunteer sample of 2,832 persons (mean baseline age 73.6; 26% African American) living independently.

INTERVENTION

Ten training sessions for memory, reasoning, or speed of processing; four sessions of booster training 11 and 35 months after initial training.

MEASUREMENTS

Objectively measured cognitive abilities and self-reported and performance-based measures of everyday function.

RESULTS

Participants in each intervention group reported less difficulty with instrumental activities of daily living (IADLs) (memory: effect size = 0.48, 99% confidence interval (CI) = 0.12-0.84; reasoning: effect size = 0.38, 99% CI = 0.02-0.74; speed of processing: effect size = 0.36, 99% CI = 0.01-0.72). At a mean age of 82, approximately 60% of trained participants, versus 50% of controls (P < .05), were at or above their baseline level of self-reported IADL function at 10 years. The reasoning and speed-of-processing interventions maintained their effects on their targeted cognitive abilities at 10 years (reasoning: effect size = 0.23, 99% CI = 0.09-0.38; speed of processing: effect size = 0.66, 99% CI = 0.43-0.88). Memory training effects were no longer maintained for memory performance. Booster training produced additional and durable improvement for the reasoning intervention for reasoning performance (effect size = 0.21, 99% CI = 0.01-0.41) and the speed-of-processing intervention for speed-of-processing performance (effect size = 0.62, 99% CI = 0.31-0.93).

CONCLUSION

Each Advanced Cognitive Training for Independent and Vital Elderly cognitive intervention resulted in less decline in self-reported IADL compared with the control group. Reasoning and speed, but not memory, training resulted in improved targeted cognitive abilities for 10 years.

The ACTIVE cognitive training interventions and trajectories of performance among older adults

OBJECTIVES

Salthouse illustrated that among Advanced Cognitive Training for Independent and Vital Elderly (ACTIVE) participants, cognitive change accelerated following training. Our goal was to determine if this finding persists net of practice, training, and loss of training gains effects.

METHODS

We evaluated change over 5 years following cognitive training among older adults (N = 1,659, age 65 to 94).

RESULTS

Reasoning training, but not memory or speed, attenuated aging-related change. Memory gains were maintained, but about half of reasoning and speed gains were lost. Performance differences at the end of the follow-up were equivalent to about 6, 4, and 8 years of aging for memory, reasoning, and speed training, respectively.

DISCUSSION

Training can appear to accelerate age-related change, because change over time is coupled with loss of training gains. Our analysis is limited by follow-up that is short for precisely characterizing aging-related change.

The association between higher order abilities, processing speed, and age are variably mediated by white matter integrity during typical aging

Although aging is associated with changes in brain structure and cognition it remains unclear which specific structural changes mediate individual cognitive changes. Several studies have reported that white matter (WM) integrity, as assessed by diffusion tensor imaging (DTI), mediates, in part, age-related differences in processing speed (PS). There is less evidence for WM integrity mediating age-related differences in higher order abilities (e.g., memory and executive functions). In 165 typically aging adults (age range 54-89) we show that WM integrity in select cerebral regions is associated with higher cognitive abilities and accounts variance not accounted for by PS or age. Specifically, voxel-wise analyses using tract-based spatial statistics (TBSS) revealed that WM integrity was associated with reasoning, cognitive flexibility and PS, but not memory or word fluency, after accounting for age and gender. While cerebral fractional anisotropy (FA) was only associated with PS; mean (MD), axial (AD) and radial (RD) diffusivity were associated with reasoning and flexibility. Reasoning was selectively associated with left prefrontal AD, while cognitive flexibility was associated with MD, AD and RD throughout the cerebrum. Average WM metrics within select WM regions of interest accounted for 18% and 29% of the variance in reasoning and flexibility, respectively, similar to the amount of variance accounted for by age. WM metrics mediated ~50% of the age-related variance in reasoning and flexibility and different proportions, 11% for reasoning and 44% for flexibility, of the variance accounted for by PS. In sum, (i) WM integrity is significantly, but variably, related to specific higher cognitive abilities and can account for a similar proportion of variance as age, and (ii) while FA is selectively associated with PS; while MD, AD and RD are associated with reasoning, flexibility and PS. This illustrates both the anatomical and cognitive selectivity of structure-cognition relationships in the aging brain.

Alcohol effects on cognitive change in middle-aged and older adults

OBJECTIVES

This study examines cognitive outcomes for alcohol drinking status over time, across cognitive ability and age groups.

METHODS

Data (1998-2005) from n = 571 Seattle Longitudinal Study participants aged 45+years (middle-aged: 45-64, young-old: 65-75, old-old: 75+) were analyzed to examine the alcohol drinking status effect (e.g., abstinent, moderate (less than seven drinks/week), at-risk (more than eight drinks/week)) on cognitive ability (e.g., memory, reasoning, spatial, verbal number, speed abilities).

RESULTS

Findings indicated that alcohol drinking status was associated with change in verbal ability, spatial ability, and perceptual speed. Decline in verbal ability was seen among alcohol abstainers and moderate alcohol consumers, but at-risk drinkers displayed relative stability. At-risk old-old adults and middle-aged adults (regardless of drinking status), displayed relative stability in spatial ability. Decline in spatial ability was however present among young-old adults across drinking status, and among abstaining and moderate drinking old-old adults. At-risk drinkers showed the most positive spatial ability trajectory. A gender effect in perceptual speed was detected, with women who abstained from drinking displaying the most decline in perceptual speed compared with women that regularly consumed alcohol, and men displaying decline in perceptual speed across drinking status.

DISCUSSION

In this study, consuming alcohol is indicative of cognitive stability. This conclusion should be considered cautiously, due to study bias created from survivor effects, analyzing two time points, health/medication change status, and overrepresentation of higher socioeconomic status and white populations in this study. Future research needs to design studies that can make concrete recommendations about the relationship between drinking status and cognition.

Cohort differences in cognitive aging and terminal decline in the Seattle Longitudinal Study

Life span researchers have long been interested in how and why fundamental aspects of human ontogeny differ between cohorts of people who have lived through different historical epochs. When examined at the same age, later born cohorts are often cognitively and physically fitter than earlier born cohorts. Less is known, however, about cohort differences in the rate of cognitive aging and if, at the very end of life, pervasive mortality-related processes overshadow and minimize cohort differences. We used data on 5 primary mental abilities from the Seattle Longitudinal Study (Schaie, 2005) to compare both age-related and mortality-related changes between earlier born cohorts (1886-1913) and later born cohorts (1914-1948). Our models covary for several individual and cohort differences in central indicators of life expectancy, education, health, and gender. Age-related growth models corroborate and extend earlier findings by documenting level differences at age 70 of up to 0.50 SD and less steep rates of cognitive aging on all abilities between 50 and 80 years of age favoring the later born cohort. In contrast, mortality-related models provide limited support for positive cohort differences. The later born cohort showed steeper mortality-related declines. We discuss possible reasons why often reported positive secular trends in age-related processes may not generalize to the vulnerable segment of the population that is close to death and suggest routes for further inquiry.

Spousal interrelations in happiness in the Seattle Longitudinal Study: considerable similarities in levels and change over time

Development does not take place in isolation and is often interrelated with close others such as marital partners. To examine interrelations in spousal happiness across midlife and old age, we used 35-year longitudinal data from both members of 178 married couples in the Seattle Longitudinal Study. Latent growth curve models revealed sizeable spousal similarities not only in levels of happiness but also in how happiness changed over time. These spousal interrelations were considerably larger in size than those found among random pairs of women and men from the same sample. Results are in line with life-span theories emphasizing an interactive minds perspective by showing that adult happiness waxes and wanes in close association with the respective spouse. Our findings also complement previous individual-level work on age-related changes in well-being by pointing to the importance of using the couple as the unit of analysis.

Cognitive predictors of everyday functioning in older adults: results from the ACTIVE Cognitive Intervention Trial

OBJECTIVE

The present study sought to predict changes in everyday functioning using cognitive tests.

METHODS

Data from the Advanced Cognitive Training for Independent and Vital Elderly trial were used to examine the extent to which competence in different cognitive domains--memory, inductive reasoning, processing speed, and global mental status--predicts prospectively measured everyday functioning among older adults. Coefficients of determination for baseline levels and trajectories of everyday functioning were estimated using parallel process latent growth models.

RESULTS

Each cognitive domain independently predicts a significant proportion of the variance in baseline and trajectory change of everyday functioning, with inductive reasoning explaining the most variance (R2 = .175) in baseline functioning and memory explaining the most variance (R2 = .057) in changes in everyday functioning.

DISCUSSION

Inductive reasoning is an important determinant of current everyday functioning in community-dwelling older adults, suggesting that successful performance in daily tasks is critically dependent on executive cognitive function. On the other hand, baseline memory function is more important in determining change over time in everyday functioning, suggesting that some participants with low baseline memory function may reflect a subgroup with incipient progressive neurologic disease.

Midlife memory improvement predicts preservation of hippocampal volume in old age

This study examines whether midlife change in episodic memory predicts hippocampal volume in old age. From the Seattle Longitudinal Study we retrospectively identified 84 healthy, cognitively normal individuals, age 52 to 87, whose episodic memory had reliably declined (n = 33), improved (n = 28) or remained stable (n = 23) over a 14-year period in midlife (age 43-63). Midlife memory improvement was associated with 13% larger hippocampal volume (p < 0.01) in old age (age 66-87), compared with old age individuals whose midlife episodic memory had either declined or remained stable during midlife. Midlife memory change did not predict total hippocampal volume for those currently in late middle age (age 52-65). The pattern of findings was not modified by gender, apolipoprotein ε4 status, education or current memory performance. Change in midlife memory scores over 14 years, but not any single assessment, predicted hippocampal volumes in old age, emphasizing the importance of longitudinal data in examining brain-cognition relationships. These findings suggest that improvement in memory in midlife is associated with sparing of hippocampal volume in later life.

Word list memory predicts everyday function and problem-solving in the elderly: results from the ACTIVE cognitive intervention trial

Data from the Advanced Cognitive Training for Independent and Vital Elderly (ACTIVE) trial (N = 2,802) were analyzed to examine whether word list learning predicts future everyday functioning. Using stepwise random effects modeling, measures from the modified administrations of the Hopkins Verbal Learning Test (HVLT) and the Auditory Verbal Learning Test (AVLT) were independently predictive of everyday IADL functioning, problem-solving, and psychomotor speed. Associations between memory scores and everyday functioning outcomes remained significant across follow-up intervals spanning 5 years. HVLT total recall score was consistently the strongest predictor of each functional outcome. Results suggest that verbal memory measures are uniquely associated with both current and future functioning and that specific verbal memory tests like the HVLT and AVLT have important clinical utility in predicting future functional ability among older adults.

Does cognitive training improve internal locus of control among older adults?

OBJECTIVES

We evaluated the effect of cognitive training among 1,534 participants in the Advanced Cognitive Training for Independent and Vital Elderly (ACTIVE) randomized controlled trial (RCT) on 5-year improvements in 3 cognitive-specific measures of locus of control-internal, chance, and powerful others.

METHODS

ACTIVE was a multisite RCT (age > or = 65), with 4 groups (memory, reasoning, speed of processing, and no-contact control). Complete 5-year follow-up data were available for 1,534 (55%) of the 2,802 participants. A propensity score model was used to adjust for potential attrition bias. Clinically important improvements (and decrements) in the cognitive-specific locus of control scale scores were defined as greater than or equal to 0.5 SD (medium) and greater than or equal to 1.0 SD (large). Multinomial logistic regression was used to simultaneously contrast those who improved and those who declined with those whose locus of control scale score was unchanged.

RESULTS

Statistically significant effects reflecting medium-sized (> or = 0.5 SD) improvements in internal locus of control between baseline and the 5-year follow-up were found for the reasoning and speed of processing intervention groups who were 76% (p < .01) and 68% (p < .05) more likely, respectively, to improve than the no-contact control group. No improvement effects were found on the chance or powerful others locus of control measures or for the memory intervention group.

CONCLUSION

Cognitive training that targets reasoning and speed of processing can improve the cognitive-specific sense of personal control over one's life in older adults.

Factors associated with cognition in adults: the Seattle Longitudinal Study

A better understanding of factors that affect cognition could lead to improved health and greater independence for older adults. We examined the association of four modifiable factors (leisure-time physical activity, leisure-time cognitive activity, self-directed work, and hypertension) with changes in two aspects of fluid intelligence (verbal memory and inductive reasoning). Data for 626 adults collected over 14 years (three time points) were analyzed by multi-level modeling. A component of self-directed work, higher work control, was associated with better verbal memory (p < .05) and inductive reasoning (p < .01). There were no significant interactions among these factors. The findings suggest that a strong sense of control at work may be protective for fluid intelligence in adults.

Health behavior risk factors across age as predictors of cardiovascular disease diagnosis

OBJECTIVE

The current study examines the prevalence of health risk behaviors and their cumulative effects on cardiovascular disease (CVD) among a sample of adults. Age cohort is also examined to determine the role of age in predicting CVD and risky health behaviors.

METHOD

Medical records of a sample of adults from the Seattle Longitudinal Study categorized into one of four age-group cohorts were examined. Data regarding participants' health risk behaviors were examined individually and cumulatively for predicting later CVD diagnosis.

RESULTS

The prevalence of CVD increases with age, obesity, and risky medical checkups. Female risky sleepers are more likely to receive a CVD diagnosis than men who report risky sleep patterns (p < .05).

DISCUSSION

A high risk of CVD appears to exist for adults across the life span, and several risky health behaviors also seem to place individuals more at risk for being diagnosed with CVD.

Factor structure and invariance of the Quality of Life in Alzheimer's Disease (QoL-AD) Scale

The factor structure and factorial invariance of the Quality of Life in Alzheimer's Disease (QoL-AD) Scale was investigated in a sample of 653 nondemented, community-dwelling older adults, ages 57 to 95 years (M = 71.62, SD = 8.86), from the Seattle Longitudinal Study. The total sample was split into two random halves to explore and confirm the structure of the QoL-AD. Confirmatory factor analyses indicated better fit for a three-factor solution than one- or two-factor solutions. Weak factorial invariance was found for the three-factor solution (Physical, Social, and Psychological Well-being) across age group and gender. These findings may help to establish a baseline quality of life before the onset of any noticeable AD symptoms.

Cognitive training and plasticity: theoretical perspective and methodological consequences

PURPOSE

To provide an overview of cognitive plasticity concepts and findings from a lifespan developmental perspective.

METHODS

After an evaluation of the general concept of cognitive plasticity, the most important approaches to study behavioral and brain plasticity are reviewed. This includes intervention studies, experimental approaches, cognitive trainings, the study of facilitating factors for strategy learning and strategy use, practice, and person-environment interactions. Transfer and durability of training-induced plasticity is discussed.

RESULTS

The review indicates that methodological and conceptual advances are needed to improve the match between levels of behavioral and brain plasticity targeted in current developmental research and study designs.

CONCLUSIONS

The results suggest that the emphasis of plasticity studies on treatment effectiveness needs to be complemented by a strong commitment to the grounding of the intervention in a conceptual framework.

The interface of medical devices and pharmaceuticals: Part II

The technical challenges of developing combination products were addressed in Part I of this two part article. Part II reviews the preclinical tests and shelf-life testing that are required using drug eluting stents and drug eluting beads as examples. Regulatory considerations and ways to simplify development are also examined.