OBJECTIVE: Processing Speed (PS) is an important domain in cognitive aging that is characterized by multiple related but nonidentical abilities. Few studies have directly investigated the relationships among PS measures, and none have used genetically informed methods. In this study, we examined the relationship between measures of PS at up to two time points during middle age. METHOD: We examined data from 1,262 middle-aged men when the sample was at a mean age of 56 and a mean age 62 years. Participants completed 6 measures of PS from three different cognitive tests. We used a genetically informative, confirmatory factor analytic approach to evaluate the phenotypic and genetic relationships cross-sectionally at both single time points and across time. RESULTS: A higher-order common PS factor accounted for the covariance among three test-specific factors, and each test-specific factor accounted for the covariance between two observed measures. The general PS factor was explained primarily by genetic influences at both time points (a²age56 = .75, a²age62 = .64), and all test-specific factors were heritable (a² range: .45 to .65). Factor loadings from the test-specific factors to the general PS factor varied from λ = .46 to .82. The model was stable over time, although there were differing rates of phenotypic change among latent factors (.20 SD to .44 SD). Cross-time genetic correlations were near unity for all latent factors. CONCLUSION: These results suggest that PS is highly heritable when considered at a latent variable level, and that there are different rates of change in tests of PS within this sample. (PsycINFO Database Record (c) 2019 APA, all rights reserved).
Last. William S. Kremen(UCSD: University of California, San Diego)H-Index: 70
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Abstract Introduction Longitudinal testing is necessary to accurately measure cognitive change. However, repeated testing is susceptible to practice effects, which may obscure true cognitive decline and delay detection of mild cognitive impairment (MCI). Methods We retested 995 late-middle-aged men in a ∼6-year follow-up of the Vietnam Era Twin Study of Aging. In addition, 170 age-matched replacements were tested for the first time at study wave 2. Group differences were used to calculate practi...
Last. Steven M. Boker(UVA: University of Virginia)H-Index: 33
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The new software package OpenMx 2.0 for structural equation and other statistical modeling is introduced and its features are described. OpenMx is evolving in a modular direction and now allows a mix-and-match computational approach that separates model expectations from fit functions and optimizers. Major backend architectural improvements include a move to swappable open-source optimizers such as the newly written CSOLNP. Entire new methodologies such as item factor analysis and state space mo...
Episodic memory is a complex construct at both the phenotypic and genetic level. Ample evidence supports age-related cognitive stability and change being accounted for by general and domain-specific factors. We hypothesized that general and specific factors would underlie change even within this single cognitive domain. We examined six measures from three episodic memory tests in a narrow age cohort at middle and late middle age. The factor structure was invariant across occasions. At both timep...
Episodic memory change is a central issue in cognitive aging, and understanding that process will require elucidation of its genetic underpinnings. A key limiting factor in genetically informed research on memory has been lack of attention to genetic and phenotypic complexity, as if “memory is memory” and all well-validated assessments are essentially equivalent. Here we applied multivariate twin models to data from late-middle-aged participants in the Vietnam Era Twin Study of Aging to examine ...
Last. Ian J. Deary(Edin.: University of Edinburgh)H-Index: 184
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Aging-related changes occur for multiple domains of cognitive functioning. An accumulating body of research indicates that, rather than representing statistically independent phenomena, aging-related cognitive changes are moderately to strongly correlated across domains. However, previous studies have typically been conducted in age-heterogeneous samples over longitudinal time lags of 6 or more years, and have failed to consider whether results are robust to a comprehensive set of controls. Capi...
The Vietnam Era Twin Study of Aging (VETSA) is a longitudinal behavioral genetic study with a primary focus on cognitive and brain aging in men. It comprises a subset of over 1,200 twins from the Vietnam Era Twin Registry. Like many other studies of aging, the VETSA includes many different phenotypes, but there are some key features that distinguish it from most other behavioral genetic aging studies. First, the initial assessment was conducted when all participants were middle-aged. Second, the...
Last. Ian J. Deary(Edin.: University of Edinburgh)H-Index: 184
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Background/Study Context: Visual working memory (VWM) has been shown to be particularly age sensitive. Determining which measures share variance with this cognitive ability in older adults may help to elucidate the key factors underlying the effects of aging. Methods: Predictors of VWM (measured by a modified Visual Patterns Test) were investigated in a subsample (N = 44, mean age = 73) of older adults from the Lothian Birth Cohort 1936 (LBC1936; Deary et al., 2007, BMC Geriatrics, 7, 28). Child...
Abstract A review of recent large-scale studies on gender differences in processing speed and on the cognitive factors assumed to affect processing speed was performed. It was found that females have an advantage in processing speed tasks involving digits and alphabets as well as in rapid naming tasks while males are faster on reaction time tests and finger tapping. Females also outperform males in reading and writing skills. However, no significant gender differences were found in general, crys...
Last. John M. Starr(Edin.: University of Edinburgh)H-Index: 120
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We examined the association between 5 processing speed measures and general cognitive ability in a large (>900) sample of relatively healthy men and women at age 70. The processing speed tests were the Wechsler Digit Symbol-Coding and Symbol Search, simple reaction time, 4-choice reaction time, and inspection time. To inquire whether the processing speed tasks might be biomarkers of cognitive aging, we examined the attenuations in their associations with general cognitive ability after adjusting...
Background: Studies examining the way in which cognitive impairment is associated with depression have produced inconsistent findings. Different severity of depressed mood across studies may account for such conflicting reports. However, inconsistent results have also been reported in relation to the specific association of depression severity with cognitive performance. Methods: A meta-analysis was conducted to examine the relationship between severity of depression and cognitive function, usin...
#1Jeremy A. Elman(UCSD: University of California, San Diego)H-Index: 15
#2Olivia K. Puckett(UCSD: University of California, San Diego)H-Index: 1
Last. William S. Kremen(UCSD: University of California, San Diego)H-Index: 70
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INTRODUCTION The locus coeruleus (LC) undergoes extensive neurodegeneration in early Alzheimer's disease (AD). The LC is implicated in regulating the sleep-wake cycle, modulating cognitive function, and AD progression. METHODS Participants were 481 men (ages 62 to 71.7) from the Vietnam Era Twin Study of Aging. LC structural integrity was indexed by neuromelanin-sensitive magnetic resonance imaging (MRI) contrast-to-noise ratio (LCCNR ). We examined LCCNR , cognition, amnestic mild cognitive imp...