Selective attrition and intraindividual variability in response time moderate cognitive change.

Objectives: Selection of a developmental time metric is useful for understanding causal processes that underlie aging-related cognitive change and for the identification of potential moderators of cognitive decline. Building on research suggesting that time to attrition is a metric sensitive to non-normative influences of aging (e.g.

The influence of cognitive impairment with no dementia on driving restriction and cessation in older adults.

Cognitively impaired older adults may be at increased risk of unsafe driving. Individuals with insight into their own impairments may minimize their risk by restricting or stopping driving. The purpose of this study was to examine the influence of cognitive impairment on driving status and driving habits and intentions.

Are neurocognitive speed and inconsistency similarly affected in type 2 diabetes?

Type 2 diabetes (T2D) is a disease of aging with indirect but detectable and cumulative neurological implications. We systematically tested whether neurocognitive speed (mean rate) or inconsistency (intraindividual variability) was the more sensitive clinical marker of T2D. Three of four research questions used a cross-sectional wave of the Victoria Longitudinal Study (VLS) divided into T2D (age 55-81 years) and control (age = 53-91 years) groups.

Aging and the shape of cognitive change before death: terminal decline or terminal drop?

Objectives: Relative to typical age-related cognitive decrements, the terms "terminal decline" and "terminal drop" refer to the phenomenon of increased cognitive decline in proximity to death. Given that these terms are not necessarily synonymous, we examined the important theoretical distinction between the two alternative trajectories or shapes of changes they imply.

Methods: We used 12-year (5-wave) data from the Victoria Longitudinal Study to directly test whether pre-death cognitive decrements follow a terminal decline (generally gradual) or a terminal drop (more abrupt) shape.

Including persistency of impairment in mild cognitive impairment classification enhances prediction of 5-year decline.

Although older adults with Mild Cognitive Impairment (MCI) show elevated rates of conversion to dementia as a group, heterogeneity of outcomes is common at the individual level. Using data from a prospective 5-year longitudinal investigation of cognitive change in healthy older adults (N = 262, aged 64-92 years), this study addressed limitations in contemporary MCI identification procedures which rely on single occasion assessment ("Single-Assessment [SA] MCI") by evaluating an alternate operational definition of MCI requiring evidence of persistent cognitive impairment over multiple-testing sessions ("Multiple-Assessment [MA] MCI"). As hypothesized, prevalence of SA-MCI exceeded that of MA-MCI.

Intraindividual variability is related to cognitive change in older adults: evidence for within-person coupling.

In this study, the authors addressed the longitudinal nature of intraindividual variability over 3 years. A sample of 304 community-dwelling older adults, initially between the ages of 64 and 92 years, completed 4 waves of annual testing on a battery of accuracy- and latency-based tests covering a wide range of cognitive complexity. Increases in response-time inconsistency on moderately and highly complex tasks were associated with increasing age, but there were significant individual differences in change across the entire sample.

Intraindividual variability in reaction time predicts cognitive outcomes 5 years later.

Objective: Building on results suggesting that intraindividual variability in reaction time (inconsistency) is highly sensitive to even subtle changes in cognitive ability, this study addressed the capacity of inconsistency to predict change in cognitive status (i.e., cognitive impairment, no dementia [CIND] classification) and attrition 5 years later.

Self-reported cognitive inconsistency in older adults.

Insight into one's own cognitive abilities, or metacognition, has been widely studied in developmental psychology. Relevance to the clinician is high, as memory complaints in older adults show an association with impending dementia, even after controlling for likely confounds. Another candidate marker of impending dementia under study is inconsistency in cognitive performance over short time intervals.

The relationship between everyday problem solving and inconsistency in reaction time in older adults.

The purpose of the present study was to investigate whether inconsistency in reaction time (RT) is predictive of older adults' ability to solve everyday problems. A sample of 304 community dwelling non-demented older adults, ranging in age from 62 to 92, completed a measure of everyday problem solving, the Everyday Problems Test (EPT). Inconsistency in latencies across trials was assessed on four RT tasks.

Functional abilities in older adults with mild cognitive impairment.

Background: A classification scheme and general set of criteria for diagnosing mild cognitive impairment (MCI) were recently proposed by a multidisciplinary group of experts who met at an international symposium on MCI. One of the proposed criteria included preserved basic activities of daily living and minimal impairment in complex instrumental activities of daily living (IADLs).

Objective: To investigate whether older adults with MCI classified according to the subtypes identified by the Working Group (i.

Cognitive abilities and functional capacity in older adults: results from the modified Scales of Independent Behavior-Revised.

The relationship between cognitive and functional abilities was examined in a sample of community-dwelling older adults. Self and informant (e.g.

Predicting impending death: inconsistency in speed is a selective and early marker.

Among older adults, deficits in both level and variability of speeded performance are linked to neurological impairment. This study examined whether and when speed (rate), speed (inconsistency), and traditional accuracy-based markers of cognitive performance foreshadow terminal decline and impending death. Victoria Longitudinal Study data spanning 12 years (5 waves) of measurement were assembled for 707 adults aged 59 to 95 years.

Intraindividual variability across cognitive domains: investigation of dispersion levels and performance profiles in older adults.

A growing body of research suggests that substantial variability exists among cognitive abilities within individuals. This within-person variability across cognitive domains is termed dispersion. The present study investigated the relationship between aging and dispersion of cognitive functions both quantitatively (overall levels of dispersion) and qualitatively (patterns of dispersion) in a sample of 304 nondemented, older adults aged 64 to 92 years (M = 74.

Within-person variability in response speed as an indicator of cognitive impairment in older adults.

Within-person variability may be an important indicator of central nervous system compromise. In this study, within-person variability in response speed was examined in community-dwelling older adults, ages 64-92 years, using a new framework that takes into account both the extent (single versus multiple domains affected) and nature (amnestic versus non-amnestic) of the cognitive impairment. Those with multiple domains of impairment were more variable than those who showed an isolated area of impairment, regardless of whether memory was one of the domains affected.

Short-term changes in general and memory-specific control beliefs and their relationship to cognition in younger and older adults.

We examined short-term changes in younger and older adults' control beliefs. Participants completed measures of general and memory-specific competence and locus of control on 10 bi-monthly occasions. At each occasion, participants rated their control beliefs prior to and following completion of a battery of cognitive tasks.

Reaction time inconsistency in a spatial stroop task: age-related differences through childhood and adulthood.

Age-related differences in inconsistency of reaction time (RT) across the life span were examined on a task with differing levels of demand on executive control. A total of 546 participants, aged 5 to 76 years, completed a spatial Stroop task that permitted observations under three conditions (congruent, incongruent, and neutral) according to the correspondence between the required response (based on stimulus direction) and stimulus location. An interference effect was observed across all ages.

Was that part of the story or did i just think so? Age and cognitive status differences in inference and story recognition.

This study expanded the inference and story recognition literature by investigating differences within the older age range, differences as a result of cognitive impairment, no dementia (CIND), and applying signal detection procedures to the analysis of accuracy data. Old-old adults and those with more severe CIND showed poorer ability to accurately recognize inferences, and less sensitivity in discriminating between statement types. Results support the proposal that participants used two different recognition strategies.

Neurocognitive markers of cognitive impairment: exploring the roles of speed and inconsistency.

A well-known challenge for research in the cognitive neuropsychology of aging is to distinguish between the deficits and changes associated with normal aging and those indicative of early cognitive impairment. In a series of 2 studies, the authors explored whether 2 neurocognitive markers, speed (mean level) and inconsistency (intraindividual variability), distinguished between age groups (64-73 and 74-90+ years) and cognitive status groups (nonimpaired, mildly impaired, and moderately impaired). Study 1 (n = 416) showed that both level and inconsistency distinguished between the age and 2 cognitive status (not impaired, mildly impaired) groups, with a modest tendency for inconsistency to predict group membership over and above mean level.

Reaction time performance in adolescents with attention deficit/hyperactivity disorder: evidence of inconsistency in the fast and slow portions of the RT distribution.

Inconsistency across trials of 2-choice reaction time (RT) data was analyzed in 72 adolescents (age 12-17 years) within 4 groups differentiated by the presence or absence of attention deficit/hyperactivity disorder (ADHD) and reading difficulties (RD). ADHD participants were more inconsistent (across all trials, and in the slow portion of the RT distribution) than controls, but only when RD was present. Within the fast portion of the RT distribution, ADHD participants were more inconsistent than controls regardless of RD.

Cognitive functioning and everyday problem solving in older adults.

The relationship between cognitive functioning and a performance-based measure of everyday problem-solving, the Everyday Problems Test (EPT), thought to index instrumental activities of daily living (IADL), was examined in 291 community-dwelling non-demented older adults. Performance on the EPT was found to vary according to age, cognitive status, and education. Hierarchical regression analyses revealed that, after adjusting for demographic and health variables, measures of cognitive functioning accounted for 23.

Intraindividual variability in vigilance performance: does degrading visual stimuli mimic age-related "neural noise"?

Intraindividual performance variability, or inconsistency, has been shown to predict neurological status, physiological functioning, and age differences and declines in cognition. However, potential moderating factors of inconsistency are not well understood. The present investigation examined whether inconsistency in vigilance response latencies varied as a function of time-on-task and task demands by degrading visual stimuli in three separate conditions (10%, 20%, and 30%).

Intraindividual variability as a marker of neurological dysfunction: a comparison of Alzheimer's disease and Parkinson's disease.

Individuals with certain neurological conditions may demonstrate greater inconsistency (i.e., intraindividual variability) on cognitive tasks compared to healthy controls.

Inconsistency in reaction time across the life span.

Inconsistency in latency across trials of 2-choice reaction time data was analyzed in 273 participants ranging in age from 6 to 81 years. A U-shaped curve defined the relationship between age and inconsistency, with increases in age associated with lower inconsistency throughout childhood and higher inconsistency throughout adulthood. Differences in inconsistency were independent of practice, fatigue, and age-related differences in mean level of performance.

Episodic memory change in late adulthood: generalizability across samples and performance indices.

Younger adults recall more information from episodic memory tasks than do older adults. Because longitudinal studies are rare and often incompatible, the extent of actual late-life memory change is not well established. We assemble two different longitudinal samples of normal older adults, each of which is tested twice at a 3-year interval, using a large battery of episodic memory indicators.

Inconsistency in serial choice decision and motor reaction times dissociate in younger and older adults.

Intraindividual variability (inconsistency) in reaction time (RT) latencies was investigated in a group of younger (M=25.46 years) and older (M=69.29 years) men.