Item Response Theory Analysis of the Texas Functional Living Scale.

Objective: The Texas Functional Living Scale (TFLS) is a performance-based measure of functional abilities assessing the domains of time, money and calculation, communication, and memory. It is likely that certain items are more sensitive at different levels of functional impairment, with some signaling milder degrees of functional difficulty. This study analyzed psychometric characteristics of individual TFLS items using item response theory (IRT) in an outpatient clinical sample.

Dual-Task Gait Assessment in a Clinical Sample: Implications for Improved Detection of Mild Cognitive Impairment.

Objectives: Research has longitudinally linked dual-task gait dysfunction to mild cognitive impairment (MCI) and dementia risk. Our group previously demonstrated that dual-task gait speed assessment distinguished between subjective cognitive complaints (SCC) and MCI in a memory clinic setting, and also found that differences in dual-task gait speed were largely attributable to executive attention processes. This study aimed to reproduce these findings in a larger diverse sample and to extend them by examining whether there were group differences in single- versus dual-task cognitive performance (number of letters correctly sequenced backward).

Hallucinations and Delusions Signal Alzheimer's Associated Cognitive Dysfunction More Strongly Compared to Other Neuropsychiatric Symptoms.

Objectives: Neuropsychiatric symptoms (NPS) are common among individuals with dementia of the Alzheimer's type (DAT). We sought to characterize which NPS more purely relate to cognitive dysfunction in DAT, relative to other NPS.

Method: Demographic, neurocognitive, neuroimaging, and NPS data were mined from the Alzheimer's Disease Neuroimaging Initiative database (n = 906).

Factor Analysis of the Texas Functional Living Scale in an Outpatient Clinical Sample.

Objective: Prior factor analysis of the Texas Functional Living Scale (TFLS), a performance-based measure of functional abilities, in a military veteran sample supported four factors discrepant from the published subscales. This study analyzed TFLS factor structure in a non-veteran clinical sample.

Method: Two hundred seventy adult outpatients completed the TFLS during neuropsychological evaluation.

Contribution of executive functioning to instrumental activities of daily living in older adults.

The Texas Functional Living Scale (TFLS) is a performance-based measure of instrumental activities of daily living (IADLs). Executive dysfunction has been linked to impairment on other IADL measures but has not been thoroughly investigated with the TFLS. This study examined the contribution of executive functioning to IADLs on the TFLS among 228 older adults ( age =76.

Statistical Model of Dynamic Markers of the Alzheimer's Pathological Cascade.

Objectives: Alzheimer's disease (AD) is a progressive disease reflected in markers across assessment modalities, including neuroimaging, cognitive testing, and evaluation of adaptive function. Identifying a single continuum of decline across assessment modalities in a single sample is statistically challenging because of the multivariate nature of the data. To address this challenge, we implemented advanced statistical analyses designed specifically to model complex data across a single continuum.

How Do Scores on the ADAS-Cog, MMSE, and CDR-SOB Correspond?

Objective: Clinicians and researchers who measure cognitive dysfunction often use the Alzheimer's Disease Assessment Scale--Cognitive Subscale (ADAS-Cog), the Mini-Mental State Examination (MMSE), or the Clinical Dementia Rating scale (CDR-SOB). But, the use of different measures can make it difficult to compare data across patients or studies. What is needed is a simple chart that shows how scores on these three important measures correspond to each other.

Adding delayed recall to the ADAS-cog improves measurement precision in mild Alzheimer's disease: Implications for predicting instrumental activities of daily living.

As research increasingly focuses on preclinical stages of Alzheimer's disease (AD), instruments must be retooled to identify early cognitive markers of AD. A supplemental delayed recall subtest for the Alzheimer's Disease Assessment Scale-cognitive (ADAS-cog; Mohs, Rosen, & Davis, 1983; Rosen, Mohs, & Davis, 1984) is commonly implemented, but it is not known precisely where along the spectrum of cognitive dysfunction this subtest yields incremental information beyond what is gained from the standard ADAS-cog, or whether it can improve prediction of functional outcomes. An item response theory approach can analyze this in a psychometrically rigorous way.

Using the Alzheimer's Association web site to improve knowledge of Alzheimer's disease in health care providers.

Background: The purpose of the current study was to investigate whether an informative Web site is effective at producing higher scores for an individual's knowledge of Alzheimer's disease (AD) relative to those who do not visit a Web site.

Methods: A total of 552 participants completed the study on Amazon's Mechanical Turk; half were randomly assigned to visit alz.org, while a control group did not.

A fresh perspective revealed by powerful trends in Alzheimer's disease research.

The paper, "Ethnicity Moderates Dementia's Biomarkers", by Royall and Palmer in this issue of Journal of Alzheimer's Disease represents the cutting edge of Alzheimer's disease (AD) research. The authors capitalize on several powerful and emerging trends in AD research that will surely reap benefits for our discipline during the next decade: latent variable models, biomarkers, and ethnicity. In this study, the authors specifically find that self-reported ethnicity moderates the dementing process and hypothesize that this is more likely due to distinct biological mechanisms than environmental influences.

Greater precision when measuring dementia severity: establishing item parameters for the Clinical Dementia Rating Scale.

Background/aims: An item response theory (IRT)-based scoring approach to the Clinical Dementia Rating Scale (CDR) can account for the pattern of scores across the CDR items (domains) and their differential abilities to indicate dementia severity. In doing so, an IRT-based approach can provide greater precision than other CDR scoring algorithms. However, neither a good set of item parameters nor an easily digestible set of instructions needed to implement this approach is readily available.

Item response theory reveals variability of functional impairment within clinical dementia rating scale stages.

Background/aims: To investigate whether an item response theory (IRT) approach to measuring variations of dementia severity within Clinical Dementia Rating (CDR) stages is associated with activities of daily living (ADLs).

Methods: IRT estimates of dementia severity within CDR stages in 1,181 patients were correlated with ADLs and analyzed.

Results: IRT-determined dementia severity was significantly correlated with ADLs in three of four impaired dementia stages.

Estimating Premorbid Intelligence among Older Adults: The Utility of the AMNART.

This study examines the utility of the American version of the National Adult Reading Test (AMNART) as a measure of premorbid intelligence for older adults. In a sample of 130 older adults, aged 56 to 104, the AMNART was compared to other tests of premorbid intelligence. The results revealed that AMNART-estimated IQ was significantly higher than other premorbid estimates.