The Influence of Processing Speed, Attention, and Inhibition on Texas Functional Living Scale Performance.

OBJECTIVE: Attention, inhibition, and processing speed are related to functional decline among older adults. This study attempts to clarify the relationships between these cognitive factors and adaptive functioning. METHOD: We examined relationships between attention, inhibition, and processing speed, with scores on the Texas Functional Living Scale (TFLS), a performance-based measure of daily functioning, in a mixed clinical sample of 530 older adults who were referred for an outpatient neuropsychological evaluation. RESULTS: The current study used a confirmatory factor analysis (CFA) to derive a three-factor cognitive model consisting of attention, inhibition, and processing speed. Results from a hierarchical regression, which included factor scores from the CFA, revealed that processing speed was the only significant predictor of TFLS performance when all three cognitive factors were included within a single model. CONCLUSION: These results highlight the influence of processing speed as an important indicator of functional decline among a clinical population of older adults.

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. METHOD: In total, 270 adult outpatients completed the TFLS during clinical neuropsychological evaluation. IRT analysis using 2PL and graded response model was applied to the TFLS. RESULTS: Item parameters, item characteristic curves, and information curves were produced. Item difficulty (a) parameters ranged from 1.05 to 2.23, and item discrimination (b) parameters ranged from -4.11 to 0.51. CONCLUSIONS: TFLS items were differentially sensitive along the continuum of functional impairment. Items that were most sensitive to milder degrees of functional impairment involved clock drawing, microwave programming, financial calculation, and prospective memory. Other items that were optimally precise in more severe degrees of functional impairment involved interacting with a calendar and a relatively simple financial calculation task. These findings suggest that the ability to pass at least some of the items on the TFLS may not necessarily reflect fully intact functional abilities. Certain TFLS items may be able to detect the presence of subtle functional difficulties.

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 (M age =76.0 +/- 6.5 years; 59% females) who completed the TFLS as part of comprehensive assessment at an outpatient neuropsychology clinic. Executive functioning measures included the Trail Making Test (TMT) Part B, the Controlled Oral Word Association Test, and the Wechsler Abbreviated Scale of Intelligence-II (WASI-II) Matrix Reasoning and Similarities subtests. Results from a hierarchical regression model revealed that only TMT Part B (ß = -.23, p = .023) and WASI-II Similarities (ß = .32, p = .002) scores significantly predicted TFLS Total scores after controlling for the contributions of demographics (i.e., age, education, and gender), and intellectual functioning and capabilities in other neurocognitive domains (i.e., WASI-II Vocabulary and Block Design subtests, TMT Part A, and Repeatable Battery for the Assessment of Neuropsychological Status Coding subtest, and the Immediate Memory, Delayed Memory, and Visuospatial/Construction Indices).

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. Principal axis factor analysis with oblique promax rotation was conducted with age and education effects partialed out. RESULTS: Parallel analysis indicated five factors for extraction that accounted for a combined 48% of the variance. The first factor independently explained 26% of the total variance. Inspection of factor loadings suggested the following factor interpretations: complex calculations/time, complex visual search, praxis, memory, and basic calculations/math concepts. Five items did not significantly load onto any of the factors. CONCLUSIONS: Current results did not entirely correspond to the published subscales or prior results in a veteran sample. Further clarification of the TFLS factor structure is warranted.

Relative Utility of Performance and Symptom Validity Tests.

This investigation adds to the burgeoning body of research concerned with discriminating performance and symptom validity tests (SVTs) through examination of their differential relationships with cognitive performance and symptom self-report measures. To the authors' current knowledge, prior studies have not assessed differences between participants who fail either a performance validity test (PVT) or an SVT but not both. As part of their neuropsychological evaluations at four Veterans Affairs medical centers across the United States, participants were administered a fixed, standardized battery that consisted of performance validity, symptom validity, cognitive performance, and symptom self-report measures. Compared with participants who failed a PVT and an SVT, participants who passed both and participants who only passed a PVT demonstrated better cognitive performance and self-reported fewer symptoms. Results support differential clinical utility of performance validity and SVTs when assessing cognitive performance and symptom self-report.

A Factor Analytic Approach to the Validation of the Word Memory Test and Test of Memory Malingering as Measures of Effort and Not Memory.

Research has demonstrated the utility of performance validity tests (PVTs) as a method of determining adequate effort during a neuropsychological evaluation. Although some studies affirm that forced-choice PVTs measure effort rather than memory, doubts remain in the literature. The purpose of the current study was to evaluate the relationship between effort and memory variables in a mild traumatic brain injury (TBI) sample (n = 160) by separating memory and effort as distinct factors while statistically controlling for the shared covariance between the variables. A two-factor solution was extracted such that the five PVT variables loaded on Factor 1 and the four memory variables loaded on Factor 2. The pattern matrix, which controls for the covariance between variables, provided clear support of two highly distinct factors with minimal cross-loadings. Our findings support assertions that PVTs measure effort independent of memory in veterans with mild TBI.

The dangers of failing one or more performance validity tests in individuals claiming mild traumatic brain injury-related postconcussive symptoms.

Evaluating performance validity is important in any neuropsychological assessment, and prior research recommends a threshold for invalid performance of two or more performance validity test (PVT) failures. However, extant findings also indicate that failing a single PVT is associated with significant changes in neuropsychological performance. The current study sought to determine if there is an appreciable difference in neuropsychological testing results between individuals failing different numbers of PVTs. In a sample of veterans with reported histories of mild traumatic brain injury (mTBI; N =178), analyses revealed that individuals failing only one PVT performed significantly worse than individuals failing no PVTs on measures of verbal learning and memory, processing speed, and cognitive flexibility. Additionally, individuals failing one versus two PVTs significantly differed only on delayed free recall scores. The current findings suggest that failure of even one PVT should elicit consideration of performance invalidity, particularly in individuals with histories of mTBI.

PTSD and cognitive functioning: importance of including performance validity testing.

Many studies have observed an association between post-traumatic stress disorder (PTSD) and cognitive deficits across several domains including memory, attention, and executive functioning. The inclusion of response bias measures in these studies, however, remains largely unaddressed. The purpose of this study was to identify possible cognitive impairments correlated with PTSD in returning OEF/OIF/OND veterans after excluding individuals failing a well-validated performance validity test. Participants included 126 men and 8 women with a history of mild traumatic brain injury (TBI) referred for a comprehensive neuropsychological evaluation as part of a consortium of five Veterans Affairs hospitals. The PTSD CheckList (PCL) and Word Memory Test (WMT) were used to establish symptoms of PTSD and invalid performance, respectively. Groups were categorized as follows: Control (PCL < 50, pass WMT), PTSD-pass (PCL ≥ 50, pass WMT), and PTSD-fail (PCL ≥ 50, fail WMT). As hypothesized, failure on the WMT was associated with significantly poorer performance on almost all cognitive tests administered; however, no significant differences were detected between individuals with and without PTSD symptoms after separating out veterans failing the WMT. These findings highlight the importance of assessing respondent validity in future research examining cognitive functioning in psychiatric illness and warrant further consideration of prior studies reporting PTSD-associated cognitive deficits.

Olfactory deficits in frontotemporal dementia as measured by the Alberta Smell Test.

The study of olfaction in neurodegeneration has primarily focused on Alzheimer's disease. Research of olfaction in frontotemporal dementia (FTD) has generally not been empirically studied. The current study compared olfaction in FTD to major depressive disorder (MDD) using the Alberta Smell Test (AST). Independent-samples t test results suggested olfaction in FTD was impaired when compared with participants diagnosed with MDD. The AST Total score (out of 20 trials) significantly predicted the diagnostic group and accounted for 40% of the variance in diagnostic group status with an odds ratio of 20.08. Results suggested that a cutoff of ≤2/20 differentiated FTD from MDD with 94% accuracy (91% sensitivity, 97% specificity) and a cutoff of ≤1/20 differentiated the groups with a 95.5% hit rate (91% sensitivity, 100% specificity). Results confirmed olfactory identification deficits in FTD and suggested that the AST is an effective tool for the demarcation of FTD from MDD. This is especially important due to the potential for significant overlap in the behavioral/emotional phenotype and cognitive deficits between the two disorders when presented with early stages of FTD.

Heterogeneity in Trail Making Test performance in OEF/OIF/OND veterans with mild traumatic brain injury.

This study used cluster analysis to examine variability in Trail Making Test (TMT) performance in a sample of Operation Enduring Freedom/Operation Iraqi Freedom/Operation New Dawn (OEF/OIF/OND) veterans referred for mild traumatic brain injury (mTBI). Three clusters were extracted, two of which were characterized by level of performance and the third with a unique performance pattern characterized by slow performance on the TMT B (Low B). Clusters did not differ on demographic or psychiatric variables. The Above Average cluster had better performance on measures of processing speed, working memory, and phonemic fluency compared with the Low B cluster. Results suggest that a subset of patients with mTBI perform poorly on TMT B, which subsequently predicts poorer cognitive functioning on several other neuropsychological measures. This subset may be vulnerable to cognitive changes in the context of mTBI and multiple comorbidities while a number of other patients remain cognitively unaffected under the same circumstances.

Brief report: the temporal stability of the Repeatable Battery for the Assessment of Neuropsychological Status Effort Index in geriatric samples.

The Effort Index (EI) of the Repeatable Battery for the Assessment of Neuropsychological Status (RBANS) was developed to identify inadequate effort. Although researchers have examined its validity, the reliability of the EI has not been evaluated. The current study examined the temporal stability of the EI across 1 year in two independent samples of older adults. One sample consisted of 445 cognitively intact older adults (mean age = 72.89; 59% having 12-15 years of education) and the second sample consisted of 51 individuals diagnosed with amnestic Mild Cognitive Impairment (mean age = 82.41; 41% having 12-15 years of education). For both samples, the EI was found to have low stability (Spearman's ρ = .32-.36). When participants were divided into those whose EI stayed stable or improved versus those whose EI worsened (i.e., declining effort) on retesting, it was observed that individuals with lower baseline RBANS Total scores tended to worsen on the EI across time. Overall, the findings suggest low temporal stability of the EI in two geriatric samples. In particular, individuals with poorer cognition at baseline could present with poorer effort across time. These findings also suggest the need to further examine the temporal stability of other effort measures.