Cognitive estimation in traumatic brain injury

Conceptualization of the term "ecological validity" in neuropsychological research on executive function assessment: a systematic review and call to action

OBJECTIVE

"Ecological validity" (EV) is classically defined as test's ability to predict real-world functioning, either alone or together with test's similarity to real-world tasks. In neuropsychological literature on assessment of executive functions (EF), EV is conceptualized inconsistently, leading to misconceptions about the utility of tests. The goal of this systematic review was to examine how EV is conceptualized in studies of EF tests described as ecologically valid.

METHOD

MEDLINE and PsychINFO Databases were searched. PRISMA guidelines were observed. After applying inclusion and exclusion criteria, this search yielded 90 articles. Deductive content analysis was employed to determine how the term EV was used.

RESULTS

About 1/3 of the studies conceptualized EV as the test's ability to predict functional outcomes, 1/3 as both the ability to predict functional outcome and similarity to real-world tasks, and 1/3 were either unclear about the meaning of the term or relied on notions unrelated to classical definitions (e.g., similarity to real-world tasks alone, association with other tests, or the ability to discriminate between populations).

CONCLUSIONS

Conceptualizations of the term EV in literature on EF assessment vary grossly, subsuming the notions of criterion, construct, and face validity, as well as sensitivity/specificity. Such inconsistency makes it difficult to interpret clinical utility of tests that are described as ecologically valid. We call on the field to require that, at minimum, the term EV be clearly defined in all publications, or replaced with more concrete terminology (e.g., criterion validity).

The role of cognitive estimation in understanding the mental states of others

Previous studies have emphasized the critical role of the prefrontal cortex in cognitive estimation and theory of mind, however, none of them has questioned the possible role of cognitive estimation processes in understanding the mental states of others. In this study, we compared 30 patients with focal prefrontal cortex damage and 30 control subjects matched by gender, age, and education level on their performances on a cognitive estimation task and two tasks assessing theory of mind: the "Faux-Pas" task and the Reading the Mind in the Eyes task. The results showed that patients were significantly impaired compared with control subjects on both abilities of cognitive estimation and theory of mind. Moreover, regression analyses showed that performance on theory of mind was predicted by the scores on cognitive estimation. Finally, using voxel-based lesion analysis, we identified a partially common bilaterally distributed prefrontal network involved in both these domains centred within the ventral and dorsomedial areas with extension to the dorsolateral prefrontal cortex.

The right anterior temporal lobe critically contributes to magnitude knowledge

Cognitive estimation is a mental ability applied to solve numerical problems when precise facts are unknown, unavailable or impractical to calculate. It has been associated with several underlying cognitive components, most often with executive functions and semantic memory. Little is known about the neural correlates of cognitive estimation. To address this issue, the present cross-sectional study applied lesion-symptom mapping in a group of 55 patients with left hemineglect due to right-hemisphere stroke. Previous evidence suggests a high prevalence of cognitive estimation impairment in these patients, as they might show a general bias towards large magnitudes. Compared to 55 age- and gender-matched healthy controls, the patient group demonstrated impaired cognitive estimation. However, the expected large magnitude bias was not found. Lesion-symptom mapping related their general estimation impairment predominantly to brain damage in the right anterior temporal lobe. Also critically involved were the right uncinate fasciculus, the anterior commissure and the right inferior frontal gyrus. The main findings of this study emphasize the role of semantic memory in cognitive estimation, with reference to a growing body of neuroscientific literature postulating a transmodal hub for semantic cognition situated in the bilateral anterior temporal lobe. That such semantic hub function may also apply to numerical knowledge is not undisputed. We here propose a critical contribution of the right anterior temporal lobe to at least one aspect of number processing, i.e. the knowledge about real-world numerical magnitudes.

Assessing Cognitive Estimation and Its Effects on Community Integration in People with Acquired Brain Injury Undergoing Rehabilitation

The purpose of the present study was to examine the convergent and divergent validity of the Biber Cognitive Estimation Test (BCET) in individuals with ABI undergoing postacute rehabilitation and to assess the measure's ability to account for unique variance in community integration following rehabilitation. Participants with ABI referred for postacute rehabilitation (N = 201) were assessed on the BCET and a number of other neuropsychological tests that have been demonstrated to rely on aspects of executive processing (Trail-Making Test, Modified Six Elements Test, and verbal fluency measures) and the Repeatable Battery for the Assessment of Neuropsychological Status (RBANS). Internal consistency of the total BCET was good; however, interpretable solutions for existing subscales were not discerned. The BCET total score demonstrated positive associations with tests of executive functioning; however, it was also significantly associated with more general aspects of neuropsychological functioning suggesting that it does not solely assess executive processes in ABI patients undergoing rehabilitation. Hierarchical multiple regression suggested that the BCET accounted for significant additional variance in community integration after severity of disability, executive functioning, and more general aspects of neuropsychological status were statistically controlled. While the subscale structure of the BCET may be somewhat inconsistent, the total scale score accounts for some unique variance in pragmatic rehabilitation outcome and may be a useful tool in postacute rehabilitation assessment protocols.

Cognitive estimations as a measure of executive dysfunction in childhood epilepsy

Children and adolescents with epilepsy are known to demonstrate executive function deficits. Despite prior work that has shown that cognitive estimation tasks are sensitive to executive dysfunction in children, such tasks have not been studied in children with epilepsy. This is particularly important given the fact that executive tasks have heretofore shown poor ecological validity, and it has been speculated that estimation tasks may show stronger ecological validity than other executive tests. One hundred and thirteen clinically referred children and adolescents with epilepsy were included. The Biber Cognitive Estimations Test was sensitive to cognitive dysfunction, with about half showing impairments on this task in comparison to age-matched normative data; the most frequently impaired subscales were quantity estimation and time estimation. Moreover, the Biber Cognitive Estimation Test showed moderate correlations with not only overall intellectual functions and academic achievement but also other commonly administered tests of executive functions, including digit span, Trailmaking, and the Tower of London but not with the contingency naming test. Cognitive estimations were also modestly correlated with age of epilepsy onset but not other epilepsy-severity variables such as number of antiepilepsy drugs (AEDs) or seizure frequency. Unfortunately, the hypothesis that the Biber Cognitive Estimation Test would show strong ecological validity was not supported, as it showed weak relations with parent-reported executive function deficits. The significance and limitations of this investigation are discussed.

Ambulant cognitive assessment using a smartphone

The focus of neuropsychology is to understand the relationship between assessment results and everyday cognitive abilities and disabilities. However, the generalizability of traditional neuropsychological tests to real-life behaviors, the ecological validity, is compromised by the test environment, among other things. Neuropsychological tests are often completed in a laboratory setting that is typically quiet with few distractions. This is very unlike most everyday environments. The aim of the present study was to investigate the possibility of using a smartphone in standardized cognitive assessment. A short-term memory task was obtained from young adults in either an everyday-life environment or a controlled test setting at four time points during a day. Results show no significant differences between the task performances in both conditions. There was no indication that fatigue, tension, or environmental noise had an effect on task performance. High correlations between subsequent time points were found in the everyday-life environment, suggesting a high test-retest reliability and commitment of the participants. The present study demonstrates that smartphones can be used to assess cognitive functions outside a laboratory setting.

A systematic review of assessments for identifying executive function impairment in adults with acquired brain injury

PURPOSE

To synthesize quantitative findings concerning measures of executive function (EF) in adults with acquired brain injury (ABI).

METHOD

Electronic databases were searched for studies of EF assessments in adults with ABI that reported any of 3 values: likelihood ratios (LRs), standardized group mean comparisons (ds), or correlations (rs) among EF tests. Forest plots were constructed for each value.

RESULTS

Searches yielded 1,417 unique citations. Full texts of 129 articles were reviewed; 34 reported at least 1 value of interest. Nineteen positive and negative LRs were calculated from 8 studies of 8 EF measures; some point estimates were in the clinically informative range, but all confidence intervals extended beyond it. From 24 studies of 14 measures, 114 d values were calculated; d values for only 11 measures had lower bounds > 0.80. From 8 studies involving 10 EF measures, 104 correlations were reported; in only 5 cases were r(2) values > .5.

CONCLUSIONS

Strong evidence concerning diagnostic accuracy and concurrent validity of EF measures for adults with ABI is lacking. Better specification of the construct of EF as well as research aimed at improving the quality of evidence concerning EF tests are needed.

Cognitive estimation abilities in healthy and clinical populations: the use of the Cognitive Estimation Test

Estimation abilities are a group of processes that involve functions such as planning, attention, abstract reasoning, and also mnemonic processes, like semantic and working memory. They are allocated in order to solve problems for which the answers are not readily available. Estimation abilities can be measured using the Cognitive Estimation Test (CET). The aim of this article was to review the use of the CET and other tests of cognitive estimation in healthy and pathological populations. We discussed studies examining correlations between the CET and other measures of executive functions and the importance of the standardization of measures that assess estimation abilities.

Functional cooking skills and neuropsychological functioning in patients with stroke: an ecological validity study

Efforts to relate neuropsychological performance to real-world task functioning have predominantly yielded lackluster results, typically with neuropsychological performance accounting for modest amounts of variance in function. Nonetheless, the ecological validity of neuropsychological measures for predicting functional abilities remains a strong research interest and clinical necessity. This study relates neuropsychological performance to performance on a standardised cooking task (Rabideau Kitchen Evaluation - Revised; RKE-R) in persons with stroke. Results showed that while the composite score of mean neuropsychological performance had the largest association with meal preparation, several neuropsychological measures were significantly related to the RKE-R. Groups of left and right hemisphere stroke patients were not significantly different in terms of RKE-R performance. These results suggest that functional cooking task performance is related to intact cognitive abilities in delayed verbal memory, simple auditory attention, and visuospatial skills, as well as overall cognitive performance. Implications for neuropsychologists are discussed.

Making decisions and advising decisions in traumatic brain injury

OBJECTIVE AND BACKGROUND

Decision under ambiguity and decision under risk are fundamental in every-day life.

METHODS

We investigated these 2 types of decision in traumatic brain injury (TBI) patients through the Iowa Gambling Task (IGT), the Probability-Associated Gambling (PAG) task, and a counsel version of the PAG task. Although in the IGT rules for gain and losses are implicit and probability information is missing, in the PAG task and the counsel task rules are explicit and probabilities are well-defined.

RESULTS

In the IGT, TBI patients selected more disadvantageously than healthy controls and failed to develop an advantageous strategy over time. Patients also made less advantageous choices than controls in the PAG task and the counsel task. Compared with controls, TBI patients gambled more frequently with low probabilities and less frequently with high probabilities. Overall, participants decided more advantageously in the counsel task, which does not provide feedback, than in the PAG task. Importantly, our results indicate that TBI patients' performance on all decision tasks correlated with executive functions.

CONCLUSIONS

Our study shows that TBI patients have difficulties in decision under risk and decision under ambiguity. Difficulties may be attributed to deficient learning from feedback and to reduced risk estimation, but not to impulsive risk taking behavior.