Assessment of executive functioning in brain injury: Collaboration between speech-language pathology and neuropsychology for an integrative neuropsychological perspective

IL-6 Enhances the Negative Impact of Cortisol on Cognition among Community-Dwelling Older People without Dementia

There is growing evidence that high basal cortisol levels and systemic inflammation independently contribute to cognitive decline among older people without dementia. The present cross-sectional study examined (a) the potential synergistic effect of cortisol levels and systemic inflammation on executive function and (b) whether this effect is more prominent among older people with mild cognitive impairment (MCI). A sub-sample of 99 patients with MCI and 84 older people without cognitive impairment (CNI) (aged 73.8 ± 7.0 years) were recruited from a large population-based cohort in Crete, Greece, and underwent comprehensive neuropsychiatric and neuropsychological evaluation and a single morning measurement of cortisol and IL-6 plasma levels. Using moderated regression models, we found that the relation between cortisol and executive function in the total sample was moderated by IL-6 levels (b = −0.994, p = 0.044) and diagnostic group separately (b = −0.632, p < 0.001). Moreover, the interaction between cortisol and IL-6 levels was significant only among persons with MCI (b = −0.562, p < 0.001). The synergistic effect of stress hormones and systemic inflammation on cognitive status appears to be stronger among older people who already display signs of cognitive decline. Targeting hypercortisolemia and inflammation may be a promising strategy toward improving the course of cognitive decline.

Protective role of IGF-1 and GLP-1 signaling activation in neurological dysfunctions

Insulin-like growth factor-1 (IGF-1), a pleiotropic polypeptide, plays an essential role in CNS development and maturation. Glucagon-like peptide-1 (GLP-1) is an endogenous incretin hormone that regulates blood glucose levels and fatty acid oxidation in the brain. GLP-1 also exhibits similar functions and growth factor-like properties to IGF-1, which is likely how it exerts its neuroprotective effects. Recent preclinical and clinical evidence indicate that IGF-1 and GLP-1, apart from regulating growth and development, prevent neuronal death mediated by amyloidogenesis, cerebral glucose deprivation, neuroinflammation and apoptosis through modulation of PI3/Akt kinase, mammalian target of rapamycin (mTOR) and mitogen-activated protein kinase (MAPK/ERK). IGF-1 resistance and GLP-1 deficiency impair protective cellular signaling mechanisms, contributing to the progression of neurodegenerative diseases. Over the past decades, IGF-1 and GLP-1 have emerged as an essential component of the neuronal system and as potential therapeutic targets for several neurodegenerative and neuropsychiatric dysfunctions. There is substantial evidence that IGF-1 and GLP-1 analogues penetrate the blood-brain barrier (BBB) and exhibit neuroprotective functions, including synaptic formation, neuronal plasticity, protein synthesis, and autophagy. Conclusively, this review represents the therapeutic potential of IGF-1 and GLP-1 signaling target activators in ameliorating neurological disorders.

Does Executive Function Training Impact on Communication? A Randomized Controlled tDCS Study on Post-Stroke Aphasia

New approaches in aphasia rehabilitation have recently identified the crucial role of executive functions (EFs) in language recovery, especially for people with severe aphasia (PWSA). Indeed, EFs include high-order cognitive abilities such as planning and problem solving, which enable humans to adapt to novel situations and are essential for everyday functional communication. In a randomized double-blind crossover design, twenty chronic Italian PWSA underwent ten days of transcranial direct current stimulation (tDCS) (20 min, 2 mA) over the right dorsolateral prefrontal cortex (DLPFC). Two conditions were considered, i.e., anodal and sham, while performing four types of cognitive training (alertness, selective attention, visuo-spatial working memory, and planning), all of which were related to executive functions. After anodal tDCS, a greater improvement in selective attention, visuospatial working memory and planning abilities was found compared to the sham condition; this improvement persisted one month after the intervention. Importantly, a significant improvement was also observed in functional communication, as measured through the Communication Activities of Daily Living Scale, in noun and verb naming, in auditory and written language comprehension tasks and in executive function abilities. This evidence emphasizes, for the first time, that tDCS over the right DLPFC combined with executive training enhances functional communication in severe aphasia.

The Neurocognitive Study for the Aging: Longitudinal Analysis on the Contribution of Sex, Age, Education and APOE ɛ4 on Cognitive Performance

Objective: The effects of normal cognitive aging on executive functions (EF), Verbal Episodic Memory (VEM) and the contribution of age, sex, education, and APOΕ ε4 in a group of old Greek Cypriots across a five-year period were investigated. Design: NEUROAGE, the first project on cognitive aging in Cyprus, is a prospective longitudinal study with a rolling admission process. Participants are assessed at baseline and retested every 24-30 months. Subjects: 170 participants completed all three testing cycles; 86 men and 84 women with ages ranging between 60 and 88 years (mean = 73.21, SD = 5.84); education, 2-20 years (mean = 9.07, SD = 4.27). Results: Α Repeated Measures Multivariate Analysis of Covariance was conducted with one between-subject factor: sex; two covariates: age and education, while Time (time 1, time 2, time 3) served as a within - subject factor. Time did not have an effect on mini mental status examination in Greek (MMSE), EF or VEM. Also, sex had no effect on MMSE, EF and VEM. There was no time by sex interaction. Age and Education significantly predicted the EF performance, F(1, 168) = 11.23, p < 0.05; F(1, 158) = 90.03, p < 0.001 and VEM performance, F(1, 171) = 17.22, p < 0.001; F(1, 171) = 61.25, p < 0.001. Furthermore, there was a significant interaction effect between time and education, for EF, F(2, 167) = 7.02, p < 0.001. Performance of the APOE ε4 carriers did not differ on any of the above measures as compared to performance of non-carriers in this older adult group. Conclusion: Cognitively healthy adults maintained overall cognitive performance across the five-year period. Male and female participants performed similarly and the pattern of change over time was similar across the two sexes. Education was predictive of VEM and EF performance across time. Furthermore, those with higher education maintained higher levels of EF performance. APOE results did not differentiate performance at baseline. Implications of findings are discussed.

Prospective Exploration of Cognitive-Communication Changes With Woodcock-Johnson IV Before and After Sport-Related Concussion

Purpose The purpose of this study was to evaluate changes in cognitive-communication performance using Woodcock-Johnson IV Tests (WJIV) from pre-injury baseline to post sport-related concussion. It was hypothesized that individual subtest performances would decrease postinjury in symptomatic individuals. Method This prospective longitudinal observational nested cohort study of collegiate athletes assessed cognitive-communicative performance at preseason baseline and postinjury. Three hundred and forty-two male and female undergraduates at high risk for sport-related concussion participated in preseason assessments, and 18 individuals met criteria post injury. WJIV subtest domains included Word Finding, Speeded Reading Comprehension, Auditory Comprehension, Verbal Working Memory, Story Retell, and Visual Processing (letter and number). The power calculation was not met, and therefore data were conservatively analyzed with descriptive statistics and a planned subgroup analysis based on symptomatology. Results Individual changes from baseline to postinjury were evaluated using differences in standard score performance. For symptomatic individuals, mean negative decreases in performance were found for Retrieval Fluency, Sentence Reading Fluency, Pattern Matchings, and all cluster scores postinjury. Individual performance declines also included decreases in story retell, verbal working memory, and visual processing. Conclusions This study identified within-subject WJIV performance decline in communication domains post sport-related concussion and reinforces that cognitive-communication dysfunction should be considered in mild traumatic brain injury. Key cognitive-communication areas included speeded naming, reading, and verbal memory, though oral comprehension was not sensitive to change. Future clinical research across diverse populations is needed to expand these preliminary findings.

What do people respond to when rating executive function? - a cognitive interviewing investigation of BRIEF-A informant ratings in severe aphasia

PURPOSE

Executive dysfunction is common in persons with severe aphasia. Assessing these functions in this population is challenging. Informant ratings, such as the BRIEF-A, might be a useful alternative to neuropsychological tests. However, research has shown weak relationships between tests and ratings. The aim of this study was to understand how significant others of people with severe aphasia interpret and respond to questions about executive function in the informant report version of BRIEF-A.

METHODS

Eleven significant others were interviewed about a subset of the BRIEF-A items, using cognitive interviewing. Interviews were subjected to thematic analysis.

RESULTS

There was variation in the interpretation of the items of BRIEF-A which frequently corrupted the items' relation to what it was intended to measure. Further, informants wavered between considering the person with aphasias' ability or actual performance and many had lowered their expectations. The language problems caused by the aphasia affected the validity of some items.

CONCLUSIONS

The quantitative results of BRIEF-A informant ratings should be interpreted with caution, since it is unclear to what extent the responses represent executive function. The use of informant ratings does not solve the problem with aphasia being a confounding factor in assessment of executive function.IMPLICATIONS FOR REHABILITATIONAssessing executive function in people with severe aphasia is important but challenging.Quantitative results of informant ratings of executive function, such as BRIEF-A, in this population should be interpreted with caution, since it is unclear to what extent the ratings represent executive function.Using informant ratings does not solve the problem of the aphasia being a confounding factor, since the aphasia impacts on the validity of some of the items.

Measurement of everyday dysexecutive symptoms in normal aging with the Greek version of the dysexecutive questionnaire-revised

The Dysexecutive Questionnaire is a sensitive and ecologically valid measure of everyday dysexecutive symptoms. Recently, a revised version of the tool has been proposed (DEX-R). The current study aimed to examine the factorial validity of the Greek DEX-R, the level of agreement between the self and informant rating versions and the effect of age on each dysexecutive symptoms component. The questionnaire was administered to a sample of older adults (n = 235) and to a sample of informants (n = 187) in the context of the Neurocognitive Study for the Aging in Cyprus. Confirmatory Factor Analysis results showed that dysexecutive symptoms can be grouped into three underlying components or factors: (a) Motivation and Attention, (b) Flexibility, Fluency and Working Memory, and (c) Social Self-Regulation. Overall, the elderly reported more symptoms than their relatives, however the difference was significant only for the Flexibility, Fluency and Working memory factor. In a structural equation model, a weak positive effect of age was observed on the Flexibility, Fluency and Working Memory factor, based on the informant ratings. This study provides empirical evidence about the use of the DEX-R questionnaire in the Greek-speaking elderly population as a valid and reliable measure of everyday dysexecutive symptoms.

Executive functions assessment in patients with language impairment A systematic review

Acquired language impairments may accompany different conditions. Most recent studies have shown that there is an important relationship between language and cognitive functions, such as executive functions (EF). Therefore, we aimed to investigate which main EF components appear to have the greatest impact in the most prevalent acquired communication disorders in adults, and which neuropsychological tests are being used to evaluate them. In addition, we sought to characterize the relationship between the executive functions and language in these conditions. Working memory (WM) was the most frequently chosen cognitive measure, being evaluated by different span tasks. A relationship between WM and narrative and conversational discourse, writing abilities and grammatical comprehension was found. Other currently used cognitive tests included the Trail Making, Wisconsin, Stroop and Verbal Fluency tests. Language and EF have a complex relationship; hence, a complete assessment should reflect the dynamic processing of cognitive brain functions.

Knowledge, Confidence, and Practice Patterns of Speech-Language Pathologists Working With Adults With Traumatic Brain Injury

PURPOSE

Although speech-language pathologists (SLPs) are important members of the health care team serving adults with traumatic brain injury (TBI) with cognitive-communication disorders, little is known about services SLPs deliver and how they rate their own knowledge and skills. The aims of this study were to identify practice patterns, knowledge, and confidence levels of SLPs working with adults with TBI with cognitive-communication disorders.

METHOD

We surveyed 100 SLPs from rural and urban hospitals, skilled nursing facilities, and outpatient clinics in Wisconsin and analyzed data descriptively.

RESULTS

SLPs in this sample had a combination of accurate and inaccurate knowledge related to TBI. Although all participants reported working with individuals with TBI, many participants rated themselves as lacking confidence or knowledge in this practice area. SLPs reported variable use of evidence-based procedures and training related to TBI.

CONCLUSION

Results confirmed the high prevalence of TBI-related practice among SLPs in medical settings, but there was variable knowledge, confidence, and use of current evidence in practice. SLP graduate training programs, individual providers, health care administrators, and the American Speech-Language-Hearing Association can use results from this study to advance and improve SLP clinical services for adults with TBI.

Ecologically Valid Assessment of Prospective Memory for Task Planning and Execution by Adults With Acquired Brain Injury

PURPOSE

Individuals with acquired brain injury (ABI) often struggle due to inadequate planning and execution skills for completing nonroutine tasks. This study's purpose was to pilot ecologically valid procedures to assess planning for and execution of prospective daily activities.

METHOD

Participants included 9 adults with histories of severe ABI and 9 controls. Data collection included both prospective task planning and execution. First, participants created a plan for later execution of daily tasks in accordance with preestablished rules. Over the subsequent 10 days, participants independently attempted task completion. Differences within and between participant groups regarding planning and task performance were evaluated statistically and through examiner observation.

RESULTS

Participants with ABI implemented minimal planning strategies. They demonstrated highly variable performance and displayed substantially greater difficulty initiating and successfully executing tasks in adherence to rules than participants without ABI.

CONCLUSIONS

Evaluating planning strategies and execution of novel prospective tasks is a crucial but often neglected aspect of assessment following ABI. Implementing ecologically valid procedures to evaluate this aspect of functioning can reveal individual strengths and challenges and provide guidance for developing effective intervention programs. Examining potential roles played by planning and strategy execution provides critical assessment information relating to independent living.

How do assessments of activities of daily living address executive functions: A scoping review

Executive functions (EF) allow persons to adapt to situations arising in daily life and can be affected following acquired brain injury (ABI). Measuring the impact of EF impairments on the accomplishment of activities of daily living (ADL) requires specific assessment tools, but choosing the right tool may be difficult.

PURPOSE

To conduct a scoping review on how assessments of ADL address EF and EF impairments in persons with ABI.

METHOD

A scoping review of literature (peer-reviewed and grey literature) published until August 2014 was conducted. Using a systematic procedure, literature was selected, results were charted, and tools were analysed with respect to their goals, underlying models, psychometric properties and applicability. The analysis also included how tools considered components of EF according to Lezak's model.

RESULTS

12 tools, developed either to assess EF in ADL, independence in ADL considering EF or ADL capacities, were identified and analysed according to multiple criteria.

CONCLUSIONS

This review provides important information about existing tools to assist in tool selection and clinical decision-making related to ABI and EF.

Use of Visual Cues by Adults With Traumatic Brain Injuries to Interpret Explicit and Inferential Information

OBJECTIVE

Concomitant visual and cognitive impairments following traumatic brain injuries (TBIs) may be problematic when the visual modality serves as a primary source for receiving information. Further difficulties comprehending visual information may occur when interpretation requires processing inferential rather than explicit content. The purpose of this study was to compare the accuracy with which people with and without severe TBI interpreted information in contextually rich drawings.

PARTICIPANTS

Fifteen adults with and 15 adults without severe TBI.

DESIGN

Repeated-measures between-groups design.

MAIN MEASURES

Participants were asked to match images to sentences that either conveyed explicit (ie, main action or background) or inferential (ie, physical or mental inference) information. The researchers compared accuracy between participant groups and among stimulus conditions.

RESULTS

Participants with TBI demonstrated significantly poorer accuracy than participants without TBI extracting information from images. In addition, participants with TBI demonstrated significantly higher response accuracy when interpreting explicit rather than inferential information; however, no significant difference emerged between sentences referencing main action versus background information or sentences providing physical versus mental inference information for this participant group.

CONCLUSIONS

Difficulties gaining information from visual environmental cues may arise for people with TBI given their difficulties interpreting inferential content presented through the visual modality.

Normative comparisons for large neuropsychological test batteries: User-friendly and sensitive solutions to minimize familywise false positives

INTRODUCTION

In neuropsychological research and clinical practice, a large battery of tests is often administered to determine whether an individual deviates from the norm. We formulate three criteria for such large battery normative comparisons. First, familywise false-positive error rate (i.e., the complement of specificity) should be controlled at, or below, a prespecified level. Second, sensitivity to detect genuine deviations from the norm should be high. Third, the comparisons should be easy enough for routine application, not only in research, but also in clinical practice. Here we show that these criteria are satisfied for current procedures used to assess an overall deviation from the norm-that is, a deviation given all test results. However, we also show that these criteria are not satisfied for current procedures used to assess test-specific deviations, which are required, for example, to investigate dissociations in a test profile. We therefore propose several new procedures to assess such test-specific deviations. These new procedures are expected to satisfy all three criteria.

METHOD

In Monte Carlo simulations and in an applied example pertaining to Parkinson disease, we compare current procedures to assess test-specific deviations (uncorrected and Bonferroni normative comparisons) to new procedures (Holm, one-step resampling, and step-down resampling normative comparisons).

RESULTS

The new procedures are shown to: (a) control familywise false-positive error rate, whereas uncorrected comparisons do not; (b) have higher sensitivity than Bonferroni corrected comparisons, where especially step-down resampling is favorable in this respect; (c) be user-friendly as they are implemented in a user-friendly normative comparisons website, and as the required normative data are provided by a database.

CONCLUSION

These new normative comparisons procedures, especially step-down resampling, are valuable additional tools to assess test-specific deviations from the norm in large test batteries.

Cognitive Rehabilitation After Traumatic Brain Injury: A Reference for Occupational Therapists

Nearly 1.7 million Americans sustain a traumatic brain injury (TBI) each year. These injuries can result in physical, emotional, and cognitive consequences. While many individuals receive cognitive rehabilitation from occupational therapists (OTs), the interdisciplinary nature of TBI research makes it difficult to remain up-to-date on relevant findings. We conducted a literature review to identify and summarize interdisciplinary evidence-based practice targeting cognitive rehabilitation for civilian adults with TBI. Our review summarizes TBI background, and our cognitive remediation section focuses on the findings from 37 recent (since 2006) empirical articles directly related to cognitive rehabilitation for individuals (i.e., excluding special populations such as veterans or athletes). This manuscript is offered as a tool for OTs engaged in cognitive rehabilitation and as a means to highlight arenas where more empirical, interdisciplinary research is needed.

Definition of Impulsivity and Related Terms Following Traumatic Brain Injury: A Review of the Different Concepts and Measures Used to Assess Impulsivity, Disinhibition and other Related Concepts

Impulsivity is a common and debilitating sequela following traumatic brain injury (TBI), but there is no consensual definition or measure to assess this construct. The following review aims to elucidate the differences and resemblances between impulsivity, disinhibition and other related terms following brain injury and the instruments that are commonly used to measure these constructs. To do so, a search through different databases was conducted in order to find articles that mention and define impulsivity, disinhibition, impulse control, regulation deficits, dyscontrol and risky behavior. The concepts that stand out from the literature, the measures used, the similarities, the differences between these concepts are observed. The fit with the UPPS model of impulsivity, according to which impulsivity is a multidimensional concept composed of four distinct dimensions (urgency, perseverance, premeditation and sensation-seeking) is discussed.