Confirmatory factor analysis of the WAIS-IV/WMS-IV

Combining neuropsychological assessment and structural neuroimaging to identify early Alzheimer's disease in a memory clinic cohort

INTRODUCTION

The current study examined the contributions of comprehensive neuropsychological assessment and volumetric assessment of selected mesial temporal subregions on structural magnetic resonance imaging (MRI) to identify patients with amnestic mild cognitive impairment (aMCI) and mild probable Alzheimer's disease (AD) dementia in a memory clinic cohort.

METHODS

Comprehensive neuropsychological assessment and automated entorhinal, transentorhinal, and hippocampal volume measurements were conducted in 40 healthy controls, 38 patients with subjective memory symptoms, 16 patients with aMCI, 16 patients with mild probable AD dementia. Multinomial logistic regression was used to compare the neuropsychological and MRI measures.

RESULTS

Combining the neuropsychological and MRI measures improved group membership prediction over the MRI measures alone but did not improve group membership prediction over the neuropsychological measures alone.

CONCLUSION

Comprehensive neuropsychological assessment was an important tool to evaluate cognitive impairment. The mesial temporal volumetric MRI measures contributed no diagnostic value over and above the determinations made through neuropsychological assessment.

Speech patterns during memory recall relates to early tau burden across adulthood

INTRODUCTION

Early cognitive decline may manifest in subtle differences in speech.

METHODS

We examined 238 cognitively unimpaired adults from the Framingham Heart Study (32-75 years) who completed amyloid and tau PET imaging. Speech patterns during delayed recall of a story memory task were quantified via five speech markers, and their associations with global amyloid status and regional tau signal were examined.

RESULTS

Total utterance time, number of between-utterance pauses, speech rate, and percentage of unique words significantly correlated with delayed recall score although the shared variance was low (2%-15%). Delayed recall score was not significantly different between β-amyoid-positive (Aβ+) and -negative (Aβ-) groups and was not associated with regional tau signal. However, longer and more between-utterance pauses, and slower speech rate were associated with increased tau signal across medial temporal and early neocortical regions.

DISCUSSION

Subtle speech changes during memory recall may reflect cognitive impairment associated with early Alzheimer's disease pathology.

HIGHLIGHTS

Speech during delayed memory recall relates to tau PET signal across adulthood. Delayed memory recall score was not associated with tau PET signal. Speech shows greater sensitivity to detecting subtle cognitive changes associated with early tau accumulation. Our cohort spans adulthood, while most PET imaging studies focus on older adults.

Computerized adaptive test strategies for the matrix reasoning subtest of the Wechsler Adult Intelligence Scale, 4th Edition (WAIS-IV)

OBJECTIVE

Most neuropsychological tests were developed without the benefit of modern psychometric theory. We used item response theory (IRT) methods to determine whether a widely used test - the 26-item Matrix Reasoning subtest of the WAIS-IV - might be used more efficiently if it were administered using computerized adaptive testing (CAT).

METHOD

Data on the Matrix Reasoning subtest from 2197 participants enrolled in the National Neuropsychology Network (NNN) were analyzed using a two-parameter logistic (2PL) IRT model. Simulated CAT results were generated to examine optimal short forms using fixed-length CATs of 3, 6, and 12 items and scores were compared to the original full subtest score. CAT models further explored how many items were needed to achieve a selected precision of measurement (standard error ≤ .40).

RESULTS

The fixed-length CATs of 3, 6, and 12 items correlated well with full-length test results (with r = .90, .97 and .99, respectively). To achieve a standard error of .40 (approximate reliability = .84) only 3-7 items had to be administered for a large percentage of individuals.

CONCLUSIONS

This proof-of-concept investigation suggests that the widely used Matrix Reasoning subtest of the WAIS-IV might be shortened by more than 70% in most examinees while maintaining acceptable measurement precision. If similar savings could be realized in other tests, the accessibility of neuropsychological assessment might be markedly enhanced, and more efficient time use could lead to broader subdomain assessment.

Resective epilepsy surgery in a limited-resource settings: A cohort from a multi-disciplinary epilepsy team in a developing country

BACKGROUND

Multidisciplinary pre-surgical evaluation is vital for epilepsy surgery decision and outcomes. Resective epilepsy surgery with assisted monitoring is currently a standard treatment for focal drug resistant epilepsy (DRE). In resource-limited countries, lack of epilepsy surgery center is a huge challenge. We presented and illustrated how to create a multidisciplinary protocol with resource-limited settings in a developing country and epilepsy surgery outcome using brain mapping and monitoring techniques for ensuring satisfactory resection.

METHODS

We created multicentric incomplete but complementary units covering all epilepsy-related sub-specialties and covering a wide geographical area in our country. Then, we conducted a prospective and multicentric study with low resource settings on patients with focal DRE, who underwent resective epilepsy surgery and were followed up for at least 12 months and were evaluated for postoperative seizure outcome and complications if present. Preoperative comprehensive clinical, neurophysiological, neuropsychological, and radiological evaluations were performed by multidisciplinary epilepsy team. Intraoperative brain mapping including awake craniotomy and direct stimulation techniques, neurophysiological monitoring, and electrocorticography was carried out during surgical resection.

RESULTS

The study included 47 patients (18 females and 29 males) with mean age 20.4 ± 10.02 years. Twenty-two (46.8%) patients were temporal epilepsy while 25 (53.2%) were extra-temporal epilepsy. The epilepsy surgery outcome at the last follow up was Engel Class I (seizure free) in 35 (74.5%), Class II (almost seizure free) in 8 (17%), Class III (worthwhile improvement) in 3 (6.4%), and Class IV (no worthwhile improvement) in 1 patient (2.1%).

CONCLUSION

With low resource settings and lack of single fully equipped epilepsy center, favorable outcomes after resective surgery in patients with focal DRE could be achieved using careful presurgical multidisciplinary selection, especially with using intraoperative brain mapping and electrocorticography techniques.

Construct identification in the neuropsychological battery: What are we measuring?

OBJECTIVE

Major obstacles to data harmonization in neuropsychology include lack of consensus about what constructs and tests are most important and invariant across healthy and clinical populations. This study addressed these challenges using data from the National Neuropsychology Network (NNN).

METHOD

Data were obtained from 5,000 NNN participants and Pearson standardization samples. Analyses included variables from four instruments: Wechsler Adult Intelligence Scale, 4th Edition (WAIS-IV); Wechsler Memory Scale, 4th Edition (WMS-IV); California Verbal Learning Test, 3rd Edition (CVLT3); and Delis-Kaplan Executive Function System (D-KEFS). We used confirmatory factor analysis to evaluate models suggested by prior work and examined fit statistics and measurement invariance across samples. We examined relations of factor scores to demographic and clinical characteristics.

RESULTS

For each instrument, we identified four first-order and one second-order factor. Optimal models in patients generally paralleled the best-fitting models in the standardization samples, including task-specific factors. Analysis of the NNN data prompted specification of a Recognition-Familiarity factor on the WMS-IV and an Inhibition-Switching factor on the D-KEFS. Analyses showed strong to strict factorial invariance across samples with expected differences in factor means and variances. The Recognition-Familiarity factor correlated with age more strongly in NNN than in the standardization sample.

CONCLUSIONS

Factor models derived from healthy groups generally fit well in patients. NNN data helped identify novel Recognition-Familiarity and Inhibition-Switching factors that were also invariant across samples and may be clinically useful. The findings support efforts to identify evidence-based and optimally efficient measurements of neuropsychological constructs that are valid across groups. (PsycInfo Database Record (c) 2023 APA, all rights reserved).

Neuropsychological performance in patients with focal drug-resistant epilepsy and different factors that affect their performance

Background

Drug-resistant epilepsy (DRE) accounts for nearly 30% of patients with epilepsy, which is associated with high incidence of cognitive comorbidity. The aim of this work was to study the role of neuropsychological assessment in patients with epilepsy, and different factors that affect their performance in patients with multiple factors (focal onset DRE).

Methods

118 patients were recruited from Kasr Alainy hospital, epilepsy outpatient clinic with focal DRE. The patients’ demographic and clinical data were collected, Electroencephalograph (EEG) interictal/ictal (when available), and brain imaging (MRI epilepsy protocol). Neuropsychological assessment by Wechsler Adult Intelligence Scale (WAIS-IV), proposed neurocognitive assessment battery and mood assessment was done. Their performance in neuropsychological assessment was correlated with the collected data. Concordance between different assessment modalities and brain lesion were done.

Results

Among recruited patients, 67.3% of patients showed Full-scale Intelligence Quotient (FSIQ) was less than average. FSIQ score significantly correlated with years of education, and number of anti-seizure medications (ASMs). Neurocognitive assessment battery could achieve cognitive profile of the patients but with poor lateralizing value. Executive function was the most affected cognitive domain. History of status epilepticus significantly affect FSIQ and executive function performance. Fifty-six percent of patients had depression. Among the analyzed factors, FSIQ and lesional brain imaging significantly affected neurocognitive performance of studied patients. Clinical semiology had better concordance in lateralization (74.7%) and localization (69.5%) with brain imaging compared to ictal EEG. Among patients who had ictal EEG recording, 36.4% patients (25% were temporal lobe) had complete concordance, while 38.6% patients had partial concordance.

Conclusions

Among analyzed factors, FSIQ was the most significant determinant of studied population’s neurocognitive performance. Clinical semiology were the best correlated with brain lesion. Complete concordance was best detected at the temporal lobe.

Southwestern Assessment of Processing Speed (SWAPS): A new brief test with demographically-corrected norms in an ethnically and educationally diverse population

Objective. Neuropsychological measures of processing speed have long been used as sensitive indices of cognitive functioning. Most of these commonly used tests are proprietary, and there is a need for brief, freely available tools that can be used in diverse clinical and research settings. The Southwestern Assessment of Processing Speed (SWAPS) is a 60-second digit-symbol transcription task developed as a brief alternative to commercially available coding tests. Demographically-corrected normative data are presented along with reliability and sensitivity/specificity values in older adults with and without cognitive impairment.Method. SWAPS data from 915 healthy aging individuals (NC) and 858 subjects with clinical diagnoses of mild cognitive impairment (MCI; n = 430) and Alzheimer's disease clinical syndrome (ADCS; n = 428) were obtained from the Texas Alzheimer's Research and Care Consortium (TARCC). TARCC participants represent ethnically and educationally diverse community-dwelling individuals age 50+.Results. SWAPS scores showed the expected associations with age, sex, and education, and the interaction between age and education were significant predictors of SWAPS scores. Test-retest reliability in NC was good, and the SWAPS distinguished impaired and non-impaired groups with adequate to excellent sensitivity and specificity for the primary analyses, with optimal cut-off points provided. Raw score- to uncorrected normalized T-scores and demographically-corrected SWAPS T-scores using regression-based norms are presented along with scoring programs for the calculation of each.Conclusions. The SWAPS is a brief, free, easily administered test with demographically-corrected regression-based norms and promising utility for detection of cognitive impairment and efficient assessment of processing speed.

Validated tests for language research with university students whose native language is English: Tests of vocabulary, general knowledge, author recognition, and reading comprehension

We present five studies aimed at developing an L1 vocabulary test for English-speaking university students. Such a test is useful as an indicator of crystallized intelligence and because vocabulary size correlates well with reading comprehension. In the first study, we tested 100 written words with four answer alternatives, based on Nation's Vocabulary Size Test. Analysis suggested two factors, which we interpreted as the possible existence of two types of difficult words: unknown words for general knowledge and unknown words for specialized knowledge. In Study 2, we attempted to develop a vocabulary test for each type of word, and these tests were then validated in Study 3. Since the test for general words proved too easy for the target population, we improved it in a fourth study by creating and testing more difficult items. Finally, a fifth study was conducted to validate the new test. Unexpectedly, Study 5 found a high correlation (r = .82) between the general knowledge vocabulary test and the specialized knowledge vocabulary test, suggesting that they measure the same latent factor, contrary to our initial assumption. Both tests have high reliability (r > .85) and correlate well (r > .4) with general knowledge, author recognition, and reading comprehension. In addition, a collection of other language tests was used and improved to verify the validity of the vocabulary tests. An exploratory factor analysis of all tests identified three factors (text comprehension, crystallized intelligence, and reading speed), with the vocabulary tests loading on the factor crystallized intelligence, which in turn correlates with reading comprehension. Structural equation modeling confirmed the interpretation.

Exploring the Semantic Structure of WMS-IV Verbal Paired Associates using the Hub-and-Spoke Model

OBJECTIVES

This study aimed to identify a well-fitting and theoretically justified item-level latent factor structure for the Wechsler Memory Scales (WMS)-IV verbal paired associates (VerbalPA) subtest to facilitate the ease and accuracy of score interpretations for patients with lateralized temporal lobe epilepsy (TLE).

METHODS

Archival data were used from 250 heterogeneous neurosciences patients who were administered the WMS-IV as part of a standard neuropsychological assessment. Three theoretically motivated models for the latent structure of VerbalPA were tested using confirmatory factor analysis. The first model, based on cognitive principles of semantic processing from hub-and-spoke theory, tested whether performance is related to specific semantic features of target words. The second, motivated by the Cattell-Horn-Carroll (CHC) model of cognitive abilities, investigated whether the associative properties of items influence performance. A third, Hybrid model tested whether performance is related to both semantic and associative properties of items. The best-fitting model was tested for diagnostic group effects contrasting the heterogeneous neuroscience patients with subsets of left and right TLE (n = 51, n = 26, respectively) patients.

RESULTS

The Hybrid model was found to have the best fit. Patients with left TLE scored significantly less well than the heterogeneous neurosciences sample on selected semantic factor scores, although the effect size was small.

CONCLUSIONS

Future editions of the WMS may consider implementing a semantic scoring structure for the VerbalPA to facilitate test score interpretation. Additionally, these results suggest that principles of hub-and-spoke theory may be integrated into CHC cognitive ability taxonomy.

Neurocognitive Effects of Cocoa and Red-Berries Consumption in Healthy Adults

In recent decades, the elderly population has increased at higher rates than any other population group, resulting in an increase in age-related diseases such as neurodegenerative and cognitive impairment. To address this global health problem, it is necessary to search for new dietary strategies that can prevent the main neurocognitive problems associated with the ageing process. Therefore, the aim of the present study was to analyze the effect of cocoa flavanols and red berry anthocyanins on brain-derived neurotrophic factor (BDNF) and nerve growth factor receptor (NGF-R) and to stablish the possible improvement in cognitive performance by using a battery of neurocognitive tests that included the Verbal Learning Test Spain-Complutense, the Spatial Recall Test 10/36 BRB-N, the Wechsler Adult Intelligence Scale III and IV, the STROOP Task and the Tower of London Test. A randomized, double-blind, parallel-group study was performed in 60 healthy volunteers between 50 and 75 years old who consumed a cocoa powder, a red berries mixture or a combination of both for 12 weeks. After the intervention, we observed a reduction in the time needed to start (p = 0.031) and finish (p = 0.018) the neurocognitive test known as the Tower of London in all groups, but the decrease in time to finish the task was more pronounced in the intervention with the combination of cocoa-red berries group. We failed to show any significant difference in BDNF and NGF-R sera levels. However we found a negative correlation between BDNF and the number of movements required to finish the TOL in women (p = 0.044). In conclusion, our study showed an improvement in executive function, without any change in neurotrofin levels, for all intervention arms.

The Relationship Between Cognitive Functioning and Symptoms of Depression, Anxiety, and Post-Traumatic Stress Disorder in Adults with a Traumatic Brain Injury: a Meta-Analysis

A thorough understanding of the relationship between cognitive test performance and symptoms of depression, anxiety, or post-traumatic stress disorder (PTSD) in people with traumatic brain injury (TBI) is important given the high prevalence of these emotional symptoms following injury. It is also important to understand whether these relationships are affected by TBI severity, and the validity of test performance and symptom report. This meta-analysis was conducted to investigate whether these symptoms are associated with cognitive test performance alterations in adults with a TBI. This meta-analysis was prospectively registered on the PROSPERO International Prospective Register of Systematic Reviews website (registration number: CRD42018089194). The electronic databases Medline, PsycINFO, and CINAHL were searched for journal articles published up until May 2020. In total, 61 studies were included, which enabled calculation of pooled effect sizes for the cognitive domains of immediate memory (verbal and visual), recent memory (verbal and visual), attention, executive function, processing speed, and language. Depression had a small, negative relationship with most cognitive domains. These relationships remained, for the most part, when samples with mild TBI (mTBI)-only were analysed separately, but not for samples with more severe TBI (sTBI)-only. A similar pattern of results was found in the anxiety analysis. PTSD had a small, negative relationship with verbal memory, in samples with mTBI-only. No data were available for the PTSD analysis with sTBI samples. Moderator analyses indicated that the relationships between emotional symptoms and cognitive test performance may be impacted to some degree by exclusion of participants with atypical performance on performance validity tests (PVTs) or symptom validity tests (SVTs), however there were small study numbers and changes in effect size were not statistically significant. These findings are useful in synthesising what is currently known about the relationship between cognitive test performance and emotional symptoms in adults with TBI, demonstrating significant, albeit small, relationships between emotional symptoms and cognitive test performance in multiple domains, in non-military samples. Some of these relationships appeared to be mildly impacted by controlling for performance validity or symptom validity, however this was based on the relatively few studies using validity tests. More research including PVTs and SVTs whilst examining the relationship between emotional symptoms and cognitive outcomes is needed.

Moving Toward Accurate Assessment of Working Memory in Adults With Neurogenically Based Communication Disorders

Purpose This article presents a viewpoint highlighting concerns regarding currently available assessments of working memory in adults with neurogenic communication disorders. Additionally, we provide recommendations for improving working memory assessment in this population. Method This viewpoint includes a critique of clinical and experimental working memory tests relevant to speech-language pathologists. We consider the terminology used to describe memory, as well as discuss language demands and test construction. Results Clinical and experimental testing of working memory in adults with neurogenic communication disorders is challenged due to theoretical, methodological, and practical limitations. The major limitations are characterized as linguistic and task demands, presentation and response modality effects, test administration, and scoring parameters. Taking these limitations into consideration, several modifications to working memory testing and their relevance to neurogenic populations are discussed. Conclusions The recommendations provided in this article can better guide clinicians and researchers to advocate for improved tests of working memory in adults with neurogenic communication disorders. Future research should continue to address these concerns and consider our recommendations.

Fluid Cognitive Abilities Are Important for Learning and Retention of a New, Explicitly Learned Walking Pattern in Individuals After Stroke

BACKGROUND

There is significant variability in poststroke locomotor learning that is poorly understood and affects individual responses to rehabilitation interventions. Cognitive abilities relate to upper extremity motor learning in neurologically intact adults, but have not been studied in poststroke locomotor learning.

OBJECTIVE

To understand the relationship between locomotor learning and retention and cognition after stroke.

METHODS

Participants with chronic (>6 months) stroke participated in 3 testing sessions. During the first session, participants walked on a treadmill and learned a new walking pattern through visual feedback about their step length. During the second session, participants walked on a treadmill and 24-hour retention was assessed. Physical and cognitive tests, including the Fugl-Meyer-Lower Extremity (FM-LE), Fluid Cognition Composite Score (FCCS) from the NIH Toolbox -Cognition Battery, and Spatial Addition from the Wechsler Memory Scale-IV, were completed in the third session. Two sequential regression models were completed: one with learning and one with retention as the dependent variables. Age, physical impairment (ie, FM-LE), and cognitive measures (ie, FCCS and Spatial Addition) were the independent variables.

RESULTS

Forty-nine and 34 participants were included in the learning and retention models, respectively. After accounting for age and FM-LE, cognitive measures explained a significant portion of variability in learning (R² = 0.17, P = .008; overall model R² = 0.31, P = .002) and retention (ΔR² = 0.17, P = .023; overall model R² = 0.44, P = .002).

CONCLUSIONS

Cognitive abilities appear to be an important factor for understanding locomotor learning and retention after stroke. This has significant implications for incorporating locomotor learning principles into the development of personalized rehabilitation interventions after stroke.

Single-neuronal predictions of others' beliefs in humans

Human social behaviour crucially depends on our ability to reason about others. This capacity for theory of mind has a vital role in social cognition because it enables us not only to form a detailed understanding of the hidden thoughts and beliefs of other individuals but also to understand that they may differ from our own^1-3. Although a number of areas in the human brain have been linked to social reasoning^4,5 and its disruption across a variety of psychosocial disorders^6-8, the basic cellular mechanisms that underlie human theory of mind remain undefined. Here, using recordings from single cells in the human dorsomedial prefrontal cortex, we identify neurons that reliably encode information about others' beliefs across richly varying scenarios and that distinguish self- from other-belief-related representations. By further following their encoding dynamics, we show how these cells represent the contents of the others' beliefs and accurately predict whether they are true or false. We also show how they track inferred beliefs from another's specific perspective and how their activities relate to behavioural performance. Together, these findings reveal a detailed cellular process in the human dorsomedial prefrontal cortex for representing another's beliefs and identify candidate neurons that could support theory of mind.

Latent Structure of a Brief Clinical Battery of Neuropsychological Tests Administered In-Home Via Telephone

Objective

To examine the factor structure and sociodemographic correlates of a battery of clinical neuropsychological tests administered in-home and via telephone.

Method

Participants included 280 healthy adults who completed a 35–40 min battery consisting of seven auditory-verbal neuropsychological tests (i.e., 10 variables) that included digit span, list learning and memory, prospective memory, verbal fluency, and oral trail making.

Results

After removing oral trail making part A, a three-factor model comprised of executive functions, memory and attention demonstrated the best fit to the data. Nevertheless, the shared variance between the nine remaining neuropsychological variables was also adequately explained by a single-factor model and a two-factor model comprised of executive functions and memory. Factor scores were variably associated with education, race/ethnicity, and IQ, but not with sex or age.

Conclusions

Findings provide preliminary support for the feasibility and factor structure and sociodemographic correlates of a brief telephone-based screening neuropsychological battery comprised mostly of commonly administered clinical measures. Future studies are needed to determine the test–retest reliability, sensitivity, and ecological relevance of this battery, as well as equivalency to in-person assessment.

Core Neuropsychological Measures for Obesity and Diabetes Trials: Initial Report

Obesity and diabetes are known to be related to cognitive abilities. The Core Neuropsychological Measures for Obesity and Diabetes Trials Project aimed to identify the key cognitive and perceptual domains in which performance can influence treatment outcomes, including predicting, mediating, and moderating treatment outcome and to generate neuropsychological batteries comprised of well-validated, easy-to-administer tests that best measure these key domains. The ultimate goal is to facilitate inclusion of neuropsychological measures in clinical studies and trials so that we can gather more information on potential mediators of obesity and diabetes treatment outcomes. We will present the rationale for the project and three options for the neuropsychological batteries to satisfy varying time and other administration constraints. Future directions are discussed. Preprint version of the document is available at https://osf.io/preprints/nutrixiv/7jygx/.

Reconsidering the RBANS Factor Structure: a Systematic Literature Review and Meta-Analytic Factor Analysis

The primary aim was to perform a systematic literature review and extract data necessary for a meta-analytic factor analysis of the RBANS. Secondary aims were to examine the potential validity and utility of the resulting factor structure. Literature was identified through a review of PsycINFO, PubMed, MEDLINE, Academic Search Complete, Psychology & Behavioral Sciences Collection, CINAHL Complete, Health Source: Nursing/Academic Edition, and SocINDEX. A two-stage meta-analytic structural equation modeling method was implemented to pool correlation matrices from primary studies and perform confirmatory factor analyses. Following model selection, factor scores were computed for two datasets and subjected to correlation and diagnostic accuracy analyses. A pooled correlation matrix was computed from 24 sample correlation matrices (N = 5299). Confirmatory factor analysis revealed that the theoretical five-factor model produced the best fit but only when error terms between Story Memory and Story Recall as well as between Figure Copy and Figure Recall were included. Regression-based factor scores showed mixed relationships with the manual-defined indices, and the overall diagnostic accuracy of the factor scores was adequate in both samples examined (AUC = 0.71 and 0.87). The five-factor model was an unexpected result given the failure of multiple previous studies to find support for that model. The five-factor model demonstrates several areas of potential improvement, including better representation of the factors by the indicators. The factor scores implied by this model also require further validation.

Traumatic brain injury and creative divergent thinking

PRIMARY OBJECTIVE

The current study examined how creative divergent thinking (i.e., the ability to produce varied and original solutions to a problem) is impacted by moderate-to-severe traumatic brain injury (TBI).

RESEARCH DESIGN

Descriptive, observational.

METHODS AND PROCEDURES

We administered two tasks of divergent thinking, the Abbreviated Torrance Test for Adults (ATTA) and the Alternative Uses Test (AUT), as well as a battery of neuropsychological tests and psychosocial variables (assessing memory and learning, processing speed, set shifting and psychological distress), to 29 individuals with TBI and 20 demographically-matched healthy comparison participants.

MAIN OUTCOMES AND RESULTS

Individuals with TBI performed similarly to healthy individuals on both tests of creative thinking, although they were impaired on the neuropsychological tasks. Moreover, there was no significant correlation between performance on the ATTA and performance on neuropsychological tests, but within the TBI group AUT performance and memory were significantly and positively associated.

CONCLUSIONS

Our findings reveal that divergent thinking, as measured by the ATTA and AUT, might be spared following moderate-to-severe TBI. These findings further our understanding of the higher-level cognitive sequelae of TBI and suggest that divergent thinking might be leveraged during treatment planning.

Spatial relational memory in individuals with traumatic brain injury

Introduction: Relational memory is the ability to bind arbitrary relations between elements of experience into durable representations and the flexible expression of these representations. It is well known that individuals with traumatic brain injury (TBI) have declarative memory impairments, but less is known about how TBI affects relational memory binding, the deficit at the heart of declarative, or relational, memory impairment. The aim of the current study is to examine such deficits.Method: We used a spatial reconstruction task (SRT) with 29 individuals with TBI and 23 normal comparison (NC) participants to investigate four different types of spatial relations: (A) identity-location relations, i.e., the relationship between a specific item and its known location; (B) item-item relations, or the relationship between one item and another; (C) item-display relations, or the relationship between an item and its position in the display; and (D) compound-item relations, i.e., relations that involve combinations of A, B, and C.Results: Our data revealed that individuals with TBI showed impairments in learning identity-location relations and increased compound errors compared to NCs. We also found evidence that when item identity is disregarded, individuals with TBI do not perform differently from NCs. An exploratory analysis revealed that while relational memory performance was significantly correlated with scores on the California Verbal Learning Test (CVLT), more participants with TBI exhibited impairment on the SRT than of the CVLT.Conclusions: Our findings show that relational memory is impaired following TBI, and provide preliminary evidence for an easy-to-administer task with increased sensitivity to memory impairment.

A meta-analysis of memory ability in synaesthesia

People with synaesthesia (e.g., experiencing colours for letters and numbers) have been reported to possess enhanced memory relative to the general population. However, there are also inconsistencies in this literature and it is unclear whether this reflects sampling error (exacerbated by low Ns) or more meaningful differences that arise because synaesthesia relates to some aspects of memory more than others. To this end, a multi-level meta-analysis was conducted. Synaesthetes have enhanced long-term (episodic) memory with a medium population effect size ( dˆ  = 0.61), whereas the effects on working memory (short-term memory) were significantly smaller ( dˆ  = 0.36) but still exceeded that of controls. Moderation analyses suggested that, aside from the division between long-term vs. working memory, the effects of synaesthesia are pervasive, i.e., they extend to all kinds of stimuli, and extend to all kinds of test formats. This pattern is hard to reconcile with the view that synaesthetic experiences directly support memory ability: for instance, digit span (where synaesthesia could be helpful) showed a small effect whereas episodic memory for abstract images (where synaesthesia is irrelevant) yielded larger effects. Synaesthesia occupies a unique position of being the only known neurodevelopmental condition linked to a pervasive enhancement of long-term memory.

Identifying Factors Associated With Severe Intellectual Disabilities in Teenagers With Cerebral Palsy Using a Predictive Learning Model

BACKGROUND

Intellectual disability and impaired adaptive functioning are common in children with cerebral palsy, but there is a lack of studies assessing these issues in teenagers with cerebral palsy. Therefore, the aim of this study was to develop and test a predictive machine learning model to identify factors associated with intellectual disability in teenagers with cerebral palsy.

METHODS

This was a multicenter controlled cohort study of 91 teenagers with cerebral palsy (53 males, 38 females; mean age ± SD = 17 ± 1 y; range: 12-18 y). Data on etiology, diagnosis, spasticity, epilepsy, clinical history, communication abilities, behaviors, motor skills, eating, and drinking abilities were collected between 2005 and 2015. Intellectual disability was classified as "mild," "moderate," "severe," or "profound" based on adaptive functioning, and according to the DSM-5 after 2013 and DSM-IV before 2013, the Wechsler Intelligence Scale for Children for patients up to ages 16 years, 11 months, and the Wechsler Adult Intelligence Scale for patients ages 17-18. Statistical analysis included Fisher's exact test and multiple logistic regressions to identify factors associated with intellectual disability. A predictive machine learning model was developed to identify factors associated with having profound intellectual disability. The guidelines of the "Transparent Reporting of a Multivariable Prediction Model for Individual Prognosis or Diagnosis Statement" were followed.

RESULTS

Poor manual abilities (P ≤ .001), gross motor function (P ≤ .001), and type of epilepsy (intractable: P = .04; well controlled: P = .01) were significantly associated with profound intellectual disability. The average model accuracy, specificity, and sensitivity was 78%.

CONCLUSION

Poor motor skills and epilepsy were associated with profound intellectual disability. The machine learning prediction model was able to adequately identify high likelihood of severe intellectual disability in teenagers with cerebral palsy.

Methamphetamine-associated difficulties in cognitive control allocation may normalize after prolonged abstinence

Chronic heavy methamphetamine use likely causes dopaminergic neurotoxicity, which is commonly thought to result in cognitive control deficits. Both of these alterations may persist even after the use is discontinued, but tend to (partly) improve with increasing duration of abstinence. While several studies have demonstrated that the reinstatement of comparatively normal dopaminergic signaling may take months, if not years, the amelioration of cognitive deficits has predominantly been investigated in much shorter intervals of several weeks to less than half a year. Against this background, we set out to investigate the effects on prolonged abstinence in n = 27 abstinent former methamphetamine users in a cross-sectional design using behavioral and neurophysiological measures of cognitive control. Our behavioral results suggest that former users struggled to identify and adapt to different degrees of cognitive control requirements, which made their behavioral performance less expedient than that of healthy controls. On the neurophysiological level, this was reflected by reduced modulations of the N2-N450 amplitude in response to high vs. low cognitive control requirements. Yet, those effects could only be observed in methamphetamine users who had been abstinent for a relatively short time (mean 9.9; max. 18 months), but not in former users who had been abstinent two years or longer. While this finding alone does not allow for causal inferences, it suggests that the amelioration of control deficits may take longer than what is commonly investigated (1-6 months). Hence, some of the statements about permanent/irreversible dopamine-dependent executive dysfunctions in former methamphetamine users should be interpreted with caution.

Methamphetamine Users Show No Behavioral Deficits in Response Selection After Protracted Abstinence

Introduction: Chronic recreational methamphetamine use causes dopaminergic neurotoxicity, which has been linked to impairments in executive functioning. Within this functional domain, response selection and the resolution of associated conflicts have repeatedly been demonstrated to be strongly modulated by dopamine. Yet, it has never been investigated whether chronic methamphetamine use leads to general impairments in response selection (i.e., irrespective of consumption-associated behavior) after substance use is discontinued. Materials and Methods: We tested n = 24 abstinent methamphetamine users (on average 2.7 years of abstinence) and n = 24 individually matched controls in a cross-sectional design with a flanker task. Results: Compared to healthy controls, former methamphetamine consumers had significantly slower reaction times, but did not show differences in the size of the flanker or Gratton effect, or post-error slowing. Complementary Bayesian analyses further substantiated this lack of effects despite prior consumption for an average of 7.2 years. Discussion: The ability to select a correct response from a subset of conflicting alternatives, as well as the selective attention required for this seem to be largely preserved in case of prolonged abstinence. Likewise, the ability to take previous contextual information into account during response selection and to process errors seem to be largely preserved as well. Complementing previously published finding of worse inhibition/interference control in abstinent consumers, our results suggest that not all executive domains are (equally) impaired by methamphetamine, possibly because different cognitive processes require different levels of dopamine activity.

Relationship of Working Memory, Processing Speed, and Fluid Reasoning in Psychiatric Patients

OBJECTIVE

The present study aimed to investigate relationship among cognitive factors (working memory and processing speed) and fluid reasoning (Gf) in psychiatric patients using a standardized clinical tool.

METHODS

We included the responses of 115 heterogeneous patients who were diagnosed with the MINI-Plus 5.0 and WAIS-IV/WMSIV was administered. For our analysis, structured equation modeling (SEM) was conducted to evaluate which cognitive variables are closely related to the Gf.

RESULTS

The results showed that the visual working memory was the strongest predictor of the Gf compared to other cognitive factors.

CONCLUSION

Processing speed was capable of predicting the Gf, when visual working memory was controlled. The inter-relationship among the Gf and other cognitive factors and its clinical implications were further discussed.

Modality-Specific Working Memory Systems Verified by Clinical Working Memory Tests

Objective

This study was to identify whether working memory (WM) can be clearly subdivided according to auditory and visual modality. To do this, we administered the most recent and universal clinical WM measures in a mixed psychiatric sample.

Methods

A total of 115 patients were diagnosed on the basis of DSM-IV diagnostic criteria and with MINI-Plus 5.0, a structured diagnostic interview. WM subtests of Korean version of Wechsler Adult Intelligence Scale-IV and Korean version of Wechsler Memory Scale-IV were administered to assess WM. Confirmatory factor analysis (CFA) was used to observe whether WM measures fit better to a one-factor or two-factor model.

Results

CFA results demonstrated that a two factor model fits the data better than one-factor model as expected.

Conclusion

Our study supports a modality model of WM, or the existence of modality-specific WM systems, and thus poses a clinical significance of assessing both auditory and visual WM tests.

Driving among Adolescents with Autism Spectrum Disorder and Attention-Deficit Hyperactivity Disorder

Over the past several decades there has been a surge of research on the contextual, biological, and psychological factors associated with transportation safety in adolescence. However, we know much less about the factors contributing to transportation safety among adolescents who do not follow a typical developmental trajectory. Adolescents with developmental disabilities (DD) such as Autism Spectrum Disorder (ASD) and Attention-Deficit/Hyperactivity Disorder (ADHD) have a wide range of behavioral and psychological deficits that may make the complex task of driving even more challenging. Because these adolescents often retain characteristic symptoms of their disorder into adulthood, it may impede their ability to achieve important milestones during the developmental transition from adolescent to adult. As the motivating force behind autonomous living and employment, the capacity for independent transportation is paramount to an adolescent’s overall success. This critical review will draw from the current body of literature on adolescent drivers with developmental disabilities to determine (1) areas of impairment; (2) safety risk factors; and (3) effective interventions for improving driving safety in this vulnerable population of adolescent drivers between the ages of 15–22. This review will also identify important unanswered research questions, and summarize the current state of the literature.

Factor structure of the NIH Toolbox Cognition Battery in individuals with acquired brain injury

OBJECTIVE

The National Institutes of Health Toolbox Cognition Battery (NIHTB-CB) measures reading, vocabulary, episodic memory, working memory, executive functioning, and processing speed. While previous research has validated the factor structure in healthy adults, the factor structure has not been examined in adults with neurological impairments. Thus, this study evaluated the NIHTB-CB factor structure in individuals with acquired brain injury.

METHOD

A sample of 392 individuals (ages 18-84) with acquired brain injury (n = 182 TBI, n = 210 stroke) completed the NIHTB-CB along with neuropsychological tests as part of a larger, multisite research project.

RESULTS

Confirmatory factor analyses supported a 5-factor solution that included reading, vocabulary, episodic memory, working memory, and processing speed/executive functioning. This structure generally held in TBI and stroke subsamples as well as in subsamples of those with severe TBI and stroke injuries.

CONCLUSIONS

The factor structure of the NIHTB-CB is similar in adults with acquired brain injury to adults from the general population. We discuss the implications of these findings for clinical practice and clinical research. (PsycINFO Database Record

Convergent thinking and traumatic brain injury: an investigation of performance on the remote associate test

OBJECTIVE

While deficits in several cognitive domains following moderate-to-severe traumatic brain injury (TBI) have been well documented, little is known about the impact of TBI on creativity. In the current study, our goal is to determine whether convergent problem solving, which contributes to creative thinking, is impaired following TBI.

METHODS

We administered a test of convergent problem solving, the Remote Associate Task (RAT), as well as a battery of neuropsychological tests, to 29 individuals with TBI and 20 healthy comparisons.

RESULTS

A mixed-effect regression analysis revealed that individuals with TBI were significantly less likely to produce a correct response, although on average they attempted to respond to the same number of items. Moreover, we found that the TBI (but not the comparison) group's performance on the RAT was significantly and positively associated with verbal learning and memory, providing further evidence supporting the association between declarative memory and creative convergent thinking.

CONCLUSION

In summary, our findings reveal that convergent thinking can be compromised by moderate-to-severe TBI, furthering our understanding of the higher-level cognitive sequelae of TBI.

Different aspects of facial affect recognition impairment following traumatic brain injury: The role of perceptual and interpretative abilities

It is well established that many individuals with traumatic brain injury (TBI) are impaired at facial affect recognition, yet little is known about the mechanisms underlying such deficits. In particular, little work has examined whether the breakdown of facial affect recognition abilities occurs at the perceptual level (e.g., recognizing a smile) or at the verbal categorization stage (e.g., assigning the label "happy" to a smiling face). The aim of the current study was to investigate the integrity of these two distinct facial affect recognition subskills in a sample of 38 individuals with moderate-to-severe TBI and 24 demographically matched healthy individuals. Participants were administered an affect matching (perceptual skills) and an affect labeling (verbal categorization skills) task. Statistical analyses revealed that, while individuals with TBI showed significantly higher levels of impairment in the verbal categorization task than in the perceptual task, they performed less well than healthy comparison participants on both tasks. These findings indicate that facial affect recognition impairment can occur at different cognitive stages following TBI, suggesting the necessity of careful screening to offer targeted treatment. Moreover, they provide further neuropsychological evidence supporting the notion that distinct types of subskills are necessary to achieve successful recognition of facial affects.

Factor Analysis of an Expanded Halstead-Reitan Battery and the Structure of Neurocognition

OBJECTIVE

The structure of neurocognition is explored by examining the neurocognitive domains underlying comprehensive neuropsychological assessment of cognitively healthy individuals.

METHOD

Exploratory factor analysis was conducted on the adult normative dataset of an expanded Halstead-Reitan Battery (eHRB), comprising Caucasian and African American participants. The factor structure contributions of the original HRB, eHRB expansion, and Wechsler intelligence scales were compared. Demographic effects were examined on composite factor scores calculated using confirmatory factor analysis.

RESULTS

The full eHRB had an eight-factor structure, with latent constructs including: 'working memory', 'fluency', 'verbal episodic memory', 'visuospatial cognition' (visuospatial memory and problem solving), 'perceptual-motor speed' (speed for processing visual/tactile material and hand-motor execution), 'perceptual attention' (attention to sensory-perceptual information), 'semantic knowledge' (knowledge acquired through education and culturally-based experiences), and 'phonological decoding' (grapheme-phoneme processing essential for sounding-out words). 'Perceptual-motor speed' and 'perceptual attention' were most negatively associated with age, whereas 'semantic knowledge' and 'phonological decoding' were most resistant to aging. 'Semantic knowledge' showed the greatest dependence on demographic background, including education and ethnicity. Gender differences in cognitive performances were negligible across all domains except 'phonological decoding' with women slightly outperforming men. The original HRB contributed four neurocognitive domains, the eHRB expansion three domains, and the Wechsler scales one additional domain but with restructuring of verbal factors.

CONCLUSION

Eight neurocognitive domains underlie performance of healthy cognitive individuals during comprehensive neuropsychological assessment. These domains serve as framework for understanding the constructs measured by commonly-used neuropsychological tests and may represent the structure of neurocognition.

Language, aging, and cognition: frontal aslant tract and superior longitudinal fasciculus contribute toward working memory performance in older adults

Previous research has documented change in white matter tract integrity with increasing age. Both interhemispheric and intrahemispheric tracts that underlie language processing are susceptible to these age-related changes. The aim of the current study was to explore age and white matter integrity in language-related tracts as predictors of cognitive task performance in younger and older adults. To this end, we carried out principal component analyses of white matter tracts and confirmatory factor analysis of neuropsychological measures. We next carried out a series of regression analyses that used white matter components to predict scores on each of the neuropsychological components. For both younger and older adults, age was a significant predictor of processing speed and working memory. However, white matter integrity did not contribute independently toward these models. In older adults only, both age and a white matter component that included the bilateral frontal aslant tract and left superior longitudinal fasciculus were significant predictors of working memory. Taken together, these results extend our understanding of the contributions of language-related white matter structure to cognitive processing and highlight the effects of age-related differences in both frontal and dorsal tracts.

The female advantage: sex as a possible protective factor against emotion recognition impairment following traumatic brain injury

Although moderate to severe traumatic brain injury (TBI) leads to facial affect recognition impairments in up to 39% of individuals, protective and risk factors for these deficits are unknown. The aim of the current study was to examine the effect of sex on emotion recognition abilities following TBI. We administered two separate emotion recognition tests (one static and one dynamic) to 53 individuals with moderate to severe TBI (females = 28) and 49 demographically matched comparisons (females = 22). We then investigated the presence of a sex-by-group interaction in emotion recognition accuracy. In the comparison group, there were no sex differences. In the TBI group, however, females significantly outperformed males in the dynamic (but not the static) task. Moreover, males (but not females) with TBI performed significantly worse than comparison participants in the dynamic task. Further analysis revealed that sex differences in emotion recognition abilities within the TBI group could not be explained by lesion location, TBI severity, or other neuropsychological variables. These findings suggest that sex may serve as a protective factor for social impairment following TBI and inform clinicians working with TBI as well as research on the neurophysiological correlates of sex differences in social functioning.

Latent structure of cognitive performance in the adult children study

OBJECTIVE

The Adult Children Study (ACS) at the Knight Alzheimer's Disease Research Center is a longitudinal investigation designed to identify and validate potential biomarkers of preclinical Alzheimer's disease (AD) in cognitively normal individuals with and without a family history of AD. The purpose of the current study was to validate the proposed latent structure of the ACS psychometric battery.

METHOD

Confirmatory factor analyses of baseline data in a sample of 229 (75 men) cognitively normal middle-aged to older adult individuals assessed a hypothesized 4-factor model of cognitive performance. Measurement invariance was investigated as a function of family history of AD and apolipoprotein E (APOE) status.

RESULTS

This study confirmed a priori hypotheses of 4 latent cognitive domains in a unique longitudinal sample of cognitively normal adults. In addition, there was evidence of a similar factor structure for family history and APOE status groups.

CONCLUSION

These robust indicators of a broad range of cognitive domains will be used in future investigations to track the influence of family history of AD on cognitive performance over time. In addition, associations with fluid, structural, and molecular biomarkers of preclinical AD will be further examined, both cross-sectionally and longitudinally in this sample.

The use of neuropsychological tests to assess intelligence

OBJECTIVE

We sought to derive a 'neuropsychological intelligence quotient' (NIQ) to replace IQ testing in some routine assessments.

METHOD

We administered neuropsychological testing and a seven-subtest short form of the Wechsler Adult Intelligence Scale to a community sample of 394 adults aged 18-96 years. We regressed Wechsler Full Scale IQs (W-FSIQ) on 23 neuropsychological scores and derived an NIQ from 9 measures that explained significant variance in W-FSIQ. We then compared subgroups of 284 healthy and 108 unhealthy participants in NIQ and W-FSIQ to assess criterion validity, correlated NIQ and W-FSIQ scores with education level and independence for activities of daily living to assess convergent validity, and compared validity coefficients for the NIQ with those of 'hold' and 'no-hold' indices.

RESULTS

By design, NIQ and W-FSIQ scores correlated highly (r = .84), and both were higher in healthy participants. The difference was larger for NIQ, which accounted for more variability in activities of daily living. The NIQ and 'no-hold' index were better predicted by health status and less predicted by educational status than the 'hold' index.

CONCLUSIONS

We constructed an NIQ that correlates highly with Wechsler FSIQ. Tests required to obtain NIQ are commonly used and can be administered in about 45 min. Validity properties of NIQ and W-FSIQ are similar. The NIQ bore greater resemblance to a 'no-hold' than 'hold' index. One can obtain a reasonably accurate estimate of current Full Scale IQ without formal intelligence testing from a brief neuropsychological battery.

RBANS factor structure in older adults with suspected cognitive impairment: Evidence for a 5-factor structure

Previous research has yielded minimal empirical support for the theoretically formulated five-factor structure of the RBANS, a brief, yet comprehensive standardized neuropsychological test battery used to assess cognitive impairment. The present study tested the theoretically formulated five-factor structure, as well as three alternative factor solutions, using a combination of exploratory and confirmatory factor analytic approaches. The present study utilized archival data from a clinical sample of 150 older adults who were evaluated at an outpatient neuropsychological service. A total of four RBANS models were specified using confirmatory factor analysis. Results of the five-factor model demonstrated good to excellent fit following modifications to the model. Results of chi-square difference tests demonstrated that the five-factor model was statistically superior to the two- and three-factor models (p < .001). In summary, results provide support for the theoretically derived five-factor structure of the RBANS in a clinical sample of older adults. Cautious interpretation of the RBANS index scores as five distinct cognitive domains may be warranted, particularly when there is minimal discrepancy across performance on the tests that comprise each index.

Frontal and Temporal Structural Connectivity Is Associated with Social Communication Impairment Following Traumatic Brain Injury

OBJECTIVES

Although it has been well documented that traumatic brain injury (TBI) can result in communication impairment, little work to date has examined the relationship between social communication skills and structural brain integrity in patients with TBI. The aim of the current study was to investigate the association between self- and other-perceived communication problems and white matter integrity in patients with mild to severe TBI.

METHODS

Forty-four individuals (TBI=24) and people with whom they frequently communicate, as well as demographically matched normal healthy comparisons (NC) and their frequent communication partners, were administered, respectively, the La-Trobe Communication Questionnaire Self form (LCQ-SELF) and Other form (LCQ-OTHER). In addition, diffusion tensor imaging data were collected, and fractional anisotropy (FA) measures were extracted for each lobe in both hemispheres.

RESULTS

Within the TBI group, but not within the NC group, participants who were perceived by their close others as having more communication problems had lower FA in the left frontal and temporal lobes (p<.01), but not in other brain regions.

CONCLUSIONS

Frontotemporal white matter microstructural integrity is associated with social communication abilities in adults with TBI. This finding contributes to our understanding of the mechanisms leading to communication impairment following TBI and can inform the development of new neuromodulation therapies as well as diagnostic tools. (JINS, 2016, 22, 705-716).

Construct Validity of Fluency and Implications for the Factorial Structure of Memory

Fluency is an important construct in clinical assessment and in cognitive taxonomies. In the Cattell–Horn–Carroll (CHC) model, Fluency is represented by several narrow factors that form a subset of the long-term memory encoding and retrieval (Glr) broad factor. The CHC broad classification of Fluency was evaluated in five data sets, and the CHC narrow classification was evaluated in an additional two data sets. The results suggest that Fluency tests are more strongly related to processing speed (Gs) and acquired knowledge (Gc) than to Glr, but Fluency may also be represented as a distinct broad factor. In the two additional data sets with a large number of Fluency tests, the CHC Fluency narrow factors failed to replicate with confirmatory factor analysis. An alternative and simpler narrow structure of Fluency was found, supporting the factorial distinction of semantic versus orthographic Fluency. The results have important implications for the factorial structure of memory, the classification of Fluency tests, and the assessment of Fluency.

"Intellectual developmental disorders": reflections on the international consensus document for redefining "mental retardation-intellectual disability" in ICD-11

PURPOSE

The debate as to whether intellectual disability (ID) should be conceptualized as a health condition or as a disability has intensified as the revision of World Health Organization's (WHO's) International Classification of Diseases (ICD) is being finalized. Defining ID as a health condition is central to retaining it in ICD, with significant implications for health policy and access to health services. The purpose of this paper is to include some reflections on the consensus document produced by the first WHO Working Group on the Classification of MR (WHO WG-MR) and on the process that was followed to realize it. The consensus report was the basis for the development of official recommendations sent to the WHO Advisory Group for ICD-11.

DESIGN/METHODOLOGY/APPROACH

A mixed qualitative approach was followed in a series of meetings leading to the final consensus report submitted to the WHO Advisory group. These recommendations combined prior expert knowledge with available evidence; a nominal approach was followed throughout with face-to-face conferences.

FINDINGS

The WG recommended a synonym set ("synset") ontological approach to the conceptualisation of this health condition underlying a clinical rationale for its diagnosis. It proposed replacing MR with Intellectual Developmental Disorders (IDD) in ICD-11, defined as "a group of developmental conditions characterized by a significant impairment of cognitive functions, which are associated with limitations of learning, adaptive behaviour and skills". The WG further advised that IDD be included under the parent category of neurodevelopmental disorders, that current distinctions (mild, moderate, severe and profound) be continued as severity qualifiers, and that problem behaviours removed from its core classification structure and instead described as associated features.

ORIGINALITY/VALUE

Within the ID/IDD synset two different names combine distinct aspects under a single construct that describes its clinical as well as social, educational and policy utilities. The single construct incorporates IDD as a clinical meta-syndrome, and ID as its functioning and disability counterpart. IDD and ID are not synonymous or mirror concepts as they have different scientific, social and policy applications. New diagnostic criteria for IDD should be based on a developmental approach, which accounts for the complex causal factors known to impact the acquisition of specific cognitive abilities and adaptive behaviours. The paper focuses on a new clinical framework for the diagnosis of IDD that also includes and complements the existing social, educational and policy components inherent in ID.

The Chronicity of HIV Infection Should Drive the Research Strategy of NeuroHIV Treatment Studies: A Critical Review

HIV infection has become a chronic illness when successfully treated with combined antiretroviral therapy (cART). The long-term health prognosis of aging with controlled HIV infection and HIV-associated neurocognitive disorder (HAND) remains unclear. In this review, we propose that, almost 20 years after the introduction of cART, a change in research focus is needed, with a greater emphasis on chronicity effects driving our research strategy. We argue that pre-emptive documentation of episodes of mild neurocognitive dysfunction is needed to determine their long-term prognosis. This strategy would also seek to optimally represent the entire HAND spectrum in therapeutic trials to assess positive and/or negative treatment effects on brain functions. In the first part of the paper, to improve the standard implementation of the Frascati HAND diagnostic criteria, we provide a brief review of relevant quantitative neuropsychology concepts to clarify their appropriate application for a non-neuropsychological audience working in HIV research and wanting to conduct randomized clinical trials on brain functions. The second part comprises a review of various antiretroviral drug classes and individual agents with respect to their effects on HAND, while also addressing the question of when cART should be initiated to potentially reduce HAND incidence. In each section, we use recent observational studies and randomized controlled trials to illustrate our perspective while also providing relevant statistical comments. We conclude with a discussion of the neuroimaging methods that could be combined with neuropsychological approaches to enhance the validity of HIV neurology (neuroHIV) treatment effect studies.

An improved spatial span test of visuospatial memory

In the widely used Corsi Block Test and Wechsler Spatial Span Tests, participants must reproduce sequences of blocks in the order touched by the examiner until two trials are missed at the same sequence length. The examiner records either the maximum number of blocks correctly reported or the total number of correct lists. Here, we describe a computerized spatial span test (C-SST) that uses psychophysical procedures to quantify visuospatial mean span (MnS) with sub-digit precision. Results from 187 participants ranging in age from 18 to 82 years showed that accuracy declined gradually with list length around the MnS (by ∼30% per item). Simulation studies revealed high variance and biases in CBT and Wechsler measures, and demonstrated that the C-SST provided the most accurate estimate of true span (i.e., the sequence length producing 50% correct). MnS declined more rapidly with age than mean digit span (MnDS) measured in the same participants. Response times correlated with both MnS and MnDS scores. Error analysis showed that omission and transposition errors predominated, with weaker primacy and recency effects in spatial span than digit span testing. The C-SST improves the precision of spatial span testing and reveals significant differences between visuospatial and verbal working memory.

A Cognitive Paradigm to Investigate Interference in Working Memory by Distractions and Interruptions

Goal-directed behavior is often impaired by interference from the external environment, either in the form of distraction by irrelevant information that one attempts to ignore, or by interrupting information that demands attention as part of another (secondary) task goal. Both forms of external interference have been shown to detrimentally impact the ability to maintain information in working memory (WM). Emerging evidence suggests that these different types of external interference exert different effects on behavior and may be mediated by distinct neural mechanisms. Better characterizing the distinct neuro-behavioral impact of irrelevant distractions versus attended interruptions is essential for advancing an understanding of top-down attention, resolution of external interference, and how these abilities become degraded in healthy aging and in neuropsychiatric conditions. This manuscript describes a novel cognitive paradigm developed the Gazzaley lab that has now been modified into several distinct versions used to elucidate behavioral and neural correlates of interference, by to-be-ignored distractors versus to-be-attended interruptors. Details are provided on variants of this paradigm for investigating interference in visual and auditory modalities, at multiple levels of stimulus complexity, and with experimental timing optimized for electroencephalography (EEG) or functional magnetic resonance imaging (fMRI) studies. In addition, data from younger and older adult participants obtained using this paradigm is reviewed and discussed in the context of its relationship with the broader literatures on external interference and age-related neuro-behavioral changes in resolving interference in working memory.

Inferences of Others' Competence Reduces Anticipation of Pain When under Threat

On a daily basis, we place our lives in the hands of strangers. From dentists to pilots, we make inferences about their competence to perform their jobs and consequently to keep us from harm. Here we explore whether the perceived competence of others can alter one's anticipation of pain. In two studies, participants (Receivers) believed their chances of experiencing an aversive stimulus were directly dependent on the performance of another person (Players). We predicted that perceiving the Players as highly competent would reduce Receivers' anxiety when anticipating the possibility of an electric shock. Results confirmed that high competence ratings consistently corresponded with lower reported anxiety, and complementary fMRI data showed that increased competence perception was further expressed as decreased activity in the bilateral posterior insula, a region localized to actual pain stimulation. These studies suggest that inferences of competence act as predictors of protection and reduce the expectation of negative outcomes.

Confirmatory Factor Analysis of the Dutch Version of the Wechsler Memory Scale-Fourth Edition (WMS-IV-NL)

The latent factor structure of the Dutch version of the Wechsler Memory Scale-Fourth Edition (WMS-IV-NL) was examined with a series of confirmatory factor analyses. As part of the Dutch standardization, 1,188 healthy participants completed the WMS-IV-NL. Four models were tested for the Adult Battery (16-69 years; N = 699), and two models were tested for the Older Adult Battery (65-90 years; N = 489). Results corroborated the presence of three WMS-IV-NL factors in the Adult Battery consisting of Auditory Memory, Visual Memory, and Visual Working Memory. A two-factor model (consisting of Auditory Memory and Visual Memory) provided the best fit for the data of the Older Adult Battery. These findings provide evidence for the structural validity of the WMS-IV-NL, and further support the psychometric integrity of the WMS-IV.