Planning impairments in frontal lobe dementia and frontal lobe lesion patients

Planning, Cognitive Reflection, Inter-Temporal Choice, and Risky Choice in Chess Players: An Expertise Approach

This study investigates the cognitive processes underlying chess expertise by examining planning, cognitive reflection, inter-temporal choice, and risky choice in chess players. The study involves 25 chess players and 25 non-chess players, comparing their performance on the Tower of London (TOL) task, Cognitive Reflection Test (CRT), inter-temporal choice (ITC), and risky choice tasks. Results indicate that chess players outperform non-chess players in TOL and CRT, showing superior planning and cognitive reflection abilities. Chess players also prefer future rewards over immediate ones in ITC, suggesting a higher propensity for future more rewarding options. In risky choice tasks, chess players made more decisions based on expected value than non-chess players, but the evidence in favour of differences between groups is very weak. Despite this study not being able to establish causality, the findings highlight the cognitive advantages associated with chess expertise and suggest potential areas for further research on the transfer of cognitive skills from chess to other domains and differences in general abilities between experts and novices.

Neurobiological characteristics associated with gender identity: Findings from neuroimaging studies in the Amsterdam cohort of children and adolescents experiencing gender incongruence

This review has been based on my invited lecture at the annual meeting of the Society for Behavioral Neuroendocrinology in 2023. Gender incongruence is defined as a marked and persistent incongruence between an individual's experienced gender and the sex assigned at birth. A prominent hypothesis on the etiology of gender incongruence proposes that it is related to an altered or less pronounced sexual differentiation of the brain. This hypothesis has primarily been based on postmortem studies of the hypothalamus in transgender individuals. To further address this hypothesis, a series of structural and functional neuroimaging studies were conducted in the Amsterdam cohort of children and adolescents experiencing gender incongruence. Additional research objectives were to determine whether any sex and gender differences are established before or after puberty, as well as whether gender affirming hormone treatment would affect brain development and function. We found some evidence in favor of the sexual differentiation hypothesis at the functional level, but this was less evident at the structural level. We also observed some specific transgender neural signatures, suggesting that they might present a unique brain phenotype rather than being shifted towards either end of the male-female spectrum. Our results further suggest that the years between childhood and mid-adolescence represent an important period in which puberty-related factors influence several neural characteristics, such as white matter development and functional connectivity patterns, in both a sex and gender identity specific way. These latter observations thus lead to the important question about the possible negative consequences of delaying puberty on neurodevelopment. To further address this question, larger-scale, longitudinal studies are required to increase our understanding of the possible neurodevelopmental impacts of delaying puberty in transgender youth.

PsycAssist: A Web-Based Artificial Intelligence System Designed for Adaptive Neuropsychological Assessment and Training

Assessing executive functions in individuals with disorders or clinical conditions can be challenging, as they may lack the abilities needed for conventional test formats. The use of more personalized test versions, such as adaptive assessments, might be helpful in evaluating individuals with specific needs. This paper introduces PsycAssist, a web-based artificial intelligence system designed for neuropsychological adaptive assessment and training. PsycAssist is a highly flexible and scalable system based on procedural knowledge space theory and may be used potentially with many types of tests. We present the architecture and adaptive assessment engine of PsycAssist and the two currently available tests: Adap-ToL, an adaptive version of the Tower of London-like test to assess planning skills, and MatriKS, a Raven-like test to evaluate fluid intelligence. Finally, we describe the results of an investigation of the usability of Adap-ToL and MatriKS: the evaluators perceived these tools as appropriate and well-suited for their intended purposes, and the test-takers perceived the assessment as a positive experience. To sum up, PsycAssist represents an innovative and promising tool to tailor evaluation and training to the specific characteristics of the individual, useful for clinical practice.

Allometry in the corpus callosum in neonates: Sexual dimorphism

The corpus callosum (CC) is the largest fiber tract in the human brain, allowing interhemispheric communication by connecting homologous areas of the two cerebral hemispheres. In adults, CC size shows a robust allometric relationship with brain size, with larger brains having larger callosa, but smaller brains having larger callosa relative to brain size. Such an allometric relationship has been shown in both males and females, with no significant difference between the sexes. But there is some evidence that there are alterations in these allometric relationships during development. However, it is currently not known whether there is sexual dimorphism in these allometric relationships from birth, or if it only develops later. We study this in neonate data. Our results indicate that there are already sex differences in these allometric relationships in neonates: male neonates show the adult‐like allometric relationship between CC size and brain size; however female neonates show a significantly more positive allometry between CC size and brain size than either male neonates or female adults. The underlying cause of this sexual dimorphism is unclear; but the existence of this sexual dimorphism in neonates suggests that sex‐differences in lateralization have prenatal origins.

Higher-Level Executive Functions in Healthy Elderly and Mild Cognitive Impairment: A Systematic Review

Mild Cognitive Impairment (MCI) is a clinical syndrome characterized by a moderate decline in one or more cognitive functions with a preserved autonomy in daily life activities. MCI exhibits cognitive, behavioral, psychological symptoms. The executive functions (EFs) are key functions for everyday life and physical and mental health and allow for the behavior to adapt to external changes. Higher-level executive functions develop from basic EFs (inhibition, working memory, attentional control, and cognitive flexibility). They are planning, reasoning, problem solving, and fluid intelligence (Gf). This systematic review investigates the relationship between higher-level executive functions and healthy and pathological aging, assuming the role of executive functions deficits as a predictor of cognitive decline. The systematic review was conducted according to the PRISMA Statement. A total of 73 studies were identified. The results indicate that 65.8% of the studies confirm significant EFs alterations in MCI (56.8% planning, 50% reasoning, 100% problem solving, 71.4% fluid intelligence). These results seem to highlight a strong prevalence of higher-level executive functions deficits in MCI elderly than in healthy elderly.

The role of steroid hormones in the sexual differentiation of the human brain

Widespread sex differences in human brain structure and function have been reported. Research on animal models has demonstrated that sex differences in brain and behavior are induced by steroid hormones during specific, hormone sensitive, developmental periods. It was shown that typical male neural and behavioral characteristics develop under the influence of testosterone, mostly acting during perinatal development. By contrast, typical female neural and behavioral characteristics may actually develop under the influence of estradiol during a specific prepubertal period. This review provides an overview of our current knowledge on the role of steroid hormones in the sexual differentiation of the human brain. Both clinical and neuroimaging data obtained in patients with altered androgen levels/actions (i.e., congenital adrenal hyperplasia or complete androgen insensitivity syndrome [CAIS]), point to an important role of (prenatal) androgens in inducing typical male neural and psychosexual characteristics in humans. In contrast to rodents, there appears to be no obvious role for estrogens in masculinizing the human brain. Furthermore, data from CAIS also suggest a contribution of sex chromosome genes to the development of the human brain. The final part of this review is dedicated to a brief discussion of gender incongruence, also known as gender dysphoria, which has been associated with an altered or less pronounced sexual differentiation of the brain.

Cognitive reserve and regional brain volume in amyotrophic lateral sclerosis

OBJECTIVE

We investigated whether cognitive reserve measured by education and premorbid IQ allows amyotrophic lateral sclerosis patients to compensate for regional brain volume loss.

METHODS

This was a cross-sectional study. We recruited sixty patients with amyotrophic lateral sclerosis from two specialist out-patient clinics. All participants underwent neuropsychological assessment; the outcomes were standardized z-scores reflecting verbal fluency, executive functions (shifting, planning, working memory), verbal memory and visuo-constructive ability. The predictor was regional brain volume. The moderating proxies of cognitive reserve were premorbid IQ (estimated by vocabulary) and educational years. We hypothesized that higher cognitive reserve would correlate with better performance on a cognitive test battery, and tested this hypothesis with Bayesian analysis of covariance.

RESULTS

The analyses provided moderate to very strong evidence in favor of our hypothesis with regard to verbal fluency functions, working memory, verbal learning and recognition, and visuo-constructive ability (all BF₀₁ > 3): higher cognitive reserve was associated with a mild increase in performance. For shifting and planning ability, the evidence was anecdotal.

CONCLUSIONS

These results indicate that cognitive reserve moderates the effect of brain morphology on cognition in ALS. Patients draw small but meaningful benefits from higher reserve, preserving fluency, memory and visuo-constructive functions. Executive functions presented a dissociation: verbally assessed functions benefitted from cognitive reserve, non-verbally assessed functions did not. This motivates future research into cognitive reserve in ALS and practical implications, such as strengthening reserve to delay decline.

A Frontal Neuropsychological Profile in Fitness to Drive

Traffic accidents are a global concern due to the elevated mortality rates of both drivers and pedestrians. The World Health Organization declared 2011-2020 as the Decade of Action for Road Safety, endorsing initiatives to reduce traffic-related deaths. Yet, despite these incentives, fatal accidents still occur. Different studies have linked deficits in executive functions to risky driving attitudes and crashes. The present study focuses on demographic, cognitive and personality factors, related to the prefrontal cortex, that are characteristic of drivers prone to risky behavior behind the wheel. The penalty Points System was used to classify drivers as "safe", with no point loss over a two-year period, or "risky", with full point loss during the same interval. A neuropsychological assessment of prefrontal cognitive functions was carried out on each group to identify variables associated with safe and risky behavior. Neuropsychological indexes were obtained from a continuous performance task without cue (Simple Attention), a continuous performance task with cue (Conditioned Attention), the Tower of Hanoi test and the Neurologically-related Changes in Personality Inventory (NECHAPI). A Discriminant Analysis (DA) found that education level, reaction times in Simple and Conditioned Attention, learning errors in the Tower of Hanoi and vulnerability in the personality test, best predicted whether drivers were likely to be in the safe or risky group. Finally, a cross-validation analysis performed on the same sample correctly classified 87.5% of the drivers. These data suggest that prefrontal dysfunction contributes to risky behavior behind the wheel. The inclusion of cognitive programs to identify and train drivers with this propensity could reduce risky driving, and consequently, save lives on the road.

The effect of physical activity on cognition relative to APOE genotype (PAAD-2): study protocol for a phase II randomized control trial

BACKGROUND

By 2050, the prevalence of Alzheimer's disease (AD) in the United States is predicted to reach 13.8 million. Despite worldwide research efforts, a cure for AD has not been identified. Thus, it is critical to identify preventive strategies that can reduce the risk of or delay the onset of AD. Physical activity (PA) has potential in this regard. This randomized clinical trial aims to (a) test the causal relationship between PA and AD-associated cognitive function for persons with a family history of AD (FH+), (b) determine the moderating role of apolipoprotein epsilon 4 (APOE4) carrier status on cognition, and (c) assess cerebral structure, cerebral function, and putative biomarkers as mediators of the effects of PA on cognition.

METHODS

We are recruiting cognitively normal, middle aged (40-65 years) sedentary adults with FH+. Participants are randomly assigned to a 12-month PA intervention for 3 days/week or to a control group maintaining their normal lifestyle. Saliva samples are taken at pre-test to determine APOE genotype. At pre-, mid-, and post-tests, participants complete a series of cognitive tests to assess information-processing speed, verbal and visual episodic memory, constructional praxis, mnemonic discrimination, and higher-order executive functions. At pre- and post-tests, brain imaging and blood biomarkers are assessed.

DISCUSSION

We hypothesize that 1) the PA group will demonstrate improved cognition compared with controls; 2) PA-derived cognitive changes will be moderated by APOE4 status; and 3) PA-induced changes in neural and blood biomarkers will contribute to cognitive changes and differ as a function of APOE4 status. Our results may provide important insights into the potential of PA to preserve neurocognitive function in people with a heightened risk of AD due to FH+ and as moderated by APOE4 status. By using sophisticated analytic techniques to assess APOE as a moderator and neurobiological mechanisms as mediators across trajectories of cognitive change in response to PA, we will advance our understanding of the potential of PA in protecting against AD.

TRIAL REGISTRATION

ClinicalTrials.gov NCT03876314. Registered March 15, 2019.

The Effect of Planning, Strategy Learning, and Working Memory Capacity on Mental Workload

In our modern society, planning and problem solving are crucial for handling a wide range of situations. Investigation of the experienced mental workload connected to planning, strategy learning, and working memory capacity is of particular interest for adjusting conditions according to the mental state of the individual. In our study, we examined 21 subjects during a planning and a working memory task. We applied the method of Dual Frequency Head Maps (DFHM) from the electroencephalogram for capturing mental workload objectively. We evaluated the DFHM-workload index and performance data during the learning and main phase of the planning task and linked the results to subjects' working memory capacity. The DFHM-workload index indicated that subjects with higher working memory capacity experienced a gradual decrease in mental workload during strategy learning of the planning task. However, the effect of learning on mental workload disappeared during the main phase.

To what extent should expert psychiatric witnesses comment on criminal culpability?

Following the Court of Appeal case of R v Edwards in England and Wales, there has been increasing pressure for expert psychiatric witnesses to comment explicitly on how a defendant’s mental disorder affects their culpability. Culpability is the degree to which a person can be held morally or legally responsible for their conduct, but defining culpability has proved difficult. Mental disorder does not translate easily into degrees of legal culpability. Although psychiatric evidence will often be central to such cases, the determination of culpability is a matter for the court, and experts should not comment on it explicitly. Nevertheless, certain areas of psychiatry may have a bearing on culpability, and ways in which experts may comment on these are suggested. Given the pressure on judges to determine culpability, experts need to be honest about the limits of medical science to answer legal questions and the professional necessity to remain within their area of expertise.

Relationships between executive function, working memory, and decision-making on the Iowa Gambling Task: Evidence from ventromedial patients, dorsolateral patients, and normal subjects

The results of previous studies are inconsistent in regard to the relationship between the Iowa Gambling Task (IGT), working-memory (WM), and executive tasks, and whether these cognitive processes could be considered as mechanisms underlying a decision-making deficit. Moreover, the relationship between the IGT and executive measures is examined based on a limited number of executive tasks, within different populations showing diffuse damage. In addition, there are fewer studies carried out within control participants, with those studies also being inconclusive. It is also suggested that the association of the IGT performance with executive tasks depends on whether the IGT was running under ambiguity or under risk. In this work, all of these issues are studied. Results showed that both patients with ventromedial (VMPFC, N = 10) and dorsolateral (DLPFC, N = 10) prefrontal cortex lesions are significantly impaired on almost all executive tasks, WM tasks, and the IGT. Furthermore, when the IGT is run under risk, there are significant correlations between executive measures and the IGT for the DLPFC patients and the control participants (N = 34) but not the VMPFC patients. No correlation was found between WM tasks and the IGT for both frontal subgroups and control participants. These findings suggested that the mechanisms underlying the IGT deficit differ according to the lesion locations.

Planning ability impairments in probable Alzheimer's disease patients: Evidence from the Tower of London test

Alzheimer's disease (AD) is associated with progressive impairment of higher-level cognitive abilities. Previous research suggests that early impairment of executive functions occurs during the course of the disease, but few studies have specifically investigated planning ability in an AD population.

The Tower of London (ToL) in Italy: standardization of the ToL test in an Italian population

Deficit in planning and problem-solving, affecting a wide range of neuropsychological patients, has been widely investigated using the Tower of London (ToL) test, as developed by Shallice (Philos Trans R Soc Lond Ser B Biol Sci 298:199-209, 1). The ToL taps on several executive functions (EF), such as planning, time for planning or rule breaks, which may be usefully indexed by different ToL measurements. However, in its original version, the different aspects involved in ToL are not evaluated in a specific way.Here, we report the standardization of the ToL, on 896 individuals aged 15-86 years, taking in account individual factors (i.e. gender, age, years of education) which may affect performances on ToL. We computed several indexes on the ToL including score, planning and execution times, perseverations, rule breaks and self-monitoring. We found that these indexes were affected by individual factors such as gender, age and education. Present results not only provide extensive normative data according to gender, as well as different age and education ranges, but also represent a very useful instrument for a more fine-grained diagnosis of EF deficits in a wide range of neuropsychological patients, including traumatic brain injury and brain-damaged patients, as well as Alzheimer's disease and Parkinson's disease patients.

A Meta-analysis on the neural basis of planning: Activation likelihood estimation of functional brain imaging results in the Tower of London task

The ability to mentally design and evaluate series of future actions has often been studied in terms of planning abilities, commonly using well-structured laboratory tasks like the Tower of London (ToL). Despite a wealth of studies, findings on the specific localization of planning processes within prefrontal cortex (PFC) and on the hemispheric lateralization are equivocal. Here, we address this issue by integrating evidence from two different sources of data: First, we provide a systematic overview of the existing lesion data on planning in the ToL (10 studies, 211 patients) which does not indicate any evidence for a general lateralization of planning processes in (pre)frontal cortex. Second, we report a quantitative meta-analysis with activation likelihood estimation based on 31 functional neuroimaging datasets on the ToL. Separate meta-analyses of the activation patterns reported for Overall Planning (537 participants) and for Planning Complexity (182 participants) congruently show bilateral contributions of mid-dorsolateral PFC, frontal eye fields, supplementary motor area, precuneus, caudate, anterior insula, and inferior parietal cortex in addition to a left-lateralized involvement of rostrolateral PFC. In contrast to previous attributions of planning-related brain activity to the entire dorsolateral prefrontal cortex (dlPFC) and either its left or right homolog derived from single studies on the ToL, the present meta-analyses stress the pivotal role specifically of the mid-dorsolateral part of PFC (mid-dlPFC), presumably corresponding to Brodmann Areas 46 and 9/46, and strongly argue for a bilateral rather than lateralized involvement of the dlPFC in planning in the ToL. Hum Brain Mapp 38:396-413, 2017. © 2016 Wiley Periodicals, Inc.

Reliability and validity of neurobehavioral function on the Psychology Experimental Building Language test battery in young adults

Background. The Psychology Experiment Building Language (PEBL) software consists of over one-hundred computerized tests based on classic and novel cognitive neuropsychology and behavioral neurology measures. Although the PEBL tests are becoming more widely utilized, there is currently very limited information about the psychometric properties of these measures.

Methods. Study I examined inter-relationships among nine PEBL tests including indices of motor-function (Pursuit Rotor and Dexterity), attention (Test of Attentional Vigilance and Time-Wall), working memory (Digit Span Forward), and executive-function (PEBL Trail Making Test, Berg/Wisconsin Card Sorting Test, Iowa Gambling Test, and Mental Rotation) in a normative sample (N = 189, ages 18–22). Study II evaluated test–retest reliability with a two-week interest interval between administrations in a separate sample (N = 79, ages 18–22).

Results. Moderate intra-test, but low inter-test, correlations were observed and ceiling/floor effects were uncommon. Sex differences were identified on the Pursuit Rotor (Cohen’s d = 0.89) and Mental Rotation (d = 0.31) tests. The correlation between the test and retest was high for tests of motor learning (Pursuit Rotor time on target r = .86) and attention (Test of Attentional Vigilance response time r = .79), intermediate for memory (digit span r = .63) but lower for the executive function indices (Wisconsin/Berg Card Sorting Test perseverative errors = .45, Tower of London moves = .15). Significant practice effects were identified on several indices of executive function.

Conclusions. These results are broadly supportive of the reliability and validity of individual PEBL tests in this sample. These findings indicate that the freely downloadable, open-source PEBL battery (http://pebl.sourceforge.net) is a versatile research tool to study individual differences in neurocognitive performance.

Working Memory and Cognitive Flexibility Mediates Visuoconstructional Abilities in Older Adults with Heterogeneous Cognitive Ability

Previous studies suggest that executive functions influence the performance on visuoconstructional tasks. This study aims to investigate whether the relationship between planning ability and the copy of complex figures is mediated by distinct components of executive functions (i.e., working memory, inhibitory control and cognitive flexibility). We included a 129 older adults with Alzheimer's disease (n=36, AD), mild cognitive impairment (MCI, n=67), and with no evidence of cognitive impairment (controls, n=26). We evaluated the mediation effect of planning abilities, working memory, cognitive flexibility and inhibitory control on visuoconstructional tasks using a multiple mediation models. We found a significant direct effect of planning on visuoconstructional abilities and a partial mediation effect of working memory and cognitive flexibility on visuoconstructional abilities. The present results indicate that the performance on visuoconstructional task is mediated by multiple interrelated executive functions components, in particular working memory and cognitive flexibility.

Executive function in psychopathy: the Tower of London, Brixton Spatial Anticipation and the Hayling Sentence Completion Tests

Executive dysfunction in those high on traits of psychopathy has often been reported, with many disagreements as to the nature of the dysfunction. We aimed to see if tests of planning and rule acquisition/adherence would discriminate those high on psychopathic traits. A battery of executive function tests (Tower of London, Brixton Spatial Anticipation, and Hayling Sentence Completion Tasks) was given to 28 British male prisoners. Psychopathy was measured using the Psychopathy Checklist-Revised. High psychopathy was related to reduced planning in the Tower of London Test and poor rule-adherence on the Brixton Test. Other tests of executive function were not related to psychopathy. The results appear supportive of the notion that function of the orbitofrontal cortex (OFC) is dysfunctional in psychopathy whilst that of the dorsolateral prefrontal cortex (DLPFC) is normal and suggest that impulsivity in those high on psychopathy traits impedes planning and rule following. We suggest the adapted Tower of London Test and the Brixton Test could be useful objective measures of this type of impulsivity in offenders which could help identify key treatment goals.

Disorganized behavior on Link's cube test is sensitive to right hemispheric frontal lobe damage in stroke patients

One of Luria's favorite neuropsychological tasks for challenging frontal lobe functions was Link's cube test (LCT). The LCT is a cube construction task in which the subject must assemble 27 small cubes into one large cube in such a manner that only the painted surfaces of the small cubes are visible. We computed two new LCT composite scores, the constructive plan composite score, reflecting the capability to envisage a cubical-shaped volume, and the behavioral (dis-) organization composite score, reflecting the goal-directedness of cube construction. Voxel-based lesion-behavior mapping (VLBM) was used to test the relationship between performance on the LCT and brain injury in a sample of stroke patients with right hemisphere damage (N = 32), concentrated in the frontal lobe. We observed a relationship between the measure of behavioral (dis-) organization on the LCT and right frontal lesions. Further work in a larger sample, including left frontal lobe damage and with more power to detect effects of right posterior brain injury, is necessary to determine whether this observation is specific for right frontal lesions.

Putative cortical dopamine levels affect cortical recruitment during planning

Planning, the decomposition of an ultimate goal into a number of sub-goals is critically dependent upon fronto-striatal dopamine (DA) levels. Here, we examined the extent to which the val158met polymorphism in the catechol O-methyltransferase (COMT) gene, which is thought to primarily alter cortical DA levels, affects performance and fronto-parietal activity during a planning task (Tower of London). COMT genotype was found to modulate activity in the left superior posterior parietal cortex (SPC) during planning, relative to subtracting, trials. Specifically, left SPC blood oxygenation level-dependent (BOLD) response was reduced in groups with putatively low or high cortical DA levels (COMT homozygotes) relative to those with intermediate cortical DA levels (COMT heterozygotes). These set of results are argued to occur either due to differences in neuronal processing in planning (and perhaps subtracting) caused by the COMT genotype and/or the cognitively heterogeneous nature of the TOL, which allows different cognitive strategies to be used whilst producing indistinguishable behavioural performance in healthy adults. The implications of this result for our understanding of COMT's effect on cognition in health and disease are discussed.

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

PURPOSE

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

METHOD

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

RESULTS

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

CONCLUSIONS

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

Language, executive function and social cognition in the diagnosis of frontotemporal dementia syndromes

Frontotemporal dementia (FTD) represents a spectrum of non-Alzheimer's degenerative conditions associated with focal atrophy of the frontal and/or temporal lobes. Frontal and temporal regions of the brain have been shown to be strongly involved in executive function, social cognition and language processing and, thus, deficits in these domains are frequently seen in patients with FTD or may even be hallmarks of a specific FTD subtype (i.e. relatively selective and progressive language impairment in primary progressive aphasia). In this review we have attempted to delineate how language, executive function, and social cognition may contribute to the diagnosis of FTD syndromes, namely the behavioural variant FTD as well as the language variants of FTD including the three subtypes of primary progressive aphasia (PPA): non-fluent/agrammatic, semantic and logopenic. This review also addresses the extent to which deficits in these cognitive areas contribute to the differential diagnosis of FTD versus Alzheimer's disease (AD). Finally, early clinical determinants of pathology are briefly discussed and contemporary challenges to the diagnosis of FTD are presented.

Planning or something else? Examining neuropsychological predictors of Zoo Map performance

The Zoo Map Test of the Behavioral Assessment of the Dysexecutive Syndrome battery is often applied to measure planning ability as part of executive function. Successful performance on this test is, however, dependent on various cognitive functions, and deficient Zoo Map performance does therefore not necessarily imply selectively disrupted planning abilities. To address this important issue, we examined whether planning is still the most important predictor of Zoo Map performance in a heterogeneous sample of neurologic and psychiatric outpatients (N = 71). In addition to the Zoo Map Test, the patients completed other neuropsychological tests of planning, inhibition, processing speed, and episodic memory. Planning was the strongest predictor of the total raw score and inappropriate places visited, and no additional contribution of other cognitive scores was found. One exception to this was the total time, which was associated with processing speed. Overall, our findings indicate that the Zoo Map Test is a valid indicator of planning ability in a heterogeneous patient sample.

Verbal mediation of cognition in children with specific language impairment

Private speech (PS) and inner speech (IS) are thought to be functionally important for children's and adults' cognition, but they have not been studied systematically in children with specific language impairment (SLI). Participants were 21 children with SLI (7-11 years, expressive or receptive verbal IQ ≤ 75, nonverbal IQ ≥ 84) and 21 age- and nonverbal IQ-matched controls. Participants completed three sets of Tower of London problems: one with no dual task (PS condition), one with articulatory suppression, and one while foot tapping (control condition). Participants also completed a digit span task. There was no group difference in the susceptibility of Tower of London performance to articulatory suppression, but the PS of the SLI group was less internalized than that of the controls on both tasks. The findings suggest that children with SLI experience a significant delay in the development of PS/IS, but that their PS/IS is effective for Tower of London performance in middle childhood. Findings are discussed with reference to the interpretation of the nonlinguistic deficits associated with SLI, and in terms of clinical implications.

Differential patterns of planning impairments in Parkinson's disease and sub-clinical signs of dementia? A latent-class model-based approach

Planning impairments mark a well-documented consequence of neurodegenerative diseases such as Parkinson's disease (PD). Recently, using the Tower of London task we demonstrated that, rather than being generally impaired, PD patients selectively fail when planning requires flexible in-breadth search strategies. For a better understanding of the interindividual patterns underlying specific planning impairments, here we performed an explorative re-analysis of the original data using a latent-class model-based approach. Data-driven classification according to subjects' performance was based on a multinomial processing tree (MPT) model accommodating the impact of increased breadth versus depth of looking ahead during planning. In order to assess interindividual variability in coping with these different task demands, an extension of MPT models was used in which sample-immanent heterogeneity is accounted for by identifying different latent classes of individuals. Two latent classes were identified that differed considerably in performance for problems placing high demands on the depth of anticipatory search processes. In addition, these impairments were independent of PD diagnosis. However, latent-class mediated search depth-related deficits in planning performance were associated with poorer outcomes in dementia screenings, albeit sub-clinical. PD patients exhibited additional deficits related to the breadth of searching ahead. Taken together, results revealed dissociable impairments in specific planning processes within a single task of visuospatial problem solving. Present analyses put forward the hypothesis that cognitive sequelae of PD and sub-clinical signs of dementia may be related to differential patterns of planning impairments.

Executive function deficits in persons with mild cognitive impairment: a study with a Tower of London task

This study assessed executive functions in persons with mild cognitive impairment (MCI) using the Tower of London (TOL). A second objective was to study the impact of three types of problem selected according to the presence or absence of a "trigger." A trigger (T) is an incitation to the participant, at the first move, to move a ball to its final position according to the model. A positive trigger (T+) is helpful, while a negative trigger (T-) creates an obstruction. Some problems have no trigger (N). This study includes 81 participants with MCI. After follow-up, one year later, two subgroups were distinguished: (a) 51 (63%) participants did not convert or decline (stable MCI); (b) 30 (37%) participants showed significant decline or progressed to dementia (decliner MCI). Persons with MCI were compared to an older adult group matched with respect to sex, age, and education. For the successes, there was a significant group difference between the three types of problem. The post hoc analysis showed that T+ took significantly less time than N or T-. There were significantly more successes for T+ than N, and these two types of problem had more success than T-. For "total number of moves," there was no significant difference between the groups. In post hoc analysis, T- involved more moves than N or T+. In qualitative analysis, T- MCI decliners produced significantly more rule breakings than the stable MCI and controls. A dysfunction in self-monitoring is a characteristic feature of persons with MCI.

A brief review of cognitive assessment in neurotoxicology

Among commercial and industrial chemicals, cosmetics, food additives, pesticides, and medicinal drugs, there are more than 50,000 substances distributed. Neurotoxic insults to the brain can manifest in many different ways, especially involving cognition. Given many possible differences in the pathophysiology of neurotoxic exposure and related cognitive sequelae, a systematic method of cognitive assessment is important for appropriate management of neurotoxic exposure. In the context of Neurotoxicology, this article briefly reviews the contemporary literature and the utility of cognitive assessment tools that are used in neuropsychology.

Everyday action planning in schizophrenia

Planning of everyday tasks was examined in 48 inpatients with schizophrenia and 26 healthy controls. Participants were administered the Naturalistic Action Test, which requires completion of three everyday tasks (e.g., make toast and coffee). Planning variables, including planning behaviours (e.g., gathering items before engaging in a subtask) and planning time (e.g., period between task instructions and first action) were coded to evaluate forward thinking in these tasks. Results showed that planning variables were reliably coded. Controls demonstrated more planning behaviours than participants with schizophrenia; however, this difference was accounted for by education. People with schizophrenia spent significantly less time planning when planning time was analysed as a proportion of the total time on tasks. Planning variables were related to the ability to accomplish everyday task steps and to perform everyday task steps accurately. Together these findings suggest that rehabilitation strategies that emphasise both planning time and planning behaviours may facilitate everyday functioning in people with schizophrenia.

"Studying injured minds" - the Vietnam head injury study and 40 years of brain injury research

The study of those who have sustained traumatic brain injuries (TBI) during military conflicts has greatly facilitated research in the fields of neuropsychology, neurosurgery, psychiatry, neurology, and neuroimaging. The Vietnam Head Injury Study (VHIS) is a prospective, long-term follow-up study of a cohort of 1,221 Vietnam veterans with mostly penetrating brain injuries, which has stretched over more than 40 years. The scope of this study, both in terms of the types of injury and fields of examination, has been extremely broad. It has been instrumental in extending the field of TBI research and in exposing pressing medical and social issues that affect those who suffer such injuries. This review summarizes the history of conflict-related TBI research and the VHIS to date, as well as the vast range of important findings the VHIS has established.

Planning abilities and chess: A comparison of chess and non-chess players on the Tower of London task

Playing chess requires problem-solving capacities in order to search through the chess problem space in an effective manner. Chess should thus require planning abilities for calculating many moves ahead. Therefore, we asked whether chess players are better problem solvers than non-chess players in a complex planning task. We compared planning performance between chess ( N=25) and non-chess players ( N=25) using a standard psychometric planning task, the Tower of London (ToL) test. We also assessed fluid intelligence (Raven Test), as well as verbal and visuospatial working memory. As expected, chess players showed better planning performance than non-chess players, an effect most strongly expressed in difficult problems. On the other hand, they showed longer planning and movement execution times, especially for incorrectly solved trials. No differences in fluid intelligence and verbal/visuospatial working memory were found between both groups. These findings indicate that better performance in chess players is associated with disproportionally longer solution times, although it remains to be investigated whether motivational or strategic differences account for this result.

Model-free fMRI group analysis using FENICA

Exploratory analysis of functional MRI data allows activation to be detected even if the time course differs from that which is expected. Independent Component Analysis (ICA) has emerged as a powerful approach, but current extensions to the analysis of group studies suffer from a number of drawbacks: they can be computationally demanding, results are dominated by technical and motion artefacts, and some methods require that time courses be the same for all subjects or that templates be defined to identify common components. We have developed a group ICA (gICA) method which is based on single-subject ICA decompositions and the assumption that the spatial distribution of signal changes in components which reflect activation is similar between subjects. This approach, which we have called Fully Exploratory Network Independent Component Analysis (FENICA), identifies group activation in two stages. ICA is performed on the single-subject level, then consistent components are identified via spatial correlation. Group activation maps are generated in a second-level GLM analysis. FENICA is applied to data from three studies employing a wide range of stimulus and presentation designs. These are an event-related motor task, a block-design cognition task and an event-related chemosensory experiment. In all cases, the group maps identified by FENICA as being the most consistent over subjects correspond to task activation. There is good agreement between FENICA results and regions identified in prior GLM-based studies. In the chemosensory task, additional regions are identified by FENICA and temporal concatenation ICA that we show is related to the stimulus, but exhibit a delayed response. FENICA is a fully exploratory method that allows activation to be identified without assumptions about temporal evolution, and isolates activation from other sources of signal fluctuation in fMRI. It has the advantage over other gICA methods that it is computationally undemanding, spotlights components relating to activation rather than artefacts, allows the use of familiar statistical thresholding through deployment of a higher level GLM analysis and can be applied to studies where the paradigm is different for all subjects.

Utilizing virtual reality to improve the ecological validity of clinical neuropsychology: an FMRI case study elucidating the neural basis of planning by comparing the Tower of London with a three-dimensional navigation task

Virtual reality (VR) was used to create an ecologically valid spatial-navigation task in hand with functional magnetic resonance imaging (fMRI) to articulate the neural basis of planning behavior. A virtual version of a traditional planning measure, the Tower of London, was also developed to ascertain convergent and divergent validity in terms of planning behavior and functional neuroanatomy. This VR-fMRI case study experiment was performed at 3.0 Tesla on a young healthy male subject. The obtained image data suggest both convergent and divergent specificity between the two conditions in terms of location and overall intensity of activation. Overall, the present case study provides supportive evidence that the activity of various brain regions associated with planning tasks is largely modulated by the ecological validity of the measure being used. This finding may extend to all domains of inquiry in neuropsychological research and assessment when deductive conclusions are formulated on the results of neuropsychological test measures that could be considered contrived in nature.

Concurrent validity of the tower tasks as measures of executive function in adults: a meta-analysis

Executive function refers to a variety of behaviors and abilities related to planning and strategy use, as well as to the maintenance of attention and behavior in the pursuit of some goal. Many instruments have been designed for the purpose of assessing executive function, and the tower tasks represent a specific group of measures commonly used in the assessment of this construct. This review and meta-analysis examines the theoretical and psychometric basis for the use of the various tower tasks in neuropsychological assessment of adults. Neuroimaging and electrophysiological evidence are consistent with theoretical hypotheses of frontal involvement (e.g., planning and strategy use) in tower task performance. Further, adults with various disorders of presumed neurological basis demonstrate impaired performance on tower tasks. Implications for the use of tower tasks in practice and research are discussed.

D-KEFS Tower Test performance in patients with lateral prefrontal cortex lesions: the importance of error monitoring

This study investigated performance on the Delis-Kaplan Executive Function System (D-KEFS) Tower Test in a sample of 12 patients with focal lesions in the lateral prefrontal cortex (PFC) and 12 control participants. PFC patients performed worse overall, spent more time on each move, and committed significantly more rule violations. The rule violation measure demonstrated 83% sensitivity and 100% specificity in the detection of lesions. Findings highlight the importance of error monitoring in the assessment of executive functioning. These preliminary results suggest that the lateral PFC may be critical for self-monitoring/inhibition and speed of processing in planning tasks.

Differential prefrontal-like deficit in children after cerebellar astrocytoma and medulloblastoma tumor

Background

This study was realized thanks to the collaboration of children and adolescents who had been resected from cerebellar tumors. The medulloblastoma group (CE+, n = 7) in addition to surgery received radiation and chemotherapy. The astrocytoma group (CE, n = 13) did not receive additional treatments. Each clinical group was compared in their executive functioning with a paired control group (n = 12). The performances of the clinical groups with respect to controls were compared considering the tumor's localization (vermis or hemisphere) and the affectation (or not) of the dentate nucleus. Executive variables were correlated with the age at surgery, the time between surgery-evaluation and the resected volume.

Methods

The executive functioning was assessed by means of WCST, Complex Rey Figure, Controlled Oral Word Association Test (letter and animal categories), Digits span (WISC-R verbal scale) and Stroop test. These tests are very sensitive to dorsolateral PFC and/or to medial frontal cortex functions. The scores for the non-verbal Raven IQ were also obtained. Direct scores were corrected by age and transformed in standard scores using normative data. The neuropsychological evaluation was made at 3.25 (SD = 2.74) years from surgery in CE group and at 6.47 (SD = 2.77) in CE+ group.

Results

The Medulloblastoma group showed severe executive deficit (≤ 1.5 SD below normal mean) in all assessed tests, the most severe occurring in vermal patients. The Astrocytoma group also showed executive deficits in digits span, semantic fluency (animal category) and moderate to slight deficit in Stroop (word and colour) tests. In the astrocytoma group, the tumor's localization and dentate affectation showed different profile and level of impairment: moderate to slight for vermal and hemispheric patients respectively. The resected volume, age at surgery and the time between surgery-evaluation correlated with some neuropsychological executive variables.

Conclusion

Results suggest a differential prefrontal-like deficit due to cerebellar lesions and/or cerebellar-frontal diaschisis, as indicate the results in astrocytoma group (without treatments), that also can be generated and/or increased by treatments in the medulloblastoma group. The need for differential rehabilitation strategies for specific clinical groups is remarked. The results are also discussed in the context of the Cerebellar Cognitive Affective Syndrome.

Discriminant validity and neuroanatomical correlates of rule monitoring in frontotemporal dementia and Alzheimer's disease

Despite the predominant frontal neuropathology of frontotemporal dementia (FTD), traditional measures of executive functioning do not reliably distinguish FTD from Alzheimer's disease (AD). Performance monitoring is an executive function that is associated with frontal lobe integrity and may be disrupted in FTD. The current study adopted a component process approach to evaluate the discriminant validity and neuroanatomical correlates of performance monitoring (i.e., rule monitoring) during an executive spatial planning task. Forty-four participants with FTD, 30 with AD, and 27 healthy comparison (HC) subjects completed the Delis-Kaplan Executive Function System (D-KEFS) Tower task. A subset of patients underwent structural magnetic resonance imaging to obtain regional measures of cortical volumes. FTD and AD groups demonstrated significantly poorer overall achievement scores on the Tower test relative to the HC sample, but did not differ from one another. In contrast, the FTD group committed significantly more rule violation errors than both HC and AD groups, indicating poorer performance monitoring. In addition, poorer overall achievement correlated with smaller brain volumes in several regions, including bilateral frontal and parietal regions, whereas an increased number of rule violations correlated specifically with decreased bilateral frontal volume. Both left and right frontal volumes remained significant predictors of rule violation errors after controlling for the contribution of overall achievement on the task and all other brain regions. Findings are consistent with literature implicating the frontal lobes in performance monitoring and highlight the importance of characterizing the component processes of performance failures in the cognitive assessment of FTD and AD.

Visuospatial planning and problem solving in Alzheimer's disease patients: a study with the Tower of London Test

BACKGROUND

Executive dysfunction in Alzheimer's disease (AD) has been recently recognized as an early and prominent clinical sign. The Tower of London (ToL), a task specifically devised to test executive functions of visuospatial planning and problem solving, has frequently been used in neuropsychological experiments, but rarely in the clinical ground.

METHODS

One hundred and sixty-one AD patients and 212 nondemented healthy controls were administered a simplified ToL version.

RESULTS

AD patients were significantly impaired (p < 0.0001) in all ToL scores and in the total execution time. The 'accuracy' score of ToL at a cut off of

CONCLUSIONS

Visuospatial planning and problem solving are significantly impaired in early dementia of the Alzheimer's type. A successful sensitivity/specificity ratio, the independence of education and the simplicity of this version of ToL make it a useful executive functioning screening test for early AD.

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MESH Headings

• Aged
• Alzheimer Disease/diagnosis
• Alzheimer Disease/epidemiology
• Cognition Disorders/diagnosis
• Cognition Disorders/epidemiology
• Female
• Humans
• Male
• Neuropsychological Tests
• Perceptual Disorders/diagnosis
• Perceptual Disorders/epidemiology
• Prevalence
• Severity of Illness Index
• Space Perception/physiology
• Visual Perception/physiology

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Affiliation(s)

Massimo Franceschi Neurology Department, IRCCS Multimedica, Castellanza, Italy.
Paolo Caffarra
Luc De Vreese
Oriana Pelati
Samantha Pradelli
Rita Savarè
Renata Cerutti
Enzo Grossi

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