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Can the frontal assessment battery (FAB) differentiate bradykinetic rigid syndromes? Relation of the FAB to formal neuropsychological testing.

The frontal assessment battery (FAB) is a bedside test of executive function. It takes less than 10 minutes to administer and a low score indicates executive dysfunction. To determine whether the FAB could detect the more severe subcortical dementia that is a feature of PSP and differentiate it from other bradykinetic rigid syndromes, we studied 17 patients with progressive supranuclear palsy (PSP); 11 with multiple system atrophy (MSA) and 12 with Parkinson's disease (PD). We compared FAB scores with the results of more detailed tests of executive and general cognitive function.FAB scores were significantly lower in PSP than in MSA or PD (p=0.02 and p<0.001) and were also found to be significantly lower in MSA than in PD (p=0.047). We divided the study group into those with an FAB score <15 and those with an FAB score>/=5, regardless of the clinical diagnosis. While 82% of the PSP group had FAB scores of <15, such scores were recorded in only 36% of the MSA and 8% of the PD groups. The lexical fluency and motor series subscores of the FAB discriminated 70% of the PSP, MSA and PD patients. The FAB scores correlated with tests of executive function, as well as with scores on the Mattis Dementia Rating Scale, the Mini Mental State Examination and other tests of general cognitive function. A stepwise regression analysis revealed that across the groups, among the variables that correlated with FAB scores, alternating semantic fluency accounted for 80% of FAB variance.These results suggest that the FAB is a valid and easily applicable bedside test to discriminate executive dysfunction in these three frequently confused bradykinetic rigid syndromes.

Aged↗

Age differences in stroop interference in working memory.

Working memory capacity can be conceptualized as the ability to use controlled attention in short term memory (Engle, Tuholski, Laughlin, & Conway, 1999). We tested this idea in young and older adults by combining the task demands of two neuropsychological tests, word span, and Stroop color-naming. Young and older adults were asked to name the colors of a series of congruent and incongruent color-words (between 2 and 6 words/trial). After all the color-words were presented participants attempted to recall the colors in their serial order. This task required inhibition of the prepotent word reading response (i.e., color naming), with a concurrent memory load (caused by the need to maintain already named colors in short-term memory). Older adults showed greater interference effects, and these interference effects increased as a function of memory load. Regression analyses showed that measures of working memory capacity and executive function accounted for unique variance in incongruent color-word errors for older adults. Defining working memory capacity as the ability to use controlled attention in short-term memory may be a fruitful way to think about this concept in studies of executive function.

Adult↗

Clustering and switching on verbal and figural fluency functions in adults with attention deficit hyperactivity disorder.

INTRODUCTION: Neuropsychological studies of adult patients with ADHD have revealed marked disturbances of executive functions including impairments of attention, working memory, impulsivity, shifting, and divergent thinking. Phonemic fluency tasks, in particular, have been shown to be sensitive measures for the assessment of executive functions of adults with ADHD. METHODS: The present study has examined figural fluency and both phonemic and semantic verbal fluency in 34 adult patients with ADHD and 34 healthy participants. For evaluation of fluency performance the number of words or designs, the number of repetitions and the number of deviations from test rules were calculated. Furthermore, clustering strategies and switching responses were analysed. In comparison with healthy participants, patients with ADHD produced significantly fewer words or designs, but they did not differ from healthy participants in the number of repetitions or rule violations. RESULTS: Analysis of switching and clustering showed that patients produced significantly fewer switching responses on both verbal fluency tasks, although patients tended to generate smaller clusters. Switching on the figural fluency task was unimpaired. CONCLUSIONS: The results of the present study suggest that adult patients with ADHD may suffer from a dysfunction that may affect retrieval processes and the categorisation of knowledge.

Journal Article↗

Prenatal exposure to marihuana and tobacco during infancy, early and middle childhood: effects and an attempt at synthesis.

Both marihuana and cigarettes appear implicated, in a differential fashion, in the neurobehaviour of infants and children born to women who used these substances during pregnancy. In a low-risk upper middle class sample, marihuana use was associated, in the newborn, with mild withdrawal symptoms and some autonomic disruption of nervous system state regulation. However, between 6 months and 3 years of age no behavioural consequences of marihuana exposure (once confounding factors were controlled) were noted. At four years of age, although global tests of intelligence did not differentiate exposed from non-marihuana exposed children, verbal ability and memory were associated with in utero marihuana exposure. At five and six years of age these general areas were also noted to be associated with maternal cannabis use as was sustained attention. These areas of neurobehavior that appear affected by marihuana exposure during fetal development are ones that are consistent with the cognitive construct of 'executive functioning' which is thought to be a marker of prefrontal lobe functioning. Consistent with the observations derived from these children is that prefrontal functioning may not be apparent until approximately four years of age and that executive functioning is disassociated from measures of global intelligence. Exposure to cigarettes during pregnancy appears to be associated with neurobehavioural deficits in the auditory domain. In the newborn this is manifested by decreased responsivity to sound and altered auditory habituation. Between the ages of one and 11 years the performance on auditory related tasks (verbal memory, language, auditory processing) were consistently the domains that differentiated the cigarette exposed from the non exposed children. The possible role of the cholinergic mediated efferent auditory system is discussed. Also associated with in utero exposure to cigarettes were general cognitive performance and parental reports and objectively derived measures of impulsivity. The striking degree of consistency over the years lends strength to the interpretation that the observations in childhood have, at least as their partial etiology, the prenatal exposure to cigarettes. However, in interpreting the evidence presented it must be recognized that the alterations in the child's behaviour may well affect the parenting behaviour. This potential transactional interaction must remain an integral part of drawing conclusions about both marihuana and cigarette's effects.

Behavior↗

A developmental perspective on the measurement of cognitive deficits in attention-deficit/hyperactivity disorder.

Research on the cognitive deficits associated with attention-deficit/hyperactivity disorder has highlighted deficits in executive function in individuals with the disorder. This article suggests deconstructing the umbrella term "executive function" and focuses on one of its component processes: cognitive inhibition. Cognitive developmental psychology research suggests that component processes, such as cognitive inhibition, should be examined from a variety of approaches to fully appreciate patterns of competency and deficit. This article contrasts cognitive inhibition from behavioral inhibition and resistance to interference. Two types of cognitive inhibition, automatic and intentional, are proposed. Finally, suggestions for guiding research design are taken from the cognitive developmental psychology literature. These include studying very limited age ranges and conducting longitudinal research, investigating qualitative and quantitative differences in performance, examining the underlying processing and strategy differences between populations, and investigating multiple aspects of performance between populations.

Animals↗

COMT genotype, gender and cognition in community-dwelling, older adults.

A common polymorphism (Val158Met) in the gene encoding for the catechol-O-methyltransferase (COMT) enzyme has been associated with differences in prefrontal cognitive function in schizophrenic patients and healthy adults. While several studies indicate that the Met allele is associated with better performance on measures of executive function, working memory and verbal fluency, results have been inconsistent. Furthermore, fewer studies have investigated this relationship in older adults, a group known to experience impairments in prefrontal cognitive functions. Additionally, findings vary according to the gender distribution of study participants. We examined whether COMT genotype interacted with gender to impact cognition in a cohort of 163 healthy, older adults. Memory, verbal ability and areas of prefrontal cognitive function, including attention, speed-of-processing, and executive function, were assessed. We found no significant association between COMT genotype and any cognitive measure. However, gender interacted with COMT genotype to impact cognitive performance. Males homozygous for the Val allele performed better than both the Val/Met and Met/Met groups on measures of delayed recall. Heterozygous women performed better than their homozygous counterparts on the measure of verbal ability. These findings suggest that gender may be an important variable in consideration of the impact of COMT on cognition. Further, when gender is taken into consideration, any negative impact of COMT genotype may extend to cognitive domains other than those associated with prefrontal regions.

Aged↗

Genetic influences on frontal brain function: WCST performance in twins.

The Wisconsin Card Sorting Test (WCST) is one of the most widely used assessments of executive functioning related to prefrontal cortex. However, little is known about genetic and environmental determinants of individual differences in WCST performance. This study assessed heritability of standard WCST scores in a sample of 168 young female twins including 58 monozygotic and 25 dizygotic pairs. Several WSCT indices, including the number and percentage of errors, the number of perseverative responses, and the number and percent of perseverative errors, showed significant heritability ranging from 37 to 46%. The results suggest that selected aspects of frontal executive functioning measured by the WCST are moderately influenced by genetic factors.

Adolescent↗

Genetically predisposed offspring with schizotypal features: an ultra high-risk group for schizophrenia?

Biomarkers proposed in the schizophrenia diathesis have included neurocognitive deficits in domains such as working memory that implicate prefrontal systems. However, the relationship between these biomarkers and psychopathological markers such as schizotypy has not been systematically assessed, particularly in adolescent offspring of schizophrenia patients. Convergence between these markers may identify individuals at especially high risk for schizophrenia. In the current study the authors assessed whether functional deficits in working memory assessed using the oculomotor delayed response task (ODR) and executive function assessed using the Wisconsin Card Sort task (WCST), and structural deficits in prefrontal cortex, in the adolescent offspring of patients were predictive of schizotypy. Schizotypal offspring made more perseverative errors on the WCST (p<.002) and showed age-related deficits on the ODR task (p<.02) compared to their non-schizotypal counterparts or healthy controls. Reduced gray matter concentration in prefrontal cortex (p<.001) was also associated with schizotypy. Schizotypy in offspring of schizophrenia patients appears to be highly associated with known biomarkers of the illness such as executive function impairment and reductions in cortical gray matter. Furthermore, schizotypy appears to interact with development leading to greater impairment in working memory in schizotypal offspring closer to the typical age of onset of schizophrenia than non-schizotypal offspring. Thus, clinical and neurocognitive biomarkers of the illness appear to be highly interrelated in this sample of at-risk offspring. We propose that schizotypy may define a hyper vulnerable sub-sample among individuals genetically predisposed to schizophrenia and that future studies that attempt to assess risk may benefit from such a convergent approach.

Adolescent↗

Deficits in predictive smooth pursuit after mild traumatic brain injury.

Given that even mild traumatic brain injury (TBI) may produce extensive diffuse axonal injury (DAI), we hypothesized that mild TBI patients would show deficits in predictive smooth pursuit eye movements (SPEM), associated with impaired cognitive functions, as these processes are dependent on common white matter connectivity between multiple cerebral and cerebellar regions. The ability to predict target trajectories during SPEM was investigated in 21 mild TBI patients using a periodic sinusoidal paradigm. Compared to 26 control subjects, TBI patients demonstrated decreased target prediction. TBI patients also showed increased eye position error and variability of eye position, which correlated with decreased target prediction. In all subjects, average target prediction, eye position error and eye position variability correlated with scores related to attention and executive function on the California Verbal Learning Test (CVLT-II). However, there were no differences between TBI and control groups in average eye gain or intra-individual eye gain variability, or in performance on the Wechsler Abbreviated Scale of Intelligence (WASI), suggesting that the observed deficits did not result from general oculomotor impairment or reduced IQ. The correlation between SPEM performance and CVLT-II scores suggests that predictive SPEM may be a sensitive assay of cognitive functioning, including attention and executive function. This is the first report to our knowledge that TBI patients show impaired predictive SPEM and eye position variability, and that these impairments correlate with cognitive deficits.

Adolescent↗

The neuropsychological phenotype of velocardiofacial syndrome (VCFS): relationship to psychopathology.

Children with velocardiofacial syndrome (VCFS; N=14) and a comparison group of siblings (N=8) underwent comprehensive neuropsychological assessment to examine the relationship between cognitive functioning and psychopathology. Significant group differences were obtained on tests of full scale and verbal intellectual functioning and perceptual-motor skills. With the exception of performance on tests of attention and executive functioning, children with VCFS displayed a profile consistent with nonverbal learning disability (NLD). However, within group comparisons revealed significantly poorer visuospatial intellectual and nonverbal memory functioning in sibling controls as well. No significant group differences were obtained on tests of motor speed, academic, language, attention, memory, or executive functioning, with significant variability in children with VCFS frequently accounting for the lack of robust differences. Parent-report measures revealed profiles consistent with ADHD. No clinically significant symptoms of psychosis, depression or anxiety were noted on either self- or parent-report measures. Wisconsin Card Sorting Test performance was found to be highly and negatively correlated with the Thought Problems subscale of the Child Behavior Checklist (CBCL) for VCFS children only, suggesting a possible at-risk indicator for later onset psychopathology.

Chromosomes, Human, Pair 21↗

Planning, problem-solving and organizational abilities in children following traumatic brain injury: intervention techniques.

Due to the mechanisms involved in traumatic brain injury (TBI), the frontal lobes are often impacted. As the frontal regions of the brain are believed to subsume executive functioning, then it follows that post-TBI deficits may be seen in this domain. Executive functioning broadly refers to a set of inter-related skills necessary to maintain an appropriate problem-solving set for the attainment of a future goal and may include areas such as attentional control, planning, problem-solving, cognitive flexibility, abstraction and information processing. The literature available on interventions for executive difficulties following TBI is minimal, with that focused on the paediatric population even more limited. From the few evaluation studies available, results tend to suggest that specific types of intervention lead to positive outcomes. However, as the interventions are few and often based on case studies, there is much need for more evaluation studies to be conducted.

Brain Injuries↗

A meta-analysis of the sensitivity and specificity of the Stroop Color and Word Test with children.

The purpose of this paper is to examine the extent to which the Stroop Color-Word Test demonstrates sensitivity and specificity for the identification of executive function deficits in children and adolescents. Meta-analytic methods were used to identify executive function deficits associated with attention deficit hyperactivity disorder (ADHD) and other developmental disorders. Weighted effect sizes were calculated for all studies found that compared groups of children on the Stroop task. Results indicated that across studies, children and adolescents with ADHD fairly consistently exhibited poorer performance when compared to individuals without clinical diagnoses on the Stroop task as measured by the weighted Word, Color, Color-Word, and Interference scores. The Stroop task did not discriminate ADHD groups from other clinical groups consistently across studies. In conclusion, while impaired performance of the Stroop task may be indicative of an underlying neurological disorder related to frontal lobe dysfunction, poor performance is not sufficient for a diagnosis of ADHD.

Adolescent↗

The clock drawing test: diagnostic, functional, and neuroimaging correlates in older medically ill adults.

This study evaluated the clock drawing test (CDT), a screening test sensitive to executive function, in 70 elderly psychiatric consultation patients. The CDT was compared to the Mini-Mental Status Examination (MMSE) on associations with psychiatric diagnoses, disposition status and radiographic findings. CDT and MMSE were correlated, and scores differed across psychiatric subgroups. In multivariate analysis, only age and CDT predicted disposition status. A lower CDT score correlated with a higher intercaudate ratio, indicating greater caudate atrophy. These findings suggest that the CDT indicates underlying subcortical pathology and deficiencies in executive function important for self-care.

Aged↗

Functional independence staging: conceptual foundation, face validity, and empirical derivation.

OBJECTIVE: To develop a staging system for functional independence across the activities of daily living (ADLs), sphincter-management, mobility, and executive-function domains (ASME) for the FIM instrument that is consistent with the International Classification of Functioning, Disability and Health. DESIGN: National data were used to define the stages. We searched for the most likely configurations of item scores that increased ability to perform component activities in each domain by approximately 1 level per item per stage. SETTING: Inpatient rehabilitation facilities. PARTICIPANTS: Data from 218,290 people discharged from 560 US inpatient rehabilitation facilities in 1995. INTERVENTIONS: Not applicable. MAIN OUTCOME MEASURES: Activity profiles formed from FIM scores. RESULTS: Seven stages were defined separately for each ASME domain. Stages approximate the average amount of effort expended by the patient when performing the component activities included in a domain, beginning with less than 25% of effort at the lowest total assistance (stage 1) and ending with 100% effort at the highest complete independence (stage 7). Consistent with developmental principles, independence is achieved at lower stages in the most fundamental activities of eating, transfers, and communication. Recovery of independence in the more difficult activities of bathing, stair climbing, and problem solving does not occur until the higher stages are reached. The degree of independence is described with a shorthand abbreviation of the domains followed by the stage the patient has reached in each domain. For example, ASME 5,1,6,7 indicates need for supervision in the ADLs (A-5), total assistance in sphincter management (S-1), modified independence in mobility (M-6), and complete independence in executive functions (E-7). CONCLUSIONS: ASME stages serve as a common language and shorthand for expressing the functional consequences of illness and injury, while complementing information about impairment and diagnosis, thereby facilitating communication, assessment, and goal setting in terms that are meaningful to patients and their care givers.

Activities of Daily Living↗

Cardiovascular risk factors and cognitive function in African Americans.

The present study examined the cross-sectional association of medically determined cardiovascular risk factors with cognitive function in 43 African Americans (aged 43-82 yr; 83% women). Measures of attention, memory, and executive functions were evaluated in relation to blood pressure (BP), total cholesterol, glycosylated hemoglobin (HbA1c), and fitness level (peak O(2)). Multiple regression analyses with age, education, number of antihypertensive medications, HbA1c, diastolic BP, and peak O(2) as predictors revealed significant (and marginally significant) associations between lower levels of fitness (peak O(2)) and poorer executive functions and delayed verbal memory. Antihypertensive medications were associated with poorer attention, but better delayed verbal memory. In addition, greater levels of HbA1c were positively related to attention. These results suggest that cardiovascular risk factors are important predictors of cognitive function among middle-aged and older African Americans.

Adult↗

Disentangling deficits in adults with attention-deficit/hyperactivity disorder.

CONTEXT: A lack of inhibitory control has been suggested to be the core deficit in attention-deficit/hyperactivity disorder (ADHD), especially in adults. This means that a primary deficit in inhibition mediates a cascade of secondary deficits in other executive functions, such as attention. Impaired stopping has been claimed to support the inhibition hypothesis. However, executive functions such as inhibition and attention are hard to disentangle. OBJECTIVE: To use event-related potentials in adult patients with ADHD to show that impaired stopping is associated with abnormalities of attention. DESIGN: The stop signal task was presented to 24 adults with ADHD combined subtype and 24 controls. Stop event-related potentials are distorted by overlap from event-related potentials to other stimuli in close temporal proximity, but we applied a method (Adjar level 2) to effectively remove this overlap. RESULTS: In line with an inhibitory control deficit, the stop signal reaction time was longer in adults with ADHD (F(1,46) = 7.12, P<.01) whereas there was no significant difference for go stimulus reaction time. Overlap-free stop event-related potentials revealed smaller stop P3s in adults with ADHD (F(1,44) = 4.20, P<.05). In children with ADHD, this has been interpreted to reflect deficient inhibitory control. However, controls were also found to have larger early responses in the auditory cortex (N1) when stop signals resulted in successful stops, relative to failed stops, signifying increased attention (F(1,23) = 11.88, P<.01). This difference was completely absent in adults with ADHD. CONCLUSIONS: Disturbed attentional processing of the stop signal contributed to impaired stopping in adults with ADHD. This finding may have implications for treatment.

Adolescent↗

Walking is more like catching than tapping: gait in the elderly as a complex cognitive task.

Walking is generally viewed as an automated, over-learned, rhythmic motor task and may even be considered the lower-limb analog of rhythmic finger tapping, another automated motor task. Thus, one might hypothesize that walking would be associated with a simple rhythmic task like tapping rather than with a complex motor task like catching. Surprisingly, however, we find that among older adults, routine walking has more in common with complex motor tasks, like catching a moving object, than it does with tapping. Tapping performance, including both the average tapping interval and the variability of tapping interval, was not significantly associated with any gait parameter (gait speed, average stride time and stride time variability). In contrast, catch game performance was significantly associated with measures of walking, suggesting that walking is more like catching than it is like tapping. For example, participants with a higher gait speed tended to have lower times to first move when catching, better catching accuracy, and less catching errors. Stride time variability was significantly associated with each of the measures of catching. Participants with a lower stride time variability (a more steady gait) had better catching accuracy, lower time to first move, fewer direction changes when moving the cursor to catch the falling object, and less catching errors. To understand this association, we compared walking performance to performance on the Stroop test, a classic measure of executive function, and tests of memory. Walking was associated with higher-level cognitive resources, specifically, executive function, but not with memory or cognitive function in general. For example, a lower (better) stride time variability was significantly associated with higher (better) scores on the Stroop test, but not with tests of memory. Similarly, when participants were stratified based on their performance on the Stroop test and tests of memory, stride time variability was dependent on the former, but not the latter. These findings underscore the interconnectedness of gait and cognitive function, indicate that even routine walking is a complex cognitive task that is associated with higher-level cognitive function, and suggest an alternative approach to the treatment of gait and fall risk in the elderly.

Aged↗

[Visuospatial context processing in untreated schizophrenic patients and relation to disorganization syndrome].

AIM: Previous studies on schizophrenia have suggested that context-processing disturbances were one of the core cognitive deficits present in schizophrenia. Schizophrenic patients have a failure either of inhibition strategy and maintenance of visuospatial information (25) in condition of contextual interference. In the present study, we explored the performances of untreated schizophrenic patients with 2 tasks exploring detection and long term retention of complex visual features and field dependence-independence tasks were selected. These abilities involve temporary maintenance of visuospatial information and executive functioning of visual working memory system. Several studies have shown that cognitive deficit may depend on schizophrenic symptomatology. However results remain controversial in determining the specific influence of negative and positive symptomatologies as well as clinical disorganization. Our goal was to explore the processing of spatial context and its relation to disorganized syndrome. This study was approved by the local ethic committee. METHODOLOGY: Thirty-six schizophrenic patients were included according to DSM IV criteria (19 neuroleptic naïve, 17 unmedicated patients during more than 3 months). Thirty-six healthy controls were matched to patients for age, gender and level of education. Absence of axis 1 pathology was attested for controls with SCID-NP. Current symptomatology was evaluated by the Positive and Negative Syndrome Scale (PANSS) (14). Clinical disorganisation was evaluated with the disorganisation score established upon a factorial analysis of PANSS by Lepine and Lançon. Items selected to distinguish the disorganised group were abstraction, disorganization, orientation, and attention. PROCEDURE: Two tasks of embedded figures were administered individually to patients and controls. The Faverge task (Research of Figures-RF) (10) evaluates the ability to recognize the target from spatial complex geometrical figures. The Group Embedded Figure Task (GEFT - Oltman) assesses the detection and maintenance of visual target and its recognition within a complex figure. Performance between patients and controls were compared with the Student T test. The comparison of two clinical subgroups of disorganized and low disorganized patients and control group was performed with an ANOVA. Tuckey test was used for pairwise comparisons. RESULTS: We defined two subgroups of patients, disorganized patients (subscore 12, n=17) and low disorganized patients (subscore<12, n=19). Theses 2 subgroups were similar for age and level of education. Concerning the two tasks, there was no significant difference between schizophrenic patients and normal controls. The comparison between subgroups of disorganized and low disorganized patients, for RF task, showed a decrease of correct answers with disorganized patients (p<0.05). For GEFT task, disorganized patients had a decrease of correct answers p<0.01) and more errors (p<0.01) and omissions (p<0.05). The low disorganized patients exhibited for the two tests comparable performance to controls. The disorganized patients had a decrease of right answers (p<0.05) and more errors (p<0.05) than controls for GEFT task and no significant difference for RF. However, with IQ (evaluated with an abstract reasoning test) introduced as covariate, only correct answers for GEFT task remain significant (p<0.05). DISCUSSION: The weak performance of disorganized schizophrenic patients for two tasks RF and GEFT showed that treatment of visuospatial information was impaired in the first perceptive phase of selection and in the organization of information (RF), especially with the maintenance of visual information in memory (GEFT). By contrast, low disorganized patients demonstrated a correct analytic treatment of elementary processing and visuospatial working memory. CONCLUSION: The severity of disorganization influences the visuospatial context processing and visuospatial working memory. These results show the heterogeneity of cognitive functioning regarding to schizophrenic symptomatologies. This difficulty could be related to a problem of central executive functioning in the visuospatial component of working memory, possibly mediated by the dysfunction of dorsolateral prefrontal cortex.

Adult↗