Attention and executive functioning profiles in children following perinatal arterial ischemic stroke

Perinatal arterial ischemic stroke (PAIS) is a form of childhood stroke; the majority of those affected experience neurologic sequelae, including motor, language and neurocognitive impairments. This study examines the attention and executive functioning (EF) profiles of children following PAIS, as well as the impact of age and sex. In this single-center cross-sectional study, 40 children aged 3 to 16 years (median age 7.2 years; 58% male) who have suffered a PAIS underwent a comprehensive neuropsychological battery to assess attention and EF. Parents completed behavioral questionnaires regarding real-world functioning. Composite scores were calculated for seven attention and EF domains (Attention, Working Memory, Verbal Retrieval, Inhibitory Control, Flexibility/Shifting, Planning/Organization, and Processing Speed). The results for all measured domains of attention and EF are significantly lower in the participants compared to the normative samples (p < .001), with the exception of Working Memory. However, increasing difficulty with Working Memory is associated with developing age. Older age at time of testing is also associated with a higher incidence of clinically-elevated attention deficit hyperactivity disorder (ADHD) symptoms. Sex is not associated with performance measures or parental report of functioning. The participants demonstrate mild-to-moderate attention and EF impairment compared to the normative population. Clinicians, families, and educators should be informed about the neurocognitive sequelae of PAIS and the need for close developmental surveillance in this population to identify vulnerable children and initiate appropriate therapeutic interventions in a timely fashion.     

Individual differences in digit span, susceptibility to proactive interference, and aptitude/achievement test scores

Individual differences in digit span, susceptibility to proactive interference, and various aptitude/achievement test scores were investigated in two experiments with adults. Susceptibility to proactive interference was estimated from performance in a position task in Experiment 1, and from the Brown-Peterson task in Experiment 2. In contrast to previous research, digit span was strongly correlated with many of the aptitude/achievement scores in both experiments, suggesting that the digit span task taps some important components of mental ability. The results of both experiments were also consistent in offering no support for the hypothesis that susceptibility to proactive interference is an important source of span differences. Finally, the results of Experiment 2 suggest that susceptibility to proactive interference is a source of individual differences in reading comprehension and knowledge of word meanings, but not in grammar and word usage skills, reading rate, or quantitative ability.     

Working memory, task switching, and executive control in the task span procedure

Four experiments explored the task span procedure: Subjects received lists of 1-10 task names to remember and then lists of 1-10 stimuli on which to perform the tasks. Task span is the number of tasks performed in order perfectly. Experiment 1 compared the task span with the traditional memory span in 6 practiced subjects and found little difference. Experiment 2 compared the task span and the memory span in 64 unpracticed subjects and also found little difference. Experiment 3 compared practice with consistent and varied lists to address retrieval from long-term memory. Experiment 4 manipulated the number of task switches and found that it had little effect on task spans. The results suggest there is no trade-off between storage and task switching, which supports some theories of executive control and challenges others.     

Transformations in the couplings among intellectual abilities and constituent cognitive processes across the life span

Abstract— Two-component theories of intellectual development over the life span postulate that fluid abilities develop earlier during child development and decline earlier during aging than crystallized abilities do, and that fluid abilities support or constrain the acquisition and expression of crystallized abilities. Thus, maturation and senescence compress the structure of intelligence by imposing age-specific constraints upon its constituent processes. Hence, the couplings among different intellectual abilities and cognitive processes are expected to be strong in childhood and old age. Findings from a population-based study of 291 individuals aged 6 to 89 years support these predictions. Furthermore, processing robustness, a frequently overlooked aspect of processing, predicted fluid intelligence beyond processing speed in old age but not in childhood, suggesting that the causes of more compressed functional organization of intelligence differ between maturation and senescence. Research on developmental changes in functional brain circuitry may profit from explicitly recognizing transformations in the organization of intellectual abilities and their underlying cognitive processes across the life span.     

Assessing acute stress with the Implicit Association Test

Assessments of acute stress using self-report questionnaires can be biased by various factors, including social desirability. The present study used a bias-free method, the Implicit Association Test (IAT), to assess stress. Unlike a previous study (Schmukle & Egloff, 2004) in which acute stress was not detected with the IAT, this study manipulated stress by generating test anxiety and threatening self-esteem. The results revealed that the IAT effect was greater in the high-stress group than in the low-stress group. Participants in the high-stress group associated their concept of self with the concept of anxiety more strongly than did those in the low-stress group. This result suggests that the IAT is a sensitive measure for detecting group differences in acute stress.     

Right hemispatial neglect: frequency and characterization following acute left hemisphere stroke

The frequency of various types of unilateral spatial neglect and associated areas of neural dysfunction after left hemisphere stroke are not well characterized. Unilateral spatial neglect (USN) in distinct spatial reference frames have been identified after acute right, but not left hemisphere stroke. We studied 47 consecutive right handed patients within 48h of left hemisphere stroke to determine the frequency and distribution of types of right USN using cognitive testing and MRI imaging. The distribution of USN types was different from the previously reported distribution following acute right hemisphere stroke. In this left hemisphere stroke population, allocentric neglect was more frequent than egocentric neglect.     

Articulatory complexity at item boundaries in serial recall: the case of Welsh and English digit span

The proposition that the difference in memory span between Welsh digits and English digits is accounted for by the longer articulatory duration of Welsh digits is critically reexamined. Two methods of measuring digit duration are contrasted. One is derived from digits spoken in isolation; the other is based on digits spoken in list format. Duration of Welsh digits was greater only when spoken in lists; with isolated production Welsh digits were significantly shorter than English digits. Also, span was shorter for Welsh digits. The results are interpreted in the light of the different articulatory demands made at the junctures between words in the English and Welsh lists. A supplementary experiment, using English words, illustrated that articulatory complexity at item boundaries increased serial recall error.     

Impact of executive dysfunctions on episodic memory abilities in patients with ruptured aneurysm of the anterior communicating artery

Executive and memory dysfunctions are among the most frequently reported deficits following a ruptured aneurysm of the anterior communicating artery (ACoA). In order to study the impact of the dysexecutive syndrome on episodic and semantic memory, the data obtained from 59 ACoA patients were examined retrospectively. All patients were assessed on a variety of episodic memory tests (Rey Auditory-Verbal Learning Test, Rey Complex Figure Test, Weschler Memory Scale), semantic memory (verbal fluency), and standardized tests of executive functions (Trail Making Test, Maze tests, Wisconsin Card Sorting Test). There was a strong positive correlation between executive dysfunction and retrieval difficulties in episodic and semantic memory tasks. Comparisons of subgroups of patients with high and low frontal lobe functioning on delayed recall and recognition revealed a significant group X condition interaction in addition to significant group and condition main effects. ACoAs patients with low frontal lobe functioning were particularly deficient in free recall (immediate and delayed) while recognition was equally well preserved in the two subgroups. Neither subgroup presented with an abnormal forgetting over time suggesting a retrieval deficit rather than a true retention impairment.     

Psychometric and behavioral measures of central auditory function: the relationship between dichotic listening and digit span tasks.

We hypothesized that the Digit Span (DS) subtest and component tasks (Wechsler, 1991) would show strong relationships with a dichotic listening test (Musiek, 1983). In two sets of archival clinical data (N = 74 and N = 51) we demonstrated that: (a) individuals with central auditory deficits had lower DS scores, F(1, 72) = 7.34, p = .008; eta2 = .09; and (b) left-ear dichotic deficits impacted forward span, F(2, 48) = 8.45, p = .001. Right-ear dichotic listening performance also accounted for significant variance in digit forward span (R2 = 0.17, p = .003). While limited in scope, the studies conclude that forward but not reverse span performance is strongly related to dichotic listening, and can serve as a marker for possible central auditory deficits.     

Predictors of distress following an acute stroke: Disability,control cognitions,and satisfaction with care

Abstract

Whilst clinical predictors of distress following acute stroke have been identified (e.g., lesion site), this study hypothesised that greater prediction would be achieved by addressing individual differences in patients' cognitions (e.g., perceived control, satisfaction with care, recovery confidence) and coping responses. We examined these relationships in a longitudinal study of 71 survivors of acute stroke. Measures were collected at three time points: 10-20 days after the stroke, and one month and six months after hospital discharge. Stepwise multiple regression analyses were performed using only significant bivariate correlates and where the dependent variables were residualised scores which controlled for baseline levels of anxiety and depression. Satisfaction with treatment and confidence in recovery at one month predicted anxiety outcome at six months, and satisfaction with advice and confidence in recovery at one month predicted depression outcome at six months. These results offer tentative suggestions for interventions targeting patient cognitions and improving patient satisfaction.     

Assessing the executive function deficits of patients with Parkinson's disease: utility of the Tower of London-Drexel

The aim of the study was to investigate the utility of the Tower of London-Drexel (TOLDX) in assessing the executive deficits associated with Parkinson's disease (PD). We sought to determine whether the TOLDX would differentiate between (a) patients with PD and healthy control participants (HCP), (b) demented and nondemented patients, and (c) depressed and nondepressed patients. A new TOLDX score, stimulus bound, was introduced to assess utilization behaviors. Furthermore, the convergent and divergent validity of the TOLDX was examined. The TOLDX total move, rule and time violation, and stimulus-bound scores of patients with PD significantly differed from the HCP. Demented and nondemented patients also differed significantly in their TOLDX performance, with the stimulus-bound score being the most significantly differentiating score. However, the depressed and nondepressed patients did not differ in their TOLDX performance. Support was found for the convergent and divergent validity of the TOLDX. The clinical and theoretical implications of the findings are discussed.     

The influence of cognitive styles and strategies in the digit span backwards task: Effects on performance and neuronal activity

The way information is processed in the brain varies strongly between individuals. A prominent distinction is made between visual and verbal processing in everyday-life as well as concrete tasks at hand. To investigate the role of routinely-used cognitive styles and task-specific cognitive strategies, n = 40 participants were presented with the digit span backwards task - which is widely used as a measure of working memory capacity - with acoustically or optically presented stimuli. In a dual task condition, the participants had to remember both an acoustically and an optically presented digit series. The task specific cognitive strategy was predictive for dual task performance, while the habitual cognitive style was not. Also, the preference for a verbal or visual cognitive style was not associated with the task specific strategy, indicating that a visual or verbal strategy can be adapted deliberately in order to perform the task at hand. Functional magnetic resonance imaging showed that a verbal processing style is associated with higher activation in the middle frontal gyrus, which is crucial for working memory performance. The results indicate that a verbal processing style is associated with more effort, possibly due to the adaptation of a task-specific strategy.     

Comparative longitudinal structural analyses of the growth and decline of multiple intellectual abilities over the life span.

Latent growth curve techniques and longitudinal data are used to examine predictions from the theory of fluid and crystallized intelligence (Gf-Gc theory; J. L. Horn & R. B. Cattell, 1966, 1967). The data examined are from a sample (N approximately 1,200) measured on the Woodcock-Johnson Psycho-Educational Battery-Revised (WJ-R). The longitudinal structural equation models used are based on latent growth models of age using two-occasion "accelerated" data (e.g., J. J. McArdle & R. Q. Bell, 2000; J. J. McArdle & R. W. Woodcock, 1997). Nonlinear mixed-effects growth models based on a dual exponential rate yield a reasonable fit to all life span cognitive data. These results suggest that most broad cognitive functions fit a generalized curve that rises and falls. Novel multilevel models directly comparing growth curves show that broad fluid reasoning (Gf) and acculturated crystallized knowledge (Gc) have different growth patterns. In all comparisons, any model of cognitive age changes with only a single g factor yields an overly simplistic view of growth and change over age.