Impaired task switching performance in children with dyslexia but not in children with autism

High autistic traits linked with reduced performance on affective task switching: An ERP study

Few studies have investigated affective flexibility in individuals with high autistic traits. In the present study, we employed affective task-switching paradigm combined with event related potential (ERP) technology to explore affective flexibility in individuals with high autistic traits. Participants were instructed to switch between identifying the gender (gender task) and emotion (emotion task) of presented faces. Two groups of participants were recruited based on the Autism Spectrum Quotient (AQ) scores: a High Autistic Group (HAG) and a Low Autistic Group (LAG). The results confirmed that the HAG exhibited greater behavioral emotion switch costs and increased N2 and decreased P3 components when switching to the emotion task. Additionally, we identified an affective asymmetric switch cost in the HAG, where the switch cost for the emotion task was larger than for the gender task at both behavioral and electrophysiological levels. In contrast, a symmetrical switch cost was observed in the LAG. These findings indicate that the HAG experiences difficulties with affective flexibility, particularly in tasks involving emotional processing. The patterns of affective asymmetric switch costs observed in both groups differed from previous results in autistic children and the general population, suggesting that the relative dominance of gender and emotion tasks may vary between the two groups. We propose that the dominance of emotion tasks declines as autistic traits increase.

Error-monitoring: A predictor of future reading skills? A 3-year longitudinal study in children

Investigation of the factors explaining individual differences in the acquisition of expert reading skills has become of particular interest these last decades. Non-verbal abilities, such as visual attention and executive functions play an important role in reading acquisition. Among those non-verbal factors, error-monitoring, which allows one to detect one's own errors and to avoid repeating them in the future, has been reported to be impaired in dyslexic readers. The present three-year longitudinal study aims at determining whether error-monitoring efficiency evaluated before and during reading instruction could improve the explanation of reading skills. To do so, 85 children will be followed from the last year of kindergarten to the second grade. The classic predictors of reading will be assessed at each grade level. Error-monitoring indices in domain-general and reading-related contexts will be derived from EMG data recorded during a Simon task in kindergarten and during both a Simon and a lexical decision tasks in the first and second grades. Findings concerning the role of error-monitoring on reading skills are expected to have an important impact on reading instruction to prevent reading difficulties in at-risk children and improve remediation to help children with reading difficulties.

Associations between Executive Functions and Sensorimotor Performance in Children at Risk for Learning Disabilities

Executive functions (EF) and sensorimotor skills play a critical role in children's goal-directed behavior and school readiness. The aim of the current study is to provide new insights into the relationship between executive functions and sensorimotor development by considering the risks associated with learning difficulties. Therefore, we investigate the predictive role of EF and sensorimotor skills in the development of learning difficulties during preschool years. Ninety-five preschool children (5-7 years old) were tested, comparing the performance of children that are at risk of learning difficulties (n = 55) to the performance of typically developing children (n = 40). Participants completed a battery for the assessment of sensorimotor skills (i.e., Southern California Sensory Integration Test: postural imitation, body midline crossing, bilateral motor coordination, and standing balance with eyes open) and executive functions (i.e., inhibition, cognitive flexibility, and verbal working memory). Our results show that children at risk for learning difficulties exhibited more impairments on sensorimotor and EF measures (inhibition and verbal working memory) when compared with TD children. We ran three separate binary logistic regression analyses to assess the relative influence of EF and sensorimotor functions on predicting risk for learning difficulties. Our findings demonstrated that verbal working memory as EF function (odd ratio (OR) = 0.91, 95% CI 0.78-0.91, P = 0.05) and standing balance skills as a sensorimotor skill (odd ratio (OR) = 0.86, 95% CI 0.81-0.98, P = 0.01) were the strongest predictors of risk for learning difficulties. The findings point to the importance of supporting children's executive function development and promoting sensorimotor development, as both fundamentally influence school readiness.

The Effects of Cognitive-Affective Switching With Unpredictable Cues in Adults and Adolescents and Their Relation to "Cool" Executive Functioning and Emotion Regulation

The impact of emotion on executive functioning is gaining interest. It has led to the differentiation of "cool" Executive Functioning (EF) processes, such as cognitive flexibility, and "hot" EF processes, such as affective flexibility. But how does affective flexibility, the ability to switch between cognitive and affective information, vary as a function of age and sex? How does this construct relate to "cool" executive functioning and cognitive-emotion regulation processes? In this study, 266 participants, including 91 adolescents (M = 16.08, SD = 1.42 years old) and 175 adults (M = 25.69, SD = 2.17 years old), completed a cognitive-affective switching task with specific (as opposed to general) unpredictable switches, as well as measures of inhibition, attention, and cognitive-emotion coping strategies. We expected cognitive to affective switching to be more costly than affective to cognitive switching in females versus males, as well as higher switch costs in adolescents. Using linear mixed modelling, we analysed the effect of age, sex, and types of switching on reaction time. Results show that adolescents are slower switchers than adults, and demonstrate that females, although faster switchers than males, are slower when switching from cognitive to affective content than when they are switching from affective to cognitive content. Multiple regression analyses revealed age-specific associations between cognitive-affective switching and inhibition. These results converge with reported developmental and gender specificities in EF and emotion processing, respectively. Additionally, affective flexibility could relate to differences in vigilance and inhibition.

Executive Functioning with the NIH EXAMINER and Inference Making in Struggling Readers

Executive functioning (EF) is a domain-general process implicated in reading, but there remains lack of clarity within the domain due to varied assessment methods. We investigated the relation of EF (indexed with the NIH EXAMINER) to word reading, reading fluency, and reading comprehension in struggling readers and evaluated the mediational role of inference making for the EF-comprehension link. Analyses revealed an overall effect of EF on reading, with significant differences between fluency and comprehension, and between single word reading and comprehension, but not between fluency and single-word reading. The EF-reading comprehension relation was fully mediated by inference making.

Effect of Single Administration of Mulberry Milk on the Cognitive Function of 6-12-Year-Old Children: Results from a Randomized, Placebo-Controlled, Crossover Study

Currently, cognitive enhancers are considered necessary because they play a critical role in daily and social behaviors. The cognitive-enhancing effect of mulberry milk has gained attention due to the cognitive-enhancing effect of this anthocyanin-rich substance and the cognitive-enhancing effect of mulberry fruit in animal models. However, the effect of anthocyanin-rich mulberry milk in clinical trials especially in children is still unknown. This study was a randomized double-blind crossover intervention. A total of forty-six healthy, normal, cognitive subjects aged 6–12 years old were provided mulberry milk (containing mulberry 10 g) or placebo milk (50 mL). Attention and cognitive function were assessed using the auditory odd ball paradigm of event-related potential, whereas working memory was assessed using a computerized battery test. The assessment was performed at baseline and then at 1.5 and 3 hours postdosing. At the end of study period, the activities of acetylcholinesterase (AChE) and monoamine oxidase (MAO) together with that of saliva cortisol were determined. Following mulberry milk intervention, the decreased N100 latency and the increased P300 amplitude were increased both at 1.5 and 3 hours after dosing. The decreased response time of digit updating was observed both at 1.5 and 3 hours after dosing, whereas the decreased response time of picture updating was observed at 3 hours after dosing. In addition, the reduction of saliva cortisol was also observed at both periods. The improvement of attention and cognitive processing capabilities together with the working memory suggests the cognitive-enhancing potential of mulberry milk for school-age children. The possible underlying mechanism may be associated partly with the reduction of cortisol, a stress hormone.

Executive Functions in Children with ADHD and/or Reading Difficulty

Abstract The objective of this study was to compare the Executive Functions performance (EFs: inhibitory control, auditory and visuospatial working memory, cognitive flexibility and verbal fluency) between children with ADHD, reading difficulties (RD), comorbidity ADHD/RD and without complaints of ADHD and RD (WRD). Participated 104 children, of both sexes, aged between eight and 11 years old. The results indicated worse performance of ADHD/RD group in the majority EFs. ADHD presented better performance than DL in semantic verbal fluency. The WRD obtained better scores than the ADHD / DL and DL in practically all the evaluated EFs, but did not differ of ADHD.

Sustained Effect of Music Training on the Enhancement of Executive Function in Preschool Children

Musical training is an enrichment activity involving multiple senses, including auditory, visual, somatosensorial, attention, memory, and executive function (EF), all of which are related to cognition. This study examined whether musical training enhances EF in preschool children who had not undergone previous systematic music learning. This study also explored the after-effects 12 weeks after cessation of musical training. Participants were 61 preschool children from a university-affiliated kindergarten in North China. The experimental group underwent 12 weeks of integrated musical training (i.e., music theory, singing, dancing, and role-playing), while the control group performed typical daily classroom activities. The three components (inhibitory control, working memory, cognitive flexibility) of executive functions were evaluated using the Day/Night Stroop, Dimensional Change Card Sort, Dot Matrix Test, and Backward Digit Span Task. In Experiment 1, EFs were tested twice-before (T1) and after (T2) the music training. The results showed that children's EFs could be promoted by musical training. In addition, EFs were tested again 12 weeks later after the end of the intervention (T3) in Experiment 2. We discovered that integrated musical training demonstrated a sustained promotion effect.

A Neuroanatomical Substrate Linking Perceptual Stability to Cognitive Rigidity in Autism

Overly stable visual perception seen in individuals with autism spectrum disorder (ASD) is related to higher-order core symptoms of the condition. However, the neural basis by which these seemingly different symptoms are simultaneously observed in individuals with ASD remains unclear. Here, we aimed to identify such a neuroanatomical substrate linking perceptual stability to autistic cognitive rigidity, a part of core restricted, repetitive behaviors (RRBs). First, using a bistable visual perception test, we measured the perceptual stability of 22 high-functioning adults with ASD and 22 age-, IQ-, and sex-matched typically developing human individuals and confirmed overstable visual perception in autism. Next, using a spontaneous task-switching (TS) test, we showed that the individuals with ASD were more likely to repeat the same task voluntarily and spontaneously, and such rigid TS behavior was associated with the severity of their RRB symptoms. We then compared these perceptual and cognitive behaviors and found a significant correlation between them for individuals with ASD. Finally, we found that this behavioral link was supported by a smaller gray matter volume (GMV) of the posterior superior parietal lobule (pSPL) in individuals with ASD. Moreover, this smaller GMV in the pSPL was also associated with the RRB symptoms and replicated in two independent datasets. Our findings suggest that the pSPL could be one of the neuroanatomical mediators of cognitive and perceptual inflexibility in autism, which could help a unified biological understanding of the mechanisms underpinning diverse symptoms of this developmental disorder.SIGNIFICANCE STATEMENT Behavioral studies show perceptual overstability in autism spectrum disorder (ASD). However, the neural mechanisms by which such sensory symptoms can coexist and often correlate with seemingly separate core symptoms remain unknown. Here, we have identified such a key neuroanatomical substrate. We have revealed that overstable sensory perception of individuals with ASD is linked with their cognitive rigidity, a part of core restricted, repetitive behavior symptoms, and such a behavioral link is underpinned by a smaller gray matter volume in the posterior superior parietal lobule in autism. These findings uncover a key neuroanatomical mediator of autistic perceptual and cognitive inflexibility and would ignite future studies on how the core symptoms of ASD interact with its unique sensory perception.

Attentional Mechanisms in Autism, ADHD, and Autism-ADHD Using a Local-Global Paradigm

OBJECTIVE

Cognitive flexibility or attentional set-shifting capacity has long been considered a core area of executive dysfunction for individuals with autism. Whether these difficulties are due to higher-level attentional difficulties associated with comorbid ADHD remains unclear.

METHOD

The current study compared the performance of 48 participants with autism, ADHD, autism-ADHD, and a comparison group ( N = 12 per group) on a set-shifting task, which included a local-global paradigm.

RESULTS

Results of this study revealed that participants with attentional difficulties (autism + ADHD and ADHD alone) exhibited a significant shifting cost (difference between maintaining and shifting attention).

CONCLUSION

Attentional difficulties associated with ADHD may be associated with an enhanced attentional shifting cost. Implications of these results were discussed in relation to screening for ADHD symptoms in studies of individuals with autism which seek to determine the neuropsychological profile of this condition.

Decreased functional connectivity of the salience network during narrative comprehension in children with reading difficulties: An fMRI study

Dyslexia is a neurobiological learning disability, reflected through deficits in written (i.e. reading) but not in spoken language. Since written and spoken language rely on cognitive control abilities, we aimed to compare functional connectivity of the understudied salience network which is related to cognitive control in children with dyslexia vs. typical readers during a functional MRI narrative comprehension task. Although children with dyslexia showed similar comprehension levels as typical readers, neuroimaging data revealed children with dyslexia showed significantly decreased functional connectivity values of an independent component (IC) related to the salience network. The functional connectivity values in the salience network IC were negatively correlated with behavioral data of working memory in those with dyslexia. These findings further express that dyslexia is manifested through atypical involvement of neural circuits related to EF, specifically the salience network even when attending narratives. Since the salience network is related to switching abilities and error detection, future research should focus on strengthening these abilities early in life for better future reading outcomes.

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Behavioral data supports executive functioning and reading deficiencies in dyslexia

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Significant greater functional connectivity in the salience network IC in typical readers vs children with dyslexia

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Negative correlation between functional connectivity of the salience network, working memory abilities and processing speed

Behavioural flexibility of children with Autism Spectrum Disorder on a card-sorting task with varying task difficulty

Inflexibility is taken to be a key characteristic of Autism Spectrum Disorder (ASD), although it is unclear which aspect of cognitive functioning is critical in this context. The current study investigated task-switching problems and inflexibility with a group of children with ASD, and a mental-aged matched control group. Participants (n = 50; mean age = 7 years) completed two card-sorting tasks, which involved learning to sort by either two or three possible dimensions, and then the sorting rule was switched although the number of dimensions required to sort the cards remained the same. Following the sorting rule change, the ASD group made more errors compared to controls. Errors were also related to task type (two or three dimensions), but this was not found to interact with ASD. If poor performance were solely dependent on executive function (working memory) problems in ASD, then a steeper decrease in performance with an increase in task difficulty for one group, compared to another group, would be expected. The current results suggest that task difficulty is an aspect of importance in set-shifting, but shifting is not differentially affected by this component.

The Role of Cognition on Navigational Skills of Children and Adolescents With Autism Spectrum Disorders

PURPOSE

This study examined the role of cognition on the navigational process of a speech-generating device (SGD) among individuals with a diagnosis of autism spectrum disorder (ASD). The objective was to investigate the role of various cognitive factors (i.e., cognitive flexibility, sustained attention, categorization, fluid reasoning, and working memory) on the ability to navigate an SGD with dynamic paging and taxonomic grids in individuals with ASD.

METHOD

Twenty individuals aged 5 to 20 years with ASD were assessed using the Leiter International Performance Scale-Revised (Roid & Miller, 1997) and the Automated Working Memory Assessment (Alloway, 2007). They also completed a navigational task using an iPad 4 (Apple, 2017; taxonomic organization).

RESULTS

Significant correlations between all of the cognitive factors and the ability to navigate an SGD were revealed. A stepwise linear regression suggested that cognitive flexibility was the best predictor of navigational ability with this population.

CONCLUSION

The importance of cognition in the navigational process of an SGD with dynamic paging in children and adolescents with ASD has been highlighted by the results of this study.

Inhibition and Updating, but Not Switching, Predict Developmental Dyslexia and Individual Variation in Reading Ability

To elucidate the core executive function profile (strengths and weaknesses in inhibition, updating, and switching) associated with dyslexia, this study explored executive function in 27 children with dyslexia and 29 age matched controls using sensitive z-mean measures of each ability and controlled for individual differences in processing speed. This study found that developmental dyslexia is associated with inhibition and updating, but not switching impairments, at the error z-mean composite level, whilst controlling for processing speed. Inhibition and updating (but not switching) error composites predicted both dyslexia likelihood and reading ability across the full range of variation from typical to atypical. The predictive relationships were such that those with poorer performance on inhibition and updating measures were significantly more likely to have a diagnosis of developmental dyslexia and also demonstrate poorer reading ability. These findings suggest that inhibition and updating abilities are associated with developmental dyslexia and predict reading ability. Future studies should explore executive function training as an intervention for children with dyslexia as core executive functions appear to be modifiable with training and may transfer to improved reading ability.

Inhibition, Updating Working Memory, and Shifting Predict Reading Disability Symptoms in a Hybrid Model: Project KIDS

Recent achievement research suggests that executive function (EF), a set of regulatory processes that control both thought and action necessary for goal-directed behavior, is related to typical and atypical reading performance. This project examines the relation of EF, as measured by its components, Inhibition, Updating Working Memory, and Shifting, with a hybrid model of reading disability (RD). Our sample included 420 children who participated in a broader intervention project when they were in KG-third grade (age M = 6.63 years, SD = 1.04 years, range = 4.79-10.40 years). At the time their EF was assessed, using a parent-report Behavior Rating Inventory of Executive Function (BRIEF), they had a mean age of 13.21 years (SD = 1.54 years; range = 10.47-16.63 years). The hybrid model of RD was operationalized as a composite consisting of four symptoms, and set so that any child could have any one, any two, any three, any four, or none of the symptoms included in the hybrid model. The four symptoms include low word reading achievement, unexpected low word reading achievement, poorer reading comprehension compared to listening comprehension, and dual-discrepancy response-to-intervention, requiring both low achievement and low growth in word reading. The results of our multilevel ordinal logistic regression analyses showed a significant relation between all three components of EF (Inhibition, Updating Working Memory, and Shifting) and the hybrid model of RD, and that the strength of EF's predictive power for RD classification was the highest when RD was modeled as having at least one or more symptoms. Importantly, the chances of being classified as having RD increased as EF performance worsened and decreased as EF performance improved. The question of whether any one EF component would emerge as a superior predictor was also examined and results showed that Inhibition, Updating Working Memory, and Shifting were equally valuable as predictors of the hybrid model of RD. In total, all EF components were significant and equally effective predictors of RD when RD was operationalized using the hybrid model.

Understanding Behavioural Rigidity in Autism Spectrum Conditions: The Role of Intentional Control

Although behavioural rigidity belongs to the core symptoms of autism spectrum conditions, little is known about its underlying cognitive mechanisms. The current study investigated the role of intentional control mechanisms in behavioural rigidity in autism. Autistic individuals and their matched controls were instructed to repeatedly choose between two simple cognitive tasks and to respond accordingly to the subsequently presented stimulus. Results showed that autistic participants chose to repeat tasks more often than their controls and when choosing to switch, they demonstrated larger performance costs. These findings illustrate that when required to make their own choices, autistic people demonstrate rigidity at different performance levels, suggesting that intentional control mechanisms might be important for a better understanding of behavioural rigidity in autism.

Associations of acute and chronic stress hormones with cognitive functions in autism spectrum disorder

Extensive studies have reported cognitive abnormalities in neurodevelopmental disorders, such as autism spectrum disorder (ASD). Another line of evidence suggests that stress also affects cognitive functions. In this study, we investigated whether there were associations between stress hormones and cognitive functions in ASD and typically developing (TD) children. Cognitive functions in ASD and TD children were evaluated with a battery of psychological tests for working memory, behavioral flexibility, and social cognition for emotional assessments of others. ASD children exhibited higher hair and salivary cortisol, which reflects chronic and acute stress hormone levels of subjects, respectively, than TD children. Autism-spectrum quotient (AQ) was positively correlated with hair cortisol and the scores of Spence Children's Anxiety Scale in ASD children. In addition, a negative correlation was present between spatial working memory performance and hair cortisol in ASD, but not in TD, children. These results suggest that chronic stress hormone elevation may have relationships with some aspects of cognitive dysfunction in ASD subjects.

Executive functions in adults with developmental dyslexia

BACKGROUND

Executive functioning (EF) deficits are well recognized in developmental dyslexia, yet the majority of studies have concerned children rather than adults, ignored the subjective experience of the individual with dyslexia (with regard to their own EFs), and have not followed current theoretical perspectives on EFs.

AIMS AND METHODS

The current study addressed these shortfalls by administering a self-report measure of EF (BRIEF-A; Roth, Isquith, & Gioia, 2005) and experimental tasks to IQ-matched groups of adults with and without dyslexia. The laboratory-based tasks tested the three factors constituting the framework of EF proposed by Miyake et al. (2000).

RESULTS

In comparison to the group without dyslexia, the participants with dyslexia self-reported more frequent EF problems in day-to-day life, with these difficulties centering on metacognitive processes (working memory, planning, task monitoring, and organization) rather than on the regulation of emotion and behaviour. The participants with dyslexia showed significant deficits in EF (inhibition, set shifting, and working memory).

CONCLUSIONS AND IMPLICATIONS

The findings indicated that dyslexia-related problems have an impact on the daily experience of adults with the condition. Further, EF difficulties are present in adulthood across a range of laboratory-based measures, and, given the nature of the experimental tasks presented, extend beyond difficulties related solely to phonological processing.

Exercise as an Intervention to Reduce Study-Related Fatigue among University Students: A Two-Arm Parallel Randomized Controlled Trial

BACKGROUND

Many university students experience high levels of study-related fatigue. This high prevalence, and the negative impact of fatigue on health and academic performance, call for prevention and reduction of these symptoms. The primary aim of the current study was to investigate to what extent an exercise intervention is effective in reducing three indicators of study-related fatigue (emotional exhaustion, overall fatigue, and need for recovery). Effects of exercise on secondary outcomes (sleep quality, self-efficacy, physical fitness, and cognitive functioning) were also investigated.

METHODS

Participants were students with high levels of study-related fatigue, currently not exercising or receiving other psychological or pharmacological treatments, and with no medical cause of fatigue. They were randomly assigned to either a six-week exercise intervention (low-intensity running three times a week, n = 49) or wait list (no intervention, n = 48). All participants were measured before the intervention (T0), and immediately after the intervention (T1). Exercisers were also investigated 4 weeks (T2) and 12 weeks (T3) after the intervention.

RESULTS

Participants in the exercise condition showed a larger decrease in two of the three indicators of study-related fatigue (i.e., overall fatigue and need for recovery) as compared to controls. Additionally, sleep quality and some indicators of cognitive functioning improved more among exercisers than among controls. No effects were found for self-efficacy, and physical fitness. The initial effects of the exercise intervention lasted at follow-up (T2 and T3). At 12-week follow up (T3), 80% of participants in the exercise condition still engaged in regular exercise, and further enhancements were seen for emotional exhaustion, overall fatigue, and sleep quality.

CONCLUSIONS

These results underline the value of low-intensity exercise for university students with high levels of study-related fatigue. The follow-up effects that were found in this study imply that the intervention has the potential to promote regular exercise and accompanying beneficial effects in the longer run.

TRIAL REGISTRATION

Netherlands Trial Register NTR4412.

Time-based prospective memory in adults with developmental dyslexia

Prospective memory (PM) is memory for delayed intentions. Despite its importance to everyday life, the few studies on PM function in adults with dyslexia which exist have relied on self-report measures. To determine whether self-reported PM deficits can be measured objectively, laboratory-based PM tasks were administered to 24 adults with dyslexia and 25 age- and IQ-matched adults without dyslexia. Self-report data indicated that people with dyslexia felt that time-based PM (TBPM; requiring responses at certain times in the future) was most problematic for them and so this form of PM was the focus of investigation. Whilst performing the ongoing task from which they were required to break out every 3 min to make a PM-related response, the participants were allowed to make clock checks whenever they wished. The cognitive demands made on ongoing behaviour were manipulated to determine whether loading executive resources had a mediating role in dyslexia-related deficits in PM, resulting in three tasks with varying working memory load. A semi-naturalistic TBPM task was also administered, in which the participants were asked to remind the experimenter to save a data file 40 min after being given this instruction. Dyslexia-related differences were found across all three computerized tasks, regardless of cognitive load. The adults with dyslexia made fewer correct PM responses and also fewer clock checks. On the semi-naturalistic task, the participants with dyslexia were less likely to remember to remind the experimenter to save the file. This is the first study to document PM deficits in dyslexia using objective measures of performance. Since TBPM impairments were found under more naturalistic conditions as well as on computerized tasks, the results have implications for workplace support for adults with dyslexia.

Efficacy of an exercise intervention for employees with work-related fatigue: study protocol of a two-arm randomized controlled trial

Background

The aim of the current study is to evaluate the efficacy of an exercise intervention to reduce work-related fatigue. Exercise is a potentially effective intervention strategy to reduce work-related fatigue, since it may enhance employees’ ability to cope with work stress and it helps to detach from work. However, based on available research, no clear causal inferences regarding its efficacy can be made. This RCT therefore investigates whether exercise is effective in reducing work-related fatigue, and in improving other indicators of employees’ mental and physical well-being and performance.

Methods/design

A two-arm parallel trial will be conducted. Participants (N = 108) who experience high levels of work-related fatigue will be randomized at a 1:1 ratio to a 6-week exercise intervention or wait list (control). The exercise intervention consists of three one-hour low-intensity outdoor running sessions a week. Each week, two sessions take place in a group under supervision of a trainer, and one session is completed individually. The running sessions will be carried out during leisure time. The primary outcome is work-related fatigue. Secondary outcomes include work ability, self-efficacy, sleep quality, cognitive functioning, and aerobic fitness. These data will be collected at pre-intervention, post-intervention, and at 6 weeks and 12 weeks after the intervention. In addition, weekly measures of employees’ well-being, and exercise activities (i.e. type, frequency, and duration) and experiences (i.e. pleasure, effort, and detachment) will be collected during the intervention period.

Discussion

This study will compare an exercise intervention to a wait list. This enables us to examine the effect of exercise on work-related fatigue compared to the natural course of these symptoms. As such, this study contributes to a better understanding of the causal link between exercise and work-related fatigue. If the intervention is proven effective, the results could provide a basis for future ‘effectiveness’ trials in which the (implementation of the) intervention can be investigated among a broader defined population in a less standardized way, eventually leading to better evidence-based policies and practices to employees, employers, health practitioners, and policy makers concerning the effect of exercise on work-related fatigue.

Trial registration

NTR5034. Registered 10 March 2015.

Visual attention shifting in autism spectrum disorders

INTRODUCTION

Abnormal visual attention has been frequently observed in autism spectrum disorders (ASD). Abnormal shifting of visual attention is related to abnormal development of social cognition and has been identified as a key neuropsychological finding in ASD. Better characterizing attention shifting in ASD and its relationship with social functioning may help to identify new targets for intervention and improving social communication in these disorders. Thus, the current study investigated deficits in attention shifting in ASD as well as relationships between attention shifting and social communication in ASD and neurotypicals (NT).

METHOD

To investigate deficits in visual attention shifting in ASD, 20 ASD and 20 age- and gender-matched NT completed visual search (VS) and Navon tasks with attention-shifting demands as well as a set-shifting task. VS was a feature search task with targets defined in one of two dimensions; Navon required identification of a target letter presented at the global or local level. Psychomotor and processing speed were entered as covariates. Relationships between visual attention shifting, set shifting, and social functioning were also examined.

RESULTS

ASD and NT showed comparable costs of shifting attention. However, psychomotor and processing speed were slower in ASD than in NT, and psychomotor and processing speed were positively correlated with attention-shifting costs on Navon and VS, respectively, for both groups. Attention shifting on VS and Navon were correlated among NT, while attention shifting on Navon was correlated with set shifting among ASD. Attention-shifting costs on Navon were positively correlated with restricted and repetitive behaviors among ASD.

CONCLUSIONS

Relationships between attention shifting and psychomotor and processing speed, as well as relationships between measures of different aspects of visual attention shifting, suggest inefficient top-down influences over preattentive visual processing in ASD. Inefficient attention shifting may be related to restricted and repetitive behaviors in these disorders.

Processing of emotion words by patients with autism spectrum disorders: evidence from reaction times and EEG

This study investigated processing of emotion words in autism spectrum disorders (ASD) using reaction times and event-related potentials (ERP). Adults with (n = 21) and without (n = 20) ASD performed a lexical decision task on emotion and neutral words while their brain activity was recorded. Both groups showed faster responses to emotion words compared to neutral, suggesting intact early processing of emotion in ASD. In the ERPs, the control group showed a typical late positive component (LPC) at 400-600 ms for emotion words compared to neutral, while the ASD group showed no LPC. The between-group difference in LPC amplitude was significant, suggesting that emotion words were processed differently by individuals with ASD, although their behavioral performance was similar to that of typical individuals.

Neural Correlates of Set-Shifting in Children With Autism

Autism spectrum disorder (ASD) is often associated with high levels of inflexible thinking and rigid behavior. The neural correlates of these behaviors have been investigated in adults and older adolescents, but not children. Prior studies utilized set-shifting tasks that engaged multiple levels of shifting, and depended on learning abstract rules and establishing a strong prepotent bias. These additional demands complicate simple interpretations of the results. We used functional magnetic resonance imaging (fMRI) to investigate the neural correlates of set-shifting in 20 children (ages 7-14) with ASD and 19 typically developing, matched, control children. Participants completed a set-shifting task that minimized nonshifting task demands through the use of concrete instructions that provide spatial mapping of stimuli-responses. The shift/stay sets were given an equal number of trials to limit the prepotent bias. Both groups showed an equivalent "switch cost," responding less accurately and slower to Switch stimuli than Stay stimuli, although the ASD group was less accurate overall. Both groups showed activation in prefrontal, striatal, parietal, and cerebellum regions known to govern effective set-shifts. Compared to controls, children with ASD demonstrated decreased activation of the right middle temporal gyrus across all trials, but increased activation in the mid-dorsal cingulate cortex/superior frontal gyrus, left middle frontal, and right inferior frontal gyri during the Switch vs. Stay contrast. The successful behavioral switching performance of children with ASD comes at the cost of requiring greater engagement of frontal regions, suggesting less efficiency at this lowest level of shifting.

Progress in reading and spelling of dyslexic children is not affected by executive functioning

Although poor reading and spelling skills have been associated with weak skills of executive functioning (EF), its role in literacy is not undisputed. Because EF has different theoretical underpinnings, methods of analysis and of assessing, it has led to varying and often contrasting results in its effects in children with dyslexia. The present study has two goals. The first goal is to establish the relationship between a large number of EF tasks and reading and spelling skills in a large number of Dutch dyslexic children (n = 229). More interesting, however, is the second aim. To what extent do EF skills predict progress in reading and spelling in dyslexic children who attended a remediation programme? The results revealed small, but significant relationships between EF and reading and spelling skills, but no relationships between EF and progress in reading and spelling. It is concluded that training EF skills is unlikely to enhance reading and spelling skills.

A specific impairment in cognitive control in individuals with high-functioning autism

Although it is largely demonstrated that Autism Spectrum Disorders (ASDs) are characterized by executive dysfunctions, little is known about the fine-grained levels of this impairment. Here, we investigated the hierarchical architecture of control modules in autism using an experimental paradigm based upon a multistage model of executive functions. This model postulates that executive functions are hierarchically organized as a cascade of three different control processes, which are implemented according to information conveyed by sensory signals (sensory control), the immediate perceptual context (contextual control), and the temporal episode in which stimuli occur (episodic control). Sixteen high-functioning adults with autism or Asperger Syndrome (HFA/AS) and sixteen matched comparison participants took part in two distinct visuo-motor association experiments designed to separately vary the demands of sensory and episodic controls (first experiment) and contextual and episodic controls (second experiment). Participants with HFA/AS demonstrated no significant differences in performances with comparison participants when they had to control sensory or contextual information. However, they showed decreased accuracy when having to control information related to episodic signals. Remarkably, performances in episodic control were associated to the autism spectrum quotient in both groups, suggesting that this episodic control impairment might be at the core of ASDs. Those results plead for a specific, rather than generalised, deficit in executive functions in autism. Our study contributes to a better understanding of the impaired cognitive processes that are unique to autism and warrants confirmation using other models of executive functions.

Alternatives to switch-cost scoring in the task-switching paradigm: their reliability and increased validity

In the task-switching paradigm, the latency switch-cost score-the difference in mean reaction time between switch and nonswitch trials-is the traditional measure of task-switching ability. However, this score does not reflect accuracy, where switch costs may also emerge. In two experiments that varied in response deadlines (unlimited vs. limited time), we evaluated the measurement properties of two traditional switch-cost scoring methods (the latency switch-cost score and the accuracy switch-cost score) and three alternatives (a rate residual score, a bin score, and an inverse efficiency score). Scores from the rate residual, bin score, and inverse efficiency methods had comparable reliability for latency switch-cost scores without response deadlines but were more reliable than latency switch-cost scores when higher error rates were induced with a response deadline. All three alternative scoring methods appropriately accounted for differences in accuracy switch costs when higher error rates were induced, whereas pure latency switch-cost scores did not. Critically, only the rate residual and bin score methods were more valid indicators of task-switching ability; they demonstrated stronger relationships with performance on an independent measure of executive functioning (the antisaccade analogue task), and they allowed the detection of larger effect sizes when examining within-task congruency effects. All of the three alternative scoring methods provide researchers with a better measure of task-switching ability than do traditional scoring methods, because they each simultaneously account for latency and accuracy costs. Overall, the three alternative scoring methods were all superior to the traditional latency switch-cost scoring method, but the strongest methods were the rate residual and bin score methods.

Cognitive performance in both clinical and non-clinical burnout

Relatively little is known about cognitive performance in burnout. The aim of the present study was to further our knowledge on this topic by examining, in one study, cognitive performance in both clinical and non-clinical burnout while focusing on three interrelated aspects of cognitive performance, namely, self-reported cognitive problems, cognitive test performance, and subjective costs associated with cognitive test performance. To this aim, a clinical burnout patient group (n = 33), a non-clinical burnout group (n = 29), and a healthy control group (n = 30) were compared on self-reported cognitive problems, assessed by a questionnaire, as well as on cognitive test performance, assessed with a cognitive test battery measuring both executive functioning and more general cognitive processing. Self-reported fatigue, motivation, effort and demands were assessed to compare the different groups on subjective costs associated with cognitive test performance. The results indicated that the clinical burnout patients reported more cognitive problems than the individuals with non-clinical burnout, who in turn reported more cognitive problems relative to the healthy controls. Evidence for impaired cognitive test performance was only found in the clinical burnout patients. Relative to the healthy controls, these patients displayed some evidence of impaired general cognitive processing, reflected in slower reaction times, but no impaired executive functioning. However, cognitive test performance of the clinical burnout patients was related to larger reported subjective costs. In conclusion, although both the clinical and the non-clinical burnout group reported cognitive problems, evidence for a relatively mild impaired cognitive test performance and larger reported subjective cost associated with cognitive test performance was only found for the clinical burnout group.

Susceptibility to distraction in autism spectrum disorder: probing the integrity of oscillatory alpha-band suppression mechanisms

When attention is directed to one information stream over another, the brain can be configured in advance to selectively process the relevant stream and suppress potentially distracting inputs. One key mechanism of suppression is through the deployment of anticipatory alpha-band (~10 Hz) oscillatory activity, with greater alpha-band power observed in cortical regions that will ultimately process the distracting stream. Atypical attention has been implicated in autism spectrum disorder (ASD), including greater interference by distracting task-irrelevant inputs. Here we tested the integrity of these alpha-band mechanisms in ASD using an intersensory attention task. Electroencephalography (EEG) was recorded while participants were cued on a trial-by-trial basis to selectively deploy attention to the visual or auditory modality in anticipation of a target within the cued modality. Whereas typically developing (TD) children showed the predicted alpha-band modulation, with increased alpha-band power over parieto-occipital scalp when attention was deployed to the auditory compared with the visual modality, this differential pattern was entirely absent at the group level in the ASD cohort. Further, only the ASD group showed impaired performance due to the presence of task-irrelevant sensory information. These data suggest that impaired modulation of alpha-band activity plays a role in increased distraction from extraneous sensory inputs in ASD.

The modality shift experiment in adults and children with high functioning autism

This study used the modality shift experiment, a relatively simple reaction time measure to visual and auditory stimuli, to examine attentional shifting within and across modalities in 33 children and 42 adults with high-functioning autism as compared to matched numbers of age- and ability-matched typical controls. An exaggerated "modality shift effect" relative to the TD children occurred for the children with autism in conditions involving the reaction time when shifting from sound to light but not from light to sound. No exaggerated MSE was found for the adults with autism; rather, their responses were characterized by a generalized slowness relative to the adults with TD. These results suggest a lag in maturational development in autism in basic information processing mechanisms.

Cognitive control of intentions for voluntary actions in individuals with a high level of autistic traits

Impairments in cognitive control generating deviant adaptive cognition have been proposed to account for the strong preference for repetitive behavior in autism. We examined if this preference reflects intentional deficits rather than problems in task execution in the broader autism phenotype using the Autism-Spectrum Quotient (AQ). Participants chose between two tasks differing in their relative strength by indicating first their voluntary task choice and then responding to the subsequently presented stimulus. We observed a stronger repetition bias for the harder task in high AQ participants, with no other differences between the two groups. These findings indicate that the interference between competing tasks significantly contributes to repetitive behavior in autism by modulating the formation of task intentions when choosing tasks voluntarily.

Cognitive flexibility in ASD; task switching with emotional faces

Children with autism spectrum disorders (ASDs) show daily cognitive flexibility deficits, but laboratory data are unconvincing. The current study aimed to bridge this gap. Thirty-one children with ASD (8–12 years) and 31 age- and IQ-matched typically developing children performed a gender emotion switch task. Unannounced switches and complex stimuli (emotional faces) improved ecological validity; minimal working memory-load prevented bias in the findings. Overall performance did not differ between groups, but in a part of the ASD group performance was slow and inaccurate. Moreover, within the ASD group switching from emotion to gender trials was slower than vice versa. Children with ASD do not show difficulties on an ecological valid switch task, but have difficulty disengaging from an emotional task set.

Brief Report: impaired Flexible Item Selection Task (FIST) in school-age children with autism spectrum disorders

Cognitive flexibility has been measured with inductive reasoning or explicit rule tasks in individuals with autism spectrum disorders (ASD). The Flexible Item Selection Task (FIST) differs from previous cognitive flexibility tasks in ASD research by giving children an abstract, ambiguous rule to switch. The ASD group (N = 22; Mean age = 8.28 years, SD = 1.52) achieved a lower shift percentage than the typically developing verbal mental-age control group (N = 22; Mean age = 6.26 years, SD = 0.82). There was a significant positive correlation between verbal mental age and shift percentage for children with ASD. Group differences on the FIST converge and extend prior evidence documenting an impaired ability to adapt rapidly to changes in task demands for individuals with ASD.

Failure to learn from feedback underlies word learning difficulties in toddlers at risk for autism

Children's assignment of novel words to nameless objects, over objects whose names they know (mutual exclusivity; ME) has been described as a driving force for vocabulary acquisition. Despite their ability to use ME to fast-map words (Preissler & Carey, 2005), children with autism show impaired language acquisition. We aimed to address this puzzle by building on studies showing that correct referent selection using ME does not lead to word learning unless ostensive feedback is provided on the child's object choice (Horst & Samuelson, 2008). We found that although toddlers aged 2;0 at risk for autism can use ME to choose the correct referent of a word, they do not benefit from feedback for long-term retention of the word-object mapping. Further, their difficulty using feedback is associated with their smaller receptive vocabularies. We propose that difficulties learning from social feedback, not lexical principles, limits vocabulary building during development in children at risk for autism.

A review of intentional and cognitive control in autism

Different clinical studies have provided empirical evidence for impairments in cognitive control in individuals with autism spectrum disorders (ASD). The challenge arises, however, when trying to specify the neurocognitive mechanisms behind the reported observations of deviant patterns of goal-directed behavior in ASD. Studies trying to test specific assumptions by applying designs that are based on a more controlled experimental conditions often fail in providing strong evidence for an impairment in specific cognitive functions. In this review, we summarize and critically reflect on behavioral findings and their theoretical explanations regarding cognitive control processing in autism, also from a developmental perspective. The specific focus of this review is the recent evidence of deficits in intentional control – a specific subset of cognitive control processes that biases the choice of our behavioral goals – coming from different research fields. We relate this evidence to the cognitive rigidity observed in ASD and argue that individuals with ASD experience problems at the intentional level rather than at the level of implementation of intentions. Both these processes are related to cognitive control mechanisms but in different ways. Finally, we discuss new directions in studying cognitive control in ASD and how these relate to adaptive cognition.

Alterations of neocortical development and maturation in autism: insight from valproic acid exposure and animal models of autism

Autism spectrum disorder (ASD) is a behaviourally defined brain disorder affecting approximately 1 in 88 children. Many pathological studies have shown that ASD is frequently associated with grey and white matter changes that can be described by their deviations from the normal trajectory of cortical maturation. For example, during the early (i.e. <2 years) postnatal period there is marked and selective tissue overgrowth in the higher-order temporal and frontal networks involved in emotional, social, and communication functions. In this focused review we first summarize some basic principles of neocortical neural organization and how they are disrupted in ASD. We will then highlight some of the potential mechanisms by which the normal developmental trajectory and organization of neocortical networks can be altered based on animal studies of valproic acid, a teratogen widely used in animal models of ASD. We argue that the trajectory of postnatal cerebral neocortex development may be influenced by several cellular and molecular mechanisms that may all converge to produce a neuropathology characterized by premature or accelerated neuronal growth.

On the relationship between autistic traits and executive functioning in a non-clinical Dutch student population

We examined the association between autistic traits and different aspects of executive functioning (EF), using non-clinical Social Science and Science students as participants. Autistic traits, and associated personality traits, were measured using the Autism Quotient (AQ) and the Temperament and Character Inventory (TCI), respectively. EF was examined by means of a random number generation test and a phonemic fluency test. Using appropriate dependent measures, the following EF components were examined: 1) inhibition of prepotent responding, 2) simple output inhibition, 3) working memory monitoring and updating, and 4) switching. No significant relationship was found between the AQ and each of the four components of EF. However, two TCI subscales were reliably correlated with either the working memory or the shifting component. These results were discussed in view of the concept of an autism spectrum with respect to executive abilities.

Dissociation between online and offline learning in developmental dyslexia

Most studies investigating procedural learning in developmental dyslexia (DD) have focused on the acquisition stage, ignoring later stages involved in the process of skill learning. The current study examined sequence learning among DD and control groups in two sessions. Both groups completed a sequence-learning task over a first session (online learning) and a second session 24 hours later (offline learning). While both groups showed improvements in performance during offline learning, only the control group showed improvements in performance during online learning. Moreover, the DD group differed from the control group in their ability to recover from the introduction of a different sequence.

Cognitive control of feature bindings: evidence from children with autistic spectrum disorder

Understanding how the brain integrates features from different domains that are processed in distinct cortical regions calls for the examination of integration processes. Recent studies of feature-repetition effects demonstrated interactions across perceptual features and action-related features: repeating only some features of the perception–action episode hinders performance. These partial-repetition costs point to the existence of temporary memory traces (event files). However, the principles and the constraints that govern the management of such traces are still unclear. Here, we investigated whether children with autistic spectrum disorder (ASD) differ from typically developing children in managing episodic memory traces. The results show that both groups integrate stimulus features along with action features, but children with ASD exhibit larger partial-repetition costs, suggesting lesser control and flexibility in updating episodic memory traces. The findings are discussed in the light of evidence for a central role of the dopaminergic system in cognitive integration, ASD, and cognitive control.

Attentional set shifting in autism spectrum disorder: differentiating between the role of perseveration, learned irrelevance, and novelty processing

Autism spectrum disorders (ASD) are associated with impaired attentional set shifting, which may reflect enhanced perseverative responding, enhanced learned irrelevance, and/or reduced novelty processing. We assessed the contribution of these potential error sources in ASD adults. A total of 17 ASD and 19 matched comparison individuals first solved a discrimination learning task. Thereafter, the participants faced three types of attentional shift, specifically designed to isolate the effect of the three possible error sources. ASD participants made more errors than comparison individuals in a shift implying a choice between a novel relevant stimulus attribute and a familiar attribute that was previously relevant but now irrelevant. However, they made fewer errors in a shift involving a choice between a novel irrelevant attribute and a familiar, previously irrelevant but now relevant attribute. The results in combination suggest that the performance difference, at least in the present shift task, is caused by reduced novelty processing in ASD participants.