Executive functions in children with Autism Spectrum Disorders

Executive dysfunction is a characteristic impairment of individuals with Autism Spectrum Disorders (ASD). However whether such deficits are related to autism per se, or to associated intellectual disability is unclear. This paper examines executive functions in a group of children with ASD (N = 54, all IQ?70) in relation to a typically developing control group individually matched on the basis of age, gender, IQ and vocabulary. Significant impairments in the inhibition of prepotent responses (Stroop, Junior Hayling Test) and planning (Tower of London) were reported for children with ASD, with preserved performance for mental flexibility (Wisconsin Card Sorting Task) and generativity (Verbal Fluency). Atypical age-related patterns of performance were reported on tasks tapping response inhibition and self-monitoring for children with ASD compared to controls. The disparity between these and previous research findings are discussed. A multidimensional notion of executive functions is proposed, with difficulties in planning, the inhibition of prepotent responses and self-monitoring reflecting characteristic features of ASD that are independent of IQ and verbal ability, and relatively stable across the childhood years.     

Auditory processing and sensory behaviours in children with autism spectrum disorders as revealed by mismatch negativity

Sensory dysfunctions may underlie key characteristics in children with Autism Spectrum Disorders (ASD). The current study aimed to investigate auditory change detection in children with ASD in order to determine event-related potentials to meaningless and meaningful speech stimuli. 11 high functioning boys with a diagnosis of autism spectrum disorders (mean age = 13.0; SD = 1.08) and 11 typically developing boys (mean age = 13.7; SD = 1.5) participated in a mismatch negativity (MMN) paradigm. Results revealed that compared to TD controls, the children with ASD showed significantly reduced MMN responses to both words and pseudowords in the frontal regions of the brain and also a significant reduction in their activation for words in the Central Parietal regions. In order to test the relationship between sensory processing and auditory processing, children completed the Adult and Adolescent Sensory Profile. As predicted, the children with ASD showed more extreme sensory behaviours and were significantly higher than their typically developing controls across three of the sensory quadrants (sensory sensitivity, low registration and sensory avoidance). Importantly, only auditory sensory sensitivity was able to account for the differences displayed for words in the frontal and central parietal regions when controlling for the effect of group, revealing an inverse relationship of the higher sensory sensitivity scores the less activation in response for words. We discuss how the expression of sensory behaviours in ASD may result in deficient neurophysiological mechanisms underlying automatic language processing.     

Cognitive Load Undermines Thought Suppression in Acute Stress Disorder

Thought suppression studies demonstrate that attempts to suppress can be undermined by cognitive load. We report the first instance in which this has been tested experimentally in a sample of recently traumatized individuals. Individuals with and without acute stress disorder (ASD) were recruited following recent trauma and randomized to load or no load conditions (N = 56). They monitored intrusive memories during baseline, suppression, and think anything phases. The impact of suppression and load on self-reported intrusions, attention bias (dot-probe), and memory priming (word-stem task) was assessed. The ASD load group were less able to suppress memories (d = 0.32, CI₉₅ [− 0.15, 0.83], p = .088) than the ASD no load group (d = 0.63, CI₉₅ [0.08, 1.24], p < .001). In the think anything phase, the ASD load group reported more intrusions than the ASD no load or non-ASD groups (with and without load). No consistent findings were observed in relation to attentional bias. ASD load individuals exhibited stronger priming responses for motor vehicle accident and assault words than all other groups (ds between 0.35–0.73). Working memory did not moderate any outcomes of interest. The findings indicate that cognitive load interferes with suppression and may enhance access to trauma memories and associated material. The study extends previous research by demonstrating these effects for the first time in a clinical sample of recent survivors of trauma.     

Younger apes and human children plan their moves in a maze task

Planning defined as the predetermination of a sequence of actions towards some goal is crucial for complex problem solving. To shed light on the evolution of executive functions, we investigated the ontogenetic and phylogenetic origins of planning. Therefore, we presented all four great apes species (N = 12) as well as 4- and 5-year-old human preschoolers (N = 24) with a vertical maze task. To gain a reward placed on the uppermost level of the maze, subjects had to move the reward to the bottom through open gaps situated at each level of the maze. In total, there were ten gaps located over three of the maze’s levels, and free passage through these gaps could be flexibly blocked using multiple traps. Due to the decision tree design of the maze, the subjects had to plan their actions depending on the trap configuration up to two steps ahead to successfully retrieve the reward. We found that (1) our measure of planning was negatively correlated with age in nonhuman apes, (2) younger apes as well as 5-year-old children planned their moves up to two steps ahead whereas 4-year-olds were limited to plan one step ahead, and (3) similar performance but different underlying limitations between apes and children. Namely, while all species of nonhuman apes were limited by a lack of motor control, human children exhibited a shortage in shifting their attention across a sequence of subgoals.     

Childhood IQ and in-service mortality in Scottish Army personnel during World War II

The Scottish Mental Survey of 1932 (SMS1932) provides a record of intelligence test scores for almost a complete year-of-birth group of children born in 1921. By linking UK Army personnel records, the Scottish National War Memorial data, and the SMS1932 dataset it was possible to examine the effect of childhood intelligence scores on wartime military service mortality in males. There were 491 matches between World War II (WWII) Scottish Army fatalities and the SMS1932 database; 470 (96%) had an age 11 mental ability score recorded. The mean (S.D.) age 11 IQ score of those who died on active service in WWII was 100.78 (15.56), compared with 97.42 (14.87) for male Army survivors (p < 0.0001; Cohen's d = 0.22). Men who took part in the SMS1932 and who were not found in the Army database had a higher mean score (100.45, S.D. =14.97) than those men who had been in the Army, regardless of whether they died or survived (mean IQ = 97.66, S.D. = 14.94; p < 0.0001; Cohen's d = 0.19). Male soldiers with a higher childhood IQ had a slightly increased risk of dying during active service in WWII. Men who did not join the Army had a higher IQ than men who did. Further research in this area should consider naval and air force personnel records in order to examine more fully the complex relationship between IQ and survival expectancy during active service in WWII.     

Intelligence in Bali — A case study on estimating mean IQ for a population using various corrections based on theory and empirical findings

A high-quality estimate of the mean IQ of a country requires giving a well-validated test to a nationally representative sample, which usually is not feasible in developing countries. So, we used a convenience sample and four corrections based on theory and empirical findings to arrive at a good-quality estimate of the mean IQ in Bali. Our study used N = 50 Balinese (age between 7 and 46 years, M = 16.86) who took the Standard Progressive Matrices. Correcting for caste membership, school attendance, age distribution, and FLynn-effect gains resulted for the entire Balinese population in an IQ of 79, for adults of 75, and for children of 84. The validity of results is discussed.     

The influence of task paradigm on motor imagery ability in children with Developmental Coordination Disorder

Children with Developmental Coordination Disorder (DCD) have difficulty imagining movements such that they conform to the customary temporal constraints of real performance. We examined whether this ability is influenced by the choice of task used to elicit motor imagery (MI). Performance of typically developing (TD) (n = 30) and children with DCD (n = 30) was compared on two tasks: the Visually Guided Pointing Task (VGPT) and the Computerized Virtual Radial Fitts Task (C-VRFT). Since the VGPT places higher demands on executive functions like working memory but requires less spatial planning, we reasoned that the C-VRFT would provide a purer measure of motor imagery (or simulation). Based on our earlier work, we predicted that imagery deficits in DCD would more likely manifest on the C-VRFT. Results showed high correlations between tasks in terms of executed and imagined movement time suggest that both tasks measure MI ability. However, group differences were more pronounced in the imagined condition of the radial Fitts’ task. Taken together, the more spatially complex C-VRFT appears to be a more sensitive measure of motor imagery, better discriminating between DCD and TD. Implications for theory and practice are discussed.     

Inbreeding depression and IQ in a study of 72 countries

In this ecological study, a robust negative correlation of r = ? .62 (P < .01) is reported between national IQs and consanguinity as measured by the log₁₀ transformed percentage of consanguineous marriages for 72 countries. This correlation is reduced in magnitude, when IQ is controlled for GDP per capita (r = ? .41, P < .01); education index (r = ? .40, P < .01); and democracy index (r = ? .42, P < .01). Multiple regression analysis revealed that in the absence of the democracy index; percentage consanguineous marriages, education index and GDP per capita all exhibited stable final standardized β coefficients, however consanguinity had the least impact (β = 0, P > .05) whereas GDP per capita had the highest (β = .35, P > .01). This result is interpreted in light of cultural feedback theory, whereby it is suggested that consanguinity could subtly influence IQ at larger scales as a result of small IQ handicaps bought about through inbreeding being amplified into much larger differences through their effect on factors that maximize IQ such as access to education and adequate nutrition. Finally, consideration is given to future potential research directions.     

Le fonctionnement cognitif d’enfants atypiques à travers leur QI

The aim of this study is to find out whether atypical children – high potential children (IQ > 130, n = 10) versus intellectually delayed children (IQ < 75, n = 10) – present not only quantitative but also qualitative differences in regard to their IQ. Children are sampled according to school performance and paired with a control group (age, gender and socioprofessional context), therefore a total sample of 40 children. After analyzing individual and average profiles in the WISC-IV and two other cognitive tasks – a computerized version of Kohs’ Block Task (Samuel) and a cognitive version of Wechsler's Similarities – we suggest that the bases of intelligence are not the same depending on the IQ-level. Gifted children are not more heterogeneous as the control group, but their crystallised intelligence seems particularly well-developed due to a snowball effect of Gc. Moreover, they show better real-time learning abilities in Samuel. Profiles of intellectually delayed children are more homogeneous and imply a general deficiency, particularly in processing resources and the capacity for abstraction.     

Are adoption gains on the g factor? A meta-analysis

When children are adopted into prosperous families they generally show IQ gains. The meta-analytic correlation between subtest g loadings and adoption gains is examined (K = 4, combined N = 3018). A number of meta-analytic corrections are applied to the estimate, yielding a correlation of −1. The results are discussed.     

Development of motor imagery and anticipatory action planning in children with developmental coordination disorder – A longitudinal approach

Children with impaired motor coordination (or Development Coordination Disorder – DCD) have difficulty with the predictive control of movements, evidenced by cross-sectional studies that show impaired motor imagery and action planning abilities. What remains unclear is whether this deficit in predictive control reflects immaturity of the motor system (a developmental delay) or some deviation from normal development (a disorder). To advance this discussion the present study used a longitudinal design to examine the development of motor imagery and action planning in children with DCD. Thirty children were included in the DCD group (aged 6–11 years) and age- and gender-matched to 30 controls. The DCD group had a mABC-2 score ≤ 16th percentile, the control group > 20th percentile. Motor imagery was assessed with the hand rotation task, action planning with a test for end-state comfort. Children participated in three measurements, with one year in between measurements. Results showed that children with DCD were slower and less accurate than their typically developing peers in all subsequent years but were able to improve their motor imagery ability over time. Furthermore, children with DCD showed less planning for ESC at the start of the present study, but were able to catch up with their peers during two-year follow up. These results exemplify that improvement of motor imagery and action planning ability is possible in DCD, and they lend theoretical support to the use of new training techniques that focus on training motor imagery to improve motor skills in children with DCD.     

A study of the performance of Egyptian college students on the Advanced Progressive Matrices

Results are reported for intelligence assessed with the Advanced Progressive Matrices of a sample of students at Ain-Shams University in Cairo (N = 2147). The Egyptian raw scores were transformed to British IQ equivalents using the published 1992 British norms for the APM, on which the sample obtained a British IQ of 89.5. Science students obtained a significantly higher average mean score than arts students by 7.5 IQ points. Male students obtained a non-significantly higher average IQ than female students 1.2 IQ points. Male students had greater variability than the female students.     

Behavioural markers for autism in infancy: Scores on the Autism Observational Scale for Infants in a prospective study of at-risk siblings

We investigated early behavioural markers of autism spectrum disorder (ASD) using the Autism Observational Scale for Infants (AOSI) in a prospective familial high-risk (HR) sample of infant siblings (N = 54) and low-risk (LR) controls (N = 50). The AOSI was completed at 7 and 14 month infant visits and children were seen again at age 24 and 36 months. Diagnostic outcome of ASD (HR-ASD) versus no ASD (HR-No ASD) was determined for the HR sample at the latter timepoint. The HR group scored higher than the LR group at 7 months and marginally but non-significantly higher than the LR group at 14 months, although these differences did not remain when verbal and nonverbal developmental level were covaried. The HR-ASD outcome group had higher AOSI scores than the LR group at 14 months but not 7 months, even when developmental level was taken into account. The HR-No ASD outcome group had scores intermediate between the HR-ASD and LR groups. At both timepoints a few individual items were higher in the HR-ASD and HR-No ASD outcome groups compared to the LR group and these included both social (e.g. orienting to name) and non-social (e.g. visual tracking) behaviours. AOSI scores at 14 months but not at 7 months were moderately correlated with later scores on the autism diagnostic observation schedule (ADOS) suggesting continuity of autistic-like behavioural atypicality but only from the second and not first year of life. The scores of HR siblings who did not go on to have ASD were intermediate between the HR-ASD outcome and LR groups, consistent with the notion of a broader autism phenotype.     

The role of executive function,personality and attitudes to risks in explaining self-reported driving behaviour in adolescent and adult male drivers

Young drivers show high levels of risky driving and are over-represented in motor vehicle crash statistics world-wide. As well as personality and attitudinal factors, high rates of risk taking during adolescence may be due to poorly developed executive functions, a result of the slow maturation of the pre-frontal cortex of the brain. This study was undertaken to investigate the roles of executive function, personality, attitudes to risk in relation to self-reported driving behaviour. Adolescent (n = 46, age 16–18 years) and adult (n = 32, 25 years and over) male drivers completed a battery of neuropsychological tests to assess general cognitive ability and executive function, and questionnaires to assess driving history, personality, attitudes to physical and psychological risk as well as questionnaires of self-reported driving behaviour (Driver risk taking and Driver Attitude Questionnaire, DAQ). The adolescent drivers showed poorer executive function, higher levels of impulsivity and risk-taking, lower levels of agreeableness and conscientiousness compared to adult drivers. Regression analyses revealed that attitudes to risk, agreeableness and working memory made unique significant contributions in explaining self-reported driving behaviour. Interestingly though, better working memory was associated with higher levels of self-reported risky driving and more accepting attitudes to risky driving. Together the findings suggest that some aspects of executive function, personality, and attitudes to risk may help to explain self-reported driving behaviour. Whether these findings are relevant to female drivers and apply to on-road driving behaviour should be the focus of future studies.     

Distributed attentional deficits in chronic methamphetamine abusers: Evidence from the Attentional Network Task (ANT)

ObjectiveThe goal of the present study was to examine distributed attentional functions in long-term but currently abstinent methamphetamine (MA) abusers using a task that measures attentional alertness, orienting, and conflict resolution.MethodsThirty currently abstinent MA abusers (1 month–5 years) and 22 healthy non-substance using adults were administered a multimodal version of the Attentional Network Task (ANT-I). In this task subjects identified the direction of a centrally presented arrow using a key press. Analyses examined the interaction between alerting tones, location cueing and congruency between the target arrows and flanking distractor stimuli.ResultsAll participants were faster when an auditory tone preceded the trial onset (p < 0.001), on trials in which a valid cue preceded the location of the target arrow (p < 0.001), and on congruent trials (i.e., when all display arrows faced in the same direction) (p < 0.001). Of primary interest was the finding that MA abusers were more influenced by the conflict between the peripheral arrows and the central target arrow (p = 0.009). There were also correlations between length of drug sobriety and executive function as well as between drug-induced psychiatric symptoms and alertness.ConclusionsThese results suggest that chronic MA abusers display cognitive deficits that may reflect a specific vulnerability to distraction on a task of executive function. These findings are consistent with other studies that have reported deficits in anterior attentional systems and top-down cognitive control.     

Self-unawareness of levodopa induced dyskinesias in patients with Parkinson’s disease

The study analyzes the presence of dyskinesias-reduced-self-awareness in forty-eight patients suffering from Parkinson’s disease (PD). As the association with executive dysfunction is a matter of debate and we hypothesize it plays an important role in dyskinesias self-unawareness, we analyzed the role of dopaminergic treatment on the medial-prefrontal-ventral-striatal circuitry using a neurocognitive approach. Special attention was given to metacognitive abilities related to action-monitoring that represent a novel explanation of the phenomenon.PD patients were assessed using different rating scales that we devised to measure movement awareness disorders. In order to ascertain whether each variable measured at a cognitive-clinical level contributes to predicting the scores of the movement-disorder-awareness-scales, we conducted multiple logistic regression models using the latter as binary dependent variables. We used the Wisconsin Card Sorting Test-metacognitive-version to assess the executive functions of the prefrontal-ventral-striatal circuitry.Data showed that a reduction of self-awareness using the Dyskinesia rating scale was associated with global monitoring (p = .04), monitoring resolution (p = .04) and control sensitivity (p = .04). Patients failed to perceive their performance, distinguish between correct and incorrect sorts, be confident in their choice and consequently decide to gamble during the task.We did not find any association with executive functions using the hypo-bradykinesia rating scale.Our findings indicate that when the comparator mechanism for monitoring attentive performance is compromised at a prefrontal striatal level, patients lose the ability to recognize their motor disturbances that do not achieve conscious awareness.     

Neurophysiological marker of inhibition distinguishes language groups on a non-linguistic executive function test

Successful interaction with the environment depends on flexible behaviors which require shifting attention, inhibiting primed responses, ignoring distracting information, and withholding motor responses. These abilities, termed executive function (EF), are believed to be mediated by inhibitory processes in the frontal lobes. Superior performance on EF tests (i.e., faster reaction times (RT), and fewer errors) has been shown in bilinguals compared to monolingual speakers. However, findings are inconsistent, and no study has directly linked this bilingual advantage to frontal lobe inhibitory processes. To clarify this uncertainty, we concomitantly tested neural inhibitory processes and behavioral responses on an EF test in bilinguals and monolinguals. Specifically, we compared English monolinguals (N = 15) to Spanish/English bilinguals (N = 13) on event-related brain potentials (ERP) during a non-linguistic, auditory Go/NoGo task, a task linked to non-motor, cognitive inhibition in monolinguals. Participants responded with a button press on trials in which target tone-pairs (Go trials) were presented and withheld their responses on non-target trials (NoGo trials). Results revealed significantly greater inhibition (i.e., greater mean N2 amplitude) in bilinguals compared to monolinguals during NoGo trials even though both groups performed the task equally well (i.e., withheld a motor response). On Go trials where participants pressed a response button, neither ERPs nor RT distinguished the groups. Additionally, scores on a second language proficiency test (i.e., English in our bilingual group) were positively correlated with N2 amplitude. These findings are the first to directly link this bilingual advantage to a neural correlate of inhibition and to reveal that inhibition in bilinguals is moderated by second language proficiency. Results are discussed in the context of plasticity, and we propose that evaluating bilinguals at varying levels of second-language proficiency may serve as a model of human neuroplasticity.     

Functioning of peripheral Ia pathways in leg muscles of newly walking toddlers

Monosynaptic and polysynaptic spinal level reflexes in the leg muscles of infants show significant dispersion across muscles, high variability, and no change in response patterns over the first 10 months. Here we tested the hypothesized relation between early walking experience and the tuning of these responses in three primary gait muscles of participants in four subgroups: cruisers (n = 7) and toddlers with one (n = 5), two (n = 5), or three (n = 5) months of walking experience. Reflex responses in multiple Ia pathways – tendon reflex (T-reflex), vibration-induced inhibition of the T-reflex (VIM-T-reflex), and tonic vibration-induced reflex (VIR), were elicited by mechanical stimuli applied to the distal tendons of the quadriceps, gastrocnemius-soleus, and tibialis anterior of both legs. Walking skill was assessed via a GAITRite mat. Generally, walking experience seemed to be related to slowly emerging improvements and, depending on muscle tested and pathway, progress was quite varied. Amplitude and latency of reflex responses were more clearly impacted by age or leg length while the ratio or distribution pattern of reflex response among antagonist pairs of muscles was impacted by walking experience and skill. As walking experience increased, the ratio of reflex responses tended to increase for the stimulated and decrease for the antagonist reflex loops with distribution of the pattern shifting gradually toward a single type of reflex response in all tested muscles. The very slow tuning of these reflexes may underlie the many missteps and falls reported to occur during early walking and suggest that subsequent studies should continue to follow the developmental trajectory through the first year of walking experience.     

Motor imagery ability and internal representation of movement in children with probable developmental coordination disorder

It has been hypothesised that deficits in the functioning of the mirror neuron system (MNS) and internal modelling may contribute to the motor impairments associated with DCD. These processes can be explored behaviourally through motor imagery paradigms. Motor imagery proficiency of children with and without probable DCD (pDCD) was examined using a complex hand rotation task to explore whether motor imagery strategies could be used during more complex tasks. Forty-four boys aged 7–13 years participated, 22 with pDCD (mean = 9.90 years ± 1.57) and 22 controls (mean = 9.68 years ± 1.53). Participants completed the task twice: with and without motor imagery instructions. Stimuli were presented in two rotational axes – palm/back, and eight 45° rotational steps. Both groups showed evidence of following the biomechanical and postural constraints of actual movements. Responses of children with pDCD were slower and less accurate than controls, with group differences increasing alongside task complexity. A greater impact of biomechanical constraints for accuracy was observed in the DCD group. The response characteristics of children with pDCD likely reflects a reduced capacity to mentally manipulate a body schema and reduced visuo-motor processing capabilities. Behaviourally, these processes are linked to MNS and internal modelling function, suggesting deficits in these systems may contribute to the movement difficulties characteristic of DCD.