Differential Diagnosis of Autism Spectrum Disorder and Attention Deficit Hyperactivity Disorder by Means of Inhibitory Control and ‘Theory of Mind’

Effective connectivity alterations of the triple network model in the co-occurrence of autism spectrum disorder and attention deficit hyperactivity disorder

Autism spectrum disorder (ASD) and attention deficit hyperactivity disorder (ADHD) are both highly prevalent disorders and frequently co-occur. The underlying neurological mechanisms of the co-occurrence of ASD and ADHD (ASD + ADHD) remain unknown. This study focuses on investigating the effective connectivity (EC) alterations within the triple network model in individuals with ASD + ADHD. Resting-state functional magnetic resonance imaging data were obtained from 44 individuals with ASD + ADHD, 60 individuals with ASD without ADHD (ASD-only), 35 individuals with ADHD without ASD (ADHD-only), and 81 healthy controls (HC) from the Autism Brain Imaging Data Exchange II and the ADHD-200 Sample database. Spectral dynamic causal modeling was employed to explore the EC alterations within and between the default mode network, salience network, and central executive network. Our analysis showed that compared to HC, ASD + ADHD, ASD-only, and ADHD-only exhibited both shared and disorder-specific EC alterations within the triple-network model. These results have potential clinical implications for identifying ASD + ADHD, facilitating diagnostic accuracy, guiding targeted treatment approaches, and informing etiological studies.

Facial emotion recognition in children and youth with attention-deficit/hyperactivity disorder and irritability

The ability to recognize emotions evident in people's faces contributes to social functioning and might be affected by ADHD and irritability. Given their high co-occurrence, we examined the relative contribution of ADHD and irritability to facial emotion recognition (FER). We hypothesized that irritability but not ADHD traits would predict increased likelihood of misrecognizing emotions as negative, and that FER performance would explain the association of ADHD and irritability traits with social skills. FER was measured using the Reading the Mind in the Eyes Test (RMET) in children (6-14 years old) referred for ADHD assessment (n = 304) and healthy controls (n = 128). ADHD, irritability and social skills were measured using parent ratings. We used repeated measure logistics regression, comparing the effects across emotion valence of images (i.e., neutral/positive/negative). High irritability but not ADHD diagnosis predicted lower RMET accuracy. ADHD traits predicted lower RMET accuracy in younger but not older participants, whereas irritability predicted poorer accuracy at all ages. ADHD traits predicted lower RMET accuracy across all emotion valences, whereas irritability predicted increased probability of misrecognizing neutral and positive but not negative emotions. Irritability did not increase the probability for erroneously recognizing emotions as negative. ADHD and irritability traits fully explained the association between RMET and social skills. ADHD and irritability traits might impact the ability to identify emotions portrayed in faces. However, irritability traits appear to selectively impair recognition of neutral and positive but not negative emotions. ADHD and irritability are important when examining the link between FER and social difficulties.

Reduced inferior fronto-insular-thalamic activation during failed inhibition in young adults with combined ASD and ADHD compared to typically developing and pure disorder groups

Autism spectrum disorder (ASD) often co-occurs with attention-deficit/hyperactivity disorder (ADHD) and people with these conditions have frontostriatal functional atypicality during motor inhibition. We compared the neural and neurocognitive correlates of motor inhibition and performance monitoring in young adult males with "pure" and combined presentations with age-and sex-matched typically developing controls, to explore shared or disorder-specific atypicality. Males aged 20-27 years with typical development (TD; n = 22), ASD (n = 21), combined diagnoses ASD + ADHD (n = 23), and ADHD (n = 25) were compared using a modified tracking fMRI stop-signal task that measures motor inhibition and performance monitoring while controlling for selective attention. In addition, they performed a behavioural go/no-go task outside the scanner. While groups did not differ behaviourally during successful stop trials, the ASD + ADHD group relative to other groups had underactivation in typical performance monitoring regions of bilateral anterior insula/inferior frontal gyrus, right posterior thalamus, and right middle temporal gyrus/hippocampus during failed inhibition, which was associated with increased stop-signal reaction time. In the behavioural go/no-go task, both ADHD groups, with and without ASD, had significantly lower motor inhibition performance compared to TD controls. In conclusion, only young adult males with ASD + ADHD had neurofunctional atypicality in brain regions associated with performance monitoring, while inhibition difficulties on go/no-go task performance was shared with ADHD. The suggests that young people with ASD + ADHD are most severely impaired during motor inhibition tasks compared to ASD and ADHD but do not reflect a combination of the difficulties associated with the pure disorders.

Do shapes have feelings? Social attribution in children with autism spectrum disorder and attention-deficit/hyperactivity disorder

Theory of mind (ToM) deficits are common in children with neurodevelopmental disorders (NDDs), such as autism spectrum disorder (ASD) and attention-deficit/hyperactivity disorder (ADHD), which contribute to their social and cognitive difficulties. The social attribution task (SAT) involves geometrical shapes moving in patterns that depict social interactions and is known to recruit brain regions from the classic ToM network. To better understand ToM in ASD and ADHD children, we examined the neural correlates using the SAT and functional magnetic resonance imaging (fMRI) in a cohort of 200 children: ASD (N = 76), ADHD (N = 74) and typically developing (TD; N = 50) (4-19 years). In the scanner, participants were presented with SAT videos corresponding to social help, social threat, and random conditions. Contrasting social vs. random, the ASD compared with TD children showed atypical activation in ToM brain areas-the middle temporal and anterior cingulate gyri. In the social help vs. social threat condition, atypical activation of the bilateral middle cingulate and right supramarginal and superior temporal gyri was shared across the NDD children, with between-diagnosis differences only being observed in the right fusiform. Data-driven subgrouping identified two distinct subgroups spanning all groups that differed in both their clinical characteristics and brain-behaviour relations with ToM ability.

The association between symptom severity and theory of mind impairment in children with attention deficit/hyperactivity disorder

The aim was to investigate the correlation between ADHD symptom severity and impairments in "theory of mind" (ToM) and empathy, and the improvement in these functions following the administration of methylphenidate (MPH). Fifty children aged 6-12 years with ADHD participated in the study. Symptom severity was assessed using the Swanson, Nolan and Pelham Questionnaire-IV (SNAP-IV). ToM performance was assessed using the "ToM test" and the "Faux-Pas Recognition Test". A significant negative correlation was found between the SNAP-IV Conners index, the oppositional and deportment subscales, and ToM test scores. MPH administration improved ToM scores in a magnitude that was negatively correlated with baseline performance. Additionally, Children with more severe behavioral problems showed greater improvement in ToM following administration of MPH. We conclude that severity of ADHD symptoms, most notably behavioral symptoms, is correlated with deficits in ToM. Administration of MPH improves ToM performance, with the greatest improvement occurring in children with more severe behavioral symptoms.

Automated Classification of Mental Arithmetic Tasks Using Recurrent Neural Network and Entropy Features Obtained from Multi-Channel EEG Signals

The automated classification of cognitive workload tasks based on the analysis of multi-channel EEG signals is vital for human–computer interface (HCI) applications. In this paper, we propose a computerized approach for categorizing mental-arithmetic-based cognitive workload tasks using multi-channel electroencephalogram (EEG) signals. The approach evaluates various entropy features, such as the approximation entropy, sample entropy, permutation entropy, dispersion entropy, and slope entropy, from each channel of the EEG signal. These features were fed to various recurrent neural network (RNN) models, such as long-short term memory (LSTM), bidirectional LSTM (BLSTM), and gated recurrent unit (GRU), for the automated classification of mental-arithmetic-based cognitive workload tasks. Two cognitive workload classification strategies (bad mental arithmetic calculation (BMAC) vs. good mental arithmetic calculation (GMAC); and before mental arithmetic calculation (BFMAC) vs. during mental arithmetic calculation (DMAC)) are considered in this work. The approach was evaluated using the publicly available mental arithmetic task-based EEG database. The results reveal that our proposed approach obtained classification accuracy values of 99.81%, 99.43%, and 99.81%, using the LSTM, BLSTM, and GRU-based RNN classifiers, respectively for the BMAC vs. GMAC cognitive workload classification strategy using all entropy features and a 10-fold cross-validation (CV) technique. The slope entropy features combined with each RNN-based model obtained higher classification accuracy compared with other entropy features for the classification of the BMAC vs. GMAC task. We obtained the average classification accuracy values of 99.39%, 99.44%, and 99.63% for the classification of the BFMAC vs. DMAC tasks, using the LSTM, BLSTM, and GRU classifiers with all entropy features and a hold-out CV scheme. Our developed automated mental arithmetic task system is ready to be tested with more databases for real-world applications.

Neuropsychological predictors of driving hazard detection in autism spectrum disorder and ADHD

Driving is a neuropsychologically complex task; this can present challenges for individuals with neurodevelopmental disorders (NDDs) such asautism spectrum disorder (ASD) and attention-deficit/hyperactivity disorder (ADHD). Deficits in theory of mind (ToM) and executive function (EF) are common features of ASD and ADHD, respectively, and may influence driving processes such as hazard perception. No studies have directly examined the neuropsychological contributions to hazard detection among drivers with ASD compared to ADHD.In the current study, 48 participants ages 16-30 years (13 ASD, 17 ADHD, 18 typically developing (TD)) completed a driving simulator task in which they encountered hazards in the driving environment. Hazards varied in whether they were social (contained a human component) or nonsocial (were physical objects) to examine the contribution of ToM and social processing to hazard response. Additionally, participants completed a neuropsychological battery targeting ToM and EF/attention skills (cognitive tasks and self-report measures).Within the ASD group, participants responded relatively slower to social compared to nonsocial hazards; no effect of hazard type was observed in the ADHD or TD groups. Additionally, measures of ToM and EF were correlated with driving performanceamong ASD participants; within the ADHD group, only self-reported behavior regulation was associated with driving performance. Broadly, this suggests that cognitive factors such as ToM and EF impact driving hazard performance in ASD and ADHD. The results of the study have implications for developing driving intervention programs for individuals with NDDs.

Developmental outcomes in adolescence of children with autism spectrum disorder without intellectual disability: A systematic review of prospective studies

Individuals with Autism Spectrum Disorder (ASD) without intellectual disability (ID) represent approximately two-thirds of the ASD population. Here we focused on prospective research assessing different areas of functioning of children with ASD, without ID, until adolescence. Based on a pre-registered protocol (PROSPERO CRD42020189029), a systematic review of prospective studies (published between 01.01.2010 and 01.01.2020) was conducted. Twenty-eight studies met eligibility criteria. Findings indicated that ASD diagnosis and the Intelligence Quotient were highly stable over time across studies. Executive Functioning, Theory of Mind and Central Coherence processes tended to improve, although deficits remained when compared to typically developed controls. Adaptive difficulties and psychiatric comorbidity were relatively stable over time. We discuss potential implications of the findings for clinicians and educators and suggest recommendations for future research.

Inhibition in developmental disorders: A comparison of inhibition profiles between children with autism spectrum disorder, attention-deficit/hyperactivity disorder, and comorbid symptom presentation

LAY ABSTRACT

Many children with autism spectrum disorder (ASD) also have symptoms of attention-deficit hyperactivity disorder (ADHD). Children with ASD and ADHD often experience difficulties with inhibition. This study had the goal of understanding inhibition in children with ASD, ADHD, ASD + ADHD, and children who are typically developing (TD) using tasks that measured several aspects of inhibition. Results indicate that children with ASD + ADHD had greater difficulty inhibiting behavioral responses than TD children. Children with ASD + ADHD also differed from children with ASD and with ADHD in their inhibition of distracting information and strategic slowing of response speed. The four groups did not differ in their avoidance of potential losses. Children with ASD + ADHD exhibit a unique profile of inhibition challenges suggesting they may benefit from targeted intervention matched to their abilities.

Functional magnetic resonance imaging multivoxel pattern analysis reveals neuronal substrates for collaboration and competition with myopic and predictive strategic reasoning

Competition and collaboration are strategies that can be used to optimize the outcomes of social interactions. Research into the neuronal substrates underlying these aspects of social behavior has been limited due to the difficulty in distinguishing complex activation via univariate analysis. Therefore, we employed multivoxel pattern analysis of functional magnetic resonance imaging to reveal the neuronal activations underlying competitive and collaborative processes when the collaborator/opponent used myopic/predictive reasoning. Twenty‐four healthy subjects participated in 2 × 2 matrix‐based sequential‐move games. Searchlight‐based multivoxel patterns were used as input for a support vector machine using nested cross‐validation to distinguish game conditions, and identified voxels were validated via the regression of the behavioral data with bootstrapping. The left anterior insula (accuracy = 78.5%) was associated with competition, and middle frontal gyrus (75.1%) was associated with predictive reasoning. The inferior/superior parietal lobules (84.8%) and middle frontal gyrus (84.7%) were associated with competition, particularly in trials with a predictive opponent. The visual/motor areas were related to response time as a proxy for visual attention and task difficulty. Our results suggest that multivoxel patterns better represent the neuronal substrates underlying the social cognition of collaboration and competition intermixed with myopic and predictive reasoning than do univariate features.

Associations Between Limbic System White Matter Structure and Socio-Emotional Functioning in Children with ADHD + ASD

Children with attention deficit/hyperactivity disorder (ADHD) combined with autism spectrum disorder (ASD) symptoms (ADHD + ASD) have poorer social and emotional functioning than those with ADHD alone. However, no studies have specifically examined the associations between ASD symptoms, measures of social and emotional functioning and limbic system white matter microstructure. Tractography on the cingulum, uncinate fasciculus and fornix were performed for 151 children with (N = 78) and without (N = 73) ADHD. Participants in the ADHD group who scored 11 or above on the Social Communication Questionnaire were classified as the ADHD + ASD group (N = 16). Significant differences in mean cingulum FA were present between the control group and the ADHD (all) group, however, no significant differences were seen between the ADHD and ADHD + ASD groups. Despite this, significant associations were seen between mean FA of the left cingulum and emotional problems for the ADHD + ASD group. Results give greater insights into the specific biological basis of emotional problems in the ADHD + ASD group, indicating that the cingulum may play a role.

Only Familiar Information is a "Curse": Children's Ability to Predict What Their Peers Know

The ability to make inferences about what one's peers know is critical for social interaction and communication. Three experiments (n = 309) examined the curse of knowledge, the tendency to be biased by one's knowledge when reasoning about others' knowledge, in children's estimates of their peers' knowledge. Four- to 7-year-olds were taught the answers to factual questions and estimated how many peers would know the answers. When children learned familiar answers, they showed a curse of knowledge in their peer estimates. But, when children learned unfamiliar answers to the same questions, they did not show a curse of knowledge. These data shed light on the mechanisms underlying perspective taking, supporting a fluency misattribution account of the curse of knowledge.

The Development and Preliminary Psychometric Evaluation of the Theory of Mind Inventory: Self Report-Adult (ToMI:SR-Adult)

This study describes the development and psychometric evaluation of a new self-report measure of social cognition: the Theory of Mind Inventory:Self-report-Adult (ToMI:SR-Adult). Adults with autism (or a suspicion of autism; n = 111) and typically developing adults (n = 109) completed a demographic questionnaire and the ToMI:SR-Adult online. Both quantitative and qualitative self-reports of one's own theory of mind functioning were collected. The ToMI:SR-Adult performed well under all examinations of reliability and validity (internal consistency, accuracy of classification, contrasting-groups). The qualitative data confirmed impressions of validity and revealed that the adults in our sample had high levels of self-insight regarding their own theory of mind. The ToMI:SR-Adult is offered as a promising research and clinical tool for the assessment of social cognition in adults.

The Specificity and Independent Contribution of Inhibition, Working Memory, and Reaction Time Variability in Relation to Symptoms of ADHD and ASD

Objective: The aim of the present study was to investigate the specificity of inhibition, working memory (WM), and reaction time variability (RTV) in relation to symptoms of ADHD and autism spectrum disorder (ASD). Method: A community-based sample of schoolchildren aged 7 to 9 years (N = 200) completed tasks designed to measure inhibition, WM, and RTV. Results: All neuropsychological functions were related to symptoms of both ADHD and ASD. The results from regression analyses showed that inhibition and RTV were related specifically to ADHD symptoms when controlling for symptoms of ASD. Regarding WM, no specific association with either symptom domain was evident after controlling for the other. Furthermore, independent contributions of inhibition and RTV were found in relation to ADHD symptoms after controlling for ASD symptoms. Conclusion: The present study underscores the relevance of controlling for ADHD symptoms when examining ASD symptoms in relation to neuropsychological functions.

The effect of methylphenidate on social cognition and oxytocin in children with attention deficit hyperactivity disorder

The current study aimed to explore the possible effect of stimulants on oxytocin (OT), a neuropeptide which regulates social behavior, as a mediator of the pro-social effect of methylphenidate (MPH) in children with attention deficit hyperactivity disorder (ADHD) compared to healthy controls (HCs). Utilizing a double-blind placebo-controlled design, we compared the performance of 50 children with ADHD and 40 HCs in "theory of mind" (ToM) tasks and examined the effect of a single dose of MPH/placebo on ToM and salivary OT levels in children with ADHD at baseline and following an interpersonal interaction. Children with ADHD displayed significantly poorer ToM performance; however, following MPH administration, their performance normalized and differences between children with ADHD and HC were no longer found. Salivary OT levels at baseline did not differ between children with ADHD and HCs. However, after a parent-child interaction, OT levels were significantly higher in the HC group compared to children with ADHD. Administration of MPH attenuated this difference such that after parent-child interaction differences in OT levels between children with ADHD and HC were no longer found. In the ADHD group, OT levels decreased from administration of placebo to the parent-child interaction. However, the administration of MPH to children with ADHD was associated with an increase in OT levels after the parent-child interaction. We conclude that OT might play a role as a mediator of social deficits in children with ADHD and that the reactivity of the OT system to social interaction in children with ADHD might be impaired. Stimulants may improve ToM and social functions in children with ADHD via its impact on the OT system. PRS: OT and Social Cognition in Children with ADHD: Impact of MPH.

Theory of Mind and Empathy in Children With ADHD

Objective: The current study compared empathy and theory of mind (ToM) between children with ADHD and healthy controls, and assessed changes in ToM among children with ADHD following administration of methylphenidate (MPH). Method: Twenty-four children with ADHD (mean age = 10.3 years) were compared with 36 healthy controls. All children completed the interpersonal reactivity index (IRI), a self-reported empathy questionnaire, and performed the "faux-pas" recognition task (FPR). Children with ADHD performed the task with and without MPH. Results: Children with ADHD showed significantly lower levels of self-reported empathy on most IRI subscales. FPR scores were significantly lower in children with ADHD and were improved, following the administration of MPH, to a level equal to that found in healthy controls. Conclusion: Children with ADHD show impaired self-reported empathy and FPR when compared with healthy controls. Stimulants improve FPR in children with ADHD to a level equal to that in healthy controls.

Children with autism and attention deficit hyperactivity disorder. Relationships between symptoms and executive function, theory of mind, and behavioral problems

BACKGROUND

The underlying mechanisms of comorbidity between autism spectrum disorder (ASD) and attention deficit hyperactivity disorder (ADHD) are still unknown. Executive function (EF) deficits and theory of mind (ToM) have been the most investigated cognitive processes.

AIMS

This study proposed to analyze EF, ToM and behavioral problems in children with ASD + ADHD, ADHD, ASD and typical development (TD). The relationship between ADHD and ASD symptoms with EF, ToM and behavioral problems in children with ASD + ADHD was also explored.

METHODS AND PROCEDURES

Participants were 124 children between 7 and 11 years old (22 ASD + ADHD, 35 ADHD, 30 ASD, and 37 TD), matched on age and IQ. Teachers evaluated EF, and parents assessed ToM skills and behavioral problems through Strengths and Difficulties Questionnaire (SDQ).

OUTCOMES AND RESULTS

Children with ASD + ADHD and ADHD showed impairments in EF whereas the difficulties in ToM skills of ASD + ADHD group were similar to ASD group. Inattention symptoms were significantly associated with EF metacognitive deficits and ToM difficulties in ASD + ADHD, while ASD symptoms were associated with total score in behavioral problems.

CONCLUSIONS AND IMPLICATIONS

These findings show the complex difficulties of children with both ASD and ADHD and support the need to take these difficulties into account when designing the treatments.

An emotion recognition subtyping approach to studying the heterogeneity and comorbidity of autism spectrum disorders and attention-deficit/hyperactivity disorder

Background

Emotion recognition dysfunction has been reported in both autism spectrum disorders (ASD) and attention-deficit/hyperactivity disorder (ADHD). This suggests that emotion recognition is a cross-disorder trait that may be utilised to understand the heterogeneous psychopathology of ASD and ADHD. We aimed to identify emotion recognition subtypes and to examine their relation with quantitative and diagnostic measures of ASD and ADHD to gain further insight into disorder comorbidity and heterogeneity.

Methods

Factor mixture modelling was used on speed and accuracy measures of auditory and visual emotion recognition tasks. These were administered to children and adolescents with ASD (N = 89), comorbid ASD + ADHD (N = 64), their unaffected siblings (N = 122), ADHD (N = 111), their unaffected siblings (N = 69), and controls (N = 220). Identified classes were compared on diagnostic and quantitative symptom measures.

Results

A four-class solution was revealed, with the following emotion recognition abilities: (1) average visual, impulsive auditory; (2) average-strong visual and auditory; (3) impulsive/imprecise visual, average auditory; (4) weak visual and auditory. The weakest performing class (4) contained the highest percentage of patients (66.07%) and the lowest percentage controls (10.09%), scoring the highest on ASD/ADHD measures. The best performing class (2) demonstrated the opposite: 48.98% patients, 15.26% controls with relatively low scores on ASD/ADHD measures.

Conclusions

Subgroups of youths can be identified that differ both in quantitative and qualitative aspects of emotion recognition abilities. Weak emotion recognition abilities across sensory domains are linked to an increased risk for ASD as well as ADHD, although emotion recognition impairments alone are neither necessary nor sufficient parts of these disorders.

Electronic supplementary material

The online version of this article (10.1186/s11689-018-9249-6) contains supplementary material, which is available to authorized users.

Executive Function and Theory of Mind in Children with ADHD: a Systematic Review

In developmental research, the relationship between Executive Function (EF) and Theory of Mind (ToM) has been extensively assessed, and EF has been considered a condition for ToM. However, few researchers have studied the relationship between EF and ToM in clinical populations, especially that of Attention Deficit Hyperactivity Disorder (ADHD), a neurodevelopmental disorder characterized by symptoms of inattention and motor hyperactivity/impulsivity, in which EF is largely impaired. Using the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) model, 201 English and Spanish articles evaluating EF and ToM in ADHD were chosen. Fifteen papers met the inclusion criteria and were selected for further analysis. The first study dates from 2001. Most of the studies' designs are cross-sectional, include mostly male children, have a small sample size, and were conducted in European countries. Unlike tasks assessing EF, tasks assessing ToM were heterogeneous across studies. The EFs most correlated with ToM were inhibitory control, working memory, cognitive flexibility, and attention. Interest in studying the relationship between EF and ToM in ADHD is recent,but increasing based on new findings and tuning of ToM instruments. However, while an association between EF and ToM is indicated in ADHD, the degree of prediction and predictability of one over the other cannot yet be established because of the studies' heterogeneity.

Specificity of executive function and theory of mind performance in relation to attention-deficit/hyperactivity symptoms in autism spectrum disorders

Background

Individuals with autism spectrum disorder (ASD) frequently demonstrate symptoms of attention-deficit/hyperactivity disorder (ADHD). Previous findings in children with ASD have suggested that these symptoms are associated with an impairment in executive function (EF) abilities. However, studies rarely considered this association within a single framework that controls for other related factors such as Theory of Mind (ToM) abilities and ASD symptoms.

Methods

We used structural equation modeling to explore the relations among EF, ToM, and symptoms of ASD and ADHD, using data from a population-based sample of 100 adolescents with ASD and full-scale IQ ≥ 50 (the Special Needs and Autism Project (SNAP) cohort). The study used a multi-measure and multi-informant approach, where performance of inhibition, planning, switching, and working memory tasks indexed EF and performance on tasks involving mentalizing indexed ToM. Measures of ASD and ADHD symptoms included parent and teacher reports and direct observation of the children. Shared source of symptom reporting was accounted for with a parental rating latent factor indexed by symptom measures reported by parents.

Results

Impairments in EF abilities were specifically associated with ADHD symptoms while impaired ToM was specifically associated with ASD symptoms, when accounting for the associations of each cognitive domain with the other factors. ASD and ADHD symptom latent factors were also correlated, but this association became nonsignificant once the shared source of reporting from parents was accounted for and within a model that also controlled for the correlated pathway between EF and ToM factors. The specific relations between the cognitive domains and behavioral symptoms remained even after controlling for IQ.

Conclusions

In this ASD sample, symptoms of ADHD and ASD are underpinned by separate cognitive domains. The association between EF and ToM impairments is a likely partial explanation for the co-occurrence of ADHD symptoms in ASD, but the role of shared reporting effects is also important and supports the inclusion of independent informants and objective measures in future research.

Relationship Between Executive Functioning and Symptoms of Attention-Deficit/Hyperactivity Disorder and Autism Spectrum Disorder in 6-8 Year Old Children

This study examined relationships between executive functioning (EF) and ADHD/ASD symptoms in 339 6-8 year-old children to characterise EF profiles associated with ADHD and ADHD + ASD. ADHD status was assessed using screening surveys and diagnostic interviews. ASD symptoms were measured using the Social Communication Questionnaire, and children completed assessments of EF. We found the EF profile of children with ADHD + ASD did not differ from ADHD-alone and that lower-order cognitive skills contributed significantly to EF. Dimensionally, ASD and inattention symptoms were differentially associated with EF, whereas hyperactivity symptoms were unrelated to EF. Differences between categorical and dimensional findings suggest it is important to use both diagnostic and symptom based approaches in clinical settings when assessing these children's functional abilities.

Oxytocin Receptor Polymorphisms are Differentially Associated with Social Abilities across Neurodevelopmental Disorders

Oxytocin is a pituitary neuropeptide that affects social behaviour. Single nucleotide polymorphisms (SNPs) in the oxytocin receptor gene (OXTR) have been shown to explain some variability in social abilities in control populations. Whether these variants similarly contribute to the severity of social deficits experienced by children with neurodevelopmental disorders is unclear. Social abilities were assessed in a group of children with autism spectrum disorder (ASD, n = 341) or attention deficit hyperactivity disorder (ADHD, n = 276) using two established social measures. Scores were compared by OXTR genotype (rs53576, rs237887, rs13316193, rs2254298). Unexpectedly, the two most frequently studied OXTR SNPs in the general population (rs53576 and rs2254298) were associated with an increased severity of social deficits in ASD (p < 0.0001 and p = 0.0005), yet fewer social deficits in ADHD (p = 0.007 and p < 0.0001). We conclude that these genetic modifier alleles are not inherently risk-conferring with respect to their impact on social abilities; molecular investigations are greatly needed.

Social Cognition in Children with High-Functioning Autism Spectrum Disorder and Attention-Deficit/Hyperactivity Disorder. Associations with Executive Functions

Autism spectrum disorder (ASD) and attention deficit hyperactivity disorder (ADHD) are neurodevelopmental disorders characterized by social impairments. The first objective of this study was to analyze social cognition deficits of children with ADHD, high-functioning ASD (HFASD), and typical development (TD) in their performance on explicit and applied measures of theory of mind (ToM). The second objective was to investigate the relationships between executive functions and social cognition in HFASD and ADHD. One hundred and twenty-six 7- to 11-year old children, 52 with HFASD, 35 with ADHD, and 39 with TD, performed the NEPSY-II social perception subtests. Parents estimated their children's ToM skills using the Theory of Mind Inventory (ToMI). Teacher-reported data from the Behavior Rating Inventory of Executive Function (BRIEF) were also obtained. The HFASD and ADHD groups showed worse performance on the verbal ToM task than the TD group, and only the performance of the HFASD group was significantly lower than the TD group on the contextual ToM task. Parents also estimated that the HFASD group had more difficulties on the applied ToM than the ADHD and TD groups. Furthermore, there is a different executive function-theory of mind link in the HFASD and ADHD groups: behavioral regulation processes such as inhibition and emotional control are more associated with social cognition in children with ADHD, whereas metacognitive processes such as initiation and planning have a strong association with social cognition in children with HFASD. These findings have implications for understanding social perception deficits in neurodevelopmental disorders, highlighting the need for early intervention.

Neuropsychological Functioning and Attachment Representations in Early School Age as Predictors of ADHD Symptoms in Late Adolescence

This study aimed to examine relations between parent and child attachment representations and neuropsychological functions at age 8, as well as relations between these constructs and ADHD symptoms over a 10-year period. A community-based sample of 105 children (52 boys) participated. Measures of attachment representations and a range of neuropsychological functions were collected at age 8. Parents rated emotion dysregulation and ADHD symptoms at age 8 and ADHD symptoms again at age 18. Significant, although modest, relations were found between disorganized attachment and some aspects of neuropsychological functioning in childhood. When studying outcomes in late adolescence and controlling for early ADHD symptom levels, spatial working memory and disorganized attachment remained significant in relation to both ADHD symptom domains, and one measure of inhibition remained significant for hyperactivity/impulsivity. When examining independent effects, spatial working memory and disorganized attachment were related to inattention, whereas spatial working memory and dysregulation of happiness/exuberance were related to hyperactivity/impulsivity. Our findings showing that disorganized attachment is longitudinally related to ADHD symptoms over and above the influence of both neuropsychological functioning and early ADHD symptom levels highlights the importance of including measures of attachment representations when trying to understand the development of ADHD symptoms. If replicated in more "at-risk" samples, these findings could also suggest that parent-child attachment should be taken into consideration when children are referred for assessment and treatment of ADHD.

The Genetic Overlap of Attention-Deficit/Hyperactivity Disorder and Autistic-like Traits: an Investigation of Individual Symptom Scales and Cognitive markers

Attention-deficit/hyperactivity disorder (ADHD) and autism spectrum disorders (ASDs) frequently co-occur. However, due to previous exclusionary diagnostic criteria, little is known about the underlying causes of this covariation. Twin studies assessing ADHD symptoms and autistic-like traits (ALTs) suggest substantial genetic overlap, but have largely failed to take into account the genetic heterogeneity of symptom subscales. This study aimed to clarify the phenotypic and genetic relations between ADHD and ASD by distinguishing between symptom subscales that characterise the two disorders. Moreover, we aimed to investigate whether ADHD-related cognitive impairments show a relationship with ALT symptom subscales; and whether potential shared cognitive impairments underlie the genetic risk shared between the ADHD and ALT symptoms. Multivariate structural equation modelling was conducted on a population-based sample of 1312 twins aged 7–10. Social-communication ALTs correlated moderately with both ADHD symptom domains (phenotypic correlations around 0.30) and showed substantial genetic overlap with both inattention and hyperactivity-impulsivity (genetic correlation = 0.52 and 0.44, respectively). In addition to previously reported associations with ADHD traits, reaction time variability (RTV) showed significant phenotypic (0.18) and genetic (0.32) association with social-communication ALTs. RTV captured a significant proportion (24 %) of the genetic influences shared between inattention and social-communication ALTs. Our findings suggest that social-communication ALTs underlie the previously observed phenotypic and genetic covariation between ALTs and ADHD symptoms. RTV is not specific to ADHD symptoms, but is also associated with social-communication ALTs and can, in part, contribute to an explanation of the co-occurrence of ASD and ADHD.

Exploratory study to evaluate plasma vasopressin and apelin-13 levels in children with attention-deficit hyperactivity disorder

AIM

Vasopressin exerts robust influences on social communication and behavior in humans. Apelin is a relatively novel neuropeptide that could counteract vasopressin's actions and has been shown to be closely related with a broad range of physiological functions. Abnormalities in vasopressin and apelin have been detected in a variety of psychiatric disorders, but their relation to attention-deficit hyperactivity disorder (ADHD) is unknown. In the present study, we explored the plasma levels of vasopressin and apelin-13 in children with ADHD.

METHODS

Thirty-four children with ADHD and 36 healthy controls were enrolled in this study. The severity of ADHD symptoms was assessed via Conners' Parent Rating Scale and Conners' Teacher Rating Scale. Plasma levels of vasopressin and apelin-13 were measured using commercial enzyme-linked immunosorbent assay kits.

RESULTS

The mean plasma apelin-13 levels were significantly higher in male children with ADHD than in male control subjects; no significant difference was found between the groups for plasma apelin-13 levels in girls or in the entire subject cohort. Plasma vasopressin levels did not show any significant differences between groups. There were no significant correlations between plasma levels of these neuropeptides and scores for Conners' Parent Rating Scale and Conners' Teacher Rating Scale.

CONCLUSION

Our results suggest a sex-specific association between plasma apelin-13 levels and ADHD. Apelin-13 may play a role in the etiopathogenesis of ADHD either with a direct impact on the apelin receptor or via its opposing effect on the vasopressinergic system.

Cognitive and affective components of Theory of Mind in preschoolers with oppositional defiance disorder: Clinical evidence

The goal of the study was to examine the affective-cognitive components of Theory of Mind (ToM), in a community sample of 538 preschoolers, and more specifically in a subsample of 40 children diagnosed with ODD. The relationship between affective and cognitive ToM and some ODD clinical characteristics was examined. Children were assessed with structured diagnostic interviews and dimensional measures of psychopathology, impairment and unemotional traits. A measure based on eye-gaze was used to assess ToM. Mixed analysis of variance compared the mean cognitive versus affective scale scores and the between-subjects factor ODD. The association between ToM-scores and clinical measures was assessed through correlation models. Execution and reaction time to emotional and cognitive components of ToM tasks are different at age 5 in normally developing children. Oppositional Defiant children had slower response time when performing the affective mentalizing condition than children without the disorder. The correlation matrix between ToM-scores and clinical measures showed specific associations depending on the impaired ToM aspect and the psychological domain. Results may have clinical implications for the prevention and management of ODD.

Meta-analysis of social cognition in attention-deficit/hyperactivity disorder (ADHD): comparison with healthy controls and autistic spectrum disorder

BACKGROUND

Impairment in social cognition is an established finding in autism spectrum disorders (ASD). Emerging evidence suggests that attention-deficit/hyperactivity disorder (ADHD) might be also associated with deficits in theory of mind (ToM) and emotion recognition. However, there are inconsistent findings, and it has been debatable whether such deficits persist beyond childhood and how similar social cognitive deficits are in ADHD v. ASD.

METHOD

We conducted a meta-analysis of social cognition, including emotion recognition and ToM, studies in ADHD compared with healthy controls and ASD. The current meta-analysis involved 44 studies comparing ADHD (n = 1999) with healthy controls (n = 1725) and 17 studies comparing ADHD (n = 772) with ASD (n = 710).

RESULTS

Facial and vocal emotion recognition (d = 0.40-0.44) and ToM (d = 0.43) abilities were significantly impaired in ADHD. The most robust facial emotion recognition deficits were evident in anger and fear. Social cognitive deficits were either very subtle (emotion recognition) or non-significant (ToM) in adults with ADHD. Deficits in social cognition, especially ToM, were significantly more pronounced in ASD compared with ADHD. General cognitive impairment has contributed to social cognitive deficits in ADHD.

CONCLUSIONS

Performance of individuals with ADHD on social cognition lies intermediate between ASD and healthy controls. However, developmental trajectories of social cognition probably differ between ADHD and ASD as social cognitive deficits in ADHD might be improving with age in most individuals. There is a need for studies investigating a potential subtype of ADHD with persistent social cognitive deficits and exploring longitudinal changes in social cognition during development.

An update on the comorbidity of ADHD and ASD: a focus on clinical management

Attention deficit/hyperactivity disorder (ADHD) and autism spectrum disorder (ASD) commonly co-occur. With the DSM-5, clinicians are permitted to make an ASD diagnosis in the context of ADHD. In earlier versions of the DSM, this was not acceptable. Both ASD and ADHD are reported to have had substantial increases in prevalence within the past 10 years. As a function of both the increased prevalence of both disorders as well as the ability to make an ASD diagnosis in ADHD, there has been a significant amount of research focusing on the comorbidity between ADHD and ASD in the past few years. Here, we provide an update on the biological, cognitive and behavioral overlap/distinctiveness between the two neurodevelopmental disorders with a focus on data published in the last four years. Treatment strategies for the comorbid condition as well as future areas of research and clinical need are discussed.

Examining and comparing social perception abilities across childhood-onset neurodevelopmental disorders

OBJECTIVE

Several neurodevelopmental disorders are associated with social processing deficits. The objective of this study was to compare patterns of social perception abilities across obsessive-compulsive disorder (OCD), attention-deficit/hyperactivity disorder (ADHD), autism spectrum disorder (ASD), and control participants.

METHOD

A total of 265 children completed the Reading the Mind in the Eyes Test-Child Version (RMET). Parents or caregivers completed established trait/symptom scales. The predicted percentage of accuracy on the RMET was compared across disorders and by item difficulty and item valence (i.e., positive/negative/neutral mental states), then analyzed for associations with trait/symptom scores.

RESULTS

The percentage of correct RMET scores varied significantly between diagnostic groups (p < .0001). On pairwise group comparisons controlling for age and sex, children with ADHD and ASD scored lower than the other groups (p < .0001). When IQ was also controlled for in the model, participants with OCD performed better than controls (p < .001), although differences between other groups were less pronounced. Participants with ASD scored lowest on easy items. Those with ASD and ADHD scored significantly lower than other groups on items with positive valence (p < .01). Greater social communication impairment and hyperactivity/impulsivity, but not OCD traits/symptoms, were associated with lower scores on the RMET, irrespective of diagnosis.

CONCLUSION

Social perception abilities in neurodevelopmental disorders exist along a continuum. Children with ASD have the greatest deficits, whereas children with OCD may be hypersensitive to social information. Social communication deficits and hyperactive/impulsive traits are associated with impaired social perception abilities; these findings highlight overlapping cognitive and behavioral manifestations across disorders.

Executive and attentional contributions to Theory of Mind deficit in attention deficit/hyperactivity disorder (ADHD)

Attention deficit/hyperactivity disorder (ADHD) in children has been associated with attentional and executive problems, but also with socioemotional difficulties possibly associated with deficits in Theory of Mind (ToM). Socioemotional problems in ADHD are associated with more negative prognoses, notably interpersonal, educational problems, and an increased risk of developing other psychiatric disorders that emphasize the need to clarify the nature of their ToM deficits. In this study, we hypothesized that ToM dysfunction in children with ADHD is largely attributable to their attentional and/or executive deficits. Thirty-one children with ADHD (8-12 years, IQ > 85) and 31 typically developing (TD) children were assessed using executive functions (inhibition, planning, and flexibility) and attentional tasks, as well as two advanced ToM tasks (Reading the Mind in the Eyes and Faux Pas) involving different levels of executive control. Children with ADHD performed more poorly than TD children in attentional, executive function, and ToM tasks. Linear regression analyses conducted in the ADHD group indicated that inhibition scores predicted performance on the "Faux Pas" task the best, while attention scores were the best for predicting performance on the Reading the Mind in the Eyes task. When controlled for inhibition and attentional variables, ToM performance in children with ADHD was actually similar to TD children. Contrarily, controlling for ToM scores did not normalize performance for inhibition and attentional tasks in children with ADHD. This unidirectional relationship suggests that deficits in the EF and attentional domains are responsible for ToM deficits in ADHD, which therefore may contribute to their socioemotional difficulties.

The comorbidity of ADHD and autism spectrum disorder

ADHD and autism spectrum disorder are common psychiatric comorbidities to each another. In addition, there is behavioral, biological and neuropsychological overlap between the two disorders. There are also several important differences between autism spectrum disorder and ADHD. Treatment strategies for the comorbid condition will also be reviewed. Future areas of research and clinical need will be discussed.

Attention and inhibition in children with ASD, ADHD and co-morbid ASD + ADHD: an event-related potential study

BACKGROUND

Substantial overlap has been reported between attention deficit hyperactivity disorder (ADHD) and autism spectrum disorder (ASD). Deficits in executive function (EF) are characteristic of both disorders but these impairments have not been compared directly across pure and co-morbid cases using event-related potentials (ERPs).

METHOD

Behavioural parameters and ERPs were recorded during a flankered cued-continuous performance test (CPT-OX) administered to 8-13-year-old boys with ASD (n = 19), ADHD (n = 18), co-morbid ASD + ADHD (n = 29) and typically developing controls (TD; n = 26). Preparatory processing (contingent negative variation, CNV) and attentional orienting (Cue-P3) at cues, response execution at targets (Go-P3), inhibitory processing at non-targets (NoGo-P3) and conflict monitoring between target and non-target trials (Go-N2 v. NoGo-N2) were examined.

RESULTS

Categorical diagnoses and quantitative trait measures indicated that participants with ADHD (ADHD/ASD + ADHD) made more omission errors and exhibited increased reaction-time (RT) variability and reduced amplitude of the Cue-P3 and NoGo-P3 compared to TD/ASD participants. Participants with ASD (ASD/ ASD + ADHD) demonstrated reduced N2 enhancement from Go to NoGo trials compared to TD/ADHD participants. Participants with ASD-only displayed enhanced CNV amplitude compared to ASD + ADHD and TD participants.

CONCLUSIONS

Children with ADHD show deficits in attentional orienting and inhibitory control whereas children with ASD show abnormalities in conflict monitoring and response preparation. Children with co-morbid ASD + ADHD present as an additive co-occurrence with deficits of both disorders, although non-additive effects are suggested for response preparation. Measuring ERPs that index attention and inhibition is useful in disentangling cognitive markers of ASD and ADHD and elucidating the basis of co-occurring ASD + ADHD to guide clinical assessment.

Stimulants improve theory of mind in children with attention deficit/hyperactivity disorder

Impairments in 'theory of mind' (ToM) were linked to social cognition and reciprocal relationships deficits in children with attention deficit/hyperactivity disorder (ADHD). Twenty-four children with ADHD (13 with inattentive type and 11 with combined type, mean age 10.2 years) completed the Interpersonal Reactivity Index (IRI), a self-reported empathy questionnaire. All children performed the 'faux pas' task and a computerized ToM task in two different sessions either with or without administration of methylphenidate (MPH). Administration of MPH was associated with an improvement in cognitive and affective ToM. Children with ADHD-combined type had significantly lower scores in total IRI and the fantasy scale compared to children with ADHD-inattentive type. We conclude that deficits in empathy and ToM may play an important role in the impairments in social cognition and peer relationship in children with ADHD, especially children a hyperactive component. Stimulants may improve ToM and empathic functions. Future studies including larger samples and additional cognitive tasks are warranted in order to generalize these results and to identify possible underlying mechanisms for improvement in ToM following the administration of MPH.

Is inhibitory control a 'no-go' in adolescents with autism spectrum disorder?

Background

Autism spectrum disorder (ASD) refers to a range of neurodevelopmental conditions characterized by social communication deficits, repetitive behaviours, and restrictive interests. Impaired inhibition has been suggested to exacerbate the core symptoms of ASD. This is particularly critical during adolescence when social skills are maturing to adult levels. Using magnetoencephalography (MEG), we identified the location and timing pattern of neural activity associated with inhibition in adolescents with autism, compared to typically developing adolescents.

Methods

The MEG data from 15 adolescents with ASD and 15 age-matched controls (13 to 17 years) were collected during a go/no-go task with inverse ratios of go/no-go trials in two conditions: an inhibition condition (1:2) and a baseline condition (2:1). No-go trials from the two conditions were analyzed using beamformer source localizations from 200 ms to 400 ms post-stimulus onset. Significant activations were determined using permutation testing.

Results

Adolescents with ASD recruited first the right middle frontal gyrus (200 to 250 ms) followed by the left postcentral gyrus (250 to 300 ms) and finally the left middle frontal and right medial frontal gyri (300 to 400 ms). Typically developing adolescents recruited first the left middle frontal gyrus (200 to 250 ms), followed by the left superior and inferior frontal gyri (250 to 300 ms), then the right middle temporal gyrus (300 to 350 ms), and finally the superior and precentral gyri and right inferior lobule (300 to 400 ms).

Conclusions

Adolescents with ASD showed recruitment limited largely to the frontal cortex unlike typically developing adolescents who recruited parietal and temporal regions as well. These findings support the presence of an atypical, restricted inhibitory network in adolescents with ASD compared to controls.

Besonderheiten in der multiaxialen Klassifizierung, Anamnese und Psychopathologie bei Kindern und Jugendlichen mit einer Autismus-Spektrum-Störung und einer Aufmerksamkeitsdefizit-/ Hyperaktivitätsstörung

Ziel der vorliegenden Untersuchung war es, bei Kindern und Jugendlichen mit einer Autismus Spektrum Störung (ASS) ohne oder mit einer Aufmerksamkeitsdefizit-/Hyperaktivitätsstörung (ADHS) die Achsen des Multiaxialen Klassifikationsschemas (MAS), anamnestische Daten, sowie Ergebnisse psychopathologischer Fragebogenverfahren zu vergleichen. Insgesamt wurden 120 Patienten (Gruppe ASS: n=60; Gruppe ASS+ADHS: n=60) untersucht. Es wurden eigen- und familienanamnestische Daten, die sechs Achsen der MAS und testpsychologische Ergebnisse erhoben (MBAS, FSK, SRS, CBCL). Deskriptiv konnten in der Gruppe ASS+ADHS ein gehäufter Konsum schädlicher Substanzen durch die Mütter in der Schwangerschaft erhoben werden. In beiden Gruppen fand sich bei den Vätern gehäuft eine Tätigkeit in einem akademisch-technischen Beruf. Hinsichtlich der Fragebogenverfahren zeigte sich eine höhere externalisierende Psychopathologie für die Gruppe ASS+ADHS. Passend zu bisherigen Studien konnte bei den Patienten mit ASS und ADHS eine stärker ausgeprägte psychopathologische Belastung beschrieben werden, auf die bei Diagnostik und Therapie geachtet werden sollte.

The relationship between autism spectrum disorders and attention-deficit/hyperactivity disorder: an overview

The autism spectrum has become a highly studied topic, perhaps the most researched of all developmental disorders. A host of related topics are being studied, with one of the most common being comorbidity of autism with other conditions such as epilepsy, sleep, and anxiety disorders. One of the most prevalent of these comorbid conditions is attention-deficit/hyperactivity disorder (AD/HD). A considerable amount of research has appeared on this topic with respect to symptom expression, prevalence of overlap, type of symptom overlap, and the effect of these two conditions co-occurrence on other symptoms and disorders. Given the substantial data base that has accrued, review and synthesis of these data are in order. This is the purpose of the present manuscript.

Conceptual issues in neurodevelopmental disorders: lives out of synch

PURPOSE OF REVIEW

Current revision of the two major psychiatric classification systems has elicited particular comment on neurodevelopmental disorders, which have seen increased provision of specialist clinical services, user group activity, fictional and biographical accounts, and research. Philosophical scrutiny of autism research and literature provides an additional perspective.

RECENT FINDINGS

Neurodevelopmental disorders show considerable overlap neuropsychologically, physiologically and genetically. They overlap diagnostically with schizophrenia, personality disorders, anxiety and depression. Of the two main diagnostic groups, there is more evidence of change with maturation in autism spectrum disorder than attention-deficit hyperactivity disorder. Interventions should combine cognitive, affective and embodied aspects of these disorders, and encompass the individual and their social environment. There is considerable evidence of the toll that caring for people with neurodevelopmental disorders exerts on parents.

SUMMARY

Neurodevelopmental disorders are multifaceted: research addressed to connection rather than further Balkanization is more likely to be fruitful. Clinicians should consider which facets are displayed symptomatically to enable people to grow through rather than surrender to their impairments. Social scaffolding optimizes functional well being. Future research should take into account the tensions in the relationship between research and user groups, and examine the experiences of adults and of the spouses and partners of those affected.

Applying an ESSENCE framework to understanding adult autism spectrum disorder and ADHD: retrospective parent reports of childhood problems

Diagnoses of autism spectrum disorder (ASD) and attention-deficit/hyperactivity disorder (ADHD) are increasingly being made in adulthood. However, assessments can fail to address the diverse range of problems that patients have experienced. The current study applied an early symptomatic syndromes eliciting neurodevelopmental clinical examinations (ESSENCE) framework to explore retrospectively reported childhood developmental and behavioral problems. It examined if adult ASD and ADHD patients would show problems outside those reflected in the respective diagnostic criteria, and also if these patient groups would show more extensive childhood problems than other psychiatric patients. Parents of adults with ADHD (n = 130), ASD (n = 57), coexisting ADHD and ASD (n = 38), and other psychiatric disorders (n = 56) reported on a range of childhood problems. Descriptions of the ADHD, ASD, and ADHD+ASD groups reflected greater impairment than descriptions for patients with other psychiatric disorders in most problem areas. Although differences were observed between ADHD and ASD patients in the core diagnostic areas, these syndromes also shared a number of childhood difficulties. The ESSENCE approach can assist in understanding the symptom history of adult ADHD and ASD patients and can be helpful to distinguish their childhood experiences from other psychiatric patients' experiences.

Neurophysiological responses to faces and gaze direction differentiate children with ASD, ADHD and ASD+ADHD

Children with autism spectrum disorder (ASD) and attention deficit hyperactivity disorder (ADHD) demonstrate face processing abnormalities that may underlie social impairment. Despite substantial overlap between ASD and ADHD, ERP markers of face and gaze processing have not been directly compared across pure and comorbid cases. Children with ASD (n=19), ADHD (n=18), comorbid ASD+ADHD (n=29) and typically developing (TD) controls (n=26) were presented with upright/inverted faces with direct/averted gaze, with concurrent recording of the P1 and N170 components. While the N170 was predominant in the right hemisphere in TD and ADHD, children with ASD (ASD/ASD+ADHD) showed a bilateral distribution. In addition, children with ASD demonstrated altered response to gaze direction on P1 latency and no sensitivity to gaze direction on midline-N170 amplitude compared to TD and ADHD. In contrast, children with ADHD (ADHD/ASD+ADHD) exhibited a reduced face inversion effect on P1 latency compared to TD and ASD. These findings suggest children with ASD have specific abnormalities in gaze processing and altered neural specialisation, whereas children with ADHD show abnormalities at early visual attention stages. Children with ASD+ADHD are an additive co-occurrence with deficits of both disorders. Elucidating the neural basis of the overlap between ASD and ADHD is likely to inform aetiological investigation and clinical assessment.

Are autism spectrum disorder and attention-deficit/hyperactivity disorder different manifestations of one overarching disorder? Cognitive and symptom evidence from a clinical and population-based sample

OBJECTIVE

Autism spectrum disorders (ASD) and attention-deficit/hyperactivity disorder (ADHD) frequently co-occur. Given the heterogeneity of both disorders, several more homogeneous ASD-ADHD comorbidity subgroups may exist. The current study examined whether such subgroups exist, and whether their overlap or distinctiveness in associated comorbid symptoms and cognitive profiles gives support for a gradient overarching disorder hypothesis or a separate disorders hypothesis.

METHOD

Latent class analysis was performed on Social Communication Questionnaire (SCQ) and Conners' Parent Rating Scale (CPRS-R:L) data for 644 children and adolescents (5 through 17 years of age). Classes were compared for comorbid symptoms and cognitive profiles of motor speed and variability, executive functioning, attention, emotion recognition, and detail-focused processing style.

RESULTS

Latent class analysis revealed five classes: two without behavioral problems, one with only ADHD behavior, and two with both clinical symptom levels of ASD and ADHD but with one domain more prominent than the other (ADHD[+ASD] and ASD[+ADHD]). In accordance with the gradient overarching disorder hypothesis were the presence of an ADHD class without ASD symptoms and the absence of an ASD class without ADHD symptoms, as well as cognitive functioning of the simple ADHD class being less impaired than that of both comorbid classes. In conflict with this hypothesis was that there was some specificity of cognitive deficits across classes.

CONCLUSIONS

The overlapping cognitive deficits may be used to further unravel the shared etiological underpinnings of ASD and ADHD, and the nonoverlapping deficits may indicate why some children develop ADHD despite their enhanced risk for ASD. The two subtypes of children with both ASD and ADHD behavior will most likely benefit from different clinical approaches.

ADHD and autism: differential diagnosis or overlapping traits? A selective review

According to DSM-IV TR and ICD-10, a diagnosis of autism or Asperger Syndrome precludes a diagnosis of attention-deficit/hyperactivity disorder (ADHD). However, despite the different conceptualization, population-based twin studies reported symptom overlap, and a recent epidemiologically based study reported a high rate of ADHD in autism and autism spectrum disorders (ASD). In the planned revision of the DSM-IV TR, dsm5 (www.dsm5.org), the diagnoses of autistic disorder and ADHD will not be mutually exclusive any longer. This provides the basis of more differentiated studies on overlap and distinction between both disorders. This review presents data on comorbidity rates and symptom overlap and discusses common and disorder-specific risk factors, including recent proteomic studies. Neuropsychological findings in the areas of attention, reward processing, and social cognition are then compared between both disorders, as these cognitive abilities show overlapping as well as specific impairment for one of both disorders. In addition, selective brain imaging findings are reported. Therapeutic options are summarized, and new approaches are discussed. The review concludes with a prospectus on open questions for research and clinical practice.

INDUCED EEG GAMMA OSCILLATION ALIGNMENT IMPROVES DIFFERENTIATION BETWEEN AUTISM AND ADHD GROUP RESPONSES IN A FACIAL CATEGORIZATION TASK

INTRODUCTION: Children diagnosed with an autism spectrum disorder (ASD) often lack the ability to recognize and properly respond to emotional stimuli. Emotional deficits also characterize children with attention deficit/hyperactivity disorder (ADHD), in addition to exhibiting limited attention span. These abnormalities may effect a difference in the induced EEG gamma wave burst (35-45 Hz) peaked approximately 300-400 milliseconds following an emotional stimulus. Because induced gamma oscillations are not fixed at a definite point in time post-stimulus, analysis of averaged EEG data with traditional methods may result in an attenuated gamma burst power. METHODS: We used a data alignment technique to improve the averaged data, making it a better representation of the individual induced EEG gamma oscillations. A study was designed to test the response of a subject to emotional stimuli, presented in the form of emotional facial expression images. In a four part experiment, the subjects were instructed to identify gender in the first two blocks of the test, followed by differentiating between basic emotions in the final two blocks (i.e. anger vs. disgust). EEG data was collected from ASD (n=10), ADHD (n=9), and control (n=11) subjects via a 128 channel EGI system, and processed through a continuous wavelet transform and bandpass filter to isolate the gamma frequencies. A custom MATLAB code was used to align the data from individual trials between 200-600 ms post-stimulus, EEG site, and condition by maximizing the Pearson product-moment correlation coefficient between trials. The gamma power for the 400 ms window of maximum induced gamma burst was then calculated and compared between subject groups. RESULTS AND CONCLUSION: Condition (anger/disgust recognition, gender recognition) × Alignment × Group (ADHD, ASD, Controls) interaction was significant at most of parietal topographies (e.g., P3-P4, P7-P8). These interactions were better manifested in the aligned data set. Our results show that alignment of the induced gamma oscillations improves sensitivity of this measure in differentiation of EEG responses to emotional facial stimuli in ADHD and ASD.