Attention-deficit/hyperactivity Disorder Sample Research Articles

The symptomatology of Attention-Deficit/Hyperactivity Disorder and the genetic control of vitamin D levels.

Vitamin D deficiency has been associated with psychiatric disorders and behavioral phenotypes such as Attention-Deficit/Hyperactivity Disorder (ADHD). Considering that vitamin D levels are polygenic, we aim to evaluate the overall effects of its genetic architecture on symptoms of inattention, hyperactivity, and impulsivity and on the serum levels of vitamin D in two independent samples of adults, as well as the specific effects of five relevant polymorphisms in vitamin D-related genes. We evaluated 870 subjects from an ADHD sample (407 cases and 463 controls) and 319 subjects from an academic community (nutrigenetic sample). Vitamin D serum levels were obtained through Elisa test and genetic data by TaqMan™ allelic discrimination and Infinium PsychArray-24 BeadChip genotyping. Polygenic Scores (PGS) were calculated on PRSice2 based on the latest GWAS for Vitamin D and statistical analyses were conducted at Plink and SPSS software. Vitamin D PGSs were associated with inattention in the ADHD sample and with hyperactivity when inattention symptoms were included as covariates. In the nutrigenetic sample, CYP2R1 rs10741657 and DHCR7 rs12785878 were nominally associated with impulsivity and hyperactivity, respectively, and both with vitamin D levels. In the clinical sample, RXRG rs2134095 was associated with impulsivity. Our findings suggest a shared genetic architecture between vitamin D levels and ADHD symptoms, as evidenced by the associations observed with PGS and specific genes related to vitamin D levels. Interestingly, differential effects for vitamin D PGS were found in inattention and hyperactivity, which should be considered in further studies involving ADHD.

Trait mindfulness and personality characteristics in a microdosing ADHD sample: a naturalistic prospective survey study.

Microdosing (MD), repeatedly taking psychedelics in small, non-hallucinogenic amounts, has been practiced by individuals to relieve attention deficit hyperactivity disorder (ADHD) symptoms. Generally, adults diagnosed with ADHD have lower levels of mindfulness and differ in personality structure from non-ADHD adults. How MD affects mindfulness and personality in adults with ADHD remains unexplored. This study aimed to investigate the effects of 4 weeks of MD on mindfulness and personality traits in adults diagnosed with ADHD and those experiencing severe ADHD symptoms. It was expected that mindfulness and the personality traits conscientiousness, extraversion, agreeableness, and openness would increase and neuroticism would decrease after 4 weeks of MD compared to baseline. It was explored if using conventional ADHD medication alongside MD and/or having comorbidities influenced MD-induced effects. An online prospective naturalistic design was used to measure participants before MD initiation and 2 and 4 weeks later. Validated self-report measures were used assessing mindfulness (15-item Five Facet Mindfulness Questionnaire) and personality traits (10-item version of the Big Five Inventory) at three time points. The sample included n = 233, n = 66, and n = 44 participants at the three time points, respectively. Trait mindfulness, specifically description and non-judging of inner experience, was increased, and neuroticism was decreased after 4 weeks of MD compared to baseline. The remaining personality traits remained unchanged. Using conventional medication and/or having comorbid diagnoses did not change the MD-induced effects on mindfulness and personality traits after 4 weeks. MD induced changes in otherwise stable traits. Future placebo-controlled studies are warranted to confirm whether these changes occur in a controlled setting.

The role of single trial variability in event related potentials in children with attention deficit hyperactivity disorder

ObjectiveChildren with attention deficit hyperactivity disorder (ADHD) show attenuated mean P3 component amplitudes compared to typically developing (TD) children. This finding may be the result of individual differences in P3 amplitudes, P3 latencies, and/or greater single trial variability (STV) in amplitude or latency, suggesting neural “noise.” MethodsEvent related potentials (ERPs) from 75 children with ADHD and 29 TD children were recorded with electroencephalography (EEG). Caregivers provided ratings on child ADHD symptoms. Single-trial ERP amplitudes and latencies were extracted from the P3 component time window during a visual oddball task. Additionally, we computed individual-centered and trial-centered P3 amplitudes to account for inter-individual and inter-trial variability in the timing of the P3 peak. ResultsIn line with prior research, greater ADHD symptom severity was associated with reduced mean P3 amplitude. This correlation was no longer significant after correcting for inter-trial differences in P3 latency. In contrast, greater ADHD symptom severity was associated with reduced STV in P3 amplitude. ConclusionsOur results suggest that attenuated average P3 amplitude in ADHD samples is due to a consistent reduction in strength of the neurophysiological signal at the single trial level, as well as increased inter-trial variability in the timing of P3 peak amplitudes. The traditional method of extracting P3 amplitudes based on a single time window for all trials may not adequately capture variability in P3 latencies associated with ADHD. SignificanceInter- and intra-individual differences in brain signatures should be considered in models of neurobiological differences in neurodevelopmental samples.

Attention Deficit Hyperactivity Disorder; Genotype-Phenotype Correlates

Attention deficit hyperactivity disorder (ADHD) is one of the prevalent neurodevelopmental disorders that starts early in life and have long term impact on all life aspects of the sufferer; academically, socially, psychologically, and occupationally. Accordingly, understanding its multifactorial origin with its correlation to its manifestations and diagnostic criteria is crucial for individualizing the management plan for each case in order to get the best outcome and improve his/her quality of life. This short communication is summarizing the results of some of our researches investigating the genotypic phenotypic profile of ADHD in samples of Egyptian children.

PASS neurocognitive assessment of children with autism spectrum disorder

AbstractAutism spectrum disorder (ASD) is a neurodevelopmental disability that can cause significant social, communication, and behavioral challenges yet it is defined and diagnosed by the absence or presence of behaviors described in, for example, the Diagnostic and Statistical Manual 5. Descriptions of the disorder include symptoms such as intellectual impairment or a neurodevelopmental disorder. In this study, we examined the pattern of scores obtained for individuals with ASD in comparison to those with specific learning disability (SLD; reading decoding) and attention deficit hyperactivity disorder (ADHD) across several traditional intelligence and neurocognitive tests. We anticipated, and found, that the profile for students with ASD (a specific weakness in attention) was observed and that pattern was different for the SLD and ADHD samples.

Cord Blood Metabolomics and Autism Spectrum Disorder

IntroductionAutism spectrum disorder (ASD) has increased dramatically in prevalence and incidence in recent years (1:59 in the US, CDC). With prenatal and/or genetic origins, early detection and intervention are critical to improve outcomes. Few studies have assessed perinatal biomarkers for later development of ASD. We hypothesize that cord blood plasma‐based metabolomics will differentiate infants who would later be diagnosed with ASD and typically developing (TD) controls.MethodsBanked cord blood plasma samples and clinical data from the Iowa Maternal Fetal Tissue Bank were used. Samples were analyzed via gas chromatography and mass spectrometry (GC‐MS) and relative MS signal intensity of a maximum of was quantified ratiometrically. All metabolites were normalized to internal controls (succinate) to account for effects of extraction, derivatization, and/or loading. Ratiometric levels of each metabolite were compared by t‐test between ASD and control groups. Results P<0.01 are reported given the pilot nature of this small study. Metabolite set enrichment analysis (MSEA) was performed against human libraries. Significantly altered metabolites were compared to a tertiary sample of cord blood from individuals later diagnosed with attention deficit hyperactivity disorder (ADHD) to determine specificity for ASD.Results91 metabolites were detected and analyzed. Homocysteine (fold change [FC]: 1.411; p=0.017), Myristic acid (FC: 1.221; p=0.084), Pentadecanoic acid (FC: 1.256; p=0.093) were increased in ASD samples, while L‐Isoleucine (FC: 0.858; p=0.047), L‐Threonine (FC: 0.7131; p=0.068), O‐Phosphoethanolamine (FC: 0.704; p=0.070), and 2‐Hydroxybutyric acid (FC: 0.615; p=0.073) were decreased. Of these, only pentadecanoic was also significantly changed in ADHD samples (FC: 1.514; p=0.002). MSEA revealed enrichment of homocysteine degradation (p=0.017), catecholamine biosynthesis (p=0.048), threonine and 2‐Oxobutanoate degradation (p=0.068), Phosphatidylcholine Biosynthesis (p=0.070), and Phosphatidylethanolamine Biosynthesis (p=0.070) in ASD cord blood samples.ConclusionWe found that cord blood plasma metabolomics reveals intriguing and specific differences between ASD and control samples. While some of differences are supported by evidence, these alterations have not previously been extended to the prenatal period. Future work will investigate concordance with maternal blood metabolomics to determine maternal‐fetal pathways.

Could immersive daydreaming underlie a deficit in attention? The prevalence and characteristics of maladaptive daydreaming in individuals with attention-deficit/hyperactivity disorder.

Maladaptive daydreaming (MD) entails excessive immersion and engagement in complex fantasy worlds, causing distress and impairing functioning. Maladaptive Daydreamers often report that existing diagnostic labels are unhelpful for them. Previous studies reported high rates of comorbid attention deficit hyperactivity disorder (ADHD) among persons with MD, raising the question of their separateness. This study explored whether MD differs essentially from ADHD by examining an ADHD sample, hypothesizing a much lower incidence of MD. Adults diagnosed with ADHD (N = 83) were assessed for ADHD symptoms, MD, depression, loneliness, and self-esteem. Participants who exceeded the study's cutoff score for suspected MD were invited to participate in a structured diagnostic interview for MD. In accordance with the hypothesis, only 20.5% of the ADHD sample met the proposed diagnostic criteria for MD. Compared with ADHD-only participants, this subgroup presented increased depression, loneliness, and lowered self-esteem. MD has unique clinical characteristics that are distinct from ADHD. We suggest that in some cases presenting with ADHD symptoms, an MD conceptualization may better explain the clinical picture. Future research should aim at a better differentiation of daydreaming, ADHD, and related constructs such as mind-wandering.

Dissecting the cross-trait effects of the FOXP2 GWAS hit on clinical and brain phenotypes in adults with ADHD.

The Forkhead box P2 (FOXP2) encodes for a transcription factor with a broad role in embryonic development. It is especially represented among GWAS hits for neurodevelopmental disorders and related traits, including attention-deficit/hyperactivity disorder (ADHD), autism spectrum disorder, neuroticism, and risk-taking behaviors. While several functional studies are underway to understand the consequences of FOXP2 variation, this study aims to expand previous findings to clinically and genetically related phenotypes and neuroanatomical features among subjects with ADHD. The sample included 407 adults with ADHD and 463 controls. Genotyping was performed on the Infinium PsychArray-24 BeadChip, and the FOXP2 gene region was extracted. A gene-wide approach was adopted to evaluate the combined effects of FOXP2 variants (n = 311) on ADHD status, severity, comorbidities, and personality traits. Independent risk variants presenting potential functional effects were further tested for association with cortical surface areas in a subsample of cases (n = 87). The gene-wide analyses within the ADHD sample showed a significant association of the FOXP2 gene with harm avoidance (P = 0.001; PFDR = 0.015) and nominal associations with hyperactivity symptoms (P = 0.026; PFDR = 0.130) and antisocial personality disorder (P = 0.026; PFDR = 0.130). An insertion/deletion variant (rs79622555) located downstream of FOXP2 was associated with the three outcomes and nominally with the surface area of superior parietal and anterior cingulate cortices. Our results extend and refine previous GWAS findings pointing to a role of FOXP2 in several neurodevelopment-related phenotypes, mainly those involving underlying symptomatic domains of self-regulation and inhibitory control. Taken together, the available evidence may constitute promising insights into the puzzle of the FOXP2-related pathophysiology.

Pain sensitivity and perceptual sensitivity are associated with severity of emotional dysregulation in children with ADHD: a cross-sectional analysis using the Temperament in Middle Childhood Questionnaire

Purpose Nearly 50% of children with attention-deficit/hyperactivity disorder (ADHD) experience emotional dysregulation or sensory over-responsiveness; this study examines their association. Methods This cross-sectional analysis (n = 124) used data from the Micronutrients for ADHD in Youth (MADDY) Study, which enrolled children aged 6–12 with ADHD and emotional dysregulation. Sensory responsiveness was assessed using two subscales from the factor-analyzed Temperament in Middle Childhood Questionnaire: Pain Sensitivity and Perceptual Sensitivity. Emotional dysregulation was assessed using the Emotional-Problems and Conduct-Problems subscales from the Strengths and Difficulties Questionnaire and a composite score from the Child & Adolescent Symptom Inventory-5. Multivariable linear regression measured the association of pain and perceptual sensitivity with the severity of emotional dysregulation. Results In adjusted models, pain sensitivity was positively associated with Emotional Problems (β = 0.97; 95% CI: 0.52, 1.41; p < 0.0001), Conduct Problems (β = 0.83; 95% CI: 0.44, 1.21; p = 0.0001), and CASI-5 composite (β = 0.25; 95% CI: 0.16, 0.34; p < 0.0001). Perceptual sensitivity was positively associated with Emotional Problems (β = 0.75; 95% CI: 0.15, 1.35; p = 0.01) but not Conduct Problems (β = 0.27; 95% CI: −0.24, 0.77; p = 0.30) or CASI-5 composite (β = 0.12; 95% CI: −0.01, 0.24; p = 0.07). Conclusion Pain sensitivity was associated with the severity of emotional dysregulation in this ADHD sample. To better understand possible causal links, longitudinal studies are warranted. Implications for rehabilitation Emotional dysregulation and sensory over-responsiveness are both common in children with ADHD and contribute to added challenges in school and family life. Two types of sensory over-responsiveness, pain sensitivity and perceptual sensitivity, were associated with emotional dysregulation in children with ADHD in our study. Sensory over-responsiveness may be a modifiable treatment target.

Sex differences in anxiety and depression in children with attention deficit hyperactivity disorder: Investigating genetic liability and comorbidity.

It is unknown why attention deficit hyperactivity disorder (ADHD) is more common in males, whereas anxiety and depression show a female population excess. We tested the hypothesis that anxiety and depression risk alleles manifest as ADHD in males. We also tested whether anxiety and depression in children with ADHD show a different etiology to typical anxiety and depression and whether this differs by sex. The primary clinical ADHD sample consisted of 885 (14% female) children. Psychiatric symptoms were assessed using standardized interviews. Polygenic risk scores (PRS) were derived using large genetic studies. Replication samples included independent clinical ADHD samples (N=3,794; 25.7% female) and broadly defined population ADHD samples (N=995; 33.4% female). We did not identify sex differences in anxiety or depression PRS in children with ADHD. In the primary sample, anxiety PRS were associated with social and generalized anxiety in males, with evidence of a sex-by-PRS interaction for social anxiety. These results did not replicate in the broadly defined ADHD sample. Depression PRS were not associated with comorbid depression symptoms. The results suggest that anxiety and depression genetic risks are not more likely to lead to ADHD in males. Also, the evidence for shared etiology between anxiety symptoms in those with ADHD and typical anxiety was weak and needs replication.

The Association between Prosocial Behaviour and Peer Relationships with Comorbid Externalizing Disorders and Quality of Life in Treatment-Naïve Children and Adolescents with Attention Deficit Hyperactivity Disorder.

Several recent studies confirmed that Attention Deficit Hyperactivity Disorder (ADHD) has a negative influence on peer relationship and quality of life in children. The aim of the current study is to investigate the association between prosocial behaviour, peer relationships and quality of life in treatment naïve ADHD samples. The samples included 79 children with ADHD (64 boys and 15 girls, mean age = 10.24 years, SD = 2.51) and 54 healthy control children (30 boys and 23 girls, mean age = 9.66 years, SD = 1.73). Measurements included: The “Mini International Neuropsychiatric Interview Kid; Strengths and Difficulties Questionnaire” and the “Inventar zur Erfassung der Lebensqualität bei Kindern und Jugendlichen”. The ADHD group showed significantly lower levels of prosocial behaviour and more problems with peer relationships than the control group. Prosocial behaviour has a weak positive correlation with the rating of the child’s quality of life by the parents, both in the ADHD group and in the control group. The rating of quality of life and peer relationship problems by the parents also showed a significant negative moderate association in both groups. The rating of quality of life by the child showed a significant negative weak relationship with peer relationships in the ADHD group, but no significant relationship was found in the control group. Children with ADHD and comorbid externalizing disorders showed more problems in peer relationships than ADHD without comorbid externalizing disorders. Based on these results, we conclude that therapy for ADHD focused on improvement of prosocial behaviour and peer relationships as well as comorbid externalizing disorders could have a favourable effect on the quality of life of these children.

Discrepancies of polygenic effects on symptom dimensions between adolescents and adults with ADHD

A significant proportion of individuals with attention-deficit/hyperactivity disorder (ADHD) show persistence into adulthood. The genetic and neural correlates of ADHD in adolescents versus adults remain poorly characterized. We investigated ADHD polygenic risk score (PRS) in relation to previously identified gray matter (GM) patterns, neurocognitive, and symptom findings in the same ADHD sample (462 adolescents & 422 adults from the NeuroIMAGE and IMpACT cohorts). Significant effects of ADHD PRS were found on hyperactivity and impulsivity symptoms in adolescents, hyperactivity symptom in adults, but not GM volume components. A distinct PRS effect between adolescents and adults on individual ADHD symptoms is suggested.

Polygenic association between attention-deficit/hyperactivity disorder liability and cognitive impairments.

A recent genome-wide association study (GWAS) identified 12 independent loci significantly associated with attention-deficit/hyperactivity disorder (ADHD). Polygenic risk scores (PRS), derived from the GWAS, can be used to assess genetic overlap between ADHD and other traits. Using ADHD samples from several international sites, we derived PRS for ADHD from the recent GWAS to test whether genetic variants that contribute to ADHD also influence two cognitive functions that show strong association with ADHD: attention regulation and response inhibition, captured by reaction time variability (RTV) and commission errors (CE). The discovery GWAS included 19 099 ADHD cases and 34 194 control participants. The combined target sample included 845 people with ADHD (age: 8-40 years). RTV and CE were available from reaction time and response inhibition tasks. ADHD PRS were calculated from the GWAS using a leave-one-study-out approach. Regression analyses were run to investigate whether ADHD PRS were associated with CE and RTV. Results across sites were combined via random effect meta-analyses. When combining the studies in meta-analyses, results were significant for RTV (R2 = 0.011, β = 0.088, p = 0.02) but not for CE (R2 = 0.011, β = 0.013, p = 0.732). No significant association was found between ADHD PRS and RTV or CE in any sample individually (p > 0.10). We detected a significant association between PRS for ADHD and RTV (but not CE) in individuals with ADHD, suggesting that common genetic risk variants for ADHD influence attention regulation.

Impulsivity and Venturesomeness in an Adult ADHD Sample: Relation to Personality, Comorbidity, and Polygenic Risk.

While impulsivity is a basic feature of attention-deficit/hyperactivity disorder (ADHD), no study explored the effect of different components of the Impulsiveness (Imp) and Venturesomeness (Vent) scale (IV7) on psychiatric comorbidities and an ADHD polygenic risk score (PRS). We used the IV7 self-report scale in an adult ADHD sample of 903 patients, 70% suffering from additional comorbid disorders, and in a subsample of 435 genotyped patients. Venturesomeness, unlike immediate Impulsivity, is not specific to ADHD. We consequently analyzed the influence of Imp and Vent also in the context of a PRS on psychiatric comorbidities of ADHD. Vent shows a distinctly different distribution of comorbidities, e.g., less anxiety and depression. PRS showed no effect on different ADHD comorbidities, but correlated with childhood hyperactivity. In a complementary analysis using principal component analysis with Diagnostic and Statistical Manual of Mental Disorders, Fourth Edition ADHD criteria, revised NEO Personality Inventory, Imp, Vent, and PRS, we identified three ADHD subtypes. These are an impulsive–neurotic type, an adventurous–hyperactive type with a stronger genetic component, and an anxious–inattentive type. Our study thus suggests the importance of adventurousness and the differential consideration of impulsivity in ADHD. The genetic risk is distributed differently between these subtypes, which underlines the importance of clinically motivated subtyping. Impulsivity subtyping might give insights into the organization of comorbid disorders in ADHD and different genetic background.

Prevalence and Risk Factors Associated With Attention-Deficit/Hyperactivity Disorder Among US Black Individuals

As stated in the DSM-5, it is generally reported that the prevalence of attention-deficit/hyperactivity disorder (ADHD) is lower among Black individuals compared with the general population. However, Black individuals living in countries where they are considered a minority population group (eg, in Northern America and Europe) are underrepresented in studies evaluating ADHD. To estimate the pooled prevalence of ADHD and identify associated risk factors among US Black individuals. This systematic review and meta-analysis identified peer-reviewed studies published until October 18, 2019, using the APA PsycInfo, MEDLINE, Embase, Cochrane CENTRAL, CINAHL, ERIC, and Education Source databases. Eligible trials were published in French or English, had empirical data on the prevalence of ADHD in samples or subsamples of Black people, and were conducted in countries with Black minority populations. All studies were assessed and passed quality evaluation. The PRISMA guideline was used for extracting and reporting data. Random-effects meta-analyses were generated to estimate the prevalence of ADHD among Black individuals using the metafor package in R. Prevalence and risk factors associated with ADHD among Black individuals were identified. A total of 24 independent samples and subsamples from 21 studies published between 1979 and 2020 (154 818 Black participants) were included in this systematic review and meta-analysis. All included studies were conducted in the US. Two studies were conducted assessing adults (aged 18 years or older), 8 assessing children (0-12 years), 1 assessing adolescents (aged 13-17 years), and 13 assessing both children and adolescents. The pooled prevalence of ADHD was 14.54% (95% CI, 10.64%-19.56%). In a narrative review of the studies in this analysis, some studies found risk factors associated with ADHD, such as sociodemographic characteristics (age, sex, race, and socioeconomic status), familial factors, environmental factors, and risk behaviors, but the data did not permit a moderation analysis to assess these findings in this study. Contrary to what is stated in the DSM-5, the results of this systematic review and meta-analysis suggest that Black individuals are at higher risk for ADHD diagnoses than the general US population. These results highlight a need to increase ADHD assessment and monitoring among Black individuals from different social backgrounds. They also higlight the importance of establishing accurate diagnoses and culturally appropriate care.

Hemodynamic and behavioral peculiarities in response to emotional stimuli in children with attention deficit hyperactivity disorder: An fNIRS study

BackgroundChildren with attention deficit hyperactivity disorder (ADHD) exhibit behavioral inhibition deficits, which often lead to emotional dysregulation (ED) affecting individual ability to control emotions and behavioral responses. In ADHD, ED is associated with poor outcomes and comorbidities, with both externalizing and internalizing disorders. This work aims to evaluate sensitivity to emotional stimuli in children with ADHD using functional Near Infrared Spectroscopy (fNIRS). MethodsDuring frontal fNIRS recording, 20 children with ADHD and 25 typically developing (TD) peers performed a visual continuous performance task with stimuli of different emotional content (i.e., positive, negative, neutral, and control stimuli without emotional content). This is a cognitive task designed to evaluate the ability to recognize emotional stimuli and to deal with emotional interference. ResultsThe ADHD sample showed more variability in response time to stimuli and more false alarms compared to TD group. fNIRS data showed between-group differences in right prefrontal and frontal cortices, with wider hemoglobin concentration changes in the TD group, during positive, negative, and neutral conditions. LimitationsOwing to the limited possibility of near infrared light to penetrate tissue, fNIRS can only measure cortical activations, while it would be of interest to identify the subcortical areas linked to emotional processing, too. ConclusionsFindings suggest the presence of emotional processing deficits in children with ADHD, as suggested by poor performances on the e-CPT task, and of peculiar sensitivity to emotional stimuli, linked to atypical hemodynamics of right prefrontal and frontal areas.

Dlg4 and Vamp2 are involved in comorbid epilepsy and attention-deficit hyperactivity disorder: A microarray data study

ObjectiveChildren with epilepsy exhibit a significantly higher risk for attention-deficit hyperactivity disorder (ADHD), which is often associated with lower quality of life. In this study, we aimed to identify molecular mechanisms associated with both epilepsy and ADHD. Materials and methodsGene expression profiles of GSE12457 and GSE47752 were downloaded from the gene expression omnibus (GEO) database. Differentially expressed genes (DEGs) were separately screened in epilepsy and ADHD samples and compared with controls. Weighted gene coexpression network analysis (WGCNA) was used to identify candidate modules associated with the two disorders. Functional annotation and analysis of hub genes and molecular complex detection (MCODE) was also performed. ResultsThree modules closely related to epilepsy and ADHD were screened using WGCNA; DEGs in this module were involved in the synaptic vesicle cycle, axon and neuron regeneration, and neurotransmission. The Dlg4 and Vamp2 genes were selected as common candidate factors in epilepsy and ADHD pathogenesis. ConclusionDlg4 and Vamp2 could play essential roles in comorbidity between epilepsy and ADHD.

Is the Motor Impairment in Attention Deficit Hyperactivity Disorder (ADHD) a Co-Occurring Deficit or a Phenotypic Characteristic?

ObjectivesMotor difficulties are often reported in individuals with attention deficit hyperactivity disorder (ADHD). The aims of this study are to detail the motor profile of children with ADHD and to determine whether the motor impairment present in a large proportion of children with ADHD represents a phenotypic characteristic of ADHD or a co-occurring deficit.MethodsParticipants with ADHD (N = 51; age 8 to 15 years) and typically developing (TD) motor matched control children (N = 75; age 4 to 11 years) completed the largest battery of assessments of motor function that have been used with this population to date, as well as a measure of inhibition as a behavioural measure of ADHD characteristics. Parents/caregivers also completed questionnaires relating to ADHD symptomology and a retrospective report of their child’s motor milestone achievement.ResultsA motor deficit was observed in 47% of our ADHD sample. Few relationships were observed between ADHD core characteristics and motor competence. Furthermore, there was an uneven profile of motor performance across different motor tasks, relative to the TD children. Interestingly, it appears that motor milestone achievement is not delayed in ADHD.ConclusionsOur findings suggest that the motor deficit observed in ADHD is not inherent to ADHD. The motor deficit observed in some children with ADHD does not represent a simple delay in development and is not observed in infancy with respect to reaching motor milestones.

Attention‐deficit/hyperactivity disorder in children and adolescents: An event‐related potential study of working memory

Working memory (WM) impairments have been frequently observed as an important feature of attention-deficit/hyperactivity disorder (ADHD). Event-related potential (ERP) differences between ADHD and healthy controls (HC) would be expected during WM task performance. Especially, the so-called slow wave (SW), which is related to the retention process, might present amplitude differences in ADHD. In this ERP study participated twenty-nine ADHD children and adolescents and thirty-four HC. WM performance was assessed using the Working Memory Test Battery for Children (WMTB-C), and ERPs were analyzed with a Delayed Match-To-Sample (DMTS) task. ADHD sample showed worse behavioral performance in both WMTB-C and DMTS task, and higher SW amplitude during the retention phase of the DMTS task. Additionally, the principal component analysis indicated that the scores on the component explaining the centro-parietal SW were significantly different between ADHD subjects and HC. The observed impaired neurophysiological activity during the encoding and retention periods in ADHD, which would be the origin of the behavioral deficits in WM task performance, might be reflecting a delayed maturation of the neural processes underlying the centro-parietal SW.

A Developmental Study of Mathematics in Children with Autism Spectrum Disorder, Symptoms of Attention Deficit Hyperactivity Disorder, or Typical Development.

This study examined mathematics achievement in school-aged children with autism spectrum disorder (ASD), symptoms of attention-deficit/hyperactivity disorder (ADHD), or typical development (TD) over a 30-month period and the associations between cognitive and reading abilities with mathematics achievement in children with ASD. Seventy-seven children with ASD without intellectual disability (ASD-WoID), 39 children with ADHD, and 43 children with TD participated in this study. The results revealed that the ASD-WoID and ADHD samples displayed significant and comparable delays in problem solving and calculation abilities. Lower VIQ was related to lower math achievement across all subgroups. The ASD-WoID sample differed from comparison samples in terms of their pattern of mathematical achievement and the role of cognitive abilities in the development of mathematics competence.