Temporal information processing in ADHD: Findings to date and new methods

Manual Dexterity and Aging: A Pilot Study Disentangling Sensorimotor From Cognitive Decline

Manual dexterity measures can be useful for early detection of age-related functional decline and for prediction of cognitive decline. However, what aspects of sensorimotor function to assess remains unclear. Manual dexterity markers should be able to separate impairments related to cognitive decline from those related to healthy aging. In this pilot study, we aimed to compare manual dexterity components in patients diagnosed with cognitive decline (mean age: 84 years, N = 11) and in age comparable cognitively intact elderly subjects (mean age: 78 years, N = 11). In order to separate impairments due to healthy aging from deficits due to cognitive decline we also included two groups of healthy young adults (mean age: 26 years, N = 10) and middle-aged adults (mean age: 41 years, N = 8). A comprehensive quantitative evaluation of manual dexterity was performed using three tasks: (i) visuomotor force tracking, (ii) isochronous single finger tapping with auditory cues, and (iii) visuomotor multi-finger tapping. Results showed a highly significant increase in force tracking error with increasing age. Subjects with cognitive decline had increased finger tapping variability and reduced ability to select the correct tapping fingers in the multi-finger tapping task compared to cognitively intact elderly subjects. Cognitively intact elderly subjects and those with cognitive decline had prolonged force release and reduced independence of finger movements compared to young adults and middle-aged adults. The findings suggest two different patterns of impaired manual dexterity: one related to cognitive decline and another related to healthy aging. Manual dexterity tasks requiring updating of performance, in accordance with (temporal or spatial) task rules maintained in short-term memory, are particularly affected in cognitive decline. Conversely, tasks requiring online matching of motor output to sensory cues were affected by age, not by cognitive status. Remarkably, no motor impairments were detected in patients with cognitive decline using clinical scales of hand function. The findings may have consequences for the development of manual dexterity markers of cognitive decline.

Feedback Timing Modulates Probabilistic Learning in Adults with ADHD

Attention deficit hyperactivity disorder (ADHD) has been associated primarily with executive function deficits. Emerging findings suggest, however, that procedural learning may be compromised as well. To this effect, we recently showed that feedback-based procedural learning is selectively impaired in ADHD, results that coincide with dopaminergic alterations associated with ADHD. Key questions, however, remain unresolved, among which are the learning conditions that may improve procedural learning in ADHD. Here we examined feedback-based probabilistic learning during conditions that engage procedural and declarative learning systems to different degrees, depending on feedback timing. ADHD and control participants carried out a probabilistic learning task in which they were required to learn to associate between cues and outcomes, where outcomes were presented either immediately or with a short/long delays. Whereas performance in probabilistic learning in ADHD participants was comparable to controls in delayed feedback conditions, during both learning and test phases, their performance diminished when feedback was immediate. Furthermore, ADHD symptom severity was negatively correlated with the ability to learn from immediate feedback. These results suggest that feedback-based probabilistic learning can be improved in ADHD, provided appropriate conditions. By shifting the load from midbrain/striatal systems to declarative memory mechanisms, behavioral performance in ADHD populations can be remediated.

A multicohort, longitudinal study of cerebellar development in attention deficit hyperactivity disorder

BACKGROUND

The cerebellum supports many cognitive functions disrupted in attention deficit hyperactivity disorder (ADHD). Prior neuroanatomic studies have been often limited by small sample sizes, inconsistent findings, and a reliance on cross-sectional data, limiting inferences about cerebellar development. Here, we conduct a multicohort study using longitudinal data, to characterize cerebellar development.

METHODS

Growth trajectories of the cerebellar vermis, hemispheres and white matter were estimated using piecewise linear regression from 1,656 youth; of whom 63% had longitudinal data, totaling 2,914 scans. Four cohorts participated, all contained childhood data (age 4-12 years); two had adolescent data (12-25 years). Growth parameters were combined using random-effects meta-analysis.

RESULTS

Diagnostic differences in growth were confined to the corpus medullare (cerebellar white matter). Here, the ADHD group showed slower growth in early childhood compared to the typically developing group (left corpus medullare z = 2.49, p = .01; right z = 2.03, p = .04). This reversed in late childhood, with faster growth in ADHD in the left corpus medullare (z = 2.06, p = .04). Findings held when gender, intelligence, comorbidity, and psychostimulant medication were considered.

DISCUSSION

Across four independent cohorts, containing predominately longitudinal data, we found diagnostic differences in the growth of cerebellar white matter. In ADHD, slower white matter growth in early childhood was followed by faster growth in late childhood. The findings are consistent with the concept of ADHD as a disorder of the brain's structural connections, formed partly by developing cortico-cerebellar white matter tracts.

Neurocognitive Pathways in Attention-Deficit/Hyperactivity Disorder and White Matter Microstructure

BACKGROUND

This study sought to identify attention-deficit/hyperactivity disorder (ADHD) abnormalities in relationships between brain white matter structure and individual differences in several types of impulsive behavior.

METHODS

Adolescents, n = 67 with ADHD combined subtype and n = 68 without ADHD, were given neuropsychological tests and underwent diffusion tensor imaging scans. Principal component analysis reduced test scores into factors representing different types of impulsive behavior. Tract-based spatial statistics quantified white matter integrity in relationship to components of impulsive behavior. ADHD versus non-ADHD differences in the strength and nature of linear relationships between regional white matter and three impulsivity components were examined using multiple regression.

RESULTS

Principal component analysis found three separate impulsivity-related factors that were interpreted as motor response inhibition, impulsive choice, and delay aversion. Relationships between regional fractional anisotropy and response inhibition or impulsive choice did not differ between ADHD and non-ADHD groups. There was a significant interaction between diagnostic group and delay aversion test performance relationships with regional fractional anisotropy. For youths without ADHD, greater anisotropy in numerous tracts predicted better delay aversion test performance. In contrast, anisotropy in regions including the corpus callosum, corona radiata, internal capsule, and corticospinal tracts had either a negative or no relationship with delay aversion test performance in ADHD.

CONCLUSIONS

The results provide additional support that different proposed etiological pathways to ADHD have discretely different neurobiological features. Large disorganization of white matter microstructure appears to contribute to reward-based ADHD pathways rather than motor inhibition.

Growing out of attention deficit hyperactivity disorder: Insights from the 'remitted' brain

We consider developmental and cognitive models to explain why some children 'grow out' of attention deficit hyperactivity disorder (ADHD) by adulthood. The first model views remission as a convergence towards more typical brain function and structure. In support, some studies find that adult remitters are indistinguishable from those who were never affected in the neural substrates of 'top-down' mechanisms of cognitive control, some 'bottom-up' processes of vigilance/response preparation, prefrontal cortical morphology and intrinsic functional connectivity. A second model postulates that remission is driven by the recruitment of new brain systems that compensate for ADHD symptoms. It draws support from demonstrations of atypical, but possibly beneficial, patterns of connectivity within the cognitive control network in adult remitters. The final model holds that some childhood ADHD anomalies show lifelong persistence, regardless of adult outcome, supported by shared reports of anomalies in remitters and persisters in posterior cerebral and striato-thalamic regions. The models are compatible: different processes driving remission might occur in different brain regions. These models provide a framework for future studies which might inform novel treatments to 'accelerate' remission.

Zur Bedeutung auffälliger Exekutivfunktionen in der Diagnostik einer Aufmerksamkeitsdefizit-/Hyperaktivitätsstörung

Zusammenfassung. Defizite in Exekutivfunktionen und insbesondere in der Inhibitionsfähigkeit gelten verschiedenen Modellen zufolge als Kerndefizite einer Aufmerksamkeitsdefizit-/Hyperaktivitätsstörung (ADHS). Die Defizite sind sowohl auf einer Verhaltensebene als auch auf neurobiologischer Ebene belegt, finden aber bislang kaum Einzug in die klinische Diagnostik. Verschiedene Erhebungsverfahren werden vorgestellt und die Probleme im Bereich der klinischen Diagnostik skizziert. Viele Aufgaben messen nicht eine spezifische Exekutivfunktion, sondern umfassen immer auch andere kognitive Prozesse wie zum Beispiel Aufmerksamkeit oder Test- und Leistungsmotivation. Die Sensitivität vieler Aufgaben ist aufgrund der Heterogenität von ADHS durch verschiedene Entwicklungspfade oft nicht gewährleistet und Defizite in Exekutivfunktionen und der Inhibitionsfähigkeit sind auch nicht spezifisch für ADHS. Dennoch ist eine Diagnostik auffälliger Exekutivfunktionen und insbesondere von Defiziten in der Inhibitionsfähigkeit angebracht, da nur so Aussagen über zugrunde liegende Prozesse und Ursachen einer ADHS getroffen werden können, welche die Voraussetzung für gezielte Interventionen darstellen, wie zum Beispiel Inhibitionstrainings oder Neurofeedback.

Timing Deficits in ADHD: Insights From the Neuroscience of Musical Rhythm

Everyday human behavior relies upon extraordinary feats of coordination within the brain. In this perspective paper, we argue that the rich temporal structure of music provides an informative context in which to investigate how the brain coordinates its complex activities in time, and how that coordination can be disrupted. We bring insights from the neuroscience of musical rhythm to considerations of timing deficits in Attention Deficit/Hyperactivity Disorder (ADHD), highlighting the significant overlap between neural systems involved in processing musical rhythm and those implicated in ADHD. We suggest that timing deficits warrant closer investigation since they could lead to the identification of potentially informative phenotypes, tied to neurobiological and genetic factors. Our novel interdisciplinary approach builds upon recent trends in both fields of research: in the neuroscience of rhythm, an increasingly nuanced understanding of the specific contributions of neural systems to rhythm processing, and in ADHD, an increasing focus on differentiating phenotypes and identifying distinct etiological pathways associated with the disorder. Finally, we consider the impact of musical experience on rhythm processing and the potential value of musical rhythm in therapeutic interventions.

Multiple Matrix Gaussian Graphs Estimation

Matrix-valued data, where the sampling unit is a matrix consisting of rows and columns of measurements, are emerging in numerous scientific and business applications. Matrix Gaussian graphical model is a useful tool to characterize the conditional dependence structure of rows and columns. In this article, we employ nonconvex penalization to tackle the estimation of multiple graphs from matrix-valued data under a matrix normal distribution. We propose a highly efficient nonconvex optimization algorithm that can scale up for graphs with hundreds of nodes. We establish the asymptotic properties of the estimator, which requires less stringent conditions and has a sharper probability error bound than existing results. We demonstrate the efficacy of our proposed method through both simulations and real functional magnetic resonance imaging analyses.

Is there a generalized timing impairment in Autism Spectrum Disorders across time scales and paradigms?

Individuals with ASD have abnormal motor and perceptual functions that do not currently form diagnostic criteria of ASD, but nevertheless may affect everyday behaviour. Temporal processing seems to be one of such non-diagnostic yet impaired domains, although the lack of systematic studies testing different aspects of timing in the same sample of participants prevents a conclusive assessment of whether there is a generalized temporal deficit in ASD associated with diagnostic symptoms. 17 children diagnosed with ASD and 18 typically developing age- and IQ-matched controls carried out a set of motor and perceptual timing tasks: free tapping, simultaneity judgment, auditory duration discrimination, and verbal duration estimation. Parents of participants filled in a questionnaire assessing the sense and management of time. Children with ASD showed faster and more variable free tapping than controls. Auditory duration discrimination thresholds were higher in the ASD group than controls in a sub-second version of the task, while there were no group differences in a supra-second discrimination of intervals. Children with ASD showed more variable thresholds of simultaneity judgment, and they received lower parental scores for their sense and management of time. No group differences were observed in the verbal duration estimation task in the minute-range. Different timing functions were correlated in the ASD group but not among controls, whilst several timing measures correlated with ASD symptoms. We conclude that children with ASD show a broad range of abnormalities in temporal processing tasks including motor timing, perceptual timing, and temporal perspective.

Effectiveness of time-related interventions in children with ADHD aged 9-15 years: a randomized controlled study

Specific problems with time and timing that affect daily routines, homework, school work, and social relations have been recognized in children with ADHD. The primary treatments for children with ADHD do not specifically focus on time-related difficulties. The aim of this randomized controlled study (RCT) was to investigate how multimodal interventions, consisting of training in time-processing ability (TPA) and compensation with time-assistive devices (TAD), affect TPA and daily time management (DTM) in children with ADHD and time difficulties, compared with only educational intervention. Thirty-eight children on stable medication for ADHD in the 9-15-year age range were randomly allocated to an intervention or a control group. The children's TPA was measured with a structured assessment (KaTid), and the children's DTM was rated by a parent questionnaire (Time-Parent scale) and by children's self-reporting (Time-Self-rating). The intervention consisted of time-skill training and compensation with TAD. Data were analysed for differences in TPA and in DTM between the control and intervention groups in the 24-week follow-up. Children in the intervention group increased their TPA significantly (p = 0.019) more compared to the control group. The largest increase was in orientation to time. In addition, the parents in the intervention group rated their children's DTM as significantly (p = 0.01) improved compared with the parents in the control group. According to the children, their DTM was not significantly changed. In conclusion, a multimodal intervention consisting of time-skill training and TAD improved TPA and DTM in children with ADHD aged 9-15 years.

Exploring the Effects of Working Memory on Time Perception in Attention Deficit Hyperactivity Disorder

Children with attention deficit hyperactivity disorder (ADHD) are often reported to have deficits of time perception. However, there is a strong relation between performance on tasks of working memory and time perception. Thus, it is possible that the poor performance of children with ADHD on time perception results from their deficit of working memory. In this study, the working memory of participants was separately assessed; therefore, we could explore the relationship between working memory and time perception of children with ADHD. Fifty-six children with ADHD and those of healthy controls completed tasks measuring working memory and time perception. The results showed that the time discrimination ability of children with ADHD was poorer than that of controls. However, there was a strong association between time perception and working memory. After controlling working memory and intelligence, the time discrimination ability of children with ADHD was not significantly poorer than that of controls. We suggest that there is an interdependent relationship between time perception and working memory for children with ADHD.

Cognitive mechanisms underlying the associations between inattention and reading abilities

This study aims to test cognitive skills underlying the association between inattention and reading in early primary school. Teachers rated inattention symptoms when children (N = 523-962) were 6-7 years old. Children were assessed at age 7-8 on phonological awareness, rapid automatized naming (RAN), rapid auditory and bimodal processing, vocabulary, and reading (decoding and comprehension). Phonological awareness, RAN of numbers, and vocabulary mediated the association between inattention and both decoding and comprehension. Rapid bimodal processing mediated the association between inattention and decoding, while RAN of colors mediated the association between inattention and comprehension. This study highlights mediators underlying inattention-reading associations.

Different cortical source activation patterns in children with attention deficit hyperactivity disorder during a time reproduction task

Several neurocognitive studies have indicated that children with attention-deficit/hyperactivity disorder (ADHD) exhibit cognitive deficits in perceptual timing functions; however, only a few electroencephalographic studies have investigated their time reproduction abilities. In the present research, 15 children with ADHD were studied along with 19 age-matched control subjects (aged 7-11 years) as they attempted to reproduce shorter (1000 ms) and longer (2200 ms) time intervals. Trial-mean event-related potential (ERP) and event-related spectral perturbation measures were used to compare the electroencephalography (EEG) source-level activity patterns of the ADHD and control subjects during the time-encoding and reproduction phases. For both short and long intervals, the performance of subjects with ADHD was significantly less accurate and more variable than that of the age-matched controls. During the encoding phase, the ADHD and control ERPs differed significantly for the midfrontal source cluster. The midfrontal P300 amplitude evoked by the onset of the encoding phase was significantly higher for the ADHD group. Similarly, the amplitude of contingent negative variation for the ADHD group was lower for the midfrontal independent component (IC) cluster during long-interval encoding. Theta event-related synchronization in the right occipital cluster also differed between groups during both the encoding and reproduction phases. Moreover, children with ADHD failed to show a frontal selection positivity component in the reproduction phase. Significant differences were found in the mean alpha power for the prefrontal source cluster during the time reproduction phase. These results suggest electrophysiological evidence for time perception deficiencies, selective visual processing disturbances, and working memory impairment in children with ADHD.

Finger tapping and pre-attentive sensorimotor timing in adults with ADHD

Sensorimotor timing deficits are considered central to attention-deficit/hyperactivity disorder (ADHD). However, the tasks establishing timing impairments often involve interconnected processes, including low-level sensorimotor timing and higher level executive processes such as attention. Thus, the source of timing deficits in ADHD remains unclear. Low-level sensorimotor timing can be isolated from higher level processes in a finger-tapping task that examines the motor response to unexpected shifts of metronome onsets. In this study, adults with ADHD and ADHD-like symptoms (n = 25) and controls (n = 26) performed two finger-tapping tasks. The first assessed tapping variability in a standard tapping task (metronome-paced and unpaced). In the other task, participants tapped along with a metronome that contained unexpected shifts (±15, 50 ms); the timing adjustment on the tap following the shift captures pre-attentive sensorimotor timing (i.e., phase correction) and thus should be free of potential higher order confounds (e.g., attention). In the standard tapping task, as expected, the ADHD group had higher timing variability in both paced and unpaced tappings. However, in the pre-attentive task, performance did not differ between the ADHD and control groups. Together, results suggest that low-level sensorimotor timing and phase correction are largely preserved in ADHD and that some timing impairments observed in ADHD may stem from higher level factors (such as sustained attention).

The opportunities of virtual reality in the rehabilitation of children with attention deficit hyperactivity disorder: a literature review

Attention deficit hyperactivity disorder (ADHD) is one of the most common psychiatric disorders in childhood. This disorder, in addition to its main symptoms, creates significant difficulties in education, social performance, and personal relationships. Given the importance of rehabilitation for these patients to combat the above issues, the use of virtual reality (VR) technology is helpful. The aim of this study was to highlight the opportunities for VR in the rehabilitation of children with ADHD. This narrative review was conducted by searching for articles in scientific databases and e-Journals, using keywords including VR, children, and ADHD. Various studies have shown that VR capabilities in the rehabilitation of children with ADHD include providing flexibility in accordance with the patients' requirements; removing distractions and creating an effective and safe environment away from real-life dangers; saving time and money; increasing patients' incentives based on their interests; providing suitable tools to perform different behavioral tests and increase ecological validity; facilitating better understanding of individuals' cognitive deficits and improving them; helping therapists with accurate diagnosis, assessment, and rehabilitation; and improving working memory, executive function, and cognitive processes such as attention in these children. Rehabilitation of children with ADHD is based on behavior and physical patterns and is thus suitable for VR interventions. This technology, by simulating and providing a virtual environment for diagnosis, training, monitoring, assessment and treatment, is effective in providing optimal rehabilitation of children with ADHD.

Multisensory integration and ADHD-like traits: Evidence for an abnormal temporal integration window in ADHD

Abnormalities in multimodal processing have been found in many developmental disorders such as autism and dyslexia. However, surprisingly little empirical work has been conducted to test the integrity of multisensory integration in Attention Deficit Hyperactivity Disorder (ADHD). The main aim of the present study was to examine links between symptoms of ADHD (as measured using a self-report scale in a healthy adult population) and the temporal aspects of multisensory processing. More specifically, a Simultaneity Judgement (SJ) and a Temporal Order Judgement (TOJ) task were used in participants with low and high levels of ADHD-like traits to measure the temporal integration window and Just-Noticeable Difference (JND) (respectively) between the timing of an auditory beep and a visual pattern presented over a broad range of stimulus onset asynchronies. The Point of Subjective Similarity (PSS) was also measured in both cases. In the SJ task, participants with high levels of ADHD-like traits considered significantly fewer stimuli to be simultaneous than participants with high levels of ADHD-like traits, and the former were found to have significantly smaller temporal windows of integration (although no difference was found in the PSS in the SJ or TOJ tasks, or the JND in the latter). This is the first study to identify an abnormal temporal integration window in individuals with ADHD-like traits. Perceived temporal misalignment of two or more modalities can lead to distractibility (e.g., when the stimulus components from different modalities occur separated by too large of a temporal gap). Hence, an abnormality in the perception of simultaneity could lead to the increased distractibility seen in ADHD.

Multimodal mapping of the brain's functional connectivity and the adult outcome of attention deficit hyperactivity disorder

We have a limited understanding of why many children with attention deficit hyperactivity disorder do not outgrow the disorder by adulthood. Around 20-30% retain the full syndrome as young adults, and about 50% show partial, rather than complete, remission. Here, to delineate the neurobiology of this variable outcome, we ask if the persistence of childhood symptoms into adulthood impacts on the brain's functional connectivity. We studied 205 participants followed clinically since childhood. In early adulthood, participants underwent magnetoencephalography (MEG) to measure neuronal activity directly and functional MRI (fMRI) to measure hemodynamic activity during a task-free period (the "resting state"). We found that symptoms of inattention persisting into adulthood were associated with disrupted patterns of typical functional connectivity in both MEG and fMRI. Specifically, those with persistent inattention lost the typical balance of connections within the default mode network (DMN; prominent during introspective thought) and connections between this network and those supporting attention and cognitive control. By contrast, adults whose childhood inattentive symptoms had resolved did not differ significantly from their never-affected peers, both hemodynamically and electrophysiologically. The anomalies in functional connectivity tied to clinically significant inattention centered on midline regions of the DMN in both MEG and fMRI, boosting confidence in a possible pathophysiological role. The findings suggest that the clinical course of this common childhood onset disorder impacts the functional connectivity of the adult brain.

The dopaminergic system dynamic in the time perception: a review of the evidence

Dopaminergic system plays a key role in perception, which is an important executive function of the brain. Modulation in dopaminergic system forms an important biochemical underpinning of neural mechanisms of time perception in a very wide range, from milliseconds to seconds to longer daily rhythms. Distinct types of temporal experience are poorly understood, and the relationship between processing of different intervals by the brain has received little attention. A comprehensive understanding of interval timing functions should be sought within a wider context of temporal processing, involving genetic aspects, pharmacological models, cognitive aspects, motor control and the neurological diseases with impaired dopaminergic system. Particularly, an unexplored question is whether the role of dopamine in interval timing can be integrated with the role of dopamine in non-interval timing temporal components. In this review, we explore a wider perspective of dopaminergic system, involving genetic polymorphisms, pharmacological models, executive functions and neurological diseases on the time perception. We conclude that the dopaminergic system has great participation in impact on time perception and neurobiological basis of the executive functions and neurological diseases.

Neurocognitive Predictors of ADHD Outcome: a 6-Year Follow-up Study

Although a broad array of neurocognitive dysfunctions are associated with ADHD, it is unknown whether these dysfunctions play a role in the course of ADHD symptoms. The present longitudinal study investigated whether neurocognitive functions assessed at study-entry (mean age = 11.5 years, SD = 2.7) predicted ADHD symptom severity and overall functioning 6 years later (mean age = 17.4 years, 82.6 % = male) in a carefully phenotyped large sample of 226 Caucasian participants from 182 families diagnosed with ADHD-combined type. Outcome measures were dimensional measures of ADHD symptom severity and the Kiddie-Global Assessment Scale (K-GAS) for overall functioning. Predictors were derived from component scores for 8 domains of neurocognitive functioning: working memory, motor inhibition, cognitive inhibition, reaction time variability, timing, information processing speed, motor control, intelligence. Effects of age, gender, and pharmacological treatment were considered. Results showed that better working memory predicted lower ADHD symptom severity (R² = 3.0 %), and less reaction time variability predicted better overall functioning (higher K-GAS-score, R² = 5.6 %). Predictors were still significant with baseline behavior included in the models. The role of neurocognitive functioning in the long term outcome of ADHD behavior is discussed.

Linking ADHD to the Neural Circuitry of Attention

Attention deficit hyperactivity disorder (ADHD) is a complex condition with a heterogeneous presentation. Current diagnosis is primarily based on subjective experience and observer reports of behavioral symptoms - an approach that has significant limitations. Many studies show that individuals with ADHD exhibit poorer performance on cognitive tasks than neurotypical controls, and at least seven main functional domains appear to be implicated in ADHD. We discuss the underlying neural mechanisms of cognitive functions associated with ADHD, with emphasis on the neural basis of selective attention, demonstrating the feasibility of basic research approaches for further understanding cognitive behavioral processes as they relate to human psychopathology. The study of circuit-level mechanisms underlying executive functions in nonhuman primates holds promise for advancing our understanding, and ultimately the treatment, of ADHD.

What to expect and when to expect it: an fMRI study of expectancy in children with ADHD symptoms

Changes in cognitive control and timing have both been implicated in ADHD. Both are involved in building and monitoring expectations about the environment, and altering behavior if those expectations are violated. In ADHD, problems with expectations about future events have high face validity, as this would be associated with behavior that is inappropriate only given a certain context, similar to symptoms of the disorder. In this fMRI study, we used a timing manipulated go/nogo task to assess brain activity related to expectations about what (cognitive control) and when (timing) events would occur. We hypothesized that problems in building expectations about the environment are a more general, trans-diagnostic characteristic of children with hyperactive, impulsive and inattentive symptoms. To address this, we included children with ASD and symptoms of ADHD, in addition to children with ADHD and typically developing children. We found between-group differences in brain activity related to expectations about when (timing), but not what events will occur (cognitive control). Specifically, we found timing-related hypo-activity that was in part unique to children with a primary diagnosis of ADHD (left pallidum) and in part shared by children with similar levels of ADHD symptoms and a primary diagnosis of ASD (left subthalamic nucleus). Moreover, we found poorer task performance related to timing, but only in children with ASD and symptoms of ADHD. Ultimately, such neurobiological changes in children with ADHD symptoms may relate to a failure to build or monitor expectations and thereby hinder the efficiency of their interaction with the environment.

The faster internal clock in ADHD is related to lower processing speed: WISC-IV profile analyses and time estimation tasks facilitate the distinction between real ADHD and pseudo-ADHD

Alterations in temporal processing may represent a primary cause of key symptoms in ADHD. This study is aimed at investigating the nature of time-processing alterations in ADHD and assessing the possible utility of testing time estimation for clinical diagnostics. Retrospective verbal time estimation in the range of several minutes was examined in 50 boys with ADHD and 53 boys with other mental disorders. All participants (age 7-16) attended an outpatient clinic for ADHD diagnostics. The diagnostic assessment included the WISC-IV. Subjects with ADHD made longer and less accurate duration estimates than the clinical control group. The ADHD group showed a specific WISC-IV profile with processing speed deficits. In the ADHD group there was a correlation between processing speed and quality of time estimation that was not observed in the comparison group: higher processing speed indices were related to more accurate duration estimates. The findings provide support for the presence of a faster internal clock in subjects with ADHD and lend further support to the existence of a specific WISC-IV profile in subjects with ADHD. The results show that analyzing WISC-IV profiles and time estimation tasks are useful differential diagnosis tools, particularly when it comes to distinguishing between "real ADHD" and pseudo-ADHD.

Neuropsicologia do Transtorno de Déficit de Atenção/Hiperatividade: Modelos Neuropsicológicos e Resultados de Estudos Empíricos

Resumo Diferentes modelos teóricos foram propostos para explicar os déficits neuropsicológicos e seu impacto no comportamento de indivíduos com Transtorno de Déficit de Atenção/Hiperatividade (TDAH). Os objetivos deste artigo serão apresentar os principais modelos neuropsicológicos do TDAH e possibilitar uma atualização acerca dos principais achados relacionados ao funcionamento neuropsicológico de pacientes com esse diagnóstico. Revisões e meta-análises sobre funcionamento executivo, aversão à resposta tardia, processamento temporal e variações intraindividuais no tempo de reação são apresentadas. O perfil neuropsicológico de pacientes com TDAH é heterogêneo e testes neuropsicológicos não são suficientemente sensíveis e específicos para realização do diagnóstico, embora sejam muito importantes na identificação do perfil cognitivo para estabelecimento de um plano de tratamento mais abrangente e adequado às necessidades especificas de cada paciente.

The Groundskeeper Gaming Platform as a Diagnostic Tool for Attention-Deficit/Hyperactivity Disorder: Sensitivity, Specificity, and Relation to Other Measures

OBJECTIVE

The purpose of this study was to assess the relative accuracies of the Conners' Brief Rating Scale, Parent Version, the Conners' Continuous Performance Test II (CPT II), and a novel interactive game called "Groundskeeper" to discriminate child psychiatric patients with and without attention-deficit/hyperactivity disorder (ADHD).

METHODS

We administered the three assessments to 113 clinically referred ADHD and non-ADHD patients who had been diagnosed with the Kiddie-Schedule of Affective Disorders and Schizophrenia- Present and Lifetime (K-SADS-PL), Version 19.

RESULTS

As measured by the area under the curve (AUC) statistic from receiver operating characteristic (ROC) analysis, the diagnostic accuracy of Groundskeeper (0.79) was as high as the accuracy of the Conners' parent rating of inattention (0.76) and better than the CPT II percent correct (0.62). Combining the three tests produced an AUC of 0.87. Correlations among the three measures were small and, mostly, not significant.

CONCLUSIONS

Our finding of similar diagnostic accuracies between Groundskeeper and the Conners' inattention scale is especially remarkable given that the Conners' inattention scale shares method variance with the diagnostic process. Although our work is preliminary, it suggests that computer games may be useful in the diagnostic process. This provides an important direction for research, given the objectivity of such measures and the fact that computer games are well tolerated by youth.

Influence of pacer continuity on continuous and discontinuous visuo-motor synchronisation

Previous research has reported that synchronising movements with an external pacer, known as sensorimotor synchronisation (SMS), is more stable when the movements are discrete/discontinuous rather than continuous. A standard explanation considers that more efficient mechanisms are involved for regulating synchronisation when producing discontinuous movements. To date, however, only discontinuous pacers (e.g., metronomes) have been investigated to compare discontinuous and continuous SMS. We propose an alternative explanation whereby the discontinuous SMS has benefited from the matching between the (dis)continuous nature of the pacer and the (dis)continuous nature of the movements of synchronisation. The present experiment tested this explanation by examining the relative stability of discontinuous and continuous SMS when synchronising with a continuous pacer. Twelve participants finger tapped (discontinuous SMS) or continuously oscillated their forearm (continuous SMS) in synchrony with an oscillatory visual target. The continuity of the pacer was manipulated by varying the kinematic (harmonic to Rayleigh-like oscillations) and the frequency (0.5 and 1Hz) of the target oscillations. Overall, the results showed a more stable continuous than discontinuous SMS. Furthermore, the stability of the discontinuous SMS improved when increasing the discontinuity of the target displacements (high nonlinear kinematic and low frequency), showing an interaction between movement type and pacer continuity in SMS.

Temporal reproduction and its neuroanatomical correlates in adults with attention deficit hyperactivity disorder and their unaffected first-degree relatives

BACKGROUND

Little is known about time perception, its putative role as cognitive endophenotype, and its neuroanatomical underpinnings in adults with attention deficit hyperactivity disorder (ADHD).

METHOD

Twenty adults with ADHD, 20 unaffected first-degree relatives and 20 typically developing controls matched for age and gender undertook structural magnetic resonance imaging scans. Voxel-based morphometry with DARTEL was performed to obtain regional grey-matter volumes. Temporal processing was investigated as a putative cognitive endophenotype using a temporal reproduction paradigm. General linear modelling was employed to examine the relationship between temporal reproduction performances and grey-matter volumes.

RESULTS

ADHD participants were impaired in temporal reproduction and unaffected first-degree relatives performed in between their ADHD probands and typically developing controls. Increased grey-matter volume in the cerebellum was associated with poorer temporal reproduction performance.

CONCLUSIONS

Adults with ADHD are impaired in time reproduction. Performances of the unaffected first-degree relatives are in between ADHD relatives and controls, suggesting that time reproduction might be a cognitive endophenotype for adult ADHD. The cerebellum is involved in time reproduction and might play a role in driving time performances.

Emotional stimuli facilitate time perception in children with attention-deficit/hyperactivity disorder

The aim of this study was to compare the effect of different emotional stimuli (neutral, positive, and negative) on time perception in children with attention-deficit/hyperactivity disorder (ADHD) and normal children in dual-task form. Five hundred and ninety-nine students from primary schools were randomly selected. The Conner's Teacher Rating Scale (CTRS) questionnaire was completed by teachers. A total of 100 children with a score above the cut-off point for the CTRS were further assessed using the Child Symptom Inventory-4 (CSI-4). A total of 34 children with ADHD and 31 controls completed an emotional time discrimination task in two blocks of 1000 and 2000 ms duration. Children were asked to compare three image groups: neutral with neutral, neutral with positive, and neutral with negative images. Children with ADHD had significantly better performance in the emotional time discrimination task across all conditions when compared with controls: On average, discrimination thresholds were approximately 35 ms shorter for the children with ADHD. Our results indicate that children with ADHD have higher sensitivity to time relative to controls in a situation in which they must distribute resources between temporal and emotional processing. On the basis of the interference effect and the working memory capacity hypothesis, this dividing of attention causes a decrease of time accuracy in normal children.

Extended Visual Glances Away from the Roadway are Associated with ADHD- and Texting-Related Driving Performance Deficits in Adolescents

The purpose of the research study was to determine whether ADHD- and texting-related driving impairments are mediated by extended visual glances away from the roadway. Sixty-one adolescents (ADHD =28, non-ADHD =33; 62% male; 11% minority) aged 16-17 with a valid driver's license were videotaped while engaging in a driving simulation that included a No Distraction, Hands-Free Phone Conversation, and Texting condition. Two indicators of visual inattention were coded: 1) percentage of time with eyes diverted from the roadway; and 2) number of extended (greater than 2 s) visual glances away from the roadway. Adolescents with ADHD displayed significantly more visual inattention to the roadway on both visual inattention measures. Increased lane position variability among adolescents with ADHD compared to those without ADHD during the Hands-Free Phone Conversation and Texting conditions was mediated by an increased number of extended glances away from the roadway. Similarly, texting resulted in decreased visual attention to the roadway. Finally, increased lane position variability during texting was also mediated by the number of extended glances away from the roadway. Both ADHD and texting impair visual attention to the roadway and the consequence of this visual inattention is increased lane position variability. Visual inattention is implicated as a possible mechanism for ADHD- and texting-related deficits and suggests that driving interventions designed to address ADHD- or texting-related deficits in adolescents need to focus on decreasing extended glances away from the roadway.

Cognitive Risk Factors for Specific Learning Disorder: Processing Speed, Temporal Processing, and Working Memory

High comorbidity rates between reading disorder (RD) and mathematics disorder (MD) indicate that, although the cognitive core deficits underlying these disorders are distinct, additional domain-general risk factors might be shared between the disorders. Three domain-general cognitive abilities were investigated in children with RD and MD: processing speed, temporal processing, and working memory. Since attention problems frequently co-occur with learning disorders, the study examined whether these three factors, which are known to be associated with attention problems, account for the comorbidity between these disorders. The sample comprised 99 primary school children in four groups: children with RD, children with MD, children with both disorders (RD+MD), and typically developing children (TD controls). Measures of processing speed, temporal processing, and memory were analyzed in a series of ANCOVAs including attention ratings as covariate. All three risk factors were associated with poor attention. After controlling for attention, associations with RD and MD differed: Although deficits in verbal memory were associated with both RD and MD, reduced processing speed was related to RD, but not MD; and the association with RD was restricted to processing speed for familiar nameable symbols. In contrast, impairments in temporal processing and visuospatial memory were associated with MD, but not RD.

A rating measure of ADHD-related neuropsychological impairment in children and adolescents: Data from the Cognition and Motivation in Everyday Life (CAMEL) Scale from population and clinical samples

A new parent-completed questionnaire, the Cognition and Motivation in Everyday Life (CAMEL) scale, was developed to provide a comprehensive assessment of neuropsychological impairment in children related to attention-deficit/hyperactivity disorder (ADHD) across diverse cognitive, motivational and energetic domains. Its psychometric properties were investigated. A total of 60 items were generated to cover a wide range of putative ADHD-related neuropsychological processes. A clinical (n = 142) and community (n = 810) sample of parents with children between 6 and 16 years of age completed the questionnaire. Data on ADHD symptoms were also collected with a commonly-used, validated parent rating scale to explore the associations between CAMEL scores and dimensional measures of child ADHD and conduct problems. Factor analysis identified six factors which we labeled (i) Cognition, (ii) Self-Direction and Organization, (iii) Effort Engagement, (iv) Arousal Regulation, (v) Motivational Responsiveness, and (vi) Cautiousness. Self-Direction and Organization and Arousal Regulation were the strongest predictors for ADHD symptomatology. Self-Direction and Organization was strongly associated with inattention and Arousal Regulation with hyperactivity-impulsivity symptoms. Parents distinguished between broad neuropsychological domains in reliable and plausible ways, making distinctions between key aspects of functioning. However, the boundaries between these domains did not map directly onto the distinctions drawn within traditional models of ADHD deficits. Further research is required to examine the predictive validity and cost-effectiveness of the CAMEL scale compared to direct objective testing using laboratory measures in predicting prognosis and treatment outcome.

Neuroenergetics

The brain uses 20% of the body’s energy. The processes delivering that energy to neurons can fail in numerous ways. The neuroenergetics theory draws out the implications of failure in the supply chain between blood capillaries and neurons. The theory is implemented as a diffusion model that yields response-latency distributions, error rates, and other predictions for typical individuals engaged in focused activities and for special populations such as those with neurodevelopmental disorders. It predicts the effects of stimulants, trial spacing, and fatigue. Here, the implications of energetic insufficiency are explored in the context of the positive manifold of abilities, disabilities, and psychiatric comorbidities.

Response Inhibition in Tic Disorders: Waiting to Respond Is Harder When ADHD Is Present

OBJECTIVE

Tic disorders such as Gilles-de-la-Tourette syndrome (TS) are associated with difficulties in withholding movements and sometimes inappropriate actions. The present study examined whether these disorders lead to a specific difficulty in withholding preprogrammed voluntary movements irrespective of decisions on whether or not to move.

METHOD

Children with TS with or without attention-deficit hyperactivity disorder (ADHD) and controls performed a fast-paced simple reaction time task involving responses to a target in a rapid letter stream (9 letters/s, average foreperiod 332 ms) with feedback on response speed.

RESULTS

The ADHD group showed more premature responses and more variable response time than other groups, whether the timing of the target was predictable or not.

CONCLUSION

The data indicate that in tic disorders, the presence of ADHD is associated with difficulties in waiting to initiate preprogrammed movements independently of response selection or response timing difficulties.

Explicit Time Deficit in Schizophrenia: Systematic Review and Meta-Analysis Indicate It Is Primary and Not Domain Specific

Although timing deficits are a robust finding in schizophrenia (SZ), the notion of a genuine time perception disorder in SZ is still being debated because distortions in timing might depend on neuropsychological deficits that are characteristics of the illness. Here we used meta-analytic methods to summarize the evidence of timing deficits in SZ and moderator analyses to determine whether defective timing in SZ arises from nontemporal sources or from defective time perception. PubMed Services, PsycNET, and Scopus were searched through March 2015, and all references in articles were investigated to find other relevant studies. Studies were selected if they included subjects with a primary diagnosis of SZ compared to a healthy control (HC) group and if they reported behavioral measures of duration estimation (perceptual and motor explicit timing). Data from 24 studies published from 1956 to 2015, which comprised 747 SZ individuals and 808 HC, were included. Results indicate that SZ individuals are less accurate than HC in estimating time duration across a wide range of tasks. Subgroup analyses showed that the fundamental timing deficit in SZ is independent from the length of the to-be-timed duration (automatic and cognitively controlled timing) and from methods of stimuli estimation (perceptual and motor timing). Thus, time perception per se is disturbed in SZ (not just task-specific timing processes) and this perturbation is independent from more generalized cognitive impairments. Behavioral evidence of disturbed automatic timing should be more thoroughly investigated with the aim of defining it as a cognitive phenotype for more homogeneous diagnostic subgrouping.

How 'core' are motor timing difficulties in ADHD? A latent class comparison of pure and comorbid ADHD classes

Children with attention-deficit/hyperactivity disorder (ADHD) have motor timing difficulties. This study examined whether affected motor timing accuracy and variability are specific for ADHD, or that comorbidity with autism spectrum disorders (ASD) contributes to these motor timing difficulties. An 80-trial motor timing task measuring accuracy (μ), variability (σ) and infrequent long response times (τ) in estimating a 1-s interval was administered to 283 children and adolescents (8-17 years) from both a clinic and population based sample. They were divided into four latent classes based on the SCQ and

CPRS-R

L data. These classes were: without behavioral problems 'Normal-class' (n = 154), with only ADHD symptoms 'ADHD-class' (n = 49), and two classes with both ASD and ADHD symptoms; ADHD(+ASD)-class (n = 39) and ASD(+ADHD)-class (n = 41). The pure ADHD-class did not deviate from the Normal class on any of the motor timing measures (mean RTs 916 and 925 ms, respectively). The comorbid ADHD(+ASD) and ASD(+ADHD) classes were significantly less accurate (more time underestimations) compared to the Normal class (mean RTs 847 and 870 ms, respectively). Variability in motor timing was reduced in the younger children in the ADHD(+ASD) class, which may reflect a tendency to rush the tedious task. Only patients with more severe behavioral symptoms show motor timing deficiencies. This cannot merely be explained by high ADHD severity with ASD playing no role, as ADHD symptom severity in the pure ADHD-class and the ASD(+ADHD) class was highly similar, with the former class showing no motor timing deficits.

Left hemispheric contributions to temporal perception: a resting electroencephalographic study

Beta brain wave frequencies, theta brain wave frequencies, and interhemispheric transfer rates were investigated in individuals to explore components of time perception. Research suggests that the left hemisphere is highly involved in attention and language, which are important components of temporal processing mechanisms. Resting state electroencephalography was used to evaluate the relationship between right and left hemispheric brain wave frequencies and performance on a duration-discrimination task and an interhemispheric transfer rate task. A stepwise multiple regression was used to investigate the absolute spectral power of right minus left hemispheric activation for each frequency (alpha, beta, gamma, theta) at each of eight paired electrode locations onto d' data for a temporal discrimination task. Higher absolute spectral power in parietal and temporal left electrodes was predictive of better performance on the duration-discrimination task. Right-to-left interhemispheric transfer approached a significant correlation with performance on the duration-discrimination task. Our results indicate that sensitivity on a temporal task is positively correlated with beta and theta brain wave frequencies, and negatively correlated with right-to-left interhemispheric transfer rates. The current study provides support for a left hemispheric advantage for temporal processing; this provides further explanation of temporal processing mechanisms and where deficits may occur in clinical populations.

Music and Sound in Time Processing of Children with ADHD

ADHD involves cognitive and behavioral aspects with impairments in many environments of children and their families' lives. Music, with its playful, spontaneous, affective, motivational, temporal, and rhythmic dimensions can be of great help for studying the aspects of time processing in ADHD. In this article, we studied time processing with simple sounds and music in children with ADHD with the hypothesis that children with ADHD have a different performance when compared with children with normal development in tasks of time estimation and production. The main objective was to develop sound and musical tasks to evaluate and correlate the performance of children with ADHD, with and without methylphenidate, compared to a control group with typical development. The study involved 36 participants of age 6-14 years, recruited at NANI-UNIFESP/SP, subdivided into three groups with 12 children in each. Data was collected through a musical keyboard using Logic Audio Software 9.0 on the computer that recorded the participant's performance in the tasks. Tasks were divided into sections: spontaneous time production, time estimation with simple sounds, and time estimation with music.

RESULTS

(1) performance of ADHD groups in temporal estimation of simple sounds in short time intervals (30 ms) were statistically lower than that of control group (p < 0.05); (2) in the task comparing musical excerpts of the same duration (7 s), ADHD groups considered the tracks longer when the musical notes had longer durations, while in the control group, the duration was related to the density of musical notes in the track. The positive average performance observed in the three groups in most tasks perhaps indicates the possibility that music can, in some way, positively modulate the symptoms of inattention in ADHD.

Adjustment of Time Perception in the Range of Seconds and Milliseconds: The Nature of Time-Processing Alterations in Children With ADHD

OBJECTIVE

The nature of time-processing alterations in ADHD was assessed by means of duration judgments and temporal set-shifting tasks lasting several seconds and milliseconds.

METHOD

After training with visual sample stimuli for long and short durations, 31 children with ADHD and 29 controls estimated the durations of test stimuli. During testing, the temporal context was systematically varied by shifting the duration of stimulus sets to longer or shorter intervals.

RESULTS

Children with ADHD generally overestimated the durations of stimuli on the seconds scale. Their assessment of stimuli on the milliseconds scale can be characterized as less-efficient adaptations to new temporal sets alongside otherwise normal discrimination performance.

CONCLUSION

Findings support a pure time perception alteration in ADHD. In addition, results provide first evidence that difficulties in mental set-shifting, which have been reported for other tasks, extend to temporal processing in children with ADHD.

The role of age in association analyses of ADHD and related neurocognitive functioning: A proof of concept for dopaminergic and serotonergic genes

Elucidating genetic mechanisms involved in Attention-Deficit/Hyperactivity Disorder (ADHD) has been challenging. Relatively unexplored is the fact that genetic mechanisms can differ with age. The current study explored the association between dopaminergic and serotonergic genes, ADHD symptoms, and neurocognitive functioning in relation to age. Associations of three genetic ADHD risk factors, DAT1, DRD4, and 5-HTT with symptoms and six neurocognitive measures were explored in two samples of the NeuroIMAGE study: 756 children, adolescents, and young adults with ADHD, their siblings, and controls (M age 17 years, SD 3.2), and 393 parents with and without ADHD (M age 48 years, SD 4.8). Association analyses were performed in both samples, and effects were compared to address dichotomous age effects. Gene*age interactions were examined to address continuous age effects. Moderating effects of age were found for DRD4-7R carriership and ADHD symptoms in the adult group only; in the adolescents the 5-HTT LL genotype was differentially associated with inhibition and with motor timing at different ages, and to inhibition in adults; DAT1 10-6 haplotype carriership showed differential working memory performance depending on age. None of our effects survived correction for multiple comparisons. Our results are preliminary, but may point to differential genotype-phenotype associations at different ages. This can be seen as a proof of concept for the importance of age in dopaminergic and serotonergic genetic association analyses. Our findings are consistent with the idea that genetic and neurocognitive mechanisms underlying ADHD may change throughout life. © 2015 Wiley Periodicals, Inc.

The Unique and Combined Effects of Reinforcement and Methylphenidate on Temporal Information Processing in Attention-Deficit/Hyperactivity Disorder

Temporal information processing and reward sensitivity are neurocognitive impairments key to attention-deficit/hyperactivity disorder (ADHD). The aim of this study was to examine the unique and combined impact of reinforcement and methylphenidate (MPH) on temporal information processing in children with ADHD. We predicted that both monetary reinforcement and MPH would ameliorate temporal information processing deficits in ADHD, and we expected that the combined effect of reinforcement and MPH would be most beneficial. Forty children (23 with ADHD and 27 typical controls, aged 8-12 y) performed a time production task under 3 conditions: reward, response cost, and feedback only. Children with ADHD also performed the task (in random order) with placebo, a low, a medium, and a high dose of MPH. Dependent variables were time production accuracy and variability. At baseline, children with ADHD displayed poor internal clock functioning compared with controls, as reflected by greater underestimations of the 1-second interval, and they showed poor motor output as reflected by increased timing variability. Reward and response cost improved motor output (timing variability), with similar effects for both groups. Methylphenidate increased performance (timing variability) compared with placebo, with a higher dose showing greater effects. Effect sizes of reinforcement and medication were medium to large. Contrary to expectations, MPH did not add to the reinforcement effect. The results of this study confirm the value of reward and response cost being similar to that of MPH to optimize (timing) performance of children with ADHD.

Interval timing deficits assessed by time reproduction dual tasks as cognitive endophenotypes for attention-deficit/hyperactivity disorder

The literature has suggested timing processing as a potential endophenotype for attention deficit/hyperactivity disorder (ADHD); however, whether the subjective internal clock speed presented by verbal estimation and limited attention capacity presented by time reproduction could be endophenotypes for ADHD is still unknown. We assessed 223 youths with DSM-IV ADHD (age range: 10-17 years), 105 unaffected siblings, and 84 typically developing (TD) youths using psychiatric interviews, intelligence tests, verbal estimation and time reproduction tasks (single task and simple and difficult dual tasks) at 5-second, 12-second, and 17-second intervals. We found that youths with ADHD tended to overestimate time in verbal estimation more than their unaffected siblings and TD youths, implying that fast subjective internal clock speed might be a characteristic of ADHD, rather than an endophenotype for ADHD. Youths with ADHD and their unaffected siblings were less precise in time reproduction dual tasks than TD youths. The magnitude of estimated errors in time reproduction was greater in youths with ADHD and their unaffected siblings than in TD youths, with an increased time interval at the 17-second interval and with increased task demands on both simple and difficult dual tasks versus the single task. Increased impaired time reproduction in dual tasks with increased intervals and task demands were shown in youths with ADHD and their unaffected siblings, suggesting that time reproduction deficits explained by limited attention capacity might be a useful endophenotype of ADHD.

Processamento auditivo temporal em crianças com transtorno do déficit de atenção com hiperatividade (TDAH)

OBJETIVO:comparar os achados da avaliação comportamental do processamento auditivo temporal em crianças com e sem Transtorno do Déficit de Atenção com Hiperatividade.MÉTODOS:participaram desse estudo 30 crianças na faixa etária de 8 a 12 anos, sendo 15 do grupo controle e 15 do grupo pesquisa, com limiares audiométricos dentro dos padrões de normalidade. Como procedimentos foram realizados os testes temporais de padrão de frequência e de duração.RESULTADOS:na comparação entre o grupo controle e grupo pesquisa em ambos os testes - padrão de frequência e padrão de duração foram verificadas diferenças significantes entre os grupos, sendo que o grupo pesquisa apresentou resultados alterados em sua maioria, enquanto que todas as crianças do grupo controle apresentaram resultados normais. Foi possível observar ainda que todas as crianças de ambos os grupos tiveram resultados inferiores para o Padrão de Duração quando comparado aos resultados do Padrão de Frequência e.CONCLUSÃO:a avaliação comportamental do processamento auditivo temporal de crianças com e sem Transtorno do Déficit de Atenção com Hiperatividade, mostrou que os sujeitos com Transtorno do Déficit de Atenção com Hiperatividade apresentaram alterações, enquanto que o grupo sem Transtorno do Déficit de Atenção com Hiperatividade resultados normais em ambos os testes. O presente estudo possibilitou um maior conhecimento da via auditiva central das crianças com e sem Transtorno do Déficit de Atenção com Hiperatividade, porém, outros estudos ainda se fazem necessários, principalmente na literatura nacional, a fim de se conhecer melhor o funcionamento do processamento auditivo dessas populações.

Integration of symptom ratings from multiple informants in ADHD diagnosis: a psychometric model with clinical utility

The Diagnostic and Statistical Manual of Mental Disorder-Fifth Edition explicitly requires that attention-deficit/hyperactivity disorder (ADHD) symptoms should be apparent across settings, taking into account reports from multiple informants. Yet, it provides no guidelines how information from different raters should be combined in ADHD diagnosis. We examined the validity of different approaches using structural equation modeling (SEM) for multiple-informant data. Participants were 725 children, 6 to 17 years old, and their primary caregivers and teachers, recruited from the community and completing a thorough research-based diagnostic assessment, including a clinician-administered diagnostic interview, parent and teacher standardized rating scales, and cognitive testing. A best-estimate ADHD diagnosis was generated by a diagnostic team. An SEM model demonstrated convergent validity among raters. We found relatively weak symptom-specific agreement among raters, suggesting that a general average scoring algorithm is preferable to symptom-specific scoring algorithms such as the "or" and "and" algorithms. Finally, to illustrate the validity of this approach, we show that averaging makes it possible to reduce the number of items from 18 items to 8 items without a significant decrease in validity. In conclusion, information from multiple raters increases the validity of ADHD diagnosis, and averaging appears to be the optimal way to integrate information from multiple raters.

Distinct neuropsychological profiles within ADHD: a latent class analysis of cognitive control, reward sensitivity and timing

BACKGROUND

Multiple pathway models of attention deficit hyperactivity disorder (ADHD) suggest that this disorder is the behavioural expression of dysfunction in one of several separable brain systems. One such model focuses on the brain systems underlying cognitive control, timing and reward sensitivity. It predicts separable subgroups among individuals with ADHD, with performance deficits in only one of these domains. We used latent class analysis (LCA) to identify subgroups of individuals with ADHD based on their overall pattern of neuropsychological performance, rather than grouping them based on cut-off criteria. We hypothesized that we would find separable subgroups with deficits in cognitive control, timing and reward sensitivity respectively.

METHOD

Ninety-six subjects with ADHD (of any subtype) and 121 typically developing controls performed a battery assessing cognitive control, timing and reward sensitivity. LCA was used to identify subgroups of individuals with ADHD with a distinct neuropsychological profile. A similar analysis was performed for controls.

RESULTS

Three subgroups represented 87% of subjects with ADHD. Two of our three hypothesized subgroups were identified, with poor cognitive control and timing. Two of the ADHD subgroups had similar profiles to control subgroups, whereas one subgroup had no equivalent in controls.

CONCLUSIONS

Our findings support multiple pathway models of ADHD, as we were able to define separable subgroups with differing cognitive profiles. Furthermore, we found both quantitative and qualitative differences from controls, suggesting that ADHD may represent both categorical and dimensional differences. These results show that by addressing heterogeneity in ADHD, we can identify more homogeneous subsets of individuals to further investigate.

The NeuroIMAGE study: a prospective phenotypic, cognitive, genetic and MRI study in children with attention-deficit/hyperactivity disorder. Design and descriptives

Attention-deficit/hyperactivity disorder (ADHD) is a persistent neuropsychiatric disorder which is associated with impairments on a variety of cognitive measures and abnormalities in structural and functional brain measures. Genetic factors are thought to play an important role in the etiology of ADHD. The NeuroIMAGE study is a follow-up of the Dutch part of the International Multicenter ADHD Genetics (IMAGE) project. It is a multi-site prospective cohort study designed to investigate the course of ADHD, its genetic and environmental determinants, its cognitive and neurobiological underpinnings, and its consequences in adolescence and adulthood. From the original 365 ADHD families and 148 control (CON) IMAGE families, consisting of 506 participants with an ADHD diagnosis, 350 unaffected siblings, and 283 healthy controls, 79 % participated in the NeuroIMAGE follow-up study. Combined with newly recruited participants the NeuroIMAGE study comprehends an assessment of 1,069 children (751 from ADHD families; 318 from CON families) and 848 parents (582 from ADHD families; 266 from CON families). For most families, data for more than one child (82 %) and both parents (82 %) were available. Collected data include a diagnostic interview, behavioural questionnaires, cognitive measures, structural and functional neuroimaging, and genome-wide genetic information. The NeuroIMAGE dataset allows examining the course of ADHD over adolescence into young adulthood, identifying phenotypic, cognitive, and neural mechanisms associated with the persistence versus remission of ADHD, and studying their genetic and environmental underpinnings. The inclusion of siblings of ADHD probands and controls allows modelling of shared familial influences on the ADHD phenotype.

Is the impairment in temporal allocation of visual attention in children with ADHD related to a developmental delay or a structural cognitive deficit?

We investigated the temporal allocation of visual attention in 11-year-old children with attention-deficit/hyperactivity disorder (ADHD) by comparing their attentional blink (AB) parameters (duration, amplitude and minimum performance) with those observed in three groups of healthy control participants (8-year-olds, 11-year-olds and adults). The AB is a marker of impaired ability to detect a second target following the identification of a first target when both appear randomly within a rapid sequence of distractor items. Our results showed developmental effects; with age, the AB duration decreased and the AB minimum moved to shorter lag times. Importantly, 11-year old children with ADHD presented much the same similar AB patterns (in terms of duration and minimum position) as the healthy 8-year-old controls. Our results support the hypothesis whereby impaired allocation of temporal selective attention in children with ADHD is due to a developmental delay and not a specific cognitive deficit.

Beyond symptom control for attention-deficit hyperactivity disorder (ADHD): what can parents do to improve outcomes?

Attention-deficit hyperactivity disorder (ADHD) and its associated behavioural manifestations develop and progress as the result of complex gene-environment interactions. Parents exert a substantial influence and play a major role in their child's social environment. Despite this, recent evidence has suggested that adapting the child's environment via parenting interventions has minimal effects on child ADHD symptoms when analysing data from informants who are probably blind to treatment allocation. However, adverse parenting and family environments may act as a source of environmental risk for a number of child outcomes beyond ADHD symptoms. This is a narrative review that critically discusses whether parenting interventions are beneficial for alternative functioning outcomes in ADHD including neuropsychological, academic and social functioning and disruptive behaviour and how parenting and familial environments may be associated with these outcomes. In addition, the review explores how parental depression and parenting efficacy impact on capacity for optimal parenting and whether parenting interventions benefit parents too. A review of the evidence suggests that with modification, parenting interventions are beneficial for a number of outcomes other than ADHD symptom reduction. Improving the parent-child relationship may have indirect benefits for disruptive behaviour. Furthermore, parenting behaviours may directly benefit child neuropsychological, academic and social functioning. Parenting interventions can have therapeutic benefits for parents as well as children, which is important as parent and child well-being is likely to have a transactional relationship. Evaluation of the clinical success of parenting interventions should focus on a wider range of outcomes in order to aid understanding of the multifaceted benefits that they may be able to offer. Parenting interventions should not be seen as a redundant adjunct to medication in multi-modal treatment approaches for ADHD; they have the potential to target outcomes that, at present, medication seems less able to improve.