A Preliminary Study of Motor Problems in Children with Attention-Deficit/Hyperactivity Disorder

Source Localization of Somatosensory Neural Generators in Adults with Attention-Deficit/Hyperactivity Disorder

Attention-Deficit/Hyperactivity Disorder (ADHD) is a neurodevelopmental disorder, where differences are often present relating to the performance of motor skills. Our previous work elucidated unique event-related potential patterns of neural activity in those with ADHD when performing visuomotor and force-matching motor paradigms. The purpose of the current study was to identify whether there were unique neural sources related to somatosensory function and motor performance in those with ADHD. Source localization (sLORETA) software identified areas where neural activity differed between those with ADHD and neurotypical controls when performing a visuomotor tracing task and force-matching task. Median nerve somatosensory evoked potentials (SEPs) were elicited, while whole-head electroencephalography (EEG) was performed. sLORETA localized greater neural activity post-FMT in those with ADHD, when compared with their baseline activity (p < 0.05). Specifically, greater activity was exhibited in BA 31, precuneus, parietal lobe (MNI coordinates: X = -5, Y = -75, and Z = 20) at 156 ms post stimulation. No significant differences were found for any other comparisons. Increased activity within BA 31 in those with ADHD at post-FMT measures may reflect increased activation within the default mode network (DMN) or attentional changes, suggesting a unique neural response to the sensory processing of force and proprioceptive afferent input in those with ADHD when performing motor skills. This may have important functional implications for motor tasks dependent on similar proprioceptive afferent input.

Sensorimotor integration and motor learning during a novel force-matching task in young adults with attention-deficit/hyperactivity disorder

Introduction

Attention-Deficit/Hyperactivity Disorder (ADHD) is a neurodevelopmental disorder that exhibits unique neurological and behavioral characteristics. Those with ADHD often have noted impairments in motor performance and coordination, including during tasks that require force modulation. The present study provides insight into the role of altered neural processing and SMI in response to a motor learning paradigm requiring force modulation and proprioception, that previous literature has suggested to be altered in those with ADHD, which can also inform our understanding of the neurophysiology underlying sensorimotor integration (SMI) in the general population.

Methods

Adults with ADHD (n = 15) and neurotypical controls (n = 15) performed a novel force-matching task, where participants used their right-thumb to match a trace template that varied from 2-12% of their Abductor Pollicis Brevis maximum voluntary contraction. This motor task was completed in pre, acquisition, and post blocks. Participants also completed a retention test 24 h later. Median nerve somatosensory-evoked potentials (SEPs) were collected pre and post motor acquisition. SEPs were stimulated at two frequencies, 2.47 Hz and 4.98 Hz, and 1,000 sweeps were recorded using 64-electrode electroencephalography (EEG) at 2,048 Hz. SEP amplitude changes were normalized to each participant's baseline values for that peak.

Results

Both groups improved at post measures (ADHD: 0.85 ± 0.09; Controls: 0.85 ± 0.10), with improvements maintained at retention (ADHD: 0.82 ± 0.11; Controls: 0.82 ± 0.11). The ADHD group had a decreased N18 post-acquisition (0.87 ± 0.48), while the control N18 increased (1.91 ± 1.43). The N30 increased in both groups, with a small increase in the ADHD group (1.03 ± 0.21) and a more pronounced increase in controls (1.15 ± 0.27).

Discussion

Unique neural differences between groups were found after the acquisition of a novel force-matching motor paradigm, particularly relating to the N18 peak. The N18 differences suggest that those with ADHD have reduced olivary-cerebellar-M1 inhibition when learning a novel motor task dependent on force-modulation, potentially due to difficulties integrating the afferent feedback necessary to perform the task. The results of this work provide evidence that young adults with ADHD have altered proprioceptive processing when learning a novel motor task when compared to neurotypical controls.

Sensorimotor integration and motor learning during a novel visuomotor tracing task in young adults with attention-deficit/hyperactivity disorder

Attention-deficit/hyperactivity disorder (ADHD) is a neurodevelopmental disorder that has noted alterations to motor performance and coordination, potentially affecting learning processes and the acquisition of motor skills. This work will provide insight into the role of altered neural processing and sensorimotor integration (SMI) while learning a novel visuomotor task in young adults with ADHD. This work compared adults with ADHD (n = 12) to neurotypical controls (n = 16), using a novel visuomotor tracing task, where participants used their right-thumb to trace a sinusoidal waveform that varied in both frequency and amplitude. This learning paradigm was completed in pre, acquisition, and post blocks, where participants additionally returned and completed a retention and transfer test 24 h later. Right median nerve short latency somatosensory-evoked potentials (SEPs) were collected pre and post motor acquisition. Performance accuracy and variability improved at post and retention measures for both groups for both normalized (P < 0.001) and absolute (P < 0.001) performance scores. N18 SEP: increased in the ADHD group post motor learning and decreased in controls (P < 0.05). N20 SEP: increased in both groups post motor learning (P < 0.01). P25: increased in both groups post motor learning (P < 0.001). N24: increased for both groups at post measures (P < 0.05). N30: decreased in the ADHD group and increased in controls (P < 0.05). These findings suggest that there may be differences in cortico-cerebellar and prefrontal processing in response to novel visuomotor tasks in those with ADHD.NEW & NOTEWORTHY Alterations to somatosensory-evoked potentials (SEPs) were present in young adults with attention-deficit/hyperactivity disorder (ADHD), when compared with neurotypical controls. The N18 and N30 SEP peak had differential changes between groups, suggesting alterations to olivary-cerebellar-M1 processing and SMI in those with ADHD when acquiring a novel visuomotor tracing task. This suggests that short-latency SEPs may be a useful biomarker in the assessment of differential responses to motor acquisition in those with ADHD.

Equine-assisted activities and therapies in children with attention-deficit/hyperactivity disorder: A systematic review

WHAT IS KNOWN ON THE SUBJECT?: Attention-deficit/hyperactivity disorder (ADHD) is characterized by problems of inattention and impulsive hyperactivity in children. Equine-assisted activities and therapies (EAATs) have been used as alternative non-pharmacological intervention option in patients with ADHD. WHAT DOES THIS PAPER ADDS TO EXISTING KNOWLEDGE?: Nowadays, more studies of high methodological quality are needed to determine whether EAAT is an effective intervention for the treatment in children with ADHD. WHAT ARE THE IMPLICATIONS FOR PRACTICE?: Between 15 and 40 min of rising horses, 8-32 total sessions, for 4-32 weeks, seem to be beneficial to reduce the symptoms of ADHD.

ABSTRACT

INTRODUCTION: Attention-deficit/hyperactivity disorder (ADHD) is a disorder characterized by problems of inattention and impulsive hyperactivity. Equine-assisted activities and therapies (EAATs) have become an emerging non-pharmacological intervention option in patients with ADHD.

AIM

To perform a systematic review of updated literature about EAAT in children with ADHD.

METHOD

A systematic review was performed until 28 November 2019, in four electronic databases: PubMed, Web of Science, Embase and Google Scholar. The inclusion criteria were as follows: (a) intervention programme, with pre- and post-data, based on EAAT, (b) children with ADHD and (c) articles written in English.

RESULTS

A total of 9 articles were found that meet the inclusion criteria. The evidence level was C for 7 studies and B for 2 studies. The level of conclusion was 3.

DISCUSSION

There are few studies with high methodological quality, and there is a high heterogeneity in the variables included, what make that the level of evidence and conclusion are low.

CONCLUSION

There is no account with enough studies of high methodological quality to determine whether EAAT is an effective intervention for the treatment in children with ADHD.

Movement Patterns in Students Diagnosed with ADHD, Objective Measurement in a Natural Learning Environment

Attention deficit hyperactivity disorder is the most common neuropsychological disorder in childhood and adolescence, affecting the basic psychological processes involved in learning, social adaptation and affective adjustment. From previous research, the disorder is linked to problems in different areas of development, with deficiencies in psychological processes leading to the development of the most common characteristics of the disorder such as inattention, excess of activity and lack of inhibitory control. As for the diagnosis, in spite of being a very frequent disorder, there are multiple controversies about which tools are the most suitable for evaluation. One of the most widespread tools in the professional field is behavior inventories such as the Strengths and Difficulties Questionnaires for Parents and Teachers or the ADHD Rating Scale-V. The main disadvantage of these assessment tools is that they do not provide an objective observation. For this reason, there are different studies focused on recording objective measures of the subjects' movement, since hyperkinesia is one of the most characteristic symptoms of this disorder. In this sense, we have developed an application that, using a Kinect device, is capable of measuring the movement of the different parts of the body of up to six subjects in the classroom, being a natural context for the student. The main objective of this work is twofold, on the one hand, to investigate whether there are correlations between excessive movement and high scores in the inventories for the diagnosis of ADHD, Rating Scale-V and Strengths and Difficulties Questionnaire (SDQ) and, on the other hand, to determine which sections of the body present the most significant mobility in subjects diagnosed with ADHD. Results show that the control group, composed of neurotypical subjects, presents less kinaesthetic activity than the clinical group diagnosed with ADHD. This indicates that the experimental group presents one of the main characteristics of the disorder. In addition, results also show that practically all the measured body parts present significant differences, being higher in the clinical group, highlighting the head as the joint with the highest effect size.

IQ and Sensory Symptom Severity Best Predict Motor Ability in Children With and Without Autism Spectrum Disorder

Motor challenges are commonly reported in autism spectrum disorder (ASD). Yet, there is substantial heterogeneity in motor ability within ASD, and it is unknown what behavioral characteristics best explain individual differences in motor ability in ASD and related conditions. This observational study examined motor ability as a function of sensory features, attention deficit/hyperactivity symptoms, ASD symptoms, and IQ in 110 children with ASD, typical development, or an intermediate behavioral profile. While motor challenges were more prevalent in the ASD group compared to other groups, sensory symptom severity and IQ across all individuals best predicted motor performance above-and-beyond group status. Therefore, motor challenges may be best characterized by individual variation in sensory features and cognitive abilities rather than diagnostic group.

Attention-deficit hyperactivity disorder: Knowledge and perception of dental care providers at Ajman

Aim:

This study aimed to improve our understanding regarding attention-deficit hyperactivity disorder (ADHD) awareness among dental care providers of Ajman University (AU), and also to identify factors that are highly associated with an increased awareness toward ADHD.

Materials and Methods:

This is a cross-sectional survey study designed and carried out among convenience sample of dental care providers. The survey was carried out by using a self-administrated questionnaire. The questionnaire was composed into demographic, socioeconomic, and ADHD information.

Results:

The study shows low level of awareness toward ADHD. Moreover, participants who provided treatment for a patient with ADHD were found to show higher degree of awareness toward ADHD.

Discussion:

The existing results will be used in developing a well-planned program and clear polices to increase the level of awareness regarding ADHD.

Oral health of children and adolescents with or without attention deficit hyperactivity disorder (ADHD) living in residential care in rural Rhineland-Palatinate, Germany

Background

Attention deficit hyperactivity disorder (ADHD) is defined as childhood neurobehavioural disorder. Due to short attention span, oral hygiene and dental treatment of such individuals can be challenging. Aim of this study was to evaluate the oral health of children and adolescents with and without ADHD living in residential care in rural Rhineland-Palatinate, Germany.

Methods

Included in the study were 79 participants (male/female:58/21, age 9–15 years) living in residential care: 34 participants with ADHD and 45 participants without ADHD (control). Oral examination included the following parameters decayed, missing, filled teeth in the primary dentition (dmft), decayed, missing, filled surfaces/teeth in the secondary dentition (DMFS/DMFT), approximal plaque index (API), bruxism and orthodontic treatment. Additionally, oral hygiene, last dental visit and treatment performed, and dietary habits were assessed by questionnaire.

Results

There were no significant differences in dmft, API, bruxism and oral hygiene habits between groups. However, participants with ADHD tended to have higher DMFS/DMFT values than the control group. Ongoing orthodontic treatment was found more often in the control group. The ADHD group tended to consume acidic/sugary beverages and sweet snacks more often than the controls. Different treatments (control visit/prophylaxis, dental therapy, orthodontic treatment) were performed at the last dental visit in the two groups.

Conclusions

Within the limitations of this study, oral health was similar in children and adolescents with or without ADHD from the same residential care setting. Parents/guardians need instructions for better supervision of oral hygiene and dietary habits to improve the poor oral health of children with or without ADHD.

Dissociation of impulsivity and aggression in mice deficient for the ADHD risk gene Adgrl3: Evidence for dopamine transporter dysregulation

Adhesion G protein-coupled receptor L3 (ADGRL3, LPHN3) has putative roles in neuronal migration and synapse function. Various polymorphisms in ADGRL3 have been linked with an increased risk of attention deficit/hyperactivity disorder (ADHD). In this study, we examined the characteristics of Adgrl3-deficient mice in multiple behavioural domains related to ADHD: locomotive activity, impulsivity, gait, visuospatial and recognition memory, sociability, anxiety-like behaviour and aggression. Additionally, we investigated the effect of Adgrl3-depletion at the transcriptomic level by RNA-sequencing three ADHD-relevant brain regions: prefrontal cortex (PFC), hippocampus and striatum. Adgrl3^-/- mice show increased locomotive activity across all tests and subtle gait abnormalities. These mice also show impairments across spatial memory and learning domains, alongside increased levels of impulsivity and sociability with decreased aggression. However, these alterations were absent in Adgrl3^+/- mice. Across all brain regions tested, the numbers of genes found to exhibit differential expression was relatively small, indicating a specific pathway of action, rather than a broad neurobiological perturbation. Gene-set analysis of differential expression in the PFC detected a number of ADHD-relevant pathways including dopaminergic synapses as well as cocaine and amphetamine addiction. The Slc6a3 gene coding for the dopamine transporter was the most dysregulated gene in the PFC. Unexpectedly, several neurohormone/peptides which are typically only expressed in the hypothamalus were found to be dysregulated in the striatum. Our study further validates Adgrl3 constitutive knockout mice as an experimental model of ADHD while providing neuroanatomical targets for future studies involving ADGRL3 modified models. This article is part of the Special Issue entitled 'Current status of the neurobiology of aggression and impulsivity'.

Dental caries in schoolchildren: influence of inattention, hyperactivity and executive functions

Attention-deficit/hyperactivity disorder (ADHD) is characterized by inappropriate levels of hyperactivity, impulsivity, and/or inattention. Individuals with ADHD may present limitations with regard to executive functions and performing activities that involve planning and/or attention/concentration. The aim of the study was to investigate the association between dental caries and signs of ADHD in a representative sample of schoolchildren. A representative sample of 851 schoolchildren aged seven to 12 years was randomly selected from public and private schools. Data acquisition involved a clinical dental examination for cavitated permanent and deciduous teeth using the DMFT/dmft indices. Neuropsychological evaluations, including the assessment of intelligence (Raven's Colored Progressive Matrix Test) and executive functions (Corsi Tapping Blocks tests and Digit Span test) were also performed. Parents/caregivers and teachers answered the SNAP-IV Questionnaire for the investigation of signs of inattention and hyperactivity in the family and school environment. Parents/caregivers also answered questionnaires addressing socioeconomic and socio-demographic characteristics. Descriptive analysis of the variables and Poisson regression with robust variance were performed. Parental reports of signs of inattention (PR: 1.28; p < 0.05) and hyperactivity (PR: 1.15; p < 0.05) were associated with a greater occurrence of caries. A better performance on the backward order of the Corsi Tapping Blocks tests (PR: 0.94; p < 0.05) and higher level of mother's schooling were associated with a lower frequency of caries. A better performance on executive function tasks was a protective factor against dental caries, whereas children considered inattentive and/or hyperactive by their parents had a higher prevalence rate of dental caries.

Do Signs of Attention-Deficit/Hyperactivity Disorder Increase the Odds of Dental Caries? A Case-Control Study

Attention-deficit/hyperactivity disorder (ADHD) is a behavioural disorder that can affect one’s performance in activities of daily living and can exert a negative impact on the oral health of children. Objective: The aim of this work was to determine the association between ADHD (signs and executive functions) and dental caries in children aged 7–12 years. Methods: A case-control study was conducted with 532 children in the city of Diamantina, Brazil. The case group was composed of children with caries and the control group was composed of children without caries. The children were submitted to a clinical oral examination for the determination of caries and neuropsychological evaluations of intellectual function and executive function. Other signs of attention deficit and hyperactivity were investigated using the Swanson, Nolan, and Pelham scale administered to parents/guardians and teachers. Socioeconomic and demographic characteristics were also evaluated. Statistical analysis involved the McNemar χ2 test and conditional logistic regression. Results: The multivariate logistic regression model demonstrated that monthly household income and parental reports of signs of attention deficit were significantly associated with the occurrence of dental caries. Conclusion: Children considered by their parents/guardians to have attention deficit have a greater chance of exhibiting dental caries, independently of household income.

Increased Anterior Pelvic Angle Characterizes the Gait of Children with Attention Deficit/Hyperactivity Disorder (ADHD)

Background

Children with attention deficit/hyperactivity disorder (ADHD) frequently have motor problems. Previous studies have reported that the characteristic gait in children with ADHD is immature and that subjects demonstrate higher levels of variability in gait characteristics for the lower extremities than healthy controls. However, little is known about body movement during gait in children with ADHD. The purpose of this study was to identify the characteristic body movements associated with ADHD symptoms in children with ADHD.

Methods

Using a three-dimensional motion analysis system, we compared gait variables in boys with ADHD (n = 19; mean age, 9.58 years) and boys with typical development (TD) (n = 21; mean age, 10.71 years) to determine the specific gait characteristics related to ADHD symptoms. We assessed spatiotemporal gait variables (i.e. speed, stride length, and cadence), and kinematic gait variables (i.e. angle of pelvis, hip, knee, and ankle) to measure body movement when walking at a self-selected pace.

Results

In comparison with the TD group, the ADHD group demonstrated significantly higher values in cadence (t = 3.33, p = 0.002) and anterior pelvic angle (t = 3.08, p = 0.004). In multiple regression analysis, anterior pelvic angle was associated with the ADHD rating scale hyperactive/impulsive scores (β = 0.62, t = 2.58, p = 0.025), but not other psychiatric symptoms in the ADHD group.

Conclusions

Our results suggest that anterior pelvic angle represents a specific gait variable related to ADHD symptoms. Our kinematic findings could have potential implications for evaluating the body movement in boys with ADHD.

What is the evidence of impaired motor skills and motor control among children with attention deficit hyperactivity disorder (ADHD)? Systematic review of the literature

This article presents a review of the studies that have analysed the motor skills of ADHD children without medication and the influence of medication on their motor skills. The following two questions guided the study: What is the evidence of impairment of motor skills and aspects of motor control among children with ADHD aged between 6 and 16 years? What are the effects of ADHD medication on motor skills and motor control? The following keywords were introduced in the main databases: attention disorder and/or ADHD, motor skills and/or handwriting, children, medication. Of the 45 articles retrieved, 30 described motor skills of children with ADHD and 15 articles analysed the influence of ADHD medication on motor skills and motor control. More than half of the children with ADHD have difficulties with gross and fine motor skills. The children with ADHD inattentive subtype seem to present more impairment of fine motor skills, slow reaction time, and online motor control during complex tasks. The proportion of children with ADHD who improved their motor skills to the normal range by using medication varied from 28% to 67% between studies. The children who still show motor deficit while on medication might meet the diagnostic criteria of developmental coordination disorder (DCD). It is important to assess motor skills among children with ADHD because of the risk of reduced participation in activities of daily living that require motor coordination and attention.

The effect of a skipped dose (placebo) of methylphenidate on the learning and retention of a motor skill in adolescents with Attention Deficit Hyperactivity Disorder

Individuals with Attention Deficit Hyperactivity Disorder (ADHD) have difficulties in achieving optimal performance in many everyday and academic tasks, deficits attributed to impaired skill acquisition and procedural memory consolidation. We tested the effect of a skipped dose of methylphenidate (MPH) on learning a movement sequence and its subsequent consolidation into procedural memory in adolescents with ADHD. A crossover double-blind design with placebo was used. Sixteen male adolescents, 16-18 years-old, with ADHD and taking MPH formulations on a daily basis, were trained on performing a 5-element sequence of finger-to-thumb opposition movements. Participants took part in two study conditions, 2 months apart. In each condition a different movement sequence was trained and tested. Participants trained on the task either with active medication or placebo on the day of training, crossed-over between study conditions. Learning effects, speed and accuracy, were assessed within-session, during a 24-h memory consolidation phase. Retention was tested by 2 weeks post-training. There were robust gains in performance both within-session and during the 24-h consolidation phase, in both conditions. However, the discontinuation of MPH on the day of training significantly reduced performance speed, with no loss of accuracy. By 2 weeks, post-training performance was comparable. Adolescents with ADHD who are treated daily but skip a dose of MPH show significant slowing of performance relative to their own performance on medication. However, on a background of daily treatment a skipped dose has no deleterious effect on memory consolidation and retention.

Motor skills in Czech children with attention-deficit/hyperactivity disorder and their neurotypical counterparts

Attention-deficit/hyperactivity disorder (ADHD) is the most commonly diagnosed neurobehavioural disorder. Characterized by recurring problems with impulsiveness and inattention in combination with hyperactivity, motor impairments have also been well documented in the literature. The aim of this study was to compare the fine and gross motor skills of male and female children with ADHD and their neurotypical counterparts within seven skill assessments. This included three fine motor tasks: (1) spiral tracing, (2) dot filling, (3) tweezers and beads; and four gross motor tasks: (1) twistbox, (2) foot tapping, (3) small plate finger tapping, and (4) large plate finger tapping. It was hypothesized that children with ADHD would display poorer motor skills in comparison to neurotypical controls in both fine and gross motor assessments. However, statistically significant differences between the groups only emerged in four of the seven tasks (spiral tracing, dot filling, tweezers and beads and foot tapping). In line with previous findings, the complexity underlying upper limb tasks solidified the divide in performance between children with ADHD and their neurotypical counterparts. In light of similar research, impairments in lower limb motor skill were also observed. Future research is required to further delineate trends in motor difficulties in ADHD, while further investigating the underlying mechanisms of impairment.

Sensory and motor secondary symptoms as indicators of brain vulnerability

In addition to the primary symptoms that distinguish one disorder from the next, clinicians have identified, yet largely overlooked, another set of symptoms that appear across many disorders, termed secondary symptoms. In the emerging era of systems neuroscience, which highlights that many disorders share common deficits in global network features, the nonspecific nature of secondary symptoms should attract attention. Herein we provide a scholarly review of the literature on a subset of secondary symptoms––sensory and motor. We demonstrate that their pattern of appearance––across a wide range of psychopathologies, much before the full-blown disorder appears, and in healthy individuals who display a variety of negative symptoms––resembles the pattern of appearance of network abnormalities. We propose that sensory and motor secondary symptoms can be important indicators of underlying network aberrations and thus of vulnerable brain states putting individuals at risk for psychopathology following extreme circumstances.

WISC-IV profiles are associated with differences in symptomatology and outcome in children with ADHD

OBJECTIVE

The current study investigated the Wechsler Intelligence Scale for Children-Fourth Edition (WISC-IV) cluster profiles of children with ADHD to examine the association between IQ profiles and diagnostic frequency, symptomatology, and outcome in this population.

METHOD

Hierarchical cluster analysis was conducted on 189 children with a diagnosis of ADHD-inattentive (ADHD-I) and ADHD-combined (ADHD-C) subtypes. Clusters were then compared across symptom rating scale factor scores, behavioral rating scales, and achievement scores.

RESULTS

A five-cluster solution was extracted. One cluster was identified to have reduced processing speed relative to other WISC-IV indexes and significantly higher ratings of inattention and incidence of ADHD-I diagnosis. A second cluster had impairments in processing speed and working memory and was associated with impaired behavioral functioning.

CONCLUSION

Findings support a relationship between reduced processing speed and inattention and provide evidence that WISC-IV profiles may be helpful in predicting symptomatology and outcome in children with ADHD.

Kognitive Basisfunktionen und motorisch-koordinative Kompetenzen in Abhängigkeit des Peerstatus bei Kindern zu Beginn der Schulzeit

Zusammenfassung. In der vorliegenden Studie wird der Frage nachgegangen, ob sich zwischen beliebten, durchschnittlichen, unbeachteten und zurückgewiesenen Kindern Unterschiede in spezifischen kognitiven und motorischen Fähigkeiten finden lassen. Zu drei verschiedenen Zeitpunkten wurden mit 177 regulär eingeschulten 7-jährigen Kindern Peernominationen und Peerratings erhoben, um reliable soziometrische Daten zu erhalten und ein Vergleich der beiden Methoden vorzunehmen. Außerdem wurde eine umfassende Testbatterie von insgesamt 20 Aufgaben in den Bereichen Informationsverarbeitungsgeschwindigkeit, Kurzzeit- und Arbeitsgedächtnis, Inhibition, Sprache und Motorik durchgeführt. Mit Ausnahme der Kurzzeitgedächtniskapazität wurden für alle Funktionsbereiche signifikante Unterschiede zwischen den Statusgruppen gefunden. Die kontinuierlichen soziometrischen Werte der Ratingmethode zeigten sich etwas sensitiver als die der Nominationsmethode. Korrelativ wurde mit beiden Methoden ersichtlich, dass bessere Leistungen im kognitiven und motorischen Bereich nicht nur mit mehr Beliebtheit zusammenhingen, sondern auch, dass schlechte Leistungen in Verbindung standen mit sozialer Zurückweisung.

Atypical acquisition and atypical expression of memory consolidation gains in a motor skill in young female adults with ADHD

Individuals with ADHD often show performance deficits in motor tasks. It is not clear, however, whether this reflects less effective acquisition of skill (procedural knowledge), or deficient consolidation into long-term memory, in ADHD. The aim of the study was to compare the acquisition of skilled motor performance, the expression of delayed--consolidation phase--gains and retention, in persons with and without ADHD. Thirty-two participants, 16 with ADHD, were trained on a sequence of finger movements using a well-established training protocol, and tested before training and immediately, 24h and 2 weeks after training. Both groups showed similar within-session gains in speed; additional, delayed gains were expressed at 24h, but less robustly in ADHD, and at 2 weeks post-training. However, while controls showed significant delayed gains in accuracy at 24h and 2 weeks post-training, accuracy deteriorated in ADHD from pre-training to 24h post-training and was only at pre-training levels by 2-weeks post-training. Our results demonstrate a latent memory consolidation phase in motor sequence learning, expressed as delayed gains in speed and a much delayed recovery of pre-training accuracy, in individuals with ADHD. However, both the acquisition and memory consolidation of motor skills are atypical in ADHD.

Effects of dyslexia on postural control in adults

Dyslexia has been shown to affect postural control. The aim of the present study was to investigate the difference in postural stability measured as torque variance in an adult dyslexic group (n=14, determined using the Adult Dyslexia Checklist (ADCL) and nonsense word repetition test) and an adult non-dyslexic group (n=39) on a firm surface and on a foam block and with eyes open and eyes closed. Another aim was to investigate the correlation between ADCL scores and postural stability. Findings showed that ADCL scores correlated with torque variance in the anteroposterior direction on foam with eyes closed (p=0.001) and in the lateral direction on the foam surface with eyes closed (p=0.040) and open (p=0.010). General Linear Model analysis showed that high dyslexia scores were associated with increased torque variance (p<0.001). However, we found no significant difference between dyslexics and non-dyslexics, though there were indications of larger torque variance in the dyslexics. The findings suggest that adults with high dyslexic ADCL scores may experience sub-clinical balance deficits. Hence, assessing motor ability and postural control in those with high ADCL scores is motivated.

Inhibition, reinforcement sensitivity and temporal information processing in ADHD and ADHD+ODD: evidence of a separate entity?

This study compared children with ADHD-only, ADHD+ODD and normal controls (age 8–12) on three key neurocognitive functions: response inhibition, reinforcement sensitivity, and temporal information processing. The goal was twofold: (a) to investigate neurocognitive impairments in children with ADHD-only and children with ADHD+ODD, and (b) to test whether ADHD+ODD is a more severe from of ADHD in terms of neurocognitive performance. In Experiment 1, inhibition abilities were measured using the Stop Task. In Experiment 2, reinforcement sensitivity and temporal information processing abilities were measured using a Timing Task with both a reward and penalty condition. Compared to controls, children with ADHD-only demonstrated impaired inhibitory control, showed more time underestimations, and showed performance deterioration in the face of reward and penalty. Children with ADHD+ODD performed in-between children with ADHD-only and controls in terms of inhibitory controls and the tendency to underestimate time, but were more impaired than controls and children with ADHD-only in terms of timing variability. In the face of reward and penalty children with ADHD+ODD improved their performance compared to a neutral condition, in contrast to children with ADHD-only. In the face of reward, the performance improvement in the ADHD+ODD group was disproportionally larger than that of controls. Taken together the findings suggest that, in terms of neurocognitive functioning, comorbid ADHD+ODD is a substantial different entity than ADHD-only.

Timing of conditioned eyeblink responses is impaired in children with attention-deficit/hyperactivity disorder

Structural changes of the cerebellum have been reported in several psychiatric diseases like schizophrenia, autism and attention-deficit/hyperactivity disorder (ADHD). Beside behavioral deficits children with ADHD often show slight motor abnormalities. Cerebellar malfunction may contribute. The cerebellum is a structure essential for motor coordination, various forms of motor learning and timing of motor responses. In the present study, eyeblink conditioning was applied to investigate learning and timing of motor responses both in children with ADHD and children with cerebellar lesions. Acquisition, timing and extinction of conditioned eyeblink responses were investigated in children with ADHD, children with chronic surgical cerebellar lesions and controls using a standard delay paradigm with two different interstimulus intervals. Timing of conditioned eyeblink responses was significantly impaired in children with ADHD in the long interstimulus interval condition. Also in children with cerebellar lesions conditioned responses (CR) tended to occur earlier than in controls. Incidences of CRs were significantly reduced in children with cerebellar lesions and tended to be less in children with ADHD than in controls. Extinction of the CRs was impaired in children with cerebellar lesions in both interstimulus interval conditions and in children with ADHD in the long interstimulus interval condition. Cerebellar malfunction may contribute to disordered eyeblink conditioning in ADHD. However, because CR abnormalities differed between ADHD and cerebellar subjects, dysfunction of non-cerebellar structures cannot be excluded.

Incidental and intentional sequence learning in youth-onset psychosis and Attention-Deficit/Hyperactivity Disorder (ADHD)

The goal was to compare incidental and intentional spatial sequence learning in youth-onset psychosis and ADHD. The authors tested 8- to 19-year-olds with psychosis or ADHD and healthy controls on a serial reaction time (RT) task and used manual and oculomotor measures to examine learning. Participants were also administered a block in which they were explicitly instructed to learn a sequence. As in our previous studies with healthy adults and children, oculomotor anticipations and RTs showed learning effects similar to those in the manual modality. Results showed intact sequence-specific learning but fewer oculomotor anticipations in both clinical groups during incidental learning. In intentional learning, only the psychosis group showed impairments compared to controls. There were no interactions between age and diagnosis. Thus, the psychosis group showed relatively preserved incidental learning despite impairments in intentional learning. Additionally, both clinical groups showed impairments in the ability to search for, extract, and anticipate regularities (whether the regularities were there or not), but not in the ability to respond to these regularities when they were there.

Postural and gait performance in children with attention deficit/hyperactivity disorder

Up to 50% of children and adolescents with attention deficit/hyperactivity disorder (ADHD) exhibit motor abnormalities including altered balance. Results from brain imaging studies indicate that these balance deficits could be of cerebellar origin as ADHD children may show atrophy in those regions of the cerebellum associated with gait and balance control. To address this question, this study investigated postural and gait abilities in ADHD children and compared their static and dynamic balance with children with known lesions in the cerebellum. Children diagnosed with ADHD according to DSM IV-TR diagnostic criteria were compared with children with chronic surgical cerebellar lesions and age-matched controls. A movement coordination test was used to assess differences in motor development. Postural and gait abilities were assessed using posturography, treadmill walking and a paced stepping task. Volumes of the cerebellum and the cerebrum were assessed on the basis of 3D magnetic resonance images (MRI). Children with cerebellar lesions showed significant performance decrements in all tasks compared with the controls, particularly in the movement coordination test and paced stepping task. During dynamic posturography ADHD-participants showed mild balance problems which correlated with findings in cerebellar children. ADHD children showed abnormalities in a backward walking task and minor abnormalities in the paced stepping test. They did not differ in treadmill walking from the controls. These findings support the notion that cerebellar dysfunction may contribute to the postural deficits seen in ADHD children. However, the observed abnormalities were minor. It needs to be examined whether balance problems become more pronounced in ADHD children exhibiting more prominent signs of clumsiness.

Learning, attention, writing, and processing speed in typical children and children with ADHD, autism, anxiety, depression, and oppositional-defiant disorder

Learning, attention, graphomotor, and processing speed scores were analyzed in 149 typical control children and 886 clinical children with normal intelligence. Nonsignificant differences were found between control children and children with anxiety, depression, and oppositional-defiant disorder. Control children performed better than children with ADHD and autism in all areas. Children with ADHD and autism did not differ, except that children with ADHD had greater learning problems. Attention, graphomotor, and speed weaknesses were likely to coexist, the majority of children with autism and ADHD had weaknesses in all three areas, and these scores contributed significantly to the prediction of academic achievement.

Modulation of response timing in ADHD, effects of reinforcement valence and magnitude

The present study investigated the impact of reinforcement valence and magnitude on response timing in children with ADHD. Children were required to estimate a 1-s interval, and both the median response time (response tendency) and the intrasubject-variability (response stability) were investigated. In addition, heart rate and skin conductance were measured to examine the autonomic responses to reinforcement. Feedback-only trials were compared to low response cost trials (response cost for incorrect responses), low reward trials (reward for correct responses), high response cost and high reward trials. In feedback-only trials, children with ADHD underestimated more severely the interval and responded more variably than controls. Children with ADHD, unlike controls, were unaffected by the reinforcement conditions in terms of time underestimations. The variability of responding, on the other hand, decreased under conditions of reinforcement to a larger extent in children with ADHD than controls. There were no indications that children with ADHD were abnormally affected by the valence or magnitude of reinforcement. Furthermore, skin conductance responses increased when feedback was coupled with reinforcement, an effect which was larger in children with ADHD than controls. This could be interpreted as demonstrating that children with ADHD suffer from a diminished awareness of the significance of feedback in the feedback-only condition. The current study suggests that children with ADHD suffer from motivation problems when reinforcement was not available, at least when variability in responding was measured. Underestimations of time may reflect more stable deficits in ADHD.

Outcomes of infants with idiopathic hypotonia

PURPOSE

To describe the outcomes of children diagnosed before the age of two with idiopathic hypotonia.

METHODS

A total of 105 parents of children who were diagnosed with hypotonia returned a questionnaire. Medical records were reviewed.

RESULTS

A transient impairment group (10.5%) reported no problems. A minimal impairment group (32.4%) had mild problems such as learning disability or language delay but no major developmental diagnosis. A globally impaired group (40.9%) had mental retardation or a recognizable genetic/developmental diagnosis. More than 50% of the minimal impairment group had poor coordination, language delay, and learning difficulties. The mean walking age (minimal group) was 22 months. Initial fine motor and cognitive, but not gross motor, developmental quotients were significantly greater in the minimal compared with global impairment group.

CONCLUSION

Deficits in motor coordination, language, and learning difficulties were common problems that persisted in the minimal and global impairment groups.

Perceptuomotor functioning in preschool children with symptoms of attention deficit hyperactivity disorder

Given limited research on perceptual-motor functioning of preschool children with symptoms of ADHD, the purpose of this study was to compare the fine motor, gross motor, visuomotor, and oral-motor functioning of 49 4- to 6-yr.-old children with symptoms of Attention Deficit Hyperactivity Disorder and 48 typically developing children. Analysis showed scores of the ADHD group were significantly lower than those of the control group on all perceptuomotor measures. In addition, scores on all measures yielded significant correlations with scores on the Hyperactive-Inattentive scale of the Preschool Behavior Questionnaire. Regression analyses indicated that the scores of gross motor and visuomotor functioning were significant predictors of group classification (with and without ADHD). These findings extend the well documented findings of perceptuomotor deficits among school-age children with ADHD into the preschool period and emphasize the importance of early assessment and treatment of these deficits in young children with symptoms of ADHD.

WISC-IV and WISC-III profiles in children with ADHD

Wechsler Intelligence Scale for Children, 3rd and 4th editions (WISC-III n = 586 and WISC-IV n = 118), profiles were compared for children with ADHD and normal intelligence. Mean Verbal Comprehension Index (VCI) and Perceptual Organization/Perceptual Reasoning Index (POI/PRI) scores were significantly higher than Freedom From Distractibility/Working Memory Index (FDI/WMI) and Processing Speed Index (PSI), and Symbol Search was higher than Coding. FDI/WMI and PSI scores were similar on both tests, but VCI and POI/PRI were higher on the WISC-IV than on the WISC-III. Therefore, index discrepancies were greater for the WISC-IV, suggesting that the WISC-IV might be better than the WISC-III in delineating the strengths and weaknesses of children with ADHD. All children in the WISC-IV sample scored lowest on WMI or PSI, whereas only 88% of the WISC-III children scored lowest on FDI or PSI. Thus, the WISC-IV may be more helpful in diagnosing ADHD than the WISC-III.

ADHD and DCD: A relationship in need of research

Although the connection between attention deficit hyperactivity disorder (ADHD) and developmental coordination disorder (DCD) has been recognized for several decades, little research has examined the relationship between these two disorders. This paper draws attention to the contribution the cognitive-energetic model (CEM) can make in determining the specific nature of these two disorders. An information processing approach such as the CEM is a useful model to identify specific and overlapping mechanisms that are disrupted in these two disorders. This paper describes the CEM and reviews the research so-far in relation to the model. The CEM has several advantages over other models: First, it predicts which task variables will be independent or may interact, thus enabling the investigator to determine the success/failure of the task manipulation(s) and identify spurious findings. Second, the CEM links energetic factors to task variables and predicts both additive and interactive effects. Third, the CEM enables executive processes such as selective attention, working memory and inhibition to be related to both energetic and lower level processes. Fourth, by employing the CEM in clinical research, taxonomy of deficits can be derived enabling further insight into the nature of the disorders and their specific neuropsychological dysfunction. Suggestions are made for future research into the neuropsychological deficits associated with ADHD and DCD.

Relationship between traumatic dental injuries and attention-deficit/hyperactivity disorder in children and adolescents: proposal of an explanatory model

The objective of the present study was to determine the association between attention-deficit/hyperactivity disorder (ADHD) and traumatic dental injuries in a child psychiatric clinical population in Istanbul. A total of 475 consecutive children aged 8-17 years were enrolled in the study. Children and their parents were interviewed about the presence of traumatic dental injury and if a positive response was obtained further questions were inquired regarding the time and cause of the injury, and whether treatment had been sought. Child psychiatric diagnosis was based on Diagnostic and Statistical Manual of Mental Disorders, 4th edition (DSM-IV) criteria. Of the 475 children, 32 reported a traumatic dental injury (6.7%) with statistically significant association with ADHD (chi(2) = 26.90, d.f. = 1, P = 0.0001; odds ratio = 17.41, 95% CI: 4.11-73.55). On the Conners Teacher Report Questionnaire, children with dental trauma group differed significantly from the non-ADHD group but not from the ADHD group (F = 17.02, d.f. = 2, P = 0.0001). Among children with ADHD and dental fracture, the most common subtype was combined ADHD (90%). This is the first study describing a significant association between dental fractures and ADHD which contributes to an explanatory model on dental traumas among children. According to us, awareness of this association is essential at child psychiatry and pediatric dentistry settings and we recommend preventive efforts to be directed at the treatment of ADHD.

Oculomotor inhibition in children with and without attention-deficit hyperactivity disorder (ADHD)

The aim of the present study was to distinguish between a general deficit in oculomotor control and a deficit restricted to inhibitory functions in children with attention deficit hyperactivity disorder (ADHD). In addition, we were interested in differentiating between a general inhibition deficit and deficient subfunctions of inhibition. We used a prosaccade task to measure general oculomotor abilities in 22 children with ADHD and in age- and gender-matched healthy controls. A fixation, an antisaccade and a countermanding saccade task were used to measure specific aspects of oculomotor inhibition. Two major results were obtained: First, our prosaccade task suggests similar saccadic response preparation and saccadic accuracy in the ADHD compared to the control children. Secondly, the fixation and the countermanding saccade task indicate deficits on measures of oculomotor inhibition in the ADHD group. While patients were specifically impaired in stopping an already initiated response or in suppressing exploratory saccades in a novel situation, inhibition of a prepotent response was not deficient. Our data thus indicate an underlying impairment in cognitive inhibition in ADHD that has been associated with prefrontal lobe functions. More specifically, as the anterior cingulate gyrus has been associated with the countermanding saccade task and group differences were most pronounced in this paradigm our data are in line with imaging data stressing the importance of this cortical structure in the pathophysiology of ADHD.

Modeling attention-deficit/hyperactivity disorder: a critical appraisal of the cognitive-energetic model

A number of theoretical models of attention-deficit/hyperactivity disorder (ADHD) have emerged in recent years that may be used as systematic guides for clinical research. The cognitive-energetic model (CEM) proposes that the overall efficiency of information processing is determined by the interplay of three levels: computational mechanisms of attention, state factors, and management/executive function (EF). The CEM encompasses both top-down and bottom-up processes and draws attention to the fact that ADHD causes defects at all three levels. These include cognitive mechanisms, such as response output; energetic mechanisms, such as activation and effort; and management/EF deficits. Increasing evidence suggests that inhibition deficits associated with ADHD may, at least in part, be explained in terms of an energetic dysfunction. The activation and effort energetic pools appear most relevant to ADHD, being directly related to response organization; however, further testing of CEM is critically dependent on the development of direct measures of these energetic pools. The CEM is a comprehensive model of ADHD but is not without limitations. In particular, further research is required to define more specifically the relationship between process dysfunction and state dysregulation in ADHD.

Motivational effects on motor timing in attention-deficit/hyperactivity disorder

OBJECTIVE

This study was designed to clarify whether poor performance of children with attention-deficit/hyperactivity disorder (ADHD) on motor timing tasks reflects a true deficit in the temporal organization of motor output or is due to a lack of intrinsic motivation.

METHOD

Eighteen children with ADHD (age 8-12) were compared with 18 age- and gender-matched normal controls with respect to timing precision, timing variability, and the frequency of extreme under- and overestimations during a 1-second interval production task. Monetary reward, response cost, and no reward were implemented to manipulate motivation.

RESULTS

Children with ADHD produced significantly more inaccurate and more variable time intervals and exhibited a larger number of extreme over- and underestimations than control children. Although all children performed significantly better when monetary incentives were applied, group differences were not eliminated.

CONCLUSIONS

In this study, no evidence was found for a motivational deficit as an explanation for impaired performance on a time production task in ADHD. Rather, results provide clear support for a generic motor timing deficit, probably due to a dysfunctional frontostriatocerebellar network involved in temporal aspects of motor preparation.