Hélène Poissant

Développement de l'autorégulation et de l'inhibition chez des enfants présentant un trouble déficitaire de l'attention avec ou sans hyperactivité (TDAH)

INTRODUCTION Self-regulation shares several affinities with executive functions. However, the specificity of self-regulation deficits in attention deficit/hyperactivity disorder (ADHD) remains unclear. The typical child starts around the age of four to develop a self-control mechanism along with an internal language that allows the child to modulate impulsively. Conversely, a child with ADHD seems to have greater difficulties delaying or retaining an action or response. OBJECTIVE In this study we aim to evaluate self-regulation of comprehension in ADHD. RESULTS Our results show that children with ADHD fail to recognize inconsistencies in presented stories at a rate ranging between 72 (eight years) and 54% (ten years). We also found a positive correlation between a better control of self-regulation and our behavioral inhibition measurement. The attentional deficits exhibited through markedly longer reaction times to continuous performance test (CPT) could be responsible for a poor ability to self-regulate. Fast reaction times were found to be associated with increased vigilance/attention that in turn would permit better self-regulation. Furthermore, our findings show that older subjects with ADHD have shorter reaction times to CPT approaching this group to the typical children. DISCUSSION This suggests that improvement overtime in self-regulation processes may be attributed to the associated development of vigilance/attention in children with ADHD. Improved vigilance/attention would result in optimal reaction times during tasks that require self-regulation. In addition, our findings suggest that subjects with ADHD have developmental trajectories similar to those observed in healthy subjects. CONCLUSION In the present study, the lack of a comparison group does not allow us to conclude if such trajectory is delayed compared to typical subjects. Finally, there was no significant relation between the degree of intelligence and the rate of self-regulation, which makes it possible to distinguish the two functions. However, in ADHD self-regulation is favourably influenced by age as observed in developmental studies on typical children. Thus, maturation independent of intelligence, influences self-regulation processes.

Neural Correlates of Forethought in ADHD

Objective: The purpose of the present investigation was to delineate the neural correlates of forethought in the ADHD children relative to typically developing (TD) children. Method: In all, 21 TD and 23 ADHD adolescents underwent functional magnetic resonance imaging (fMRI) while performing a forethought task. The participants had to identify congruent and incongruent stimuli from cartoon stories representing sequences of action. Results: The findings revealed significantly greater activation in the bilateral prefrontal cortex (PFC) in TD versus ADHD children, and more activation in the cerebellar vermis in the adolescents with ADHD versus TD, during performance of the incongruent relative to congruent condition. Conclusion: The inverse pattern of activation of the PFC and the cerebellar vermis in both groups could reflect a compensatory role played by the cerebellum or suggest the malfunction of the neural network between those regions in ADHD. Further research of the neural correlates of forethought in ADHD is warranted.

A Verbal Planning Impairment in Adult ADHD Indexed by Script Generation Tasks

Objective: Though juvenile and adult ADHD cases are well known to have a nonverbal planning impairment, a verbal-planning impairment has been demonstrated only in juvenile ADHD. The purpose of this investigation is to determine whether a verbal planning impairment also characterizes adult ADHD. Methods: A cohort of 30 adult ADHD clients of a university psychological clinic are compared to 30 age-, education-, gender-, and IQ-matched persons recruited from the general population who did not have ADHD. The dependent measure is a set of 6 paper/pencil 10-item script generation tasks. Results: The findings reveal that the ADHD cohort was significantly impaired on the script task and the script task correlated significantly with severity of ADHD (CAARS index + WURS), whereas several neuropsychological measures of executive function (Stroop, COWA, Rey’s Complex Figure, D2, CVLT, CPT-II) did not. Findings further showed that the script measure was weakly correlated with the other established neuropsychological measures of executive function (r < .46, shared variance of less than 21%). Conclusions: On the basis of the study findings, it is concluded that verbal planning measured with script generation tasks is distinctly impaired in clinically referred adult ADHD.

Résolution de problèmes, autorégulation et apprentissage

L’objectif principal de cet article consiste a definir ce qu’est un probleme et les diffe- rentes etapes de sa resolution. Nous insisterons aussi sur la composante d’autoregulation inherente au processus de resolution de problemes. Bien que le terme d’autoregulation ait ses origines dans les theories de la metacognition, il peut etre rapproche de l’etape d’evaluation et de surveillance developpee dans le cadre des theories de la resolution de problemes. Cette composante nous parait cruciale puisqu’elle permet une remise en cause constante des actions de l’apprenant. Sa maitrise permet de rendre celui-ci plus autonome a l’egard de ses apprentissages. We argue that problem solving is, in part, self-regulating. Although metacognitive theory may have encouraged this view, autoregulation is, practically speaking, linked to the evaluative state of problem solving. Because it repeatedly encourages learners to review their choices and actions, autoregulation helps them to become autonomous.

Processing of musical structure by high-functioning adolescents with autism spectrum disorders

Enhanced pitch perception and memory have been cited as evidence of a local processing bias in autism spectrum disorders (ASD). This bias is argued to account for enhanced perceptual functioning (Mottron & Burack, 2001; Mottron, Dawson, Soulières, Hubert, & Burack, 2006) and central coherence theories of ASD (Frith, 1989; Happé & Frith, 2006). A local processing bias confers a different cognitive style to individuals with ASD (Happé, 1999), which accounts in part for their good visuospatial and visuoconstructive skills. Here, we present analogues in the auditory domain, audiotemporal or audioconstructive processing, which we assess using a novel experimental task: a musical puzzle. This task evaluates the ability of individuals with ASD to process temporal sequences of musical events as well as various elements of musical structure and thus indexes their ability to employ a global processing style. Musical structures created and replicated by children and adolescents with ASD (10–19 years old) and typically developing children and adolescents (7–17 years old) were found to be similar in global coherence. Presenting a musical template for reference increased accuracy equally for both groups, with performance associated to performance IQ and short-term auditory memory. The overall pattern of performance was similar for both groups; some puzzles were easier than others and this was the case for both groups. Task performance was further found to be correlated with the ability to perceive musical emotions, more so for typically developing participants. Findings are discussed in light of the empathizing-systemizing theory of ASD (Baron-Cohen, 2009) and the importance of describing the strengths of individuals with ASD (Happé, 1999; Heaton, 2009).

Atypical Activations of Fronto-Cerebellar Regions During Forethought in Parents of Children With ADHD

Objective: Although several studies suggest heritability of ADHD, only a few investigations of possible associations between people at risk and neural abnormalities in ADHD exist. In this study, we tested whether parents of children with ADHD would show atypical patterns of cerebral activations during forethought, a feature of working memory. Method: Using Functional Magnetic Resonance Imaging (fMRI), we compared 12 parents of children with ADHD and 9 parents of control children during a forethought task. Results: Parents of children with ADHD exhibited significantly increased neural activations in the posterior lobes of the cerebellum and in the left inferior frontal gyrus, relative to parents of control children. Conclusion: These findings are consistent with previous reports in children and suggest the fronto-cerebellar circuit’s abnormalities during forethought in parents of children with ADHD. Future studies of people at risk of ADHD are needed to fully understand the extent of the fronto-cerebellar heritability.

Forethought in Youth with Attention Deficit/Hyperactivity Disorder: An fMRI Study of Sex-Specific Differences

Objective. The majority of studies investigating neurocognitive processing in attention deficit/hyperactivity disorder (ADHD) have been conducted on male participants. Few studies evaluated females or examined sex differences. Among various cognitive anomalies in ADHD, deficit in forethought seems particularly important as children with ADHD often fail to adequately use previous information in order to prepare for responses. The main goal of this study was to assess sex-specific differences in behavioral and neural correlates of forethought in youth with ADHD. Methods. 21 typically developing (TD) youth and 23 youth with ADHD were asked to judge whether two pictures told a congruent or incongruent story. Reaction time, performance accuracy, and cerebral activations were recorded during functional magnetic resonance imaging (fMRI). Results. Significant sex-specific differences in cerebral activations appeared, despite equivalent performance. Relative to the boys TD participants, boys with ADHD had extensive bilateral frontal and parietal hypoactivations, while girls with ADHD demonstrated more scattered hypoactivations in the right cerebral regions. Conclusion. Present results revealed that youth with ADHD exhibit reduced cerebral activations during forethought. Nevertheless, the pattern of deficits differed between boys and girls, suggesting the use of a different neurocognitive strategy. This emphasizes the importance of including both genders in the investigations of ADHD.

Structural and functional neuroanatomy in attention deficit and hyperactivity disorder (ADHD)

Introduction: This review provides an overview of the main imaging studies that investigated the neurobiological substrate of attention deficit hyperactivity disorder (ADHD) a common and impairing neuropsychiatric disorder with preschool onset. Three subtypes have been proposed: inattentive, hyperactive-impulsive and combined type. Researchers have emphasized poor behavioural inhibition as the central impairment of the disorder. Impairment of the ‘‘hot’’ affective aspects of executive functions like behavioural inhibition and attention and the more cognitive, ‘‘cool’’ aspects of executive functions like self-regulation,workingmemory, planning, cognitive flexibility are often reported by studies on ADHD. The hot executive functions are associated with ventral and medial regions of prefrontal cortex (anterior cingulated cortex) and named hotbrain and the cool executive functions are associated with dorsolateral prefrontal cortex and are called coolbrain. Methods: The paradigms mostly used in functional magnetic resonance imaging (fMRI) are tasks of motor inhibition, interference and attention like the go/no-go, stop-signal and the Stroop. Results from previous studies: Convergent data from neuroimaging, neuropsychological, genetics and neurochemical studies consistently point to the involvement of fronto-striatal circuitry asa likely contributor to thepathophysiologyofADHD.This circuitry involves the lateral prefrontal cortex, the dorsal anterior cingulate cortex, the caudate nucleus and putamen. A growing literature demonstrates abnormalities affecting other cortical regions and the cerebellum. Anatomical studies suggest widespread reductions in volume throughout the cerebrum and cerebellum. Functional imaging studies suggest that affected individuals activate more diffuse areas than controls during the performance of cognitive tasks. Reduction in volume has been observed in the total cerebral volume, theprefrontal cortex, thebasal ganglia (striatum), thedorsal anterior cingulate cortex, the corpus callosum and the cerebellum. Hypoactivation of the dorsal anterior cingulate cortex, the frontal cortex and the basal ganglia (striatum) have also been reported. Discussion: Some guidelines for future functional magnetic imaging studies are suggested.

The Effect of Visual-Motor Imagery Training on CPT Performance in Children with Attention Deficit Hyperactivity Disorder

Attention Deficit Hyperactivity Disorder is a widespread problem that affects many aspects of the academic and social system. The development of techniques aimed at cognitive remediation of attention disorders is one approach to helping deal with the high prevalence of ADHD in school-age children. In order to serve most efficiently students with attention deficits, these techniques should be implemented on an institutional level. We have developed a cognitive training program, the Attention Education Program (AEP), that uses techniques of visual-motor imagery to increase ADHD children’s attention control. In this study we examined the effects of AEP training on elementary school children with ADHD. Thirty children from the Quebec special education system, who were rated as having ADHD, participated in two testing sessions on the Conners CPT with sessions six months apart. Approximately one-half of the subjects received AEP training during the six-month interval between tests, while the other group received no training. AEP training led to improvement on CPT reaction times in ADHD children, and to a reduction in CPT errors in a subgroup of hyperactive subjects. These results suggest potential therapeutic value of cognitive remediation programs implemented in the school system.

Intergenerational transmission of fronto-parietal dysfunction during forethought in attention deficit/hyperactivity disorder: A pilot study

There are only a few published reports of neural abnormalities within the families of children with attention deficit/hyperactivity disorder (ADHD). Functional magnetic resonance imaging was used to compare cerebral activation of ADHD and control biological parent-child dyads during forethought, a prospective function of working memory. Reduced activations in ADHD dyads were found in the inferior frontal gyrus, right superior parietal lobule and left inferior parietal lobule. This suggests that fronto-parietal abnormalities are shared within ADHD families.