Hand preference in attention deficit hyperactivity disorder

In our Outpatient Department, we studied 56 subjects (41 males, 15 females; aged 5-16 yr.) with Attention Deficit Hyperactivity Disorder (ADHD) with respect to hand use in functional tasks via parental report. Left-hand use was markedly preferred, compared to that of a control group, more for complex than simple and for external (touching food and objects) than internal (scratching, rubbing eyes) tasks, suggesting a deficit in cerebral control of right-hand use. More patients were reported to have a left-hand preference than in the non-ADHD population. Furthermore, extent of laterality was greater for complex than simple external tasks and for external than for internal.     

Deficient inhibitory control in attention deficit hyperactivity disorder

The purpose of this study was to examine two executive control processes — response inhibition and re-engagement of responses after inhibition in children with attention deficit hyperactivity disorder (ADHD). Thirty-three children with ADHD and 22 normal control children of similar age (7 to 11 years) and mean IQ (107) were tested with the change paradigm. ADHD subgroups were defined by the context in which the ADHD symptoms predominated (in the home only; at school only; and in both, i.e., pervasive ADHD). Children with marked oppositional defiant or conduct disorder were excluded. Children with ADHD exhibited deficits in inhibitory control and in response re-engagement. Deficits were greatest in pervasive ADHD and, to a lesser extent, in those with ADHD limited to the school context. ADHD limited to the home context showed the least deficit. These results replicate an earlier study that found deficient inhibitory control in pervasive ADHD and demonstrate that the deficit in ADHD involves a second aspect of executive control.We are grateful to Anne Rhodes and Isobelle Williams for their assistance in the conduct of this research. This research was supported by grants from Health and Welfare Canada and the Medical Research Council of Canada. This paper was prepared with the assistance of Medical Publications, The Hospital for Sick Children, Toronto, Ontario.     

Inhibition and attention deficit hyperactivity disorder in adults

The inhibitory account of attention deficit hyperactivity disorder (ADHD) was tested by examining the performance of college-aged adults on a variety of inhibitory tasks. The poorer performance of adults with ADHD compared with controls on negative priming, stopping, and continuous performance tasks, combined with similar group performances on a test of working memory capacity, indicates a specific inhibitory deficit as opposed to a general limitation in attentional capacity. Overall results provide evidence for extending the inhibitory deficit hypothesis to adult ADHD, not only for mechanisms of response (or motor) inhibition but also for mechanisms of cognitive inhibition.     

External validation of oppositional disorder and attention deficit disorder with hyperactivity

Validity of the distinction between oppositional disorder (OD) and attention deficit disorder with hyperactivity (ADDH) was examined in a sample of 6- to 12-year-old boys with behavior problems. Problem identification, cognitive/attentional, family context, and behavioral symptom differences were examined among nine boys with OD only, 20 with ADDH, 40 with comorbid OD and ADDH, and 28 with neither disruptive behavior disorder. Systematic comparisons of groups including and excluding the OD and ADDH diagnoses were undertaken to determine the existence of pure OD and pure ADDH disorder effects. The most consistent result was the lack of evidence for either pure OD or pure ADDH effects. Most of the significant findings reflected differences between the nondisruptive (neither) and comorbid groups. The results support the importance of comorbidity, but they provide little support for disorder-specific distinctions between oppositional and attention deficit disorders.     

On-line story representation in boys with attention deficit hyperactivity disorder

Children with attention deficit hyperactivity disorder (ADHD) face an increased risk of poor achievement in school. Thus, knowledge of the cognitive processing abilities of children with ADHD is critical to understanding and improving their academic performance. Although many studies have focused on the specific nature of the attention deficit experienced by children with ADHD, few have examined higher order cognitive processing such as comprehension of stories. The present study examined the processes of encoding story information, building a story representation, and modifying a story representation in boys with ADHD and nonreferred boys. Boys were asked to narrate a story from a picture book twice. Boys with ADHD showed deficits in representing goals and goal plans in their narrations, as compared to nonreferred boys. Boys with ADHD also committed more errors than nonreferred boys, but did correct certain types of errors on their second telling. Implications are discussed in terms of future research needed to identify the cognitive deficits that account for these narrative deficits.     

Frontal lobe functioning in adolescents with attention deficit hyperactivity disorder

A prominent hypothesis regarding the etiology of attention deficit hyperactivity disorder (ADHD) is that its presence and magnitude reflect frontal lobe dysfunction. Past tests of this hypothesis have been inconsistent. The present study examined frontal lobe functioning in adolescents with ADHD. A sample of 10 ADHD adolescents and 10 controls between the ages of 12 and 17 served as participants for the study. The control group was matched on age (within six months) and gender. This study aided in clarifying past contradictory studies by using clearly defined criteria to determine ADHD, a representative age range of participants, carefully selected tests, and a control task. The two measures that were administered to assess frontal lobe functioning were the Wisconsin Card Sorting Test and the Stroop Color and Word Test. The Purdue Pegboard was used as a control measure that did not assess frontal lobe functioning. The findings indicate that the ADHD group performed significantly worse on the following: color score, color/word score, and interference score of the Stroop Color and Word Test; percent of perseverative responses, percent of perseverative errors, and number of completed categories of the Wisconsin Card Sorting Test. No differences were found on the Purdue Pegboard task.     

Self-paced learning in children with attention deficit disorder with hyperactivity

Attention deficit (ADDH) children self-paced the delivery of response pairs for paired-associate learning at about the rate previously shown to be conducive to relatively good learning in attention deficit. The self-pacing opportunity did not seem either to impair or to enhance the learning performance. On methylphenidate they paced themselves at about the same rate but learned much more. Stimulant therapy does not help by slowing the child down but permits more effective memorizing at the same presentation rate.     

Elevated attention deficit hyperactivity disorder symptoms in children who stutter

PurposeThis study described the proportion of children who stutter who exhibit Attention Deficit Hyperactivity Disorder (ADHD) symptoms, manifesting in inattentive and hyperactive/impulsive behaviours. Children who stutter with these challenging behaviours may not respond as quickly and successfully to stuttering treatment. A preliminary exploration of differences in treatment responsiveness for children with and without ADHD symptoms was undertaken.MethodParticipants were 185 preschool children who stutter who had completed stuttering therapy within 3 months prior to study commencement. Differences between groups of children who stutter with and without elevated ADHD symptoms were investigated, in terms of pre-treatment stuttering features (stuttering severity and typography), demographic variables (age at onset, time between onset and commencement of therapy, family history and sex) and treatment data (post-treatment stuttering severity and number of sessions to achieve discharge criteria).ResultsOne-half (50%) of participants exhibited elevated ADHD symptoms. These children required 25% more clinical intervention time to achieve successful fluency outcomes than children without elevated ADHD symptoms. Findings suggest that more ADHD symptoms, increased pre-treatment stuttering severity, and male sex were associated with poorer responsiveness to stuttering treatment.ConclusionThe large proportion of children exhibiting elevated ADHD symptoms, and the increase in clinical contact time required in this subgroup to achieve successful fluency outcomes, is suggestive of the need for clinicians to tailor stuttering intervention to address these concomitant behaviour challenges. Findings support the use of careful caseload management strategies to account for individual differences between children, and strengthen prognostic information available to parents and clinicians.     

Use of peer-mediated intervention in children with attention deficit hyperactivity disorder

The present experiment extended and replicated the use of functional analysis and a peer-mediated intervention to decrease disruptive behavior displayed by children diagnosed with attention deficit hyperactivity disorder in an afterschool program. After determining that the participants displayed off-task behavior maintained by peer attention via a functional analysis, peer-implemented differential reinforcement of other behavior with extinction was effective in reducing participants' off-task behaviors. The use of peers as behavior-change agents is discussed, as are avenues for future research.     

Sex differences in school-aged children with pervasive attention deficit hyperactivity disorder

This study investigated 54 children (37 boys and 17 girls) with cross-situational attention deficit hyperactivity disorder (ADHD) to determine whether there are sex differences in the expression of either the primary or secondary symptomatology of ADHD. Results indicated that the male and female ADHD groups were strikingly similar on all measures of primary (impulsivity, inattention, and overactivity) and secondary (learning problems, externalizing symptoms, internalizing symptoms, peer relationship difficulties, and self-perceptions) symptomatology included in this study. The lack of significant sex differences conflicts with prior reports in the literature, and these conflicting results are discussed in terms of differences in inclusion criteria. Implications for understanding the long-term outcome of ADHD in girls are also discussed.     

Computerized stroop test to assess selective attention in children with attention deficit hyperactivity disorder

Research shows abnormal function of the pre-frontal cortex in Attention Deficit Hyperactivity Disorder (ADHD). This cortex is involved in the control of executive functions related to planning and execution of goal-oriented strategies, working memory, inhibitions, cognitive flexibility, and selective attention. Selective attention involves focus on the target stimulus, ignoring competing distractions. The Stroop Test (Stroop, 1935) is usually used to evaluate selective attention. This study investigated whether children with ADHD could exhibit modified performance in the Stroop Test. Using a computerized version of this test (Capovilla, Montiel, Macedo, & Charin, 2005), the study compared the reaction times (RTs) of 62 Brazilian children, between 8 and 12 years of age, 31 of whom were diagnosed with ADHD and sent to psychiatric clinics, and 31 without ADHD studying in regular schools. All children with ADHD satisfied the criteria of the DSM-IV-TR and were evaluated with the Conners Abbreviated Questionnaire (Goyette, Conners, & Ulrich, 1978), completed by parents and teachers. The results revealed that children with ADHD exhibit greater interference in RT than children without ADHD. This corroborated the hypothesis that children with ADHD exhibit a deficit in selective attention, consisting in augmented RTs, as measured by the Computerized Stroop Test.     

Parenting stress among families of children with attention deficit hyperactivity disorder

Prior research has shown that parenting stress levels can be quite high among families of children with attention deficit hyperactivity disorder (ADHD). This study investigated the degree to which such stress was related not only to the child's ADHD, but also to various other child, parent, and family-environment circumstances. Multimethod assessments were conducted on 104 clinic-referred children with ADHD. Data collected from these subjects were entered into hierarchical multiple-regression analyses, utilizing the Parenting Stress Index as the criterion. The results showed that child and parent characteristics accounted for a substantial portion of the variance in overall parenting stress. The child's oppositional-defiant behavior and maternal psychopathology were especially potent predictors. The severity of the child's ADHD, the child's health status, and maternal health status also emerged as significant predictors. These findings are discussed in terms of their impact upon the clinical management of children with ADHD.The authors are grateful to Mary Maher and Paula Nevins for their assistance in collecting and coding the data. The authors would also like to thank Dr. Kenneth Fletcher for his helpful comments regarding the statistical analyses.     

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.     

Traits of attention deficit/hyperactivity disorder in school-age children who stutter

PurposeThe purpose of this study was to explore whether parents of CWS reported the presence of ADHD symptoms that would warrant a referral to a psychologist to rule out the disorder. This study also aimed to describe the characteristics of the sample in terms of gender, family history of stuttering, presence of neurological impairment, concomitant diagnoses, and stuttering severity. Finally, this study sought to explore the possible statistical relations among these same variables.MethodsParticipants were 36 school-age CWS (32 males and 4 females) between the ages of 3.9 and 17.2 years (M = 10.4, SD = 4.0). Parent responses on the ADHD Rating Scale (Power et al., 2001) were collected via a retrospective chart review.ResultsFor this sample 58% (n = 21), of the participants met criteria for needing referral for additional evaluation for symptoms related to ADHD. A strong positive relation (r = .720, p < .001) was found between a reported family history of recovered stuttering and the presence of a concomitant diagnosis.ConclusionThe results of the present study demonstrate the need for further training and education for SLPs working with CWS regarding ADHD.Educational objectives: The reader will be able to (1) describe the main characteristics of ADHD, (2) discuss the evidence suggesting a possible relationship between ADHD and stuttering and (3) discuss how ADHD characteristics could impact clinical outcomes for CWS.     

Prepotent response inhibition predicts treatment outcome in attention deficit/hyperactivity disorder

Objective: Inhibition deficits, including deficits in prepotent response inhibition and interference control, are core deficits in ADHD. The predictive value of prepotent response inhibition and interference control was assessed for outcome in a 10-week treatment trial with methylphenidate. Methods: Thirty-four children with ADHD (ages 8–12) received 10 weeks of methylphenidate treatment. At pretest prepotent response inhibition was assessed using the Stop-Signal Task; interference control was assessed using the Stroop Color-Word task. Methylphenidate was individually titrated to an optimal dose. Treatment outcome was assessed by parent- and teacher-rated ADHD behavior. Results: Only stop-signal reaction time of the Stop-Signal Task was a significant predictor of parent-rated levels of inattention and hyperactivity/impulsivity at outcome. Children with lower levels of inhibition showed worse outcome after 10 weeks of treatment, independent of medication dose. Conclusions: Low levels of prepotent response inhibition are associated with worse response to treatment with methylphenidate. Prepotent response inhibition may be an intermediate phenotypical predictor of treatment outcome.     

Stimulant effects in attention deficit hyperactivity disorder: theoretical and empirical issues

The explanatory utility of a theory or model of ADHD or any disorder depends fundamentally on its capacity to address issues of causality. What causes a particular child to develop ADHD? What mechanisms are responsible for temporal and setting-related variations in symptom severity, and how are these mechanisms affected by pharmacological intervention? And, what processes determine whether gains in one domain will propagate across one or more others? It should be evident from the foregoing discussion that comprehensive answers to such questions are most likely to emerge through implementation of research strategies that (a) integrate biological and psychological levels of explanation, (b) permit analysis of causal hypotheses, and (c) address mechanisms involved in both etiology and mediation of treatment response. Although extant neurobiological studies of ADHD are as compelling as they are exciting, they are limited by a troubling reductionistic emphasis. The predominant animal models focus on a narrow range of behaviors that are presumed to be central to ADHD because of the topographic similarity they bear to those represented by the diagnostic criteria incorporated into the diagnostic nomenclature. These models would become increasingly valuable to the extent that future research examined the extent to which ecologically relevant behaviors (e.g., social behavior) are compromised in the animal strains and whether the observed compromises are parallel to the correlates of ADHD observed in humans. Similarly, human molecular genetic studies have provided a glimpse into the possible role that genes related to dopaminergic neurotransmission may play in the etiology of ADHD. Yet, the features of ADHD have been conceptualized in these investigations as a unitary collection of characteristics, and this has precluded analysis of what specific syndromal feature (if any single one) is affected by the implicated genes. It is intriguing to speculate whether varying combinations of genes governing properties of DA receptors and reuptake molecules are associated with different patterns of symptom severity or responses to stimulant medications. As testing procedures for determining genotypes with respect to these features become more affordable and available, it should become increasingly feasible to examine such issues empirically. Research on the utility of stimulant drugs as a treatment for ADHD also has yielded useful information. Although the effects of MPH are of short duration, the breadth of their impact is impressive. The clinical effectiveness of these medications is no longer in doubt, and patterns of relations among outcome measures represent a potentially fruitful target of scientific inquiry. Finally, data supporting a neurobiological substrate for ADHD, evidence indicating that task and setting variables moderate the expression of the syndrome's diagnostic features (see Barkley, 1998, for a review), and the causal emphasis of the conceptual model with which the discussion began collectively argue for a diathesis-stress conception of the syndrome. And, as foregoing comments make clear, task and setting variables and the mechanisms through which they influence symptom expression are as important to the phenomenon as are neurobiological predisposing causes. This has significant implications for assessment strategies employed in diagnosis and evaluation of treatment-outcome. Specifically, it suggests that theory-based experimental manipulations of task and setting variables designed to impose challenge on hypothesized core features of the disorder are more likely to yield insights into the causal mechanisms governing behavioral organization in affected children than strategies emphasizing static identification of diagnostic correlates. It is hoped that such an approach will accelerate the discovery of increasingly effective assessment and intervention strategies.     

Facial affect interpretation in boys with attention deficit/hyperactivity disorder.

Recent studies have produced mixed evidence of impairments in facial affect interpretation for children with attention deficit/hyperactivity disorder (ADHD). This study investigated the presence and nature of such impairments across different stimulus formats. Twenty-four boys with ADHD and 24 age-matched comparison boys completed a 72-trial task that included facial expressions of happiness, sadness, fear, anger, surprise, and disgust. Three versions of each expression were used: a static version, a dynamic version, and a dynamic version presented within a relevant situational context. Expressions were also presented in one of two portrayal modes (cartoon versus real-life). Results indicated significant impairments for boys with ADHD on two of the six emotions (fear and disgust), which were consistent across stimulus formats. Directions for further research to identify mediating factors in the expression of such impairments in children with ADHD are discussed.     

Interference and negative priming effects in adolescents with attention deficit hyperactivity disorder

Three visual selective attention tasks were used to measure potential differences in susceptibility to interference and inhibitory cognitive control processes in 16 adolescents diagnosed with attention deficit hyperactivity disorder (ADHD) and 45 similar-aged controls. Susceptibility to interference was assessed using the Stroop color and word naming test. Efficiency of distractor inhibition was assessed in two conceptual negative priming tasks. The majority of studies in this area indicate that people with ADHD demonstrate higher levels of interference and lower negative priming effects in comparison with age-matched peers. However, we found that although the ADHD group was consistently slower to name target stimuli than the control group, there were no differences in interference or negative priming between the two groups.