Interference Control in Children with Attention Deficit/Hyperactivity Disorder

The view that Attention Deficit/Hyperactivity Disorder (ADHD) is associated with a diminished ability to control interfference is controversial and based exclusively on results of (verbal)-visual interference tasks, primarily the Stroop Color Word task. The present study compares medication-naïve children with ADHD (n?=?35 and n?=?51 in Experiments 1 and 2, respectively) with normal controls (n?=?26 and n?=?32, respectively) on two interference tasks to assess interference control in both the auditory and the visual modality: an Auditory Stroop task and a Simon task. Both groups showed reliable but equal degrees of interference on both tasks, suggesting that children with ADHD do not differ from normal controls in their ability to control interference in either modality.     

The pars triangularis in dyslexia and ADHD: A comprehensive approach

Limited research has been conducted on the structure of the pars triangularis (PT) in dyslexia despite functional neuroimaging research finding it may play a role in phonological processing. Furthermore, research to date has not examined PT size in ADHD even though the right inferior frontal region has been implicated in the disorder. Hence, one of the purposes of this study was to examine the structure of the PT in dyslexia and ADHD. The other purposes included examining the PT in relation to overall expressive language ability and in relation to several specific linguistic functions given language functioning often is affected in both dyslexia and ADHD. Participants included 50 children: 10 with dyslexia, 15 with comorbid dyslexia/ADHD, 15 with ADHD, and 10 controls. Using a 2 (dyslexia or not) × 2 (ADHD or not) MANCOVA, findings revealed PT length and shape were comparable between those with and without dyslexia. However, children with ADHD had smaller right PT lengths than those without ADHD, and right anterior ascending ramus length was related to attention problems in the total sample. In terms of linguistic functioning, presence of an extra sulcus in the left PT was related to poor expressive language ability. In those with adequate expressive language functioning, left PT length was related to phonological awareness, phonological short-term memory and rapid automatic naming (RAN). Right PT length was related to RAN and semantic processing. Further work on PT morphology in relation to ADHD and linguistic functioning is warranted.     

An evaluation of methylphenidate as a potential establishing operation for some common classroom reinforcers.

We conducted reinforcer assessments for 3 boys with a diagnosis of attention deficit hyperactivity disorder who alternately received either placebo or previously prescribed methylphenidate. Our purpose was to evaluate whether methylphenidate altered the relative reinforcing effectiveness of various stimuli that are often used in classroom-based behavioral treatment programs (e.g., activities, tangible items). Results showed clear differences for some stimuli between reinforcer assessments conducted when participants had received methylphenidate compared to placebo. Results suggest that methylphenidate might act as an establishing operation for some common classroom reinforcers. Implications for the development and evaluation of behavioral treatments are discussed.     

Comprehensive school-based behavioral assessment of the effects of methylphenidate.

Individualized assessments of the effects of three doses of methylphenidate (MPH) were conducted for 2 students with attention deficit hyperactivity disorder within each child's classroom using behavioral, academic, and social measures. A double-blind, placebo-controlled, multielement design was used to evaluate the results. Results suggested that at least one or more dosages of MPH were associated with some degree of improvement for both children in each area of functioning as compared to placebo. However, the degree of improvement at times varied substantially across dosage and area of functioning. Results suggest that MPH dosage and area of child functioning are critical assessment parameters and that controlled clinical trials are necessary to optimize the effectiveness of treatment with MPH for the individual child.     

A RAPID METHOD FOR EVALUATING THE NECESSITY FOR BOTH A BEHAVIORAL INTERVENTION AND METHYLPHENIDATE

We examined the effects of a behavioral intervention and methylphenidate (MPH) on inappropriate behavior and sleep disturbance displayed by a 6-year-old boy who had been diagnosed with attention deficit hyperactivity disorder. Results showed that the behavioral intervention was effective in reducing inappropriate behaviors to near-zero levels regardless of the presence or absence of MPH.     

Evaluation of pharmacological treatment of impulsivity in children with attention deficit hyperactivity disorder

We used an assessment that involved competing reinforcer dimensions in a concurrent-schedules arrangement to examine the effects of stimulant medication on impulsivity (i.e., sensitivity of choices to reinforcer immediacy relative to rate, quality, and effort) with 4 students with attention deficit hyperactivity disorder. The assessments were administered in the context of a double-blind, placebo-controlled, counterbalanced reversal design. Reinforcer immediacy was the most influential dimension for 3 of the students and the second most influential dimension for 1 of the students across placebo and medication conditions; medication did not affect these sensitivities.     

Understanding the Covariation Among Childhood Externalizing Symptoms: Genetic and Environmental Influences on Conduct Disorder,Attention Deficit Hyperactivity Disorder,and Oppositional Defiant Disorder Symptoms

Conduct disorder (CD), attention deficit hyperactivity disorder (ADHD), and oppositional defiant disorder (ODD) are common childhood externalizing disorders that frequently co-occur. However, the causes of their comorbidity are not well understood. To address that question, we analyzed data from > 600 Finnish twin pairs, who completed standardized interviews at age 14. Behavior genetic methods were used to examine how genetic/environmental factors contribute to each disorders symptoms and to their covariation. We found significant genetic effects on each disorder with only modest evidence of shared environmental influences. Our data suggest the comorbidity among CD, ADHD, and ODD is primarily explained by shared genetic influences; however, each disorder was also under unique genetic influence, supporting the distinction of each disorder.     

A COMPARISON OF REINFORCER ASSESSMENT METHODS: THE UTILITY OF VERBAL AND PICTORIAL CHOICE PROCEDURES

We compared three methods of stimulus preference assessment for verbal children and specifically evaluated the utility of a verbal choice procedure for assessing relative reinforcer value. Using a token system, relative preference for five categories of reinforcers, representing 15 different stimuli, was assessed by three methods: a reinforcer survey, a verbal stimulus-choice questionnaire, and a pictorial stimulus-choice procedure. Results showed that the verbal and pictorial stimulus-choice assessments accurately identified high- and low-preference categories for 3 of 4 participants. Survey results alone often rated multiple categories as high preference, were less likely to identify low-preference categories, and were less likely to correspond with the results of a reinforcer assessment.     

THE DIFFERENTIAL EFFECTS OF TEACHER AND PEER ATTENTION ON THE DISRUPTIVE CLASSROOM BEHAVIOR OF THREE CHILDREN WITH A DIAGNOSIS OF ATTENTION DEFICIT HYPERACTIVITY DISORDER

We conducted functional analyses of classroom disruption during contingent teacher and peer attention conditions for 3 children with attention deficit hyperactivity disorder. Attention provided by peer confederates appeared to function as a distinct form of positive reinforcement for all 3 children.     

Agreement of parent and teacher rating scales with comprehensive clinical assessments of attention deficit disorder with hyperactivity

Forty-one clinic-referred children were given the DSM-III diagnosis of attention deficit disorder with hyperactivity (ADD/H) based on structured diagnostic interviews of the child and mother and on two teacher and two parent rating scales. The degree of agreement between diagnostic classification of ADD/H based solely on criterion scores on each rating scale and classification based on the comprehensive clinical assessments that included use of the same rating scaleswas assessed by comparing the ratings of the 41 children with ADD/H to those of 47 clinic-referred children given other diagnoses or no diagnosis. The accuracy of classification was highly similar across scales. Increasing the cutoff score increased the acing true positives. Using the point of intersection of these two curves to choose the optimal cutoff scores resulted in 70–75% accurate classification and 25–30% misclassification of children given clinical diagnoses of ADD/H. This rate of misclassification suggests that rating scales alone should not be used to classify ADD/H for most clinical and research purposes, especially because the method of comparison used in this study favored finding a high degree of correspondence.