Michael D. Weiler

Processing Speed in Children With Attention Deficit/Hyperactivity Disorder, Inattentive Type

Attention Deficit/Hyperactivity Disorder (ADHD) is among the most common and most often reconceptualized neurobehavioral disorders of childhood. In the most recent DSM-IV, a primarily inattentive subtype of ADHD (AD) has again been identified. This study explores the neuropsychological profile of this group of children. Eighty-two children referred for school-related problems participated. Twenty-five met criteria for AD; 52 met criteria for reading disability (RD); 9 were comorbid for RD and AD. AD children performed poorly on measures of information processing speed. Children with comorbid AD/RD were distinguishable from those with RD on speed of processing measures only. Vulnerability to information processing load may be at the root of many of the behavioral manifestations of AD.

Processing of Rapid Auditory Stimuli in School-Age Children Referred for Evaluation of Learning Disorders

Tallal hypothesized that reading disabled children have a domain-general deficit in processing rapidly occurring auditory stimuli that degrades speech perception, thereby limiting phonologic awareness and thus reading acquisition. She predicted they would be disproportionately affected by rapidly presented auditory stimuli. In this study, one hundred 7- to 11-year-old children with learning impairment (LI) and 243 non-learning impaired (NLI) children were evaluated on a two-tone auditory discrimination paradigm. LI committed more errors, but effects of timing were comparable. The same result was obtained for a subsample of good and poor readers. Task performance predicted reading, spelling, and calculation. Neural processes underlying perception of speech and other auditory stimuli may be less effective in poor readers; however, contrary to Tallals hypothesis, rate may not be specifically affected.

Mother and teacher reports of ADHD symptoms: DSM-IV Questionnaire data.

OBJECTIVE Diagnosis of attention-deficit/hyperactivity disorder (ADHD) is thought to be best accomplished by a multimodal approach. In many research and clinical settings, such extensive procedures may not be feasible. A screening instrument that could identify children meeting necessary (but not sufficient) criteria would permit selection of subgroups for more resource-intensive diagnostic procedures. METHOD The Diagnostic Rating Scale (DRS) was completed by the mothers and teachers of 124 children referred to hospital-based clinics and 225 nonreferred children. The authors performed principal components analysis (PCA) on the questionnaire, compared the scores obtained by children from the 2 samples, and examined age and gender effects. Diagnoses derived from the DRS were not validated against structured diagnostic interviews. RESULTS PCAs replicated the DSM-IV symptom combinations. Children from the referred sample exhibited more symptoms (p < .001) than children from the community sample. Boys were overrepresented among the children who received DRS-derived ADHD diagnoses. Girls were more likely (92%) to receive a diagnosis of ADHD, predominantly inattentive subtype, than other ADHD diagnoses. CONCLUSIONS The results of this study provide preliminary support for the validity of the parent and teacher DRS as time- and resource-efficient screening instruments for examining symptoms associated with ADHD.

Information Processing Deficits in Children with Attention-Deficit/Hyperactivity Disorder, Inattentive Type, and Children with Reading Disability

We examined the information processing capabilities of children diagnosed with the inattentive subtype of attention-deficit/hyperactivity disorder (ADHD) who had been characterized as having a sluggish cognitive tempo. Children referred for school-related problems (n = 81) and nonreferred community controls (n = 149) participated. Of the referred children, 24 met criteria for ADHD, 42 met criteria for reading disability (RD), and 9 of these were comorbid for RD and ADHD. Children with ADHD differed from those without ADHD on a visual search task but not on an auditory processing task; the reverse was true for children with RD. Decomposition of the visual search task into component operations demonstrated that children in the ADHD group had a slow processing rate that was not attributable to inattention. The children with ADHD were not globally poor at information processing or inattentive, but they demonstrated diminished speed of visual processing.

Sources of poor performance on the Rey-Osterrieth Complex Figure Test among children with learning difficulties: a dynamic assessment approach.

A dynamic assessment approach was used to examine the source of poor performance on the Rey–Osterrieth Complex Figure Test (ROCF) among 202 school-age children referred for learning difficulties. The ROCF was administered in the standard format and then in a structured format that highlighted the designs organizational framework. Manipulating encoding in this way improved recall to at least age-level for the majority of children. Those children who did not benefit from the structured format had relatively poor visual organizational skills. For most children with learning problems, poor ROCF performance stems from metacognitive difficulties; for a minority, the source appears to be more perceptual. A dynamic assessment procedure can enhance the diagnostic utility of the ROCF for children.

Rapid Automatized Naming in Children Referred for Evaluation of Heterogeneous Learning Problems: How Specific Are Naming Speed Deficits to Reading Disability?

Because the Rapid Automatized Naming (RAN) test reliably predicts reading skill, it is typically viewed as a diagnostic indicator of risk for reading disability (RD). Since most of the work on naming speed has been undertaken within the framework of reading research, however, the extent to which poor RAN is specifically associated with RD or with learning impairment (LI) in general is uncertain. We tested the hypothesis that slow naming speed is specific to RD. Participants were 188 children (ages 7 to 11) referred for evaluation of learning problems. Receiver operating characteristic (ROC) analysis was used to evaluate the utility of the RAN task for classifying children in diagnostic groups. RAN was an excellent tool for detecting risk for learning problems in general, but it was much less effective at distinguishing LI children with and without RD from each other.

Neural Substrates of Childhood Attention-Deficit/Hyperactivity Disorder: Electroencephalographic and Magnetic Resonance Imaging Evidence

Research methods based on electroencephalogram (EEG) and anatomical and functional MRI have been used with increasing frequency in the study of childhood Attention-Deficit/Hyperactivity Disorder (ADHD). Both methods are safe and noninvasive, and their results can complement each other because of the good temporal (but relatively poorer spatial) resolution of EEG and the good spatial (but relatively poorer temporal) resolution of MRI. These methods are described, and associated recent research on childhood ADHD is summarized and critically examined. Results of this research support theories of ADHD that focus on a frontal-striatal neurological circuitry substrate, which has been implicated in neuropsychological executive functioning. A number of issues, however, such as the specificity of this finding for ADHD, remain unresolved. We conclude with an overview of advances and issues to be considered in future research on the neural substrates of childhood ADHD and advocate a developmental-contextual perspective on this disorder that acknowledges the reciprocal relations between neural structures and functions.

Diminished motor timing control in children referred for diagnosis of learning problems.

Disabled readers exhibit motor timing control (MTC) deficits in bimanual coordination relative to average readers. This article evaluates to what extent poor MTC is specific to reading or if it is related to learning problems in general. Children (7 to 11 years of age) referred for learning impairment (LI; n = 100) and same-age children nonlearning impaired (NLI; n = 243) performed a paced finger-tapping task. Greater variability of interresponse intervals was associated with poorer reading, spelling, and arithmetic achievement. The LI group performed more poorly than the NLI group, a difference that persisted even after adjusting for reading skill. Poor MTC is associated with poor reading but may also be a characteristic of children referred for learning problems, possibly signaling increased vulnerability of underlying neural integrative processes relevant to the childs adaptation to academic demands, including reading.

Reliability and Validity of a DSM-IV Based ADHD Screener

The Diagnostic Rating Scale (DRS) was completed by the parents and teachers of 82 children referred for clinical evaluations, 73 referred children seen twice, and 218 non-referred children from the community. The DRS, which uses a categorical rather than a dimensional rating approach, was 70% to 90% sensitive to diagnoses of Attention Deficit/Hyperactivity Disorder (ADHD) made by blind clinical teams. In research and clinical applications, the DRS could improve screening efficiency, especially in situations where it would be desirable to exclude all children who might have ADHD or identify all children with Hyperactive-Impulsive symptoms. Because of its objectivity and consistency with the Diagnostic and Statistical Manual (DSM)-IV criteria, the DRS could facilitate comparison of participant samples across studies.

Psychosocial Adjustment Over a Two–Year Period in Children Referred for Learning Problems: Risk, Resilience, and Adaptation

Children with learning difficulties have an increased prevalence of psychosocial adjustment problems. We hypothesized that within the context of a risk and resilience model contextual variables influence adjustment, over and above any effects of academic performance. The Behavior Assessment System for Children (BASC) was used to evaluate the relationship between psychosocial adjustment, changes in academic skills, and contextual factors longitudinally over a two–year period in 100 children (ages 7 to 11) referred for learning problems. Although there was little improvement in academic skills, contextual factors contributed to observed psychosocial outcome. Different factors were salient for parents, teachers, and children. Context–derived vulnerability and protective factors can be important determinants of adjustment in children with learning problems, even though the academic difficulties can remain chronic.