Differences Between ADHD Inattentive and Combined Types on the CPT

Two samples of school-age boys with attention-deficit/hyperactivity disorder (ADHD-Combined and ADHD-Inattentive Types) and a non-ADHD control group were administered an AX version of the continuous performance task (CPT) to examine specific sustained attention deficits. Three levels of time-on-task were included to study performance declines, and 3 interstimulus intervals were included to examine vigilance deficits. As predicted by R. A. Barkley's and H. C. Quay's behavior inhibition deficit models (R. A. Barkley, 1997; H. C. Quay, 1997), the performance of the ADHD-Combined Type (ADHD-C) participants deteriorated more quickly than the other samples. No significant evidence of vigilance deficits among the inattentive (ADHD-IA) sample was found. These findings suggest that distinct criteria for the two ADHD subtypes may be warranted when the CPT is used for diagnostic assessment, and sustained attention-related declines in performance may be typical of the ADHD-C Type only.     

Executive Functioning, Temporal Discounting, and Sense of Time in Adolescents with Attention Deficit Hyperactivity Disorder (ADHD) and Oppositional Defiant Disorder (ODD)

Clinic-referred teens (ages 12–19) with ADHD and ODD (N = 101) were compared to community control (CC) teens, equated for age and sex, (N = 39) on a variety of psychological tasks assessing executive functioning (EF), temporal reward discounting, and time estimation and reproduction. A factor analysis reduced the EF measures to three dimensions, representing CPT Inattention, Working Memory, and CPT Inhibition. Results indicated that the ADHD group had significantly more CPT Inattention than the CC group. No differences were found for Working Memory or CPT Inhibition. The ADHD group displayed significantly greater temporal discounting of delayed hypothetical monetary rewards relative to immediate ones and manifested more impaired time reproduction, but not time estimation, than did the CC group. Main effects for level of IQ were found only on the Working Memory factor and largely did not interact with the group factor otherwise. The group differences in CPT Inattention, temporal discounting, and time reproduction were not a function of level of comorbid oppositional defiant disorder, delinquency, or anxiety–depression. Results are reasonably consistent with past research on EF and sense of time in children with ADHD and extend these findings to the adolescent age group. Problems with working memory and CPT inhibition found in prior studies of children with ADHD, however, were not evident here, perhaps owing to age-related improvements or insufficient task difficulty.     

Reported prevalence of attentional difficulties in a general sample of college students

The present study investigated the self-reported prevalence of attention-deficit hyperactivity disorder (ADHD)symptoms in 770 college students using the Adult Rating Scale and the Wender Utah Rating Scale. Psychometric properties of these scales were explored. The study also investigated the performance of students with ADHD symptoms, relative to students without ADHD symptoms, on a battery of neuropsychological tasks. Results revealed that 7 and 8% of the students reported significant symptoms (i.e., 1.5 SD above the mean) on the Adult Rating Scale and the Wender Utah Rating scale, respectively, and 2.5% reported significant symptoms on both the Adult Rating Scale and the Wender Utah Rating Scale. Using more stringent criteria (two standard deviations), fewer (i.e, 4, 3.8%, and 0.5%) subjects reported significant symptoms associated with ADHD. Between-group differences were found on one of the neuropsychological tasks. The construct validity of the rating scales was supported. Limitations and implications for future research are advanced.Presented at the International Neuropsychological Society's Sixteenth European Conference, Angers, France, June 1994, and the Annual Convention of the American Psychological Association, Los Angeles, CA, August 1994.     

认知能量模型--一种更为综合的ADHD认知理论

认知能量模型是J.A.Sergeant等人提出的一种解释ADHD缺陷机制的综合性实证理论。该模型基于信息加工理论,结合了状态因素理论和几种相对成熟的模型,尝试对ADHD提供一种较为理想的解释。本文在此对该模型的基本观点、模型结构及其有关的实证研究进行介绍,并探讨认知能量模型对于未来ADHD研究的启示。     

ADHD outside the laboratory: boys' executive function performance on tasks in videogame play and on a visit to the zoo

One current theory of attention-deficit/hyperactivity disorder (ADHD) proposes that a primary deficit in behavioral inhibition gives rise to secondary deficits in 4 executive functions and motor control. To date, empirical support for this model is based primarily on laboratory-based cognitive methods. This study assessed behavioral inhibition and executive functioning in children with ADHD in 2 real-life contexts: videogames (motor-skill target game, cognitively demanding adventure game) and an outing at the zoo (route tasks). Participants were a community sample of 57 boys diagnosed with ADHD (20 inattentive, 37 combined type) and 57 normally developing control boys, matched individually for age and nonverbal IQ. Operationally defined measures of behavioral inhibition and specific executive functions were derived from these activities and assessed under contrasting conditions of low or high working memory and distractor loads. There were no group differences in basic motor skills on the target game, nor in terms of the ability to inhibit a prepotent or ongoing response in the adventure videogame. However, boys with ADHD exhibited more self-talk, more effortful response preparation, and completed fewer challenges in the latter videogame. Also, they manifested inhibition deficits in terms of interference control during the route task at the zoo and took longer to complete the tasks. Typically, these differences were greatest under conditions of high working memory and distractor loads. Findings from this study suggest that cognitive difficulties in ADHD may be context dependent and that ADHD is associated with deficits in some but not all aspects of behavioral inhibition.     

Direct assessment of the cognitive correlates of attention deficit disorders with and without hyperactivity

The cognitive functioning of children identified as attention deficit disorder with hyperactivity (ADD/H) was compared to that of children identified as attention deficit disorder without hyperactivity (ADD/WO). Based on information on symptoms supplied by teachers, 20 ADD/H and 15 ADD/ WO children were selected according to DSM-III criteria from a large elementaryschool learning disabilities and behavior disorders population. For comparison purposes, 16 normal children from regular classrooms were also selected. Children from all three groups were evaluated with a battery of cognitive tests. Intelligence test scores differentiated the two ADD groups, with the ADD/H children obtaining significantly lower Full Scale IQ scores than both ADD/WO and control children. In addition, ADD/H children obtained significantly lower Verbal IQ scores than ADD/WO children. Both ADD groups performed more poorly than controls on Spelling and Reading Achievement, and the ADD/WO group performed more poorly on Math Achievement. The two ADD groups took longer to complete six Stroop and rapid naming tasks than the control groups but did not differ among themselves. The ADD/WO group made more errors on a visual matching task than the controls, but neither ADD group differed from controls on the accuracy of the Stroop tasks, rapid naming tasks, measures of receptive and expressive language, visual-motor integration, or sustained visual attention. The differences between the two ADD groups were fewer than expected on the basis of previous research and are more global than specific.The assistance of John Junginger, Jason Walker, and Cynthia Jones at various stages of the project is gratefully acknowledged. Particular thanks are extended to the teachers and staff of Clarke County schools.     

Which Executive Functioning Deficits Are Associated With AD/HD,ODD/CD and Comorbid AD/HD+ODD/CD?

This study investigated (1) whether attention deficit/hyperactivity disorder (AD/HD) is associated with executive functioning (EF) deficits while controlling for oppositional defiant disorder/conduct disorder (ODD/CD), (2) whether ODD/CD is associated with EF deficits while controlling for AD/HD, and (3)~whether a combination of AD/HD and ODD/CD is associated with EF deficits (and the possibility that there is no association between EF deficits and AD/HD or ODD/CD in isolation). Subjects were 99~children ages 6–12 years. Three putative domains of EF were investigated using well-validated tests: verbal fluency, working memory, and planning. Independent of ODD/CD, AD/HD was associated with deficits in planning and working memory, but not in verbal fluency. Only teacher rated AD/HD, but not parent rated AD/HD, significantly contributed to the prediction of EF task performance. No EF deficits were associated with ODD/CD. The presence of comorbid AD/HD accounts for the EF deficits in children with comorbid AD/HD+ODD/CD. These results suggest that EF deficits are unique to AD/HD and support the model proposed by R. A. Barkley (1997).     

Do Executive Function Deficits Differentiate Between Adolescents with ADHD and Oppositional Defiant/Conduct Disorder? A Neuropsychological Study Using the Six Elements Test and Hayling Sentence Completion Test

Two neuropsychological measures of executive functions—Six Elements Tests (SET) and Hayling Sentence Completion Test (HSCT)—were administered to 110 adolescents, aged 12–15 years. Participants comprised four groups: Attention Deficit Hyperactivity Disorder (ADHD) only (n = 35), ADHD and Oppositional Defiant Disorder/Conduct Disorder (ODD/CD) (n = 38), ODD/CD only (n = 11), and a normal community control group (n = 26). Results indicated that adolescents with ADHD performed significantly worse on both the SET and HSCT than those without ADHD, whether or not they also had ODD/CD. The adolescents with ADHD and with comorbid ADHD and ODD/CD were significantly more impaired in their ability to generate strategies and to monitor their ongoing behavior compared with age-matched controls and adolescents with ODD/CD only. It is argued that among adolescents with clinically significant levels of externalizing behavior problems, executive function deficits are specific to those with ADHD. The findings support the sensitivity of these two relatively new tests of executive functions and their ecological validity in tapping into everyday situations, which are potentially problematic for individuals with ADHD.     

Parent Ratings of Attention-Deficit/Hyperactivity Disorder Symptoms: Factor Structure and Normative Data

Changes in the diagnostic criteria for attention-deficit/hyperactivity disorder (ADHD) have necessitated the creation of new measures for clinical assessment. The factor structure of a parent rating scale containing the 18 symptoms of ADHD was examined in this study. Factor analyses and assessment of differences in ADHD ratings across sex, age, and ethnic group were conducted using a sample of 4666 participants ranging in age from 4 to 20 years old who attended kindergarten through 12th grade in 22 school districts across the United States. Two factors (Inattention and Hyperactivity–Impulsivity) were derived and normative data for a nationally representative sample are presented. A higher frequency of ADHD symptoms was found for boys, younger children, and African-American participants. Potential uses of this scale in clinical practice and research are discussed.     

Adult ADHD and/or Sleep Apnea? Differential Diagnostic Considerations with Six Case Studies

An increased interest in the persistence of attention-deficit hyperactivity disorder (ADHD) into adulthood brings concern that adult ADHD may become overdiagnosed. As with ADHD in childhood, various other adult psychological and medical disorders may be associated with ADHD in adulthood, and these related disorders may be mislabeled and mistreated as simple ADHD. One such medical condition is sleep apnea. This paper reviews similarities and differences between ADHD and sleep apnea and presents case histories of six adult patients diagnosed with ADHD who were subsequently found to have at least comorbid obstructive sleep apnea (OSA). Clinicians who diagnose and treat patients with ADHD are advised to become familiar with sleep apnea as a life-threatening condition that presents with overlapping symptoms.     

Exploratory Eye Movements to Pictures in Childhood-Onset Schizophrenia and Attention-Deficit/Hyperactivity Disorder (ADHD)

We investigated exploratory eye movements to thematic pictures in schizophrenic, attention-deficit/hyperactivity disorder (ADHD), and normal children. For each picture, children were asked three questions varying in amount of structure. We tested if schizophrenic children would stare or scan extensively and if their scan patterns were differentially affected by the question. Time spent viewing relevant and irrelevant regions, fixation duration (an estimate of processing rate), and distance between fixations (an estimate of breadth of attention) were measured. ADHD children showed a trend toward shorter fixations than normals on the question requiring the most detailed analysis. Schizophrenic children looked at fewer relevant, but not more irrelevant, regions than normals. They showed a tendency to stare more when asked to decide what was happening but not when asked to attend to specific regions. Thus, lower levels of visual attention (e.g., basic control of eye movements) were intact in schizophrenic children. In contrast, they had difficulty with top-down control of selective attention in the service of self-guided behavior.     

Paired-Associate Learning in Attention-Deficit/Hyperactivity Disorder as a Function of Hyperactivity-Impulsivity and Oppositional Defiant Disorder

A paired-associate learning (PAL) test was administered to 22 community volunteers without disruptive disorders and 197 children (7.5–13.5 years-old) presenting with the inattentive and combined subtypes of attention-deficit/hyperactivity disorder (ADHD) either in combination with or without oppositional defiant disorder (ODD). Participants were screened for learning disorders. In comparison to non-ADHD participants, children with ADHD achieved worse PAL and made errors rated as more acoustically and less semantically similar to the correct paired associates. These deficits were not related to hyperactivity–impulsivity or comorbid ODD. These results suggest that ADHD children are less competent at PAL and use less efficient learning strategies than their non-ADHD peers.     

Working Memory and Motor Activity: A Comparison Across Attention-Deficit/Hyperactivity Disorder,Generalized Anxiety Disorder,and Healthy Control Groups

Converging findings from recent research suggest a functional relationship between attention-deficit/hyperactivity disorder (ADHD)-related hyperactivity and demands on working memory (WM) in both children and adults. Excessive motor activity such as restlessness and fidgeting are not pathognomonic symptoms of ADHD, however, and are often associated with other diagnoses such as generalized anxiety disorder (GAD). Further, previous research indicates that anticipatory processing associated with anxiety can directly interfere with storage and rehearsal processes of WM. The topographical similarity of excessive motor activity seen in both ADHD and anxiety disorders, as well as similar WM deficits, may indicate a common relationship between WM deficits and increased motor activity. The relationship between objectively measured motor activity (actigraphy) and PH and visuospatial WM demands in adults with ADHD (n = 21), adults with GAD (n = 21), and healthy control adults (n = 20) was examined. Although all groups exhibited significant increases in activity from control to WM conditions, the ADHD group exhibited a disproportionate increase in activity, while activity exhibited by the GAD and healthy control groups was not different. Findings indicate that ADHD-related hyperactivity is uniquely related to WM demands, and appear to suggest that adults with GAD are no more active relative to healthy control adults during a cognitively demanding laboratory task.