Are hyperactive children deficient in attentional capacity?

A dual task was used to study attentional capcity in three groups: in 6- to 12- year- old boys with attention deficit disorder plus hyperactivity (ADDH) or with ADDH and conduct disorder, and in normal children. Subjects performed a primary-choice reaction-time task first without and then with a secondary task that also required a response. Our prediction that the reaction time of ADDH subjects to the secondary task would increase more with increasing temporal overlap of the primary and secondary stimuli, if they were deficient in capacity, was not supported. However, the performance of ADDH subjects on the primary task deteriorated more than that of control subjects with the introduction of the secondary task, indicating a greater concurrence cost or a different allocation policy. Moreover, ADDH subjects had longer reaction times to the secondary task, indicating greater refractory effects or difficulty shifting capacity from primary- to secondary-task processes.The authors would like to acknowledge the support of the Ontario Mental Health Foundation and the assistance of Diane Chajczyk. This paper was prepared with the assistance of Medical Publications, The Hospital for Sick Children, Toronto, Ontario.     

Attaining and maintaining preparation: A comparison of attention in hyperactive,normal, and disturbed control children

The hypothesis that hyperactive children have a deficit in sustained attention was investigated. Eighteen children who had attention deficit disorder with hyperactivity (ADDH), aged 7 to 11 years, were compared with children who had conduct disorder (n = 15), mixed conduct disorder and ADDH (n = 26), emotional disorder (n = 18), or learning disability (n = 22), and with normal controls (n = 15). The subjects were tested on three versions of the Continuous Performance Task. Sustained attention was assessed from performance with increasing time on task and from ability to prepare attention in response to a warning. Performance of all subjects deteriorated with increasing time and improved with the opportunity to prepare attention. Hyperactive subjects were not more adversely affected by increasing time, nor did they benefit less than controls from the opportunity to prepare attention. Data reanalysis after rediagnosis according to ICD-9 criteria did not change the results. This study did not confirm the hypothesis that hyperactive children have a unique sustained attention deficit.     

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.     

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.     

The effects of background illumination and stimulant medication on smooth pursuit eye movements of hyperactive children

Problems with visual information processing have been reported in children with the diagnosis of attention deficit disorder with hyperactivity (ADD H), and deficits in oculomotor control have been posited as an important factor in this phenomenon. To assess aspects of oculomotor performance, smooth pursuit eye movements (PEMs) were recorded electrooculographically in 20 ADD H and 20 age-matched control children and computer-analyzed for discrete (velocity arrests) and global (root mean square error) disruptions. The effects of stimulant medication (methylphenidate), together with manipulations designed to influence behavioral (attention) and physiological (cerebellar) processes involved in PEM performance, were examined. The tracking patterns of nonmedicated ADD H children contained significantly more discrete aberrations on baseline conditions. Although no single experimental manipulation significantly improved tracking performance in ADD H children, combining all experimental conditions did normalize PEMs in these subjects. Slight improvements in PEM performance in association with medication correlated positively with does of madication of with medication-related improvments of behavior. In light of these data, arguments are presented in supported of (a) hyporousal as a contributing factor underlying oculomotor difficulties in ADD H children and (b) subcortical involbment in PEM dysfunction.This research was funded in part by grants from The Hospital for Sick Children Foundation and the Ontario Mental Health Foundation (RTP). The authors thank Susan Anthony, Dr. Pamela M. Cooper, Stella Cowley, Dr. Kathy Margittai, and Ralph Nevins for technical assistance, Martin Gillett for computer programming, Dr. Phil Firestone and the staff of the University of Ottawa Child Study Centre, and Dr. B. Lena of the Family and Child Unit, Ottawa General Hospital, for subject referral.     

The hyperactive child at adolescence: Cognitive,emotional, and social functioning

In view of the paucity of detailed followup studies on hyperactive children, the performance of 15 adolescents diagnosed hyperactive 5 years previously was compared to that of a control group of equivalent age, sex, intelligence, and social class. Eleven cognitive tests measuring sustained attention, visual-motor and motor skills, abstraction, and reading ability, as well as three self-assessment tests examining selfesteem, activity level, social functioning, academic status, and career aspirations were administered. The hyperactives performed significantly worse than the controls on the sustained attention, visualmotor, and motor tasks, and on two of the four reading tests. They also gave themselves significantly lower ratings on some of the selfesteem and sociability items. It would appear that the hyperactives at adolescence still have attentional and stimulus-processing difficulties, which affect not only their academic performance but also their social functioning.This study was supported by a Federal-Provincial Mental Health Grant to Dr. G. Weiss. The authors wish to thank Katherine Levine and Margaret Radigan for their assistance with test preparation and scoring. Thanks are also extended to Ken MacRae for his computer-processing advice, particularly his help with several multivariate and principal components analyses from which the present authors have derived their current theoretical position. Klaus Minde and Nancy Cohen are now at the Toronto Hospital for Sick Children, while Elizabeth Hoy is at the Queen's University of Belfast, Northern Ireland.     

Reading,spelling, and vigilance in attention deficit and conduct disorder

A group of 51 male children, average age 9.1 years, presenting at a child psychiatric clinic because of attention and conduct problems were investigated for reading and phonetic spelling ability, vigilance, and intellectual level. Each child was given a DSM- III diagnosis prior to being tested. The Boder Test of Reading and Spelling patterns was used to obtain scores for reading age, number of syllables read correctly in the word list at the child's reading level, and number of phonetically correct syllables spelled in the known and unknown word lists, at and just above the child's reading level. A factor analysis with varimax rotation produced two significant factors, a Reading factor with high loadings for verbal and reading scores, aand a second Vigilance factor. Phonetic spelling ability loaded separately from reading into the Vigilance factor. The Vigilance factor was significantly related to the diagnosis of moderate and severe attention deficit disorder with hyperactivity (ADDH). The correlation of short- term working memory with vigilance in moderate to severe ADDH children is discussed.Fundling assistance was provided by the New South Wales Institute of Psychiatry.     

Music and Video as Distractors for Boys with ADHD in the Classroom: Comparison with Controls,Individual Differences,and Medication Effects

This study examined the effects of music and video on the classroom behavior and performance of boys with and without attention deficit hyperactivity disorder (ADHD) and examined the effects of 0.3 mg/kg methylphenidate (MPH). In one study, 41 boys with ADHD and 26 controls worked in the presence of no distractor, music, or video. Video produced significant distraction, particularly for the boys with ADHD, and MPH improved the performance of boys with ADHD across distractor conditions.There were individual differences in response to the music such that some boys were adversely affected and others benefited relative to no-distractor.In a second study, music and MPH were assessed in an additional 86 boys with ADHD to examine further the music results. In the presence or absence of music, MPH improved performance relative to placebo. Similar individual differences were found as in Experiment 1.     

Neuropsychological characteristics and test behaviors of boys with early onset conduct problems.

School-age children and adolescents with conduct problems typically exhibit deficits in verbal IQ, language abilities, and executive functions. This study examined the extent to which this pattern was evident in a clinic group of preschool boys with early onset conduct problems who met criteria for oppositional defiant disorder (ODD) with and without attention deficit hyperactivity disorder (ADHD). A 2nd question focused on the strength of relation between clinic boys' uncooperative or inattentive test behaviors and their test performance. As expected, the clinic boys showed a neuropsychological profile highly similar to the one found in older conduct problem populations. Verbal tests distinguished clinic from matched comparison boys even after controlling for observers' ratings of disruptive behavior during testing. Clinic boys with ODD and ADHD had lower verbal and executive function scores than clinic boys with ODD alone. After general vocabulary knowledge and test behavior were controlled, clinic boys were found to have poorer vocabularies for describing affective states than comparison group boys.     

Supraspan verbal memory in attention deficit disorder with hyperactivity normal and reading-disabled boys

To assess memory problems associated with attention deficit disorder with hyperactivity (ADDH) and reading disability (RD), nonverbal subspan, span, and supraspan measures was administered to 30 ADDH, 30 normal, and 24 RD boys, ages 7 to 12. Results from the supraspan verbal measures, which included word lists and related and unrelated paired associates, are reported. Across all verbal tasks, deficits became most apparent in ADDH boys on measures requiring organized, deliberate rehearsal strategies, sustained strategic effort, and careful consideration of response alternatives. This pattern suggests impaired self-regulatory or executive processes. RDs showed more generalized deficits across the verbal measures, suggesting problems with verbal processing. Recent studies supporting this interpretation are reviewed.This research was partially supported by Grant MA-6913 from the Medical Research Council of Canada. We are grateful for the help of Rhonda Amsel in the various stages of this project.     

Attention deficit,conduct, oppositional,and anxiety disorders in children: III. Laboratory differences

Children aged 5–13 years with DSM-III diagnoses of Attention Deficit (ADDH), Anxiety, (ANX), or Conduct plus ADDH (HC) Disorder and matched normal controls were compared on a set of laboratory measures of impulsivity, arousal, motor performance, activity level, and cognition, and on behavior ratings during testing. While ANX patients did not differ from their controls, ADDH and HC patients did on Verbal IQ, most of the behavior ratings, and on about one-third of the test variables. ANX patients were about 1 year older, and more likely to be female, than ADDH and HC patients. When age, sex, and verbal IQ effects were partialed out, very few differences among the three diagnostic groups remained. The importance of precise control of such variables is emphasized and the impact of the failure to do so in past studies is discussed. The question is raised whether the deficit in verbal IQ is not so much a defect of matching as the essential feature of ADDH from which most of the other commonly reported cognitive symptoms stem.This research was supported by the Medical Research Council of New Zealand.     

Attention, temporal predictability, and the time course of context effects in naming performance

Models of attention and context effects in naming performance should be able to account for the time course of color-word Stroop interference revealed by manipulations of the stimulus onset asynchrony (SOA) between color and word. Prominent models of Stroop task performance ( [Cohen et al., 1990], [Cohen and Huston, 1994] and [Phaf et al., 1990]) fail to account for the fact that response time (RT) and Stroop interference peak at zero SOA and diminish with word preexposure. The models may be saved by assuming that the time course of interference is determined by a strategic orienting of attention to color onsets when SOA is predictable. To test this temporal predictability hypothesis, SOA was blocked or randomly mixed in Experiment 1. In addition, the time interval between color onsets was randomly variable in Experiment 2. Although RTs were affected, none of the randomization manipulations influenced the typical shape of the time course of Stroop effects. These findings provide evidence against the temporal predictability hypothesis and thereby against prominent models of the Stroop task.     

Sustained attention in normal and in reading-disabled youngsters with and without ADDH

Three groups of children — one normal, one reading-disabled, and one reading-disabled with an additional diagnosis of attention deficit disorder with hyperactivity (ADDH)-were administered the Continuous Performance Test and compared on correct detections and three types of commission errors. All three groups showed a decline in sustained attention over the course of the task but not differentially according to diagnostic group. When younger and older subgroups were compared, the reading-disabled children were found to make significantly more correct detections with increased age, but not when the reading disability was accompanied by ADDH. The latter group of children also were differentiated by a type of commission error, previously associated with impulsive responding, that remained prominent in the older subgroup of dually diagnosed children. Reading-disabled children were differentiated by a second type of commission error which possibly was associated with inattention or short-term memory deficit and which diminished with age.The author would like to thank the staff of St. Patricks School and in particular its principal Sister Patrick Mary for her able administrative support of the study. The author would also like to thank the administration and staff of the Unitas Clinic for their cooperation.     

Reaction time indices of attention deficits in boys with disruptive behavior disorders

Boys with diagnoses in the disruptive behavior disorder (DBD) spectrum and normal controls were tested in two reaction time (RT) experiments. In Experiment I simple warned RT was measured and the length and regularity of the preparatory intervals were varied in order to study sustained attention in the sense of preparation. With age and IQ controlled, DBD boys had slower and more variable RT overall than controls and showed generally more pronounced effects of variations in the length and sequence of the preparatory intervals. The results suggest that DBD boys are subject to lapses of attention which are increased by a relatively long preparatory interval, and that they have a particular problem with temporal uncertainty. In Experiment II some aspects of selective attention were studied in a paradigm in which stimulus modality uncertainty and response selection were varied. DBD boys showed greater effects of modality uncertainty but not response selection than controls. No differences between subdiagnoses within the DBD spectrum could be demonstrated.     

Contribution of ADHD symptoms to substance problems and delinquency in conduct-disordered adolescents

We examined adolescents with conduct disorder (CD) and substance problems to determine if those with attention deficit hyperactivity disorder (ADHD) symptomatology had more severe delinquency and substance involvement. ADHD symptomatology was assessed in two ways: (1) by self-reports using the Diagnostic Interview Schedule for Children (DISC) and (2) by use of DISC plus reports of others (parents, program staff, and program teacher). We divided boys into three ADHD groups based on DISC: those who met criteria, those who reported at least eight current symptoms, and those who reported fewer than eight symptoms. We also divided the same boys into two groups: those with reports of ADHD by two or more sources and those without this multisource ADHD. Examining these definitions of ADHD revealed that boys with either self- or multisource ADHD had more CD symptoms, earlier age of CD onset, more substance dependence diagnoses, and more comorbid depression and anxiety.This investigation was supported by the National Institute on Drug Abuse Grant No. DAO6941.     

Facilitative and inhibitory effects of cuing sound duration, intensity, and timbre.

Two experiments are reported in which the possibility that auditory attention may be controlled in a stimulus-driven manner by duration, intensity, and timbre cues was examined. In both experiments, listeners were presented with a cue followed, after a variable time period of a 150-, 450-, or 750-msec stimulus onset asynchrony (SOA), by a target. In three different conditions for each experiment, the duration, intensity, or timbre relation between the cue and the target was varied so that, on 50% of the trials, the two sounds were identical and, on 50% of the trials, the two sounds were different in the manipulated feature. The two experiments differed only in the judgment required, with listeners in Experiment 1 identifying the duration, intensity, or timbre of the target and listeners in Experiment 2 indicating whether the target incorporated a brief silent gap. In both experiments, performance was observed to depend on both the similarity of and the time between the cue and the target. Specifically, whereas at the 150-msec SOA performance was best when the target was identical to the preceding cue, at the 750-msec SOA performance was best when the cue and the target differed. This pattern establishes the existence of duration-, intensity-, and timbre-based auditory inhibition of return. The theoretical implications of these results are considered.     

Facilitative and inhibitory effects of cuing sound duration, intensity, and timbre

Two experiments are reported in which the possibility that auditory attention may be controlled in a stimulus-driven manner by duration, intensity, and timbre cues was examined. In both experiments, listeners were presented with a cue followed, after a variable time period of a 150-, 450-, or 750-msec stimulus onset asynchrony (SOA), by a target. In three different conditions for each experiment, the duration, intensity, or timbre relation between the cue and the target was varied so that, on 50% of the trials, the two sounds were identical and, on 50% of the trials, the two sounds were different in the manipulated feature. The two experiments differed only in the judgment required, with listeners in Experiment 1 identifying the duration, intensity, or timbre of the target and listeners in Experiment 2 indicating whether the target incorporated a brief silent gap. In both experiments, performance was observed to depend on both the similarity of and the time between the cue and the target. Specifically, whereas at the 150-msec SOA performance was best when the target was identical to the preceding cue, at the 750-msec SOA performance was best when the cue and the target differed. This pattern establishes the existence of duration-, intensity-, and timbre-based auditory inhibition of return. The theoretical implications of these results are considered.     

Childhood conduct problems,attention deficit behaviors,and adolescent alcohol,tobacco, and illicit drug use

The relationships between conduct problems and attention deficit behaviors at age 8 years and the use of alcohol, tobacco, and illicit drugs at 15 years were studied in a birth cohort of over 900 New Zealand children. The analysis showed that while early conduct problems were significantly associated with later substance use there were no significant associations between early attention deficit behaviors and later substance use once the correlations between conduct problems and attention deficit behaviors were taken into account. These associations persisted after control for a range of potentially confounding covariates. Children who showed tendencies to conduct problems at age 8 consumed 1.5 to 1.9 times more alcohol and had rates of alcohol-related problems, daily cigarette smoking, and illicit drug use that were 1.9 to 2.0 times higher than children with low conduct problem scores. It is concluded that attention deficit behaviors, in the absence of conduct problems, are not associated with later substance use. However, even when due allowance is made for social and contextual factors associated with both early conduct problems and later substance use, early conduct problems are a risk factor for later substance use.This research was funded by grants from the Health Research Council of New Zealand and the National Child Health Research foundation.     

Enhancement,extension, and reversal of the frequency selectivity effect

The influence of a frequency cue on judgments of whether or not a subsequent target incorporated a brief silent gap was examined. In Experiment 1, there was no predictive frequency relation and evidence of auditory inhibition of return was obtained with frequency repetitions, producing a facilitative effect at 175-msec stimulus onset asynchrony (SOA) and an inhibitory effect at 775-msec SOA. Relative to this baseline performance pattern, increasing the probability of a frequency match to .75 (Experiment 2) served to generate a beneficial effect of frequency repetitions at lengthy SOAs and to enlarge its magnitude at 175-msec SOA. In contrast, a reduction in the probability of a frequency match to .25 (Experiment 3) resulted in the elimination of any facilitative effect of repetition at 175-msec SOA and the development of an inhibitory effect at 475- and 1,075-msec SOA. These results establish that a frequency cue may engage both exogenous and endogenous attentional processes within 175 msec following its presentation.     

Reliability and magnitude of auditory laterality effects: the influence of attention

Three experiments investigated the effect of attention on the reliability and magnitude of laterality effects in a dichotic listening task. In Experiment 1, 40 undergraduate students were randomly assigned to either a free-recall or focused-attention condition. In Experiment 2, 40 undergraduate students completed a dichotic listening task with exogenous cueing. They were randomly assigned to either a 150-ms stimulus onset asynchrony (SOA) or a 450-ms SOA condition. In Experiment 3, 20 participants completed a task where the SOA for the exogenous cue was randomized on a trial to trial basis. Results indicated that focused attention increased the magnitude of the laterality effect. Contrary to predictions, this finding was not due to reduced variability in the focused-attention task compared to the free-recall task. In addition, a cueing tone was only effective at directing attention in Experiment 3. Specifically, a significant right ear advantage observed at the 150-ms SOA was reduced at the 450-ms SOA. It appears that, in Experiment 3, the tone was effective at controlling attention because it reduced the systematic bias that has been suggested to account for the laterality effects observed in dichotic tasks.