Effects of amphetamine on vigilance performance in normal and hyperactive children

Deficient sustained attention is a symptom of hyperactivity that can be improved by stimulant medication. Recently, amphetamine has been shown to increase detections during a vigilance task in both normal and hyperactive boys. The present study applied signal detection analysis to the vigilance performance of 15 hyperactive and 14 normal boys divided into two age groups (6–9 and 10–12). A computerized continuous performance test was administered under amphetamine and placebo. Overall group comparisons indicated that perceptual sensitivity or d was higher for the normal boys and the older groups, and analysis of drug treatments showed that amphetamine significantly increased d. Interactions between drugs and age groups demonstrated that amphetamine affected the younger boys to a significantly greater degree than the older children for both d and response bias or . It is notable that the results were essentially parallel for both normal and hyperactive children.     

Schedule-induced behavior in hyperactive children

A schedule-induced behavior paradigm was used to investigate the activity patterns of hyperactive children in a standardized situation. In Experiment I, 10 hyperactive and 10 normal control children matched for age, sex, and IQ were observed under conditions of baseline and schedule. Measures of a number of categorized activities were taken on a time-sampling basis. Hyperactive children were more active than controls in baseline and did not respond to the schedule, unlike the controls who became significantly more active in schedule conditions. In Experiment II, 12 hyperactive and 6 normal children were again subjected to the same experimental paradigm, but in two of the four experimental sessions the stimulant drug methylphenidate was administered in an attempt to reduce the amount of baseline activity. Results were substantially similar to those of Experiment I, with hyperactive children more active than controls in baseline and insensitive to the schedule. There was no overall effect of drug administration on the behavior of either group. There were some ratedependent effects of both drug and schedule conditions.     

An analysis of the hyperactive syndrome: A comparison of hyperactive,behavior problem,asthmatic, and normal children

In an attempt to determine whether the commonly described deficits associated with hyperactivity — inappropriate activity, short attention span, low frustration tolerance, and impulsivity — are unique to this population, hyperactive, behavior problem, asthmatic, and normal control children were studied. The tests most often used in research with hyperactives were administered. Hyperactives, when compared to normals, did show deficits in the aforementioned areas. However, when compared to the behavior problem and asthmatic children only the attentional deficits clearly differentiated hyperactives from the other children.This research was supported, in part, by grants from the Ontario Ministry of Health (DM-304) and the Ontario Mental Health Foundation (#652-76A).     

Self-control behavior in hyperactive and nonhyperactive children

This study was aimed at evaluating the self-control behaviors of hyperactive (HA) and nonhyperactive (NHA) first-grade pupils under conditions of repeated failure on a previously learned concept formation task. Subjects were divided into HA and NHA groups on the basis of their scores on the Conners (1969) Teacher Rating Scale. During the training stage of the experiment the children learned a concept formation task under a schedule of contingent positive reinforcement. In the test stage they performed the same task but under a negative noncontingent reinforcement schedule. The results revealed no differences in initial rate of learning the task between the groups. After the introduction of the negative noncontingent reinforcement schedule, however, the HA group showed a marked decrease in the use of effective problem-solving strategies. The HA children's performance on the concept formation task was accompanied by the emission of negative self-evaluations and solution-irrelevant statements. The NHA group used significantly more statements showing useful goal directed cognitive mediations than the HA children. The results suggested that HA children may have deficits in self-control skills.Grateful acknowledgment is made to the two anonymous reviewers whose insightful comments were very helpful in producing the final form of this paper.     

Stimulus-seeking behavior in hyperactive and nonhyperactive children

Auditory and visual stimulus-seeking behavior was measured in hyperactive and nonhyperactive youngsters. The design controlled for motor activity level. The results indicate that hyperactive children preferred auditory stimulation more than the control children. There were no differences in stimulus-seeking preferences in the visual modality. The groups did not differ in motor activity. It was concluded that abnormally high needs for stimulation are important in hyperactivity.The authors would like to express their appreciation to James Fogarty, Superintendent, Walter Galvin, Principal, and the many teachers, students, and parents of the Greene Avenue Learning Center of BOCES II in Sayville, New York for their cooperation and support in this study. We would also like to thank Susan O'Leary, Ph.D. Director of the Point of Woods Laboratory School and the students and parents for participation and support in this study.     

Laterality and selective attention in hyperactive children

Laterality and selective attention were investigated in a group of 20 hyperactive children and their matched controls using a dichotic listening task. There was a strong rightear advantage for both groups indicating that hyperactive children were not different from normal children in hemispheric specialization for verbal stimuli. In the selective attention experiment hyperactive children were again not different from normal children in their ability either to select the input designated as relevant or to resist the distraction of input designated irrelevant. Both groups gave more correct responses from the right ear than from the left ear, and more intrusions from the right ear than from the left. The results do not suggest abnormalities of lateralization for verbal material or indicate the existence of a selective attentional deficit. It is suggested that such reported deftcits may be situation or taskspecific.     

Attention styles of hyperactive and normal girls

Behavioral characteristics and cognitive skills of teacher-identified hyperactive (n=24) and normally active (n=24) first- and second-grade girls were investigated. Teachers rated subjects on the Conners Teacher Rating Scale (TRS). Subjects were given several tasks measuring attentional styles and motor skills. Results suggested that hyperactive girls, like hyperactive boys, have short attention spans and poor concentration when compared with normals. Unlike hyperactive boys, hyperactive girls did not show an impulsive response style, and presented few conduct problems to their teachers. TRS profile patterns of the hyperactive girls were similar to those of hyperactive boys, but cutoff scores currently used for males may not be applicable to females. A direct comparison of hyperactive females and males is advocated.This study is based on a doctoral dissertation submitted to the Department of Psychology, Indiana University, by the first author. Thanks are expressed to the students and teachers of the Monroe County Community School Corporation who took part in the study.     

Focused attention in pervasively hyperactive children

This experiment was designed to investigate the hypothesized distractibility of hyperactive children in a focused attention task. Distractibility was defined in terms of Shiffrin and Schneider's model of focused attention as the ability to ignore irrelevant in favor of relevant information. Failure to inhibit processing of irrelevant information indicates a focused attention deficit. Task efficiency in all children decreased when irrelevant information was presented. The mean reaction time, within-subject variance of reaction time, and error percentage all increased compared with a nondistraction condition. Thus, the demands of focused attention, as formulated in the model, were measured optimally. Since hyperactives and controls did not differ significantly with respect to task efficiency in the distraction condition, a focused attention deficit in hyperactives was not demonstrated. The hyperactives did nevertheless make more errors and their responding was more variable than the controls. However, the difference in error percentages between hyperactives and controls was associated with the difference in IQ. It is speculated that the variable responding in hyperactives is caused by a less optimal state of performance unrelated to distractibility.The authors wish to thank L. Leertouwer for making the drawings. This research was supported by grants from the Netherlands Foundation for the Advancement of Pure Research (ZWO) and the Professor Duijker Fund.     

Auditory attention switching in hyperactive children

The ability to rapidly reorient attention in the auditory modality was studied in hyperactive children. Hyperactive and nonhyperactive subjects matched on age, sex, and IQ listened to dichotically presented lists for prespecified targets. Reorientation was studied by comparing performance on trials requiring subjects to reorient their attention during a list to performance on trials requiring no switching of attention. The results indicate that although nonhyperactive children were temporarily disrupted by the switch, they eventually reoriented to the cued ear. In contrast, once hyperactive children were disrupted by the switch, they did not reorient to the cued ear. As the pattern in performance comparing hyperactive and nonhyperactive subjects resembles the pattern previously found in comparing younger and older subjects, these results are consistent with the hypothesis that the auditory reorientation skills of hyperactive children are developmentally immature.     

The effects of reward and punishment on reaction times and autonomic activity in hyperactive and normal children

The performance of hyperactive and control children was compared on a delayed reaction time task under three reinforcement conditions: reward, punishment, and reward plus punishment. Hyperactives had slower and more variable reaction times, suggesting an attentional deficit. Although each of the three reinforcement conditons was successful in improving reaction times for both subject groups, reward led to a significant increase in impulsive responses in the hyperactive children. Autonomic data revealed that reward also increased arousal to a greater extent than punishment or reward plus punishment. Although resting skin conductance was not different in the two groups of subjects, hyperactives produced fewer specific autonomic responses to signal stimuli.     

Production deficiencies in free recall: A comparison of hyperactive,learning-disabled,and normal children

Free recall of weakly categorizable words was compared in hyperactive (ADDH), reading-disabled, and normal boys. During a baseline trial, hyperactive boys recalled fewer words and showed less category organization than both reading-disabled and normal boys. Following a manipulation designed to encourage semantic encoding of words, hyperactive boys showed an immediate improvement in item recall and organization so that their free-recall performance was similar to that of reading-disabled and normal children. During later trials of a multiple-trial format, hyperactive boys recalled fewer words than did the reading-disabled and normal boys, despite maintaining equality in category organization. Rather than lacking the skill to use semantic organization as a strategy in free recall, hyperactive boys had difficulty in spontaneously generating the organizational strategy in response to instructions to remember and sustaining sufficient effort to task completion.     

Psychostimulant medication and perceived intensity in hyperactive children

Adult ratings of children's activity, based on impressionistic scales, are good indicators of psychostimulant medication effects. These ratings seldom correlate with objective indicators, however, and their behavioral referents are poorly understood. Two separate studies tested the hypothesis that intensity of child behavior, as perceived by others, would differentiate medicated and unmedicated states. College student subjects assessed randomized videotaped segments of children's behaviors. The perceived intensity of hyperactive children's responses decreased with medication, while there were no medicationrelated changes in either gross motor locomotion or off-task behaviors. In a test for observer sensitization or expectancy, the results for subjects who were looking for medication effects did not differ from those for uninformed subjects.This research was supported in part by NIMH grant 29475 and NIDA grant 01070. We thank Andy Christensen and Carol Whalen for helpful comments.     

Methylphenidate in hyperactive children: Differential effects of dose on academic,learning, and social behavior

Methylphenidate (Ritalin) has been shown to have differential effects on hyperactive children's behavior as a function of dose level. In the present investigation, a triple-blind, placebo-control, within-subject (crossover) experimental design was employed in which 12 hyperactive boys between 6 and 10 years received three different dosages of methylphenidate (5, 10, and 15 mg) in a randomly assigned sequence. Dosage effects were assessed on clinic(PAL-Paired Associates Learning test) and school-(percent on task, teacher ratings, work completion rates, and accuracy) related behaviors. For 10 of the children, classified as responders to medication by the PAL using the criteria of Swanson, Kinsbourne, and colleagues, a series of ANCOVAs with repeated measures showed significant dosage effects on teacher ratings (p 01), percent on task (p 01), academic accuracy (p 05), and assignment completion rates (p 05). PAL performance was also significantly enhanced (p 01) after optimal dose levels were considered. Subsequent trend analysis showed a significant positive linear relationship between dose and each of the dependent variables. A comparison of fixed-dose and miligram-per-kilogram plots showed that children's performance across the different dosages were clearly individualistic and task-specific, even when similar body weights were compared. The implications of using clinic-based testing to determine optimal medication responsivity were discussed.We would like to express our sincere appreciation to the following pediatricians for their valuable assistance: W. H. McDermott, D. J. Chronley, R. B. Trivett, F. J. Jehle, P. M. Small, and F. T. Leong. Grateful acknowledgement is also extended to the two anonymous reviewers whose comments contributed to the content of this paper, and to the undergraduate and graduate student members of the Children's Learning Clinic.     

An analysis of observational learning in autistic and normal children

The present investigation studied observational learning in autistic children. Fifteen autistic and 15 normal children watched an adult model engage in a set of behaviors under specific verbal instructions. After observing this situation, the children were tested to determine what they had acquired through observation. The results showed that (1) the majority of the autistic and the youngest normal children acquired only some limited features of the observational situation and (2) chronological age was related to the amount of learning through observation in the normal children but not in the autistics. The deficit that the autistic children showed in observational learning may be related to a failure to discriminate or attend to the total stimulus input presented. Their failure in observational learning can be seen to contribute in a major way to the severely impoverished behavioral repertoires of these children.     

Effects of event rate and display time on sustained attention in hyperactive,normal, and control children

Two experiments were conducted to determine whether hyperactive boys have a unique deficit in sustained attention. Groups with DSM-III diagnoses of attention deficit disorder (ADDH), conduct disorder (CD), ADDH+CD, and learning disorder were compared with normal controls on the Continuous Performance Task. In Experiment 1, stimulus presentation rate (stimulus onset asynchrony, SOA) and display time were varied to manipulate attentional demand, and speed and accuracy of performance were measured. The ADDH group was uniquely affected, with less accurate performance at the fastest and slowest SOA. To distinguish the effects of time on task and SOA, the duration of each SOA condition was held constant in Experiment 2. The poorer performance of the ADDH group at the fastest SOA was no longer evident. This finding indicates that the deficit of sustained attention in boys who have ADDH is associated with a greater susceptibility to refractory effects, which is influenced by practice.This research was supported by the Ontario Mental Health and Ruth Schwartz Foundations through a graduate fellowship awarded to P. Chee and a research grant to R. Schachar, G. Logan, and R. Wachsmuth. Dr. Schachar was also supported by the Canadian Psychiatric Research Foundation. This article is based, in part, on a doctoral dissertation submitted by the first author to the Ontario Institute for Studies in Education. The authors thank Dr. John Lovering and the staff of the Departments of Psychiatry and Psychology, The Hospital for Sick Children, for their cooperation in the conduct of this study. This paper was prepared with the assistance of the Medical Publications Department, The Hospital for Sick Children, Toronto.