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Biomedical subjects

V I Douglas

Publications and source records attributed to V I Douglas.

At least 19 recordsLinked to original sources
PubMed1998

Effect of reinforcement on facial responsivity and persistence in children with attention-deficit hyperactivity disorder.

Children with Attention Deficit-Hyperactivity Disorder (ADHD) may learn poorly under conditions of inconsistent (partial) reinforcement because they are easily frustrated and fail to develop persistence. To test this hypothesis, a nonsense word spelling task was used with 22 ADHD and 20 control children to investigate the effects of partial and continuous reinforcement on facial responsivity (frustration measure), words spelled correctly (learning performance measure), and persistence ratings. Partially reinforced ADHD children manifested higher levels of frustration in both acquisition and extinction than any other group and gave significantly lower persistence ratings across acquisition than partially reinforced control children. ADHD children spelled fewer words correctly than controls, regardless of reinforcement schedule. These findings suggest that partial reinforcement training develops persistence in normal but not ADHD children. The findings have theoretical implications for the etiology of ADHD as well as practical implications for designing behavior modification programs to treat ADHD.

Attention↗
PubMed1997

Psychophysiological response of ADHD children to reward and extinction.

In this study, we examined heart rate and skin conductance levels of 18 children with attention-deficit hyperactivity disorder (ADHD) and 18 normal children as they performed a repetitive motor task during reward and extinction conditions. Fowles (1980, Psychophysiology, 17, 87-104; 1988, Psychophysiology, 25, 373-391) suggested that psychophysiological responsivity reflects activity in two of Gray's (1982, The neuropsychology of anxiety, Oxford University Press; 1987, The psychology of fear and stress, Cambridge University Press) motivational systems; heart rate reactivity during reward reflects activity in the behavioral activation system, and skin conductance reactivity during extinction reflects activity in the behavioral inhibition system. As predicted, control children showed increased heart rate when reward was present and increased skin conductance when reward was removed. Compared with controls, ADHD children failed to show increased skin conductance levels during extinction, suggesting a weak behavioral inhibition system. ADHD children also displayed faster heart rate habituation to reward.

Adolescent↗
PubMed1996

Rehearsal strategies and recall performance in boys with and without attention deficit hyperactivity disorder.

Examined differences in recall performance and rehearsal strategies in boys with Attention Deficit Hyperactivity Disorder (ADHD) and comparison boys using an overt rehearsal procedure on a self-paced, multitrial, free recall task. Boys with ADHD recalled fewer words, tended to spend less time rehearsing the items, and spent less time attempting to retrieve them. Although they did not rehearse items less frequently than comparison boys, they relied almost exclusively on repetition of single items. In contrast, comparison boys showed some evidence of using active, multi-item (cumulative) rehearsal. Despite their failure to use cumulative rehearsal, boys with ADHD identified it as more effective than single-item rehearsal in a subsequent forced-choice assessment of strategy knowledge.

Analysis of Variance↗
PubMed1995

Do high doses of stimulants impair flexible thinking in attention-deficit hyperactivity disorder?

OBJECTIVE: To test the hypothesis that high doses of methylphenidate (MPH) impair cognitive flexibility in attention-deficit hyperactivity disorder (ADHD). METHOD: A double-blind crossover design was used in an acute dosage trial to assess effects of three dosages (0.3, 0.6, and 0.9 mg/kg) of MPH on the performance of 17 ADHD children on five tasks designed to assess divergent thinking, perseveration, and ability to shift mental set. The tasks also assessed convergent thinking, problem solving, and speed and accuracy of processing. RESULTS: There was minimal evidence of deleterious effects on flexible thinking or other cognitive processes, either in the ADHD group as a whole or in any subgroup. The most common pattern indicated linear improvement across dosages. CONCLUSIONS: Under the acute dosage conditions used in this study, MPH doses up to 0.9 mg/kg had an increasingly positive effect on measures of mental flexibility and other cognitive processes. Rather than eliciting perseveration, MPH appeared to improve persistence. The generalized nature of the cognitive and motivational changes observed suggests that MPH acts on central, self-regulatory processes. Because effects of two or more daily doses can accumulate when MPH is prescribed in the clinical situation, clinical doses of more than 0.6 mg/kg were not recommended.

Attention Deficit Disorder with Hyperactivity↗
PubMed1994

Effects of reward and nonreward on frustration and attention in attention deficit disorder.

The effects of reward schedule (100%, 50%, and 30%) and termination of rewards (extinction) on 30 attention deficit disorder with hyperactivity (ADD-H) and 30 normal children were studied using measures of frustration (speed/strength of lever pulling) and attention (reaction time to a light signal). ADD-Hs pulled harder on the lever than controls during extinction and on the lowest (30%) partial schedule, providing empirical evidence that they respond with greater frustration than normals when expected rewards fail to appear. The groups did not differ on the attentional measure on 100% reward. However, the partial schedules appeared to have an alerting or motivating effect on the controls, so that they responded more quickly and consistently than ADD-Hs on the partial schedules. Findings are discussed with reference to opposing theories regarding the nature of the abnormal response of ADD-Hs to reward.

Analysis of Variance↗
PubMed1992

Attention deficit hyperactivity disorder and the frontal lobe syndrome.

The usefulness of frontal lobe (FL) dysfunction as a conceptual model for Attention Deficit Hyperactivity Disorder (ADHD) was investigated. Twenty-four ADHD and 24 normal control (NC) children were tested using two batteries of tasks. The first was sensitive to FL deficits in motor control and problem solving skills. The second consisted of memory tasks sensitive to temporal lobe dysfunction. ADHD children differed significantly from NCs on measures of FL function, but not on tests of temporal lobe functions. Where norms were available for normal children on the same FL tests, ADHDs performed like 6- to 7-year-olds, despite their mean age of 10 years and minimum age of 8 years. The differential performance of ADHDs on tasks sensitive to FL and temporal lobe dysfunction supports the hypothesis that ADHD deficits are analogous to FL dysfunction and demonstrates that the children's deficits do not reflect generalized cognitive impairment.

Attention Deficit Disorder with Hyperactivity↗
PubMed1991

Study strategies and story recall in attention deficit disorder and reading disability.

The role of metacognition and executive processes in mediating use of study skills was examined in groups of attention deficit disorder with hyperactivity (ADD-H), normal, and non-ADD-H reading-disabled (RD) boys, matched on age and verbal IQ. On a story recall task, ADD-H boys did not differ from normals in their immediate gist recall of a story or in their recall following a study period. RD boys demonstrated inferior recall in both conditions. Study skills of the ADD-H boys were poorer than those of normal boys on all measures. They spent less time studying, expended less effort, and employed more superficial strategies. However, their poor strategies did not appear to reflect a lack of metacognitive awareness. Results are discussed in terms of the impact of motivational variables in modulating strategy use in ADD-H boys and the impact of verbal processing problems in reading disabilities. Implications for treatment and the relationship between ADD-H and RD are discussed.

Achievement↗
PubMed1990

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.

Attention↗
PubMed1988

Short-term serial recall in ADDH, normal, and reading-disabled boys.

Short-term retention of verbal items of span and subspan length was examined in hyperactive (ADDH), normal and non-ADDH reading-disabled boys. Performance of ADDH and normal boys did not differ on three measures of verbal serial recall. Thus, it appears that the cognitive deficits of ADDH children cannot be attributed to deficient retention of stimuli. In contrast, reading-disabled (RD) boys performed significantly more poorly than both normal and ADDH boys when required to recall verbal items following "filled" delay intervals in which the children were required to perform a competing verbal activity. The results suggest that verbal encoding of RD children is particularly vulnerable to interference from other verbal stimuli. ADDH and RD children may represent subsamples of children demonstrating academic difficulties, with each group showing a characteristic pattern of cognitive deficits.

Attention↗
PubMed1988

Dosage effects and individual responsivity to methylphenidate in attention deficit disorder.

Effects of three dosages of methylphenidate (0.15, 0.30 and 0.60 mg/kg) were assessed in 19 ADD-H children on a variety of cognitive, academic and behavioral measures in the laboratory and the classroom. A predominant linear pattern of improvement was found across almost all measures. A slight decrease between 0.3 and 0.6 mg/kg on one cognitive task leaves open the possibility that higher dosages reduce stimulant effectiveness or cause decrements on some kinds of "high-level/high load" tasks. Response patterns of individual children varied considerably across measures. All children improved on at least several measures. Results were interpreted as evidence for stimulant activation of self-regulatory processes.

Attention↗
PubMed1986

Short term effects of methylphenidate on the cognitive, learning and academic performance of children with attention deficit disorder in the laboratory and the classroom.

Sixteen children meeting diagnostic criteria for Attention Deficit Disorder with Hyperactivity (ADD-H) were tested on methylphenidate (0.3 mg/kg) and placebo on cognitive, learning, academic and behavioral measures in a double-blind study. Assessments were carried out in the laboratory and in the children's regular classrooms. Results indicate methylphenidate-induced improvements on a majority of the measures. Drug-induced changes reflected increased output, accuracy and efficiency and improved learning acquisition. There was also evidence of increased effort and self-correcting behaviours. It is argued that reviewers have underestimated the potential of stimulants to improve the performance of ADD-H children on academic, learning and cognitive tasks.

Achievement↗
PubMed1983

Effects of reward on delayed reaction time task performance of hyperactive children.

This experiment was designed to investigate the effects of continuous, partial, and noncontingent schedules of reward, as well as the withdrawal of rewards, on the performance of hyperactive and normal control children on a delayed reaction time task. Although noncontingent reward resulted in faster reaction times for control subjects, performance of hyperactives deteriorated under noncontingent reward and improved when it was withdrawn. Also, reaction times of controls during extinction remained superior to baseline, whereas performance of hyperactives returned to baseline level. It was suggested that these and other findings reviewed point to an unusual sensitivity to rewards in hyperactive children.

Attention Deficit Disorder with Hyperactivity↗
PubMed1983

Effects of reinforcement on concept identification in hyperactive children.

The effects of continuous and partial reward on the performance of hyperactive and normal children on a concept identification task were compared. Because reduction in information feedback is usually associated with partial reward schedules, the study was designed to yield information regarding the contribution of reduced feedback to performance in the partial reward condition. Previous findings of a performance deficit in hyperactives under partial reward were replicated. The findings help rule out an information feedback explanation for this deficit. The authors suggest that a motivational factor involving the elicitation of frustration when expected rewards fail to appear may be responsible for the poor performance of hyperactives on the partial schedule.

Attention Deficit Disorder with Hyperactivity↗
PubMed1982

Problem solving in hyperactive, normal, and reading-disabled boys.

Diagnostic problem solving was examined in groups of hyperactive, normal, and nonhyperactive reading-disabled boys matched on age and verbal IQ. On the matrix solution task employed (a version of the game of 20 Questions) hyperactives used less efficient questions and strategies than the other two groups, in spite of the task being designed to maximize the performance of the hyperactives. Reading-disabled children were not significantly worse than normal children on the task. The results were interpreted as suggesting that the attentional difficulties of hyperactives retard the development of strategies for solving complex problems. Nonhyperactive reading-disabled children may be less affected in this area because of the absence of significant attentional difficulties.

Attention↗
PubMed1976

Assessment of a cognitive training program for hyperactive children.

Modeling, self-verbalization, and self-reinforcement techniques were used to train hyperactive children in more effective and less impulsive strategies for approaching cognitive tasks, academic problems, and social situations. Eighteen hyperactive children took part in the training program. The control group, which received no training, consisted of 11 children, matched with the experimental group on age, IQ, and measures of hyperactivity and impulsivity. Several tests and measures, some of which have been shown to differentiate between hyperactive and normal children, were administered prior to training at the end of the 3-month training period, and after a further 3-month period in which no training took place. The trained group showed significantly greater improvement on several of the measures, both at the time of posttesting and on the follow-up evaluation.

Attention↗