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Biomedical subjects

V I Douglas

Publications and source records attributed to V I Douglas.

10 recordsLinked to original sources
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↗
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↗