Biomedical subjects

R Tannock

Publications and source records attributed to R Tannock.

59 records · Page 4Linked to original sources

PubMed1989

Dose-response effects of methylphenidate on academic performance and overt behavior in hyperactive children.

In the present study, the effects of 0.3 mg/kg and 1.0 mg/kg of methylphenidate on the overt behavior and academic functioning of 12 children with an established diagnosis of attention deficit disorder with hyperactivity were evaluated. A double-blind, placebo-control, within-subject (crossover) design was used, in which each child was tested four times in each drug condition. Drug conditions were alternated on a bidaily basis and each child received two different drug conditions each day. The academic tasks were designed for evaluation of the relationship between task complexity and dose. Whereas overt behavior improved with increasing dose, academic functioning was improved with methylphenidate, but did not vary with either dose or task complexity. Also, investigated were potential carryover effects of a morning dose of methylphenidate on performance in the afternoon. Behavioral and academic improvements produced by a dose of 0.3 mg/kg in the morning were no longer evident in the afternoon, but a morning dose of 1.0 mg/kg produced behavioral improvements that were clinically and statistically discernible in the afternoon, although the academic improvements had dissipated.

Attention Deficit Disorder with Hyperactivity↗

PubMed1988

Mothers' directiveness in their interactions with their children with and without Down syndrome.

Preschool-aged children (11 with and 11 without Down syndrome), individually matched for communicative ability, mental age, and demographic variables, were videotaped while interacting with their mothers during 15-minutes of free play in a simulated playroom. Maternal responsiveness and three components of maternal directiveness were examined in the context of the child's interactional behavior. Both groups of mothers used a high frequency of controls, but used them primarily to support and encourage the child's participation in interaction. Although mothers of children with Down syndrome exerted greater control in most of the aspects of directiveness, they were not less responsive. Mothers of children without Down syndrome were more likely to silently watch their children who, in turn, were more likely to initiate topics than were the children with the syndrome.

Attention↗

PubMed1987

A scanning computer access system for children with severe physical disabilities.

This article discusses scan access to microcomputers and describes a scanning keyboard designed to allow children who are severely physically disabled to access microcomputers for writing, playing, and engaging in educational activities. Two case examples are presented to illustrate potential applications of this keyboard.

Cerebral Palsy↗

PubMed1984

Do individuals with Down's syndrome possess right hemisphere language dominance?

A dichotic digits task with selective listening and attention-switching instructions, was administered to 10 mentally retarded individuals with Down's Syndrome between the ages of 10 and 37 years. Attention was focused on one ear for 20 trials before switching attention to the opposite ear after a 5-minute interval. A majority displayed a right ear-left hemisphere advantage for correct responses, although this advantage failed to reach significance. Comparison of left and right ear intrusion errors when each ear was attended first showed significantly more intrusions from the unattended right ear. No priming effects were found. The results do not support the hemispheric reversed specialization hypothesis. Rather, it is suggested that while Down's Syndrome individuals do possess an inherent left hemisphere advantage for language, such individuals may suffer from a left hemisphere information processing disorder that can produce functional reversals in dichotic listening.

Adolescent↗

PubMedDate not supplied

Attention deficit/hyperactivity disorder: characteristics, interventions and models.

An epidemiological study of Attention Deficit/Hyperactivity Disorder (ADHD) suggests that the prevalence may be two to three times higher than the figure of 3-5% often cited. In addition, the data suggest that both underdiagnosis and overdiagnosis occur frequently. Rodent animal models of ADHD, like the Spontaneously Hypertensive Rat (SHR) and other rat models such as those with chemical and radiation-induced brain lesions and cerebellar stunting, and the Coloboma mouse model exhibit clear similarities with several aspects of the human disorder and should prove useful in studying specific traits. Operant behavioral tasks that model learning, short-term memory and simple discriminations are sensitive to ADHD and methylphenidate has been shown to normalize ADHD performance in a short-term memory task. Recent findings challenge not only the current postulate that response inhibition is a unique deficit in ADHD, but also the concepts of ADHD and its treatment, which presume intact perceptual abilities. Time perception deficits may account, in part, for the excessive variability in motor response times on speeded reaction time tasks, motor control problems and motor clumsiness associated with ADHD. The Multimodality Treatment Study of ADHD (MTA) provided data suggesting that pharmacological interventions that included systematic and frequent follow-up with parents and teachers, with or without psychosocial interventions, are superior to psychosocial interventions or standard community care alone. Additionally, the MTA was one of the first studies to demonstrate benefits of multimodal and pharmacological interventions lasting longer than 1 year. Imaging studies have demonstrated differences in brain areas in children with ADHD: anterior corpus callosum, right anterior white matter, and cerebellar volumes are all decreased in children with ADHD and there is less brain asymmetry in ADHD subjects. Additionally, functional imaging studies, coupled with pharmacological manipulations, suggest decreased blood flow and energy utilization in prefrontal cortex and striatum and the dysregulation of catecholamine systems in persons with ADHD.

Animals↗