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Biomedical subjects

R Tannock

Publications and source records attributed to R Tannock.

At least 55 records · Page 3Linked to original sources
PubMed1999

Response to methylphenidate in children with ADHD and comorbid anxiety.

OBJECTIVE: To determine whether comorbid anxiety alters response to methylphenidate (MPH) in children with attention-deficit hyperactivity disorder (ADHD). METHOD: Ninety-one children with ADHD were assessed for anxiety. Children were randomly assigned to receive MPH or placebo, titrated to a dose of 0.7 mg/kg, while side effects were minimized. Measures of side effects and behavioral response were obtained from parents and teachers before treatment, after titration to optimal dose, and after 4 months of treatment. These measures, dose of drug, and rate of adherence to assigned medication assignment were compared for nonanxious (ADHD- ANX) and anxious ADHD children (ADHD+ ANX). RESULTS: Rates of adherence to original medication assignment did not differ between the groups. ADHD+ ANX on both MPH and placebo titrated to a lower dose at the end of titration, although the dose of drug did not differ among the groups after 4 months of treatment. No differential response to MPH between ADHD+ ANX and ADHD- ANX was noted at end-titration or at 4 months on any side effect or behavioral measures. CONCLUSIONS: Comorbid anxiety does not appear to influence development of side effects or behavioral response to MPH when dose is titrated as in standard clinical practice.

Anxiety Disorders↗
PubMed1999

Sleep problems in children with attention-deficit/hyperactivity disorder: impact of subtype, comorbidity, and stimulant medication.

OBJECTIVE: To determine the relationship of sleep problems to attention-deficit/hyperactivity disorder (ADHD), diagnostic subtype, comorbid disorders, and the effects of stimulant treatment. METHOD: On the basis of clinical diagnostic interviews, children aged 6 to 12 years were assigned to 4 groups: unmedicated ADHD (n = 79), medicated ADHD (n = 22), clinical comparison (n = 35), and healthy nonclinical comparison (n = 36). These groups were compared on 2 sleep questionnaires completed by the parents that assessed current sleep problems and factors associated with sleep difficulties (i.e., sleep routines, sleep practices, child and family sleep history). RESULTS: Factor analysis revealed 3 sleep problem categories: dyssomnias, parasomnias, and sleep-related involuntary movements. Linear regression analyses showed that (1) dyssomnias were related to confounding factors (i.e., comorbid oppositional defiant disorder and stimulant medication) rather than ADHD; (2) parasomnias were similar in clinical and nonclinical children; and (3) the DSM-IV combined subtype of ADHD was associated with sleep-related involuntary movements. However, sleep-related involuntary movements were more highly associated with separation anxiety. CONCLUSIONS: The results suggest that the relationship between sleep problems and ADHD is complex and depends on the type of sleep problem assessed as well as confounding factors such as comorbid clinical disorders and treatment with stimulant medication.

Attention Deficit Disorder with Hyperactivity↗
PubMed1998

Sleep disturbances in children with attention-deficit/hyperactivity disorder.

OBJECTIVE: To evaluate the relationship between sleep disturbances and attention-deficit/hyperactivity disorder (ADHD). METHOD: Empirical research published since 1970 on sleep disturbances in children with ADHD was systematically reviewed. A "box-score" approach was used to examine consistency of findings across the studies, which used different outcome measures. RESULTS: Although subjective accounts of sleep disturbances in ADHD were prevalent, objective verification of these disturbances was less robust. The only consistent objective findings were that children with ADHD displayed more movements during sleep but did not differ from normal controls in total sleep time. An additional finding was that stimulant medication led to changes in the children's sleep (e.g., prolonged sleep latency, increased length of onset to first rapid eye movement cycle), but these changes were believed to be nonpathological. CONCLUSIONS: The exact nature of the sleep problems in children with ADHD remains to be determined. Many of the relevant issues have not been adequately addressed. Factors such as poorly defined diagnostic groups, small sample sizes, few studies, and methodological and procedural limitations make it difficult to determine the relationship between ADHD and sleep problems.

Attention Deficit Disorder with Hyperactivity↗
PubMed1998

Attention deficit hyperactivity disorder: advances in cognitive, neurobiological, and genetic research.

Conceptual and technological advances in cognitive neuroscience and molecular genetics have the potential to identify the pathogenesis of psychiatric disorders. This article reviews the application of these technologies to the scientific study of attention deficit hyperactivity disorder. It begins with a summary of shifts in conceptualization and scientific study of this common condition. This is followed by a critical review of findings from recent cognitive, neuroimaging, and genetic studies. The available data do not yet permit an integration across these different levels of enquiry, but implicate problems in response inhibition, dysfunction of frontostriatal networks, and genetic factors in the pathogenesis of this complex behavioral phenotype. The review closes with suggestions for future interdisciplinary research.

Attention Deficit Disorder with Hyperactivity↗
PubMed1997

Language abilities in children with attention deficit hyperactivity disorder, reading disabilities, and normal controls.

Research has demonstrated a high prevalence of language impairments (LI) and reading disabilities (RD) in children with attention deficit hyperactivity disorder (ADHD). Since RD is also associated with LI, it is unclear whether the language impairments are specific to ADHD or associated with comorbid RD. The language abilities of ADHD children with and without RD were investigated in a task requiring recall of a lengthy narrative, and in tests assessing knowledge of the semantic aspects of language. The study was conducted with 50 boys--14 ADHD, 14 ADHD + RD, 8 RD, and 14 normal controls, aged 7 to 11. Children with ADHD (ADHD-only, ADHD + RD) exhibited difficulties in organizing and monitoring their story retelling. Children with RD (RD-only, ADHD + RD) demonstrated deficits in receptive and expressive semantic language abilities on the language processing tests. The comorbid group (ADHD + RD) exhibited the deficits of both ADHD and RD children. The deficiencies of ADHD children are consistent with higher-order executive function deficits while the deficits of RD children are consistent with deficits in the basic semantics of language processing.

Achievement↗
PubMed1997

Behavioral, situational, and temporal effects of treatment of ADHD with methylphenidate.

OBJECTIVE: To determine the behavioral, situational, and temporal effects of 4 months of methylphenidate (MPH) treatment for attention-deficit hyperactivity disorder (ADHD). METHOD: Ninety-one children with ADHD were randomly assigned to receive either MPH (titrated to a target dose of 0.7 mg/kg twice a day) or a placebo. Treatment effects were investigated with measures sensitive to various behaviors (core and associated symptoms), situations (home and school), time periods (morning and afternoon, after reaching the target dose, and after 4 months of treatment), and side effects. RESULTS: MPH treatment improved symptoms of ADHD and oppositional behavior at school, both in the morning and afternoon, but not at home. Side effects (increase in physiological and effective symptoms, lack of weight gain) were significantly more frequent with MPH than with placebo treatment. Benefit was evident after titration, but the onset of some side effects was delayed. Side effects were reported by parents but not by teachers. CONCLUSIONS: Positive effects of MPH on behavior are evident in the classroom, but with MPH given twice daily, parents do not report that MPH improves behavior at home. Greater impact on home behavior may require three times daily MPH and combined treatments.

Affect↗
PubMed1997

Impact of comorbid oppositional or conduct problems on attention-deficit hyperactivity disorder.

OBJECTIVE: To investigate whether the presence of comorbid oppositional defiant disorder (ODD) or conduct disorder (CD) alters the correlates of attention-deficit hyperactivity disorder (ADHD). METHOD: Three groups of children (33 "pure" ADHD, 46 ADHD + ODD, and 12 ADHD + CD) were compared on measures of ADHD, aggression, anxiety, parental psychopathology, self-esteem, school, and social-emotional functioning. RESULTS: Findings indicated that the presence of comorbid oppositional or conduct problems in children with ADHD altered the correlates of ADHD across a number of areas, including greater ADHD symptom severity and social dysfunction. Nevertheless, some correlates were more closely linked with the comorbid condition of ADHD + CD (e.g., higher aggression, anxiety, and maternal pathology, as well as decreased self-esteem), while others appeared more closely linked with ADHD + ODD (e.g., social withdrawal, elevated academic achievement paired with higher perceived scholastic competence). CONCLUSIONS: Findings support the distinctive profiles of the disruptive behavior disorder groups and emphasize the deleterious effects on the quality of life experienced by the comorbid conditions. The need for syndrome-specific interventions is stressed.

Achievement↗
PubMed1996

Cognitive differences between anxious, normal, and ADHD children on a dichotic listening task.

To compare the performance of children with anxiety disorders with that of children with attention-deficit hyperactivity disorder (ADHD) and normal controls in the processing of emotional information. A total of 57 children ages 8 to 11 years (18 anxious, 20 ADHD, 19 normal control) were administered a dichotic listening task for the detection of words and emotions. Comparisons of overall performance, false alarms, and a sensitivity index (which took false alarms into account) were done using repeated measures analyses of variance. Anxious children made fewer false alarms for emotion targets compared to both ADHD children and normal controls, and fewer false alarms for words compared to normal controls. When controlling for false alarms, their performance exceeded that of both ADHD children and normal controls. There were no group differences in correct responses. Performance on a dichotic listening task differentiates anxious, ADHD, and normal children, particularly when listening for emotional targets. Further studies using this task may therefore elucidate differences in the processing of words and emotions between these three groups of children.

Anxiety Disorders↗
PubMed1995

Methylphenidate and cognitive flexibility: dissociated dose effects in hyperactive children.

A randomized, double-blind, placebo-controlled trial was conducted to assess the acute effects of placebo and three doses of methylphenidate (MPH) (0.3, 0.6, 0.9 mg/kg) on cognitive flexibility and overt behavior in 28 children with a confirmed diagnosis of attention deficit-hyperactivity disorder. Two underlying cognitive processes (response inhibition and response reengagement) were assessed by measuring the probability and speed with which subjects could inhibit responses to a primary task (forced-choice letter discrimination) and immediately execute a response to a secondary task (simple reaction time) when given a signal to do so. Results indicated that MPH enhanced cognitive flexibility, although the high dose was less effective than lower doses in enhancing response inhibition. Dissociations of dose effects on cognitive function and behavior were demonstrated: Dose-response functions for changes in behavior were linear, whereas the function for response inhibition was U-shaped. Findings argue against the typical clinical practice of determining the response to stimulant treatment from a single measure such as parent report of child behavior.

Arousal↗
PubMed1995

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.

Attention Deficit Disorder with Hyperactivity↗
PubMed1995

Test of four hypotheses for the comorbidity of attention-deficit hyperactivity disorder and conduct disorder.

OBJECTIVE: To study the basis of the comorbidity of two common psychiatric disorders of childhood: attention-deficit hyperactivity disorder (ADHD) and conduct disorder (CD). METHOD: Subjects were 45 boys (aged 7 to 11 years) with either ADHD, CD, or ADHD + CD and 16 normal control children (NC) studied by means of a 2 (ADHD versus no ADHD) x 2 (CD versus no CD) design. We (1) tested whether similar or different patterns of cognitive, developmental risk, and psychosocial factors characterize the "pure" forms of the two disorders (i.e., ADHD and CD), and (2) compared the profile of the comorbid group (ADHD + CD) with those of the two pure groups. RESULTS: The ADHD group was significantly impaired on cognitive measures (inhibitory control and response alteration) and had greater delay in development and greater reading problems compared with CD and NC children; the CD group was exposed to significantly greater environmental adversity and had more severe problems in arithmetic than the ADHD and NC groups. The ADHD+CD group was similar to the ADHD group on cognitive, developmental, and reading measures and similar to the CD group on psychosocial and arithmetic measures. CONCLUSIONS: These results support the distinctiveness of ADHD and CD and the hypothesis that the comorbid condition of ADHD + CD is a hybrid of pure ADHD and pure CD.

Attention Deficit Disorder with Hyperactivity↗
PubMed1995

Differential effects of methylphenidate on working memory in ADHD children with and without comorbid anxiety.

OBJECTIVE: To examine the effects of methylphenidate (MPH) on working memory and behavior in anxious and nonanxious children with attention-deficit hyperactivity disorder (ADHD). METHOD: A total of 40 ADHD children (22 nonanxious, 18 anxious) completed a randomized, double-blind, placebo-controlled, crossover trial with three doses (0.3, 0.6, 0.9 mg/kg) of MPH. A serial addition task was used to assess working memory; direct observation of motor activity indexed behavior. RESULTS: MPH improved working memory in the nonanxious ADHD group but not in the comorbidity anxious group. By contrast, MPH reduced activity level in both groups. The presence of concurrent learning disabilities did not influence stimulant response. CONCLUSIONS: The presence of comorbid anxiety in children with ADHD predicts a less robust response to stimulant treatment and suggests that ADHD with anxiety may constitute a distinct and clinically meaningful subtype of ADHD.

Anxiety Disorders↗
PubMed1994

Correlates of directiveness in the interactions of fathers and mothers of children with developmental delays.

Twenty preschool-age children with developmental delays and language impairment participated in this study, which compared fathers' and mothers' directiveness and parental stress. Similarities between fathers and mothers were found for turntaking control, response referents, and responses to the child's participation. However, fathers differed from mothers in two of the dimensions of directiveness examined: fathers used more response control and topic control than mothers. Both parents reported similarly low levels of child-related and parenting stress, but mothers perceived more stress than fathers related to the responsibilities associated with parenting a child with a handicap. Correlations between directiveness, child characteristics, and stress revealed that fathers used greater turntaking control and topic control with children who were developmentally less mature, whereas mothers used greater topic control with children who were less involved in interaction. Both fathers' and mothers' use of response control was positively related to stress. Implications for involving fathers in parent-focused intervention include screening father-child interactions before intervention, interpreting parent-child interaction styles in terms of their role in enhancing the child's social participation, and acknowledging the role of familial factors (such as stress) on interaction styles.

Adult↗
PubMed1993

Narrative abilities in children with attention deficit hyperactivity disorder and normal peers.

A story retelling task was used to assess narrative abilities in 30 boys with attention deficit hyperactivity disorder (ADHD) and 30 normally developing boys, matched on age and IQ. Each boy listened to two stories and retold them for another child. Results indicated that the two groups did not differ in their ability to comprehend and extract the main ideas from the stories, but did differ in the production of narratives. Boys with ADHD provided less information overall, and their stories were more poorly organized and less cohesive and contained more inaccuracies. As a result, their stories were often confused and hard to follow. Organization and monitoring of information are functions of executive control. Thus the observed deficits in narrative production in children with ADHD may reflect underlying deficits in executive processes.

Attention Deficit Disorder with Hyperactivity↗
PubMed1992

Methylphenidate and cognitive perseveration in hyperactive children.

Effects of methylphenidate on cognitive flexibility were investigated in 26 children with Attention Deficit Hyperactivity Disorder (ADHD), by assessing perseverative errors on the Wisconsin Card Sorting Test (WCST) and the emergence of clinical symptoms indicative of cognitive perseveration. A double-blind, placebo-control, randomized crossover design was used in which each child was assessed twice in each drug condition (placebo, 0.3 and 1.0 mg/kg). Results indicated that methylphenidate increased perseverative errors on the first assessment but decreased them on the second; clinical symptoms of perseveration occurred at both assessments. Findings suggest that MPH may reduce cognitive flexibility temporarily in some ADHD children.

Attention↗
PubMed1992

Language intervention with children who have developmental delays: effects of an interactive approach.

The interactive model of language intervention instructs parents to use techniques that promote reciprocal social interactions and facilitate the development of communication and language abilities. In this evaluation study, 32 mothers and their preschool-age children with developmental delays were randomly assigned to treatment and control (delayed treatment) groups. Consistent with the interactive model, mothers in the treatment group became more responsive, less directive, and provided clearer linguistic models. Furthermore, these changes were maintained for at least 4 months after intervention, and involvement in the parent-centered intervention program did not increase maternal stress. More important, these changes were accompanied by concomitant increases in children's use of vocal turns. Contrary to predictions, developmental improvements in children's communicative and linguistic abilities were comparable in both groups. Findings suggest that an interactive model may afford a useful adjunct to other intervention approaches by instructing parents on how to promote children's use of existing abilities, but an interactive model may have no effect on language acquisition of at least some children with developmental delays.

Adult↗
PubMed1989

Effects of methylphenidate on inhibitory control in hyperactive children.

This study investigated the effects of methylphenidate (MPH) on inhibitory control in hyperactive children. A double-blind, placebo-control, within-subject (crossover) design was used in which 12 children, between 6 and 11 years of age, were each tested four times in each drug condition: 0.3 mg/kg and 1.0 mg/kg of methylphenidate, and placebo. Dependent measures included (a) the probability of inhibiting responses to a primary choice reaction time task given a stop signal, on the Stopping Task, and (b) response latency and errors on the Matching Familiar Figures Test (MFFT). MPH improved the efficiency of the central inhibitory mechanism by speeding the inhibitory process, thereby affording the children greater control over their actions and enabling them to increase the probability with which they inhibited responses given a stop signal. MPH increased response latency but did not reduce errors on the MFFT, and observation of the children's task performance highlighted the interpretive problems associated with this task. Performance on both tasks was better at a dosage of 1.0 mg/kg than at 0.3 mg/kg.

Arousal↗