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Biomedical subjects

Rosemary Tannock

Publications and source records attributed to Rosemary Tannock.

At least 37 records · Page 2Linked to original sources
PubMed2005

Inhibition of motor responses in siblings concordant and discordant for attention deficit hyperactivity disorder.

OBJECTIVE: The authors sought to determine whether nonaffected siblings of ADHD probands have a motor response inhibition deficit and to assess concordance for this inhibition deficit in ADHD-concordant and ADHD-discordant sibling pairs. METHOD: ADHD-concordant pairs (21 probands and their affected siblings), ADHD-discordant pairs (18 probands and their nonaffected siblings), and a group of unrelated, demographically balanced, healthy individuals (N=24) were compared on measures of response inhibition, ADHD behavior, impairment, and environmental risk. RESULTS: Concordant-pair probands, their affected siblings, and discordant-pair probands exhibited inhibitory control impairment relative to healthy comparison subjects. The performance of nonaffected siblings was intermediate between that of ADHD children and the healthy comparison subjects. Group differences persisted after age was controlled, and performance was not correlated with the number of ADHD symptoms. In ADHD-concordant sibling pairs, there was a significant relationship between proband and sibling inhibition deficit. In ADHD-discordant sibling pairs, inhibition deficit was evident in half of the nonaffected siblings of probands with an inhibition deficit. Groups did not differ in exposure to environmental risks. CONCLUSIONS: Impaired inhibitory control aggregates in the family members of individuals with ADHD and may serve as an indicator of genetic vulnerability to the disorder.

Attention Deficit Disorder with Hyperactivity↗
PubMed2004

Reading comprehension and reading related abilities in adolescents with reading disabilities and attention-deficit/hyperactivity disorder.

Reading comprehension is a very complex task that requires different cognitive processes and reading abilities over the life span. There are fewer studies of reading comprehension relative to investigations of word reading abilities. Reading comprehension difficulties, however, have been identified in two common and frequently overlapping childhood disorders: reading disability (RD) and attention-deficit/hyperactivity disorder (ADHD). The nature of reading comprehension difficulties in these groups remains unclear. The performance of four groups of adolescents (RD, ADHD, comorbid ADHD and RD, and normal controls) was compared on reading comprehension tasks as well as on reading rate and accuracy tasks. Adolescents with RD showed difficulties across most reading tasks, although their comprehension scores were average. Adolescents with ADHD exhibited adequate single word reading abilities. Subtle difficulties were observed, however, on measures of text reading rate and accuracy as well as on silent reading comprehension, but scores remained in the average range. The comorbid group demonstrated similar difficulties to the RD group on word reading accuracy and on reading rate but experienced problems on only silent reading comprehension. Implications for reading interventions are outlined, as well as the clinical relevance for diagnosis.

Adolescent↗
PubMed2004

The Strengths and Difficulties Questionnaire overseas: evaluations and applications of the SDQ beyond Europe.

BACKGROUND: During the few years that have passed since it became available, the Strengths and Difficulties Questionnaire (SDQ) has been extensively evaluated and widely applied to assess behaviour disorders of children and adolescents in European countries. In contrast, relatively few reports have published SDQ results obtained in other parts of the world, although its briefness and availability in over 40 languages make this instrument particularly attractive for international collaborations and cross-cultural comparisons concerning clinical and epidemiological issues. OBJECTIVES: This initial overview summarises some of these non-European experiences with the SDQ by presenting a selection of projects that have either psychometrically evaluated this novel questionnaire, applied it to screen for behaviour disorders, or employed its parent-, teacher- or self-rated versions as research tools. Since a large part of the mentioned studies are ongoing or have only recently been completed, much of the work reported here is still unpublished. CONCLUSIONS: Across a huge variety of cultures and languages, experience gained with the SDQ in other continents has supported European evidence of good psychometric properties and clinical utility of this questionnaire. Since worldwide usage of the SDQ can be expected to increase in the future, more international coordination is encouraged, in order to fully exploit the promising potentials of this versatile assessment tool and systematically investigate cross-cultural differences and similarities in child and adolescent behaviour.

Adolescent↗
PubMed2004

Narrative skills in children with selective mutism: an exploratory study.

Selective mutism (SM) is a rare and complex disorder associated with anxiety symptoms and speech-language deficits; however, the nature of these language deficits has not been studied systematically. A novel cross-disciplinary assessment protocol was used to assess anxiety and nonverbal cognitive, receptive language, and expressive narrative abilities in 7 children with SM and a comparison group of 7 children with social phobia (SP). The children with SM produced significantly shorter narratives than children with SP, despite showing normal nonverbal cognitive and receptive language abilities. The findings suggest that SM may involve subtle expressive language deficits that may influence academic performance and raise additional questions for further research. The assessment procedure developed for this study may be potentially useful for language clinicians.

Anxiety↗
PubMed2004

Methylphenidate improves visual-spatial memory in children with attention-deficit/hyperactivity disorder.

OBJECTIVE: To investigate the effect of methylphenidate (MPH) on visual-spatial memory, as measured by subtests of the Cambridge Neuropsychological Testing Automated Battery (CANTAB), in children with attention-deficit/hyperactivity disorder (ADHD). Visual-spatial memory is a core component of working memory that has been shown to be impaired in ADHD, irrespective of comorbid reading and/or language problems. METHOD: A clinic-referred sample of school-age children with a confirmed DSM-IV diagnosis of ADHD (n = 26) completed tests of visual-spatial memory, planning ability, and recognition memory in an acute, randomized, placebo-controlled, crossover trial with three single fixed doses of MPH. MPH effects on right-handed and left-handed motor control were also assessed. RESULTS: MPH significantly improved performance on a self-ordered, updating visual-spatial working memory task and on maintenance of visual-spatial information but had no effects on measures of visual-spatial planning ability or recognition memory. Also, MPH significantly improved left-handed motor control. CONCLUSIONS: Beneficial effects of MPH on visual-spatial processing in ADHD are selective and restricted to visual-spatial memory.

Attention Deficit Disorder with Hyperactivity↗
PubMed2004

Replication test for association of the IL-1 receptor antagonist gene, IL1RN, with attention-deficit/hyperactivity disorder.

Attention-deficit/hyperactivity disorder (ADHD) has a strong genetic basis, and aberrant brain dopaminergic and noradrenergic activity is implicated in its etiology. Interleukin-1 (IL-1), its antagonist, IL-1Ra, and IL-1 receptors are all present in the brain, and IL-1 has been shown to influence both dopaminergic and noradrenergic function. Recently, Segman et al. [1] tested the IL-1Ra gene, IL1RN, as a candidate for involvement in ADHD. Using the transmission/disequilibrium test (TDT) to examine 77 nuclear ADHD families for the inheritance of alleles of an intronic 86-bp VNTR polymorphism, they found significant evidence for biased transmission of the 4-repeat allele (p=0.04) and non-transmission of the 2-repeat allele (p=0.03). Here, we sought to replicate this in an independent sample of families. In contrast to the previous findings, our analysis of 178 ADHD families showed no evidence for biased transmission of these alleles (p=0.81 and p=1.00, respectively). Our lack of evidence for association of this IL1RN polymorphism with ADHD, based on a much larger sample of families, suggests that the original finding may have been a spurious (i.e. false-positive) result. These findings highlight the need for further investigations of this marker, in additional independent ADHD samples, in the future.

Adolescent↗
PubMed2004

Executive function and ADHD: a comparison of children's performance during neuropsychological testing and real-world activities.

OBJECTIVE: Current understanding of executive function deficits in Attention-Deficit/Hyperactivity Disorder (ADHD) is derived almost exclusively from neuropsychological testing conducted in laboratory settings. This study compared children's performance on both neuropsychological and real-life measures of executive function and processing speed. METHOD: The Stroop and Wisconsin Card Sorting Task (WCST) were selected as neuropsychological measures, whereas route tasks in a videogame and at the zoo were used to index real-life measures. Participants comprised a community sample of 22 unmedicated boys with ADHD individually matched on age and IQ with 22 normally developing control boys. RESULTS: There were no group differences in executive function on the Stroop or zoo tasks, but the ADHD group exhibited deficits in set-shifting as assessed by the WCST (perseverative errors and responses) and videogame play (fewer challenges completed). Also, the ADHD group showed slowed processing speed on the Stroop (slower color naming) and zoo activity (longer time to complete task), as well as a slower rate of acquisition of the sorting rule on the WCST (more trials to complete first category). Efficient and flexible videogame play (number of challenges completed) was related positively to efficacy on the Stroop (number of items named correctly in the interference and two control conditions) and inversely related to set-shifting problems on the WCST (perseverative responses and errors). Also, problems in goal-directed behavior at the zoo (number of deviations from designated route) were related to problems in set-shifting on the WCST (perseverative responding). CONCLUSIONS: Children with ADHD exhibit impairments in executive function and processing speed in real-world activities as well as in neuropsychological testing. Cognitive deficits detected by standardized neuropsychological testing are related to performance difficulties in real-world activities.

Attention Deficit Disorder with Hyperactivity↗
PubMed2003

Characterizing selective mutism: is it more than social anxiety?

Selective mutism (SM) occurs when a child persistently lacks speech in some social situations but not in others, despite the ability to use and comprehend language. While considered to be related to anxiety, SM is poorly understood and studies of SM children are often based on parent reports. This study developed a unique, non-verbally based assessment protocol for SM children in order to better characterize their clinical profile, language abilities, and learning abilities. A comparison was done with a group of children of similar age, with social phobia (SP) but no SM, to search for characteristics that might distinguish SM from other anxiety disorders. Twenty-three children participated in the study (14 SM and 9 SP). The assessment protocol included standardized anxiety rating scales, cognitive and academic tests, and a speech and language assessment. SM and SP groups showed similar levels of anxiety and academic ability, but the SM group showed some language impairments relative to the SP group. Though requiring replication with a larger sample and nonclinical comparison group, the results suggest that SM children can be assessed by non-verbal means and that their disorder is characterized by anxiety and subtle language impairments.

Adolescent↗
PubMed2003

Selective inhibition in children with attention-deficit hyperactivity disorder off and on stimulant medication.

Selective inhibition requires discrimination between auditory signals and is assessed using a modification of the stop-signal task. Selective inhibition was assessed in a group of 59 clinic-referred, DSM-IV-diagnosed children with attention-deficit hyperactivity disorder (ADHD) and compared to that of a community sample of 59 children. Methylphenidate (MPH) effects on selective inhibition were assessed in a subset of the ADHD sample that participated in an acute, randomized, placebo-controlled, crossover trial with 3 fixed doses of MPH. Children with ADHD performed more poorly than controls on the majority of selective stop-signal task parameters: they exhibited more anticipatory (invalid) responses, with less accurate and more variable responses on the response execution task, as well as a slower selective inhibition process. MPH improved speed of both inhibition and response execution processes; it also reduced variability of response execution and decreased nonselective inhibition. On the one hand, findings are consistent with purported inhibition deficit in ADHD, but on the other hand, suggest that neither the impairment itself, nor MPH effects, were restricted to inhibition.

Attention Deficit Disorder with Hyperactivity↗
PubMed2003

Listening comprehension and working memory are impaired in attention-deficit hyperactivity disorder irrespective of language impairment.

This study investigated listening comprehension and working memory abilities in children with attention-deficit hyperactivity disorder (ADHD), presenting with and without language impairments (LI). A 4-group design classified a community sample (n = 77) of boys aged 9-12 into ADHD, ADHD + LI, LI, and Normal groups. Children completed tests of basic language and cognitive skills, verbal and spatial working memory, and passage-level listening comprehension. Multivariate analyses and post hoc comparisons indicated that ADHD children who did not have co-occurring LI comprehended factual information from spoken passages as well as normal children, but were poorer at comprehending inferences and monitoring comprehension of instructions. ADHD children did not differ from normal children in verbal span, but showed significantly poorer verbal working memory, spatial span, and spatial working memory. The ADHD + LI and LI groups were most impaired in listening comprehension and working memory performance, but did not differ from each other. Listening comprehension skills were significantly correlated with both verbal and spatial working memory, and parent-teacher ratings of inattention and hyperactivity/impulsivity. Findings that children with ADHD but no LI showed subtle higher-level listening comprehension deficits have implications for both current diagnostic practices and conceptualizations of ADHD.

Attention Deficit Disorder with Hyperactivity↗
PubMed2002

The norepinephrine transporter gene and attention-deficit hyperactivity disorder.

The adrenergic system plays a known role in attentional systems and a suspected causal role in attention-deficit hyperactivity disorder (ADHD), based on evidence from pharmacological interventions and animal models. The efficacy of the highly selective noradrenergic reuptake inhibitor, tomoxetine, in treating ADHD symptoms supports the system's role in ADHD and points to the norephinephrine transporter as a candidate gene. This study tested the gene for the norepinephrine transporter (NET1) as a susceptibility factor in ADHD using three polymorphisms located in exon 9, intron 9, and intron 13. We examined the inheritance of these polymorphisms in a sample of 122 families with a total of 155 children with ADHD identified through an ADHD proband. Use of the transmission disequilibrium test failed to show significant evidence for biased transmission of any of the alleles or the haplotypes of these polymorphisms. We further investigated this gene by screening the probands for five known amino acid variants to determine if they contributed to the ADHD phenotype but observed only one (Thr99Ile) in our sample. Since the frequency of this variant (1.8%) was similar to that previously reported in a control sample (2.2%), it is unlikely that this variant is related to the ADHD phenotype. Our results do not support the NET1 gene as a major genetic susceptibility factor in ADHD.

Alleles↗
PubMed2002

Measuring anxiety: parent-child reporting differences in clinical samples.

This study examines parent-child reporting differences for childhood anxiety in normal controls (n = 16) and in children with diagnosed anxiety disorders (ANX; n = 15), attention-deficit hyperactivity disorder (ADHD; n = 15), and comorbid ANX and ADHD (n = 16). Correspondence between child reports of anxiety on two self-report inventories and diagnosis based on structured parent interview was assessed for all four groups. Parent-child agreement did not appear to be measurement dependent but did differ by diagnostic group, with poorer agreement for clinical groups. Though needing replication, these findings suggest that it is inadvisable to rely exclusively on self-report measures when assessing childhood anxiety, especially in clinical populations. Such measures can be useful in monitoring clinical progress, however, provided parent and child reports are examined separately.

Anxiety↗
PubMed2002

ADHD outside the laboratory: boys' executive function performance on tasks in videogame play and on a visit to the zoo.

One current theory of attention-deficit/hyperactivity disorder (ADHD) proposes that a primary deficit in behavioral inhibition gives rise to secondary deficits in 4 executive functions and motor control. To date, empirical support for this model is based primarily on laboratory-based cognitive methods. This study assessed behavioral inhibition and executive functioning in children with ADHD in 2 real-life contexts: videogames (motor-skill target game, cognitively demanding adventure game) and an outing at the zoo (route tasks). Participants were a community sample of 57 boys diagnosed with ADHD (20 inattentive, 37 combined type) and 57 normally developing control boys, matched individually for age and nonverbal IQ. Operationally defined measures of behavioral inhibition and specific executive functions were derived from these activities and assessed under contrasting conditions of low or high working memory and distractor loads. There were no group differences in basic motor skills on the target game, nor in terms of the ability to inhibit a prepotent or ongoing response in the adventure videogame. However, boys with ADHD exhibited more self-talk, more effortful response preparation, and completed fewer challenges in the latter videogame. Also, they manifested inhibition deficits in terms of interference control during the route task at the zoo and took longer to complete the tasks. Typically, these differences were greatest under conditions of high working memory and distractor loads. Findings from this study suggest that cognitive difficulties in ADHD may be context dependent and that ADHD is associated with deficits in some but not all aspects of behavioral inhibition.

Analysis of Variance↗
PubMed2002

Methylphenidate improves Stroop naming speed, but not response interference, in children with attention deficit hyperactivity disorder.

OBJECTIVE: The goal of this study was to investigate the effect of methylphenidate (MPH) on response interference, as measured by the Stoop Color and Word Test, in children with attention deficit hyperactivity disorder (ADHD). Response interference is a core component of response inhibition that has been shown to be impaired in children with ADHD. METHODS: A clinic-referred sample of school-aged children with a confirmed Diagnostic and Statistical Manual of Mental Disorders (4th ed.) diagnosis of ADHD and good reading skills (n = 31) completed the Stroop Color and Word Test in an acute, randomized, placebo-controlled, crossover trial with three single fixed doses of MPH. RESULTS: MPH did not improve response interference on the Stroop Color and Word Test but did significantly improve color naming and word naming abilities. CONCLUSION: Response interference, as measured by the Stroop Color and Word Test, is not improved by MPH in children with ADHD. In addition, findings demonstrate strongly positive MPH effects on the highly effortful process of color naming, which has previously been demonstrated as impaired in children with ADHD. MPH was also shown to have a positive but smaller effect on word naming speed.

Attention Deficit Disorder with Hyperactivity↗
PubMed2002

Neuropsychological profiles of adolescents with ADHD: effects of reading difficulties and gender.

BACKGROUND: Executive function, particularly behavioral inhibition, has been implicated as a core deficit specific to Attention-Deficit/Hyperactivity Disorder (ADHD) whereas rapid naming has been implicated as a core deficit specific to reading disabilities (RD). Females may be less impaired in executive function although adolescent females with ADHD have yet to be studied. METHOD: Neuropsychological profiles of four adolescent groups aged 13-16 with equal female representation were investigated: 35 ADHD, 12 RD, 24 ADHD+RD, and 37 normal controls. A semi-structured interview (K-SADS-PL), the Conners Rating Scales and the Ontario Child Health Study Scales were used to diagnose ADHD. RD was defined as a standard score below 90 on at least one of the following: Reading or Spelling of the WRAT3 or Word Attack or Word Identification of the WRMT-R. The WISC-III, Rapid Automatized Naming, Stroop and Stop tasks were used as measures of cognitive and executive function. RESULTS: The two ADHD groups (ADHD, ADHD+RD) showed deficits in processing speed, naming of objects, poor behavioral inhibition and greater variability in reaction times whereas the two RD groups (RD, RD+ADHD) showed verbal working memory deficits and slower verbal retrieval speed. Only the comorbid group was slower with naming of numbers and colors and had slower reaction times. Regression analyses indicated that incongruent color naming (Stroop) and variability in go reaction time were the best predictors of hyperactive/impulsive ADHD symptoms whereas variability in go reaction time and processing speed were the best predictors of inattentive ADHD symptoms. Speed of letter naming and verbal working memory accounted for the most variability in composite achievement scores. No gender differences were found on any of the cognitive tests. CONCLUSIONS: This study challenges the importance of behavioral inhibition deficits in ADHD and that naming deficits are specific to RD. Further investigation into cognitive deficits in these groups is required.

Adolescent↗