Controlled Visuomotor Preparation Deficits in Attention-Deficit/Hyperactivity Disorder.

To the best of the authors' knowledge, there are no published reports on visuomotor preparation in attention-deficit/hyperactivity disorder (ADHD). This is unfortunate, because research suggests that ADHD is an output-related deficit, and suboptimal execution of tasks may be the result of incomplete visuomotor preparation. The authors compared 19 children with ADHD with 124 healthy and 120 pathological controls in terms of their performance (speed, speed variability, and accuracy) on the finger precuing test, a test measuring (automatic and controlled) visuomotor preparation. The data implied that children with ADHD have an impaired ability to engage in effortful, controlled visuomotor preparation activities. Fast, automatic response preparation was not affected by ADHD. In addition, children with ADHD showed more variability in overall test performance than other children. No group differences were found in response accuracy. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Meta-Analysis of Intellectual and Neuropsychological Test Performance in Attention-Deficit/Hyperactivity Disorder.

Cognitive measures are used frequently in the assessment and diagnosis of attention-deficit/hyperactivity disorder (ADHD). In this meta-analytic review, the authors sought to examine the magnitude of differences between ADHD and healthy participants on several commonly used intellectual and neuropsychological measures. Effect sizes for overall intellectual ability (Full Scale IQ; FSIQ) were significantly different between ADHD and healthy participants (weighted d = .61). Effect sizes for FSIQ were significantly smaller than those for spelling and arithmetic achievement tests and marginally significantly smaller than those for continuous performance tests but were comparable to effect sizes for all other measures. These findings indicate that overall cognitive ability is significantly lower among persons with ADHD and that FSIQ may show as large a difference between ADHD and control participants as most other measures. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Perceived social support by children with characteristics of Attention-Deficit/Hyperactivity Disorder.

Examined students' perceptions of social support behaviors exhibited by significant adults and peers at school. A total of 29 teachers and 94 boys, in Grades 3–6, and their parents participated in the study. Approximately half of the boys displayed significant levels of behaviors characteristic of attention deficit hyperactivity disorder (ADHD). The remaining boys did not display characteristics of ADHD. Information on students' academic performance, social skills, self-concept, and problem behaviors was assessed via rating scales completed by the students and their respective parents and teachers. Brief questionnaires were also used to collect perceptions of social support from the teachers and parents. The data indicated that children with characteristics of ADHD perceived lower frequencies of overall social support. Both the ADHD characteristics group and comparison group perceived the importance of social support similarly; social support was moderately and significantly correlated with self-concept and student-reported positive social skill behaviors; and students' perceptions of social support were moderately related to parents' and teachers' perceptions of the frequency of social support they make available. These results are discussed and their implications for future research and practice are outlined. (PsycINFO Database Record (c) 2011 APA, all rights reserved)     

Effect of Methylphenidate on Time Perception in Children With Attention-Deficit/Hyperactivity Disorder.

The effects of methylphenidate (MPH) on performance of a time-production task were studied in 17 children with attention-deficit/hyperactivity disorder who participated in 1 test session on and 1 off MPH. Participants held a response lever down for at least 10 but no longer than 14 s. Administration of MPH had no effect on the number of correct responses or on the mean duration of lever holds. MPH administration significantly decreased timing response variability, increased holds of 10- to 11-s duration, and decreased lever holds of extremely short durations. These results indicate that administration of MPH resulted in more precise timing performance without changing the mean duration of lever holds, suggesting an enhancement in working memory. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

A Psychophysical Measure of Attention Deficit in Children With Attention-Deficit/Hyperactivity Disorder.

The authors explored the temporal mechanism of attention deficit in children with attention-deficit/hyperactivity disorder (ADHD). In rapid serial visual presentation tasks in which two targets (T? and T?) were presented in close temporal proximity among distractors, participants tried to identify T? and detect T? in one (dual-task) experiment and only to detect T? in a second control (single-task) experiment. The sensitivity of T? detection was analyzed using signal detection theory. The attentional blink--the impairment in T? detection following the identification of T?--was increased in magnitude and protracted in the patients. Moreover, some ADHD children appeared to have a blink largely normal in magnitude but temporally displaced toward a later time. The authors hypothesize that a slower closing of the attention gate may mediate this specific attention impairment in ADHD children. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Neuropsychology of Adults With Attention-Deficit/Hyperactivity Disorder: A Meta-Analytic Review.

A comprehensive, empirically based review of the published studies addressing neuropsychological performance in adults diagnosed with attention-deficit/hyperactivity disorder (ADHD) was conducted to identify patterns of performance deficits. Findings from 33 published studies were submitted to a meta-analytic procedure producing sample-size-weighted mean effect sizes across test measures. Results suggest that neuropsychological deficits are expressed in adults with ADHD across multiple domains of functioning, with notable impairments in attention, behavioral inhibition, and memory, whereas normal performance is noted in simple reaction time. Theoretical and developmental considerations are discussed, including the role of behavioral inhibition and working memory impairment. Future directions for research based on these findings are highlighted, including further exploration of specific impairments and an emphasis on particular tests and testing conditions. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

What Aspects of Peer Relationships Are Impaired in Children With Attention-Deficit/Hyperactivity Disorder?

Participants included 165 children with attention-deficit/hyperactivity disorder (ADHD; 130 boys, 35 girls) and their 1,298 same-sex classmates (1,026 boys, 272 girls) who served as raters. For each child with ADHD, a child of the same sex was randomly selected from the same classroom to serve as a comparison child, which yielded 165 dyads. Consistent with predictions, contrasted with the comparison children, those with ADHD were lower on social preference, higher on social impact, less well liked, and more often in the rejected social status category; they also had fewer dyadic friends. When liking ratings that children made versus received were examined, children with ADHD had less positive imbalance and greater negative imbalance relative to comparison children. Analyses that considered the types of peers who chose children with ADHD as friends or nonfriends demonstrated that children with ADHD were nominated as nonfriends by children of higher social preference and who were better liked by others. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Adapting Psychotherapy to Meet the Needs of Adults With Attention-Deficit/Hyperactivity Disorder.

Requests for the assessment and treatment of attention-deficit/hyperactivity disorder (ADHD) among adult patients are on the rise. The findings from longitudinal research indicate that clinically significant symptoms persist into adulthood for many children diagnosed with ADHD. Many other patients' symptoms are not identified until they are in active treatment for other complaints in adulthood. Thus, psychotherapists are increasingly likely to encounter adult patients with ADHD-related issues. However, the same core symptoms of inattention, impulsivity, and hyperactivity that create functional problems in patients' lives also interfere with the effectiveness of psychotherapy. The aim of this article is to summarize the accumulated clinical and empirical wisdom about how to effectively adapt psychotherapy to meet the needs of adult patients with ADHD. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Effects of Recess on the Classroom Behavior of Children With and Without Attention-Deficit Hyperactivity Disorder.

The primary purpose of this study was to evaluate the effects of a traditional recess on the subsequent classroom behavior of children with a diagnosis of Attention-Deficit Hyperactivity Disorder (ADHD). In addition, the time of recess was matched to the behavior of the individual children diagnosed with ADHD based on prior assessment of their classroom behavior as a function of time of confinement in the classroom. All results were evaluated using single-case designs. Results showed that levels of inappropriate behavior were consistently higher on days when participants did not have recess, compared with days when they did have recess. Results also showed that the level of inappropriate behavior for all participants progressively increased over time on days when they did not have recess. However, this progressive increase did not occur on days when the participants had recess. (PsycINFO Database Record (c) 2011 APA, all rights reserved)     

Contribution of Organizational Strategy to Verbal Learning and Memory in Adults With Attention-Deficit/Hyperactivity Disorder.

Statistical mediation modeling was used to test the hypothesis that poor use of a semantic organizational strategy contributes to verbal learning and memory deficits in adults with attention-deficit/hyperactivity disorder (ADHD). Comparison of 28 adults with ADHD and 34 healthy controls revealed lower performance by the ADHD group on tests of verbal learning and memory, sustained attention, and use of semantic organization during encoding. Mediation modeling indicated that state anxiety, but not semantic organization, significantly contributed to the prediction of both learning and delayed recall in the ADHD group. The pattern of findings suggests that decreased verbal learning and memory in adult ADHD is due in part to situational anxiety and not to poor use of organizational strategies during encoding. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

The role of mitochondrial dysfunction and neuronal nitric oxide in animal models of neurodegenerative diseases

Excitotoxicity, mitochondrial dysfunction and free radical induced oxidative damage have been implicated in the pathogenesis of several different neurodegenerative diseases, such as amyotrophic lateral sclerosis, Parkinson's disease (PD), Alzheimer's disease (AD), and Huntington's disease. Much of the interest in the association of neurodegeneration with mitochondrial dysfunction and oxidative damage emerged from animal studies using mitochondrial toxins. Within mitochondria 1-methyl-4-phenylpyridinium (MPP+), the active metabolite of 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP), acts to inhibit NADH-coenzyme Q reductase (complex I) of the electron transport chain. MPTP produces Parkinsonism in humans, primates, and mice. Similarly, lesions produced by the reversible inhibitor of succinate dehydrogenase (complex II), malonate, and the irreversible inhibitor, 3-nitropropionic acid (3-NP), closely resemble the histologic, neurochemical and clinical features of HD in both rats and non-human primates. The interruption of oxidative phosphorylation results in decreased levels of ATP. A consequence is partial neuronal depolarization and secondary activation of voltage-dependent NMDA receptors, which may result in excitotoxic neuronal cell death (secondary excitotoxicity). The increase in intracellular Ca2+ concentration leads to an activation of Ca2+ dependent enzymes, including the constitutive neuronal nitric oxide synthase (cnNOS) which produces NO.. NO. may react with the superoxide anion to from peroxynitrite. We show that systemic administration of 7-nitroindazole (7-NI), a relatively specific inhibitor of cnNOS in vivo. attenuates lesions produced by striatal malonate injections or systemic treatment with 3-NP or MPTP. Furthermore 7-NI attenuated increases in lactate production and hydroxyl radical and 3-nitrotyrosine generation in vivo, which may be a consequence of peroxynitrite formation. Our results suggest that neuronal nitric oxide synthase inhibitors may be useful in the treatment of neurologic diseases in which excitotoxic mechanisms play a role.     

A Meta-Analytic Review of Stopping Performance in Attention-Deficit/Hyperactivity Disorder: Deficient Inhibitory Motor Control?

This review discusses whether deficient inhibitory motor control is the core deficit of attention-deficit/hyperactivity disorder (ADHD). Inhibitory motor control is commonly assessed using the stop-signal paradigm. Since the last meta-analysis that was performed, 33 new studies have appeared. The current meta-analysis revealed a significant difference between ADHD patients and matched controls in stop latency (stop-signal reaction time) in both children and adults. Basic reaction time was significantly longer in children with ADHD, but not in adults, and there was a significant interaction between the elongation of the latency to stop and to respond in adults, but not in children. Deficient inhibitory motor control may be less crucial in children than in adults with ADHD. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Atomoxetine: A Selective Norepinephrine Reuptake Inhibitor for the Treatment of Attention-Deficit/Hyperactivity Disorder.

This column offers data related to attention deficit disorder with hyperactivity and related psychopharmacological treatments. The author focuses on atomoxetime, a selective norepinephrine reuptake inhibitor, and offers efficacy and safety data. Conclusions point out the limitations of stimulant use and praise the alleged non-abusive nature of atomoxetine. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Differential Prefrontal Cortex Activation During Inhibitory Control in Adolescents With and Without Childhood Attention-Deficit/Hyperactivity Disorder.

The authors examined inhibitory control processes in 8 adolescents diagnosed with attention-deficit/ hyperactivity disorder (ADHD) during childhood and in 8 adolescent control participants using functional MRI with the Stimulus and Response Conflict Tasks (K. W. Nassauer & J. M. Halperin, 2003). No group differences in performance were evident on measures of interference control and/or response competition created by location and direction stimuli. However, the ADHD group demonstrated significantly greater activation of the left ventrolateral prefrontal cortex during interference control as well as greater activation of the left anterior cingulate cortex, right ventrolateral prefrontal cortex, and left basal ganglia during the dual task of interference control and response competition. The magnitude of the prefrontal and basal ganglia activation was positively correlated with severity of ADHD. Response competition alone did not yield group differences in activation. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Impact of Executive Function Deficits and Attention-Deficit/Hyperactivity Disorder (ADHD) on Academic Outcomes in Children.

The association between executive function deficits (EFDs) and functional outcomes were examined among children and adolescents with attention-deficit/hyperactivity disorder (ADHD). Participants were children and adolescents with (n = 259) and without (n = 222) ADHD, as ascertained from pediatric and psychiatric clinics. The authors defined EFD as at least 2 executive function measures impaired. Significantly more children and adolescents with ADHD had EFDs than did control participants. ADHD with EFDs was associated with an increased risk for grade retention and a decrease in academic achievement relative to (a) ADHD alone, (b) controlled socioeconomic status, (c) learning disabilities, and (d) IQ. No differences were noted in social functioning or psychiatric comorbidity. Children and adolescents with ADHD and EFDs were found to be at high risk for significant impairments in academic functioning. These results support screening children with ADHD for EFDs to prevent academic failure. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Hyperactivity and attention deficits.

Substantive progress has been made in our understanding of children considered hyperactive, especially in the interpersonal sphere. Evolving conceptualizations of hyperactivity and attention deficits are reviewed briefly, including changes in clinical diagnostic practices and in knowledge about developmental course. The hypothesis is advanced that the cognitive and social difficulties of hyperactive children may be better understood in terms of motivational and self-regulatory processes than as deficiencies in basic information processing. The role of stimulant medication is emphasized, both as a controversial treatment approach and as an adjunct to research on the children's problems. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

The Role of Children's Ethnicity in the Relationship Between Teacher Ratings of Attention-Deficit/Hyperactivity Disorder and Observed Classroom Behavior.

Significant ethnic differences have been consistently documented on attention-deficit/hyperactivity disorder (ADHD) teacher rating scales. Whether these ethnic differences result from a teacher rating bias or reflect actual classroom behavior patterns is unknown. Ethnic differences between Caucasian and African American (AA) elementary schoolchildren on teacher ratings and codings of observed classroom behavior were examined with latent variables. In structural equation models, correlations between teacher ratings and observed classroom behavior suggested nonbiased teacher ratings of AA schoolchildren with diagnosed ADHD. Ethnic differences were documented for both teacher ratings of ADHD and classroom behavior. Differences in classroom behavior were attenuated when the behavior of an average child in the classroom was taken into account. Multiple explanations for this pattern of results are discussed. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Endogenous nitric oxide in the airways of different animal species

BACKGROUND: High amounts of endogenous nitric oxide (NO) have been demonstrated in the human upper airway, but the role of nasal NO is still unclear. The present study aims to describe nasal NO excretion in different animal species with special living conditions or anatomy. METHODS: Domestic animals (horse, cow, pig, sheep, dog, cat) and zoo-animals (Rhesus monkey, chimpanzee, gorilla, elephant, fur seal, alpaca, yak, dolphin, camel, capybara, bear, tiger, wolf, giraffe, alligator, Harris' hawk, kangaroo) were studied awake, resting or anaesthetised. NO concentrations were measured by chemiluminescence using different analysers and techniques, including measurements on mixed exhaled air, during continuous or intermittent gas sampling, and on single breaths. RESULTS: Rhesus monkeys (number of individuals N = 5) and pigs (N = 2) were compared and displayed quite different excretion patterns. Allowing NO to accumulate in the nose during timed occlusions yielded peak concentrations in monkeys of 0.46 +/- 0.07 parts per million (ppm, mean +/- SEM), 0.59 +/- 0.08 ppm, 0.70 +/- 0.08 ppm and 1.02 +/- 0.05 ppm NO after 15, 30, 60 and 120 s of occlusion. In pigs, 0.012-0.021 ppm NO were recorded, independent of occlusion time. The chimpanzee was similar to the Rhesus monkey and the highest NO value, 2.9 ppm, was recorded after 4-5 min of occlusion. In single breaths from 3 elephants 0.031-0.082 ppm, from 1 gorilla 0.029 ppm, and from 1 chimpanzee 0.069 +/- 0.003 ppm NO (8 observations) were recorded. CONCLUSIONS: We found considerable species difference in nasal NO excretion with pronounced amounts only in primates and elephants. The physiological implications of these findings remain to be defined.     

Anticonvulsant and proconvulsant roles of nitric oxide in experimental epilepsy models

The effect of acute (120 mg/kg) and chronic (25 mg/kg, twice a day, for 4 days) intraperitonial injection of the nitric oxide (NO) synthase (NOS) inhibitor NG-nitro-L-arginine (L-NOARG) was evaluated on seizure induction by drugs such as pilocarpine and pentylenetetrazole (PTZ) and by sound stimulation of audiogenic seizure-resistant (R) and audiogenic seizure-susceptible (S) rats. Seizures were elicited by a subconvulsant dose of pilocarpine (100 mg/kg) only after NOS inhibition. NOS inhibition also simultaneously potentiated the severity of PTZ-induced limbic seizures (60 mg/kg) and protected against PTZ-induced tonic seizures (80 mg/kg). The audiogenic seizure susceptibility of S or R rats did not change after similar treatments. In conclusion, proconvulsant effects of NOS inhibition are suggested to occur in the pilocarpine model and in the limbic components of PTZ-induced seizures, while an anticonvulsant role is suggested for the tonic seizures induced by higher doses of PTZ, revealing inhibitor-specific interactions with convulsant dose and also confirming the hypothesis that the effects of NOS inhibitors vary with the model of seizure.