Evidence that response inhibition is a primary deficit in ADHD

The present study examined response inhibition in children with attention deficit hyperactivity disorder (ADHD; n = 58) and controls (n = 84) using three go/no-go tests -- one with high working memory demand (cognitive), one with low working memory demand (simple), and one with rewards and response costs (motivation linked) in which emphasis was on reward for responding to "go" stimuli. Results of a repeated measure analysis of variance showed a significant effect of diagnosis for errors of commission for the simple, cognitive, and motivation-linked go/no-go tests, such that children with ADHD made significantly more errors than controls. Furthermore, a significant effect of test was noted across groups, such that both children in the ADHD and control groups performed worse on the cognitive and motivation-linked tests than they did on the simple test. The diagnosis by test interaction was not significant, suggesting that ADHD participants showed a similar degree of impairment to that of controls, regardless of the degree of working memory load or feedback provided in the test. In children with ADHD, response inhibition appears to be a primary deficit that is observed even when executive function demands of tasks are minimal. Although increasing working memory demand appears to impede response inhibition, this effect is similar in ADHD and typically developing children.     

Abnormal brain activation during inhibition and error detection in medication-naive adolescents with ADHD

OBJECTIVE: Patients with attention deficit hyperactivity disorder (ADHD) and a medication history have shown abnormal brain activation in prefrontal and striatal brain regions during cognitive challenge. Previous findings have been confounded, however, by potential long-term effects of stimulant medication exposure and group discrepancies in task performance. The aim of this study was to investigate whether medication-naive adolescents with ADHD would still show abnormal brain activation in prefrontal brain regions during motor response inhibition in a task designed to control for intergroup performance discrepancies. METHOD: Rapid, event-related functional magnetic resonance imaging was used to compare brain activation in 16 medication-naive ADHD adolescents and 21 IQ-, age-, and sex-matched healthy comparison volunteers during a challenging, idiosyncratically adjusted task that required withholding of a triggered motor response. The design, which manipulated task parameters to force each subject to fail on 50% of trials, ensured that subjects worked at the edge of their own inhibitory performance, thereby controlling for intersubject and intergroup performance discrepancies and furthermore allowing for investigation of differences in brain activation related to inhibition and inhibition failure. RESULTS: Medication-naive adolescents with ADHD showed significantly reduced brain activation in the right inferior prefrontal cortex during successful motor response inhibition and in the precuneus and posterior cingulate gyrus during inhibition failure, both of which correlated with behavioral scores of ADHD. CONCLUSIONS: The study shows that abnormal brain activation during inhibitory challenge in ADHD is specific to the disorder, since it persists when medication history and performance discrepancies are excluded.     

A novel multidomain computerized cognitive assessment for attention-deficit hyperactivity disorder: evidence for widespread and circumscribed cognitive deficits

Multidomain assessment may enhance the diagnosis of cognitive impairment in children with attention-deficit hyperactivity disorder (ADHD). A set of novel Web-enabled computerized tests has recently been shown to be valid for identifying mild cognitive impairment and characterizing the cognitive profile associated with various disorders. It was anticipated that these tests would be well suited for use in children with ADHD. The authors tested this idea in a pilot study of 15 children (12 males, 3 females; mean age, 11 years 10 months; range, 9-15 years) with ADHD and 15 age-, education-, and gender-matched controls. The profile of cognitive impairment in ADHD children off methylphenidate across 6 cognitive domains (memory, executive function, visual-spatial skills, verbal function, attention, and motor skills) was described relative to controls. The effect of treatment with methylphenidate was examined by comparing the ADHD children on methylphenidate and on placebo (administered in a double-blind randomized fashion) relative to controls and by comparing the ADHD children on methylphenidate relative to placebo. Significant impairment in ADHD was evident in memory, visual-spatial, verbal, and attention domains, and near-significant impairment was observed in executive function and motor skills. On methylphenidate but not placebo, performance was comparable to controls in immediate verbal memory, psychomotor accuracy, visual-spatial, verbal rhyming, and overall battery performance. Significant improvement with administration of methylphenidate relative to placebo was evident for psychomotor accuracy, verbal rhyming, and overall battery performance. Hence, on the limited basis of this pilot study, the set of computerized tests studied appears to be useful for measuring cognitive function in ADHD; however, additional studies are needed to confirm this.     

Deficits in oculomotor performance in pediatric epilepsy

Purpose: Given evidence of limitations in neuropsychological performance in epilepsy, we probed the integrity of components of cognition—including speed of processing, response inhibition, and spatial working memory—supporting executive function in pediatric epilepsy patients and matched controls. Methods: A total of 44 pairs of controls and medically treated pediatric epilepsy patients with no known brain pathology completed cognitive oculomotor tasks, computerized neuropsychological testing, and psychiatric assessment. Key Findings: Patients showed slower reaction time to initiate a saccadic response compared to controls but had intact saccade accuracy. Cognitively driven responses including response inhibition were impaired in the patient group. Patients had increased incidence of comorbid psychopathology, but comorbidity did not predict worse functioning compared to patients with no Attention Deficit Hyperactivity Disorder (ADHD). Epilepsy type and medication status were not predictive of outcome. More complex neuropsychological performance was impaired in tasks requiring visual memory and sequential processing, which was correlated with inhibitory control and antisaccade accuracy. Significance: Pediatric epilepsy may be associated with vulnerabilities that specifically undermine speed of processing and response inhibition but not working memory, and may underlie known neuropsychological performance limitations. This particular profile of abnormalities may be associated with seizure‐mediated compromises in brain maturation early in development.     

Task-specific hypoactivation in prefrontal and temporoparietal brain regions during motor inhibition and task switching in medication-naive children and adolescents with attention deficit hyperactivity disorder

OBJECTIVE: A relatively small number of functional imaging studies of attention deficit hyperactivity disorder (ADHD) have shown abnormal prefrontal and striatal brain activation during tasks of motor response inhibition. However, the potential confound of previous medication exposure has not yet been addressed, and no functional imaging study exists to date on medication-naive children and adolescents with ADHD. The aim of this study was to investigate the neural substrates of a range of motor and cognitive inhibitory functions in a relatively large group of children and adolescents with ADHD who had never previously been exposed to medication. METHOD: Nineteen boys with ADHD and 27 healthy age- and IQ-matched boys underwent functional MRI to compare brain activation during performance of tasks that assessed motor response inhibition (go/no go task), cognitive interference inhibition (motor Stroop task), and cognitive flexibility (switch task). RESULTS: Boys with ADHD showed decreased activation in the left rostral mesial frontal cortex during the go/no go task and decreased activation in the bilateral prefrontal and temporal lobes and right parietal lobe during the switch task. No significant group differences were observed during motor Stroop task performance. CONCLUSION: Abnormal brain activation was observed in medication-naive children and adolescents with ADHD during tasks involving motor inhibition and task switching, suggesting that hypoactivation in this patient group is unrelated to long-term stimulant exposure. Furthermore, functional abnormalities are task-specific and extend from frontostriatal to parietal and temporal cortices.     

Response Inhibition in Adults with Autism Spectrum Disorder Compared to Attention Deficit/Hyperactivity Disorder

Autism spectrum disorder (ASD) and attention deficit/hyperactivity disorder (ADHD) are hypothesised to involve core deficits in executive function. Previous studies have found evidence of a double dissociation between the disorders on specific executive functions (planning and response inhibition). To date most research has been conducted with children. No studies have directly compared the stable cognitive profile of adults. It was hypothesised that adults with ASD would show generally intact response inhibition whereas those with ADHD would show more global impairment. Participants were 24 adults aged 18–55 with high functioning ASD, 24 with ADHD, and 14 age and IQ matched controls. Participants completed three standardised measures of response inhibition. Participants with ASD had generally intact response inhibition but slow response latencies, possibly due to deficits in response initiation. Adults with ADHD did not show the more global impairments hypothesised. There were some significant differences between the clinical groups across measures of inhibition. In terms of performance style, adults with ASD were slow and accurate whilst those with ADHD showed an impulsive style.     

Neural correlates of inhibitory control in adult attention deficit/hyperactivity disorder: evidence from the Milwaukee longitudinal sample

Only a few studies have investigated the neural substrate of response inhibition in adult attention deficit hyperactivity disorder (ADHD) using Stop-Signal and Go/No-Go tasks. Inconsistencies and methodological limitations in the existing literature have resulted in limited conclusions regarding underlying pathophysiology. We examined the neural basis of response inhibition in a group of adults diagnosed with ADHD in childhood and who continue to meet criteria for ADHD. Adults with ADHD (n=12) and controls (n=12) were recruited from an ongoing longitudinal study and were matched for age, IQ, and education. Individuals with comorbid conditions were excluded. Functional magnetic resonance imaging (fMRI) was used to identify and compare the brain activation patterns during correct trials of a response-inhibition task (Go/No-Go). Our results showed that the control group recruited a more extensive network of brain regions than the ADHD group during correct inhibition trials. Adults with ADHD showed reduced brain activation in the right frontal eye field, pre-supplementary motor area, left precentral gyrus, and the inferior parietal lobe bilaterally. During successful inhibition of an inappropriate response, adults with ADHD display reduced activation in fronto-parietal networks previously implicated in working memory, goal-oriented attention, and response selection. This profile of brain activation may be specifically associated with ADHD in adulthood.     

Altered neural substrates of cognitive control in childhood ADHD: evidence from functional magnetic resonance imaging

OBJECTIVE: The study compared the neural bases of two cognitive control operations, interference suppression and response inhibition, between children with and children without attention deficit hyperactivity disorder (ADHD). METHOD: Ten children (7-11 years of age) with combined-type ADHD and 10 comparison subjects matched for age and gender underwent rapid event-related functional magnetic resonance imaging (fMRI) during performance of a modified flanker task. Functional maps were generated through group averaging and performance-based correlational analyses. RESULTS: Interference suppression in ADHD subjects was characterized by reduced engagement of a frontal-striatal-temporal-parietal network that subserved healthy performance. In contrast, response inhibition performance relied upon different regions in the two groups, frontal-striatal in comparison subjects but right superior temporal in ADHD children. CONCLUSIONS: Alteration in the neural basis of two cognitive control operations in childhood ADHD was characterized by distinct, rather than unitary, patterns of functional abnormality. Greater between-group overlap in the neural network activated for interference suppression than in response inhibition suggests that components of cognitive control are differentially sensitive to ADHD. The ADHD children's inability to activate the caudate nucleus constitutes a core abnormality in ADHD. Observed functional abnormalities did not result from prolonged stimulant exposure, since most children were medication naive.     

Attention and executive functions profile in drug naive ADHD subtypes

Attention deficit hyperactivity disorder (ADHD) has been associated with executive functioning and sustained and divided attention deficits. In order to clarify the questions on neurocognitive impairment in ADHD, we investigated the presence of specific executive functions (EFs) and attention deficit patterns in ADHD clinical subtypes. 50 patients with ADHD and 44 controls were evaluated. All subjects were boys and performed a clinical-psychopathological and neuropsychological battery. Five main domains of EFs and attention were studied. Executive functions-related neurocognitive abilities were used as control tasks. ADHD patients, inattentive and combined subtypes differ from controls on response inhibition, divided attention, phonological, and visual object working memory and on variability of reaction times measured with CPT. Comparison of ADHD subtypes, in five main domains of EFs, did not show evidence of different executive functioning profiles. Response inhibition can predict performance on working memory tests but it cannot predict performance on divided attention/set shifting and on sustained attention. ADHD boys exhibit a selective impairment on executive functions and attention tasks. These data suggest the involvement of partially independent neural circuits which control inhibition and divided attention in ADHD. Since right prefrontal cortex seems to be crucial in controlling response inhibition, while left dorsolateral prefrontal cortex seems important in modulating divided attention, these areas are deputated to be involved in the pathogenesis of neuropsychological deficits in ADHD subtypes. In addition, this study candidates the impairment in phonological and visual-object working memory as a possible neuropsychological trait in ADHD males with inattentive or combined subtypes.     

Oculomotor abnormalities in attention deficit hyperactivity disorder: a preliminary study

BACKGROUND: Prevailing hypotheses suggest that attention deficit hyperactivity disorder (ADHD) is secondary to dysfunction of motor intentional systems mediated by prefrontal circuitry. Oculomotor paradigms provide a mechanism for examining and localizing dysfunction at the interface between movement and cognition. OBJECTIVE: Three different saccade tasks (reflexive or prosaccades, antisaccades, and memory-guided saccades) were used to examine functions necessary for the planning and the execution of eye movements, including motor response preparation, response inhibition, and working memory. METHODS: The study included 19 children with ADHD, divided into two groups: a group of 8 children on methylphenidate at the time of testing and a group of 11 children not taking any psychoactive medication. Results from the two groups were compared with those from 25 age- and gender-matched normal control children. RESULTS: Both groups of children with ADHD made significantly more directional errors than did controls on the antisaccade task and significantly more anticipatory errors than did controls on the memory-guided saccade task, findings that are consistent with deficits in response inhibition. There were no significant differences in prosaccade latency, although unmedicated children with ADHD showed significantly greater variability in latency on the prosaccade task than did controls. On the memory-guided saccade task there were no significant differences in saccade accuracy; however, unmedicated children with ADHD showed longer saccade latency than did either controls or medicated children with ADHD. CONCLUSIONS: Oculomotor findings suggest that deficits in prefrontal functions, in particular response inhibition, contribute to behavioral abnormalities observed in ADHD. Findings also suggest that the administration of methylphenidate is associated with improvements in the consistency of motor response. Although there were no observed improvements in response inhibition with methylphenidate, conclusions await a design in which subjects complete testing both on and off medication.     

Effect of trait anxiety on cognitive test performance in adolescents with and without attention-deficit/hyperactivity disorder

Introduction: Attention-deficit/hyperactivity disorder (ADHD) and anxiety are frequently comorbid disorders associated with different types of abnormal performance on neuropsychological tests. Although some studies have shown that comorbid anxiety alters ADHD test performance, results inconsistently show both improvements and worsening of different abilities, with failures to replicate across different anxiety disorders. Alternatively, trait anxiety may reflect a more stable influence on ADHD test performance than various diagnosable anxiety disorders. Method: To better understand the possible enhancing or deleterious effects of anxiety on ADHD cognitive impairments, this study examined the effect of individual differences in trait anxiety measured by the Multidimensional Anxiety Scale for Children (MASC) on a battery of computerized, rapid-performance tests measuring attention and impulsivity-related performance in 98 Diagnostic and Statistical Manual of Mental Disorders–Fourth Edition (DSM–IV) Combined-Subtype ADHD adolescents and 123 healthy controls. It was hypothesized that trait anxiety would attenuate response inhibition and attention deficits in ADHD. Results: ADHD-diagnosed adolescents with higher trait anxiety performed better on indices of sustained attention, reaction time, and motor variability, and had altered overall test-performance strategy, while response inhibition was affected in both ADHD and non-ADHD. Conclusions: This study provides the first evidence that pathological levels of anxiety are not needed to see differences in ADHD neuropsychological test performance. Instead, mildly elevated trait anxiety confers a protective influence by reducing the degree of impairment seen in ADHD. These findings suggest that better performing ADHD adolescents might have optimized levels of cortical arousal, and raise new questions about how best to identify the neurobiological substrates responsible for the beneficial effects.     

Impact of ADHD on the neurocognitive functioning of adolescents with bipolar disorder.

BACKGROUND: Pediatric Bipolar Disorder (BD) has been associated with a number of neurocognitive deficits not dissimilar to ADHD. This study compared neuropsychological profiles of 4 groups of adolescents (14-17 years): 41 Normal Controls (NC), 30 ADHD, 12 BD and 12 combined (BD+ADHD). METHODS: Participants were identified according to a standardized protocol (WASHU-KSADS mood section, K-SADS-PL and Conners Scales) and completed tests of processing speed, memory, executive functioning, set shifting, and inhibition. ADHD adolescents on stimulant medication did not take it on the day. RESULTS: After controlling for covariates, the ADHD-only and combined groups were most impaired, including processing and naming speed, working memory, and response inhibition. The ADHD-only group showed specific impairment in naming objects, numbers and letters than the NC and showed greater deficits than the BD-only group on tests of naming speed. The combined group showed greatest deficits in verbal memory and inhibitory control. Other than working memory, there were no differences between the BD-only and NC groups. Removal of BD-NOS did not impact on the results. CONCLUSIONS: This study failed to find broad neurocognitive deficits in BD-only adolescents. Only those with comorbid ADHD showed cognitive deficits, highlighting the impact ADHD may have on neurocognitive functioning of BD.     

Neuropsychological function in obsessive-compulsive disorder

Obsessive-compulsive disorder (OCD) is a chronic disease characterized by repetitive, unwanted intrusive thoughts and ritualistic behaviors. Studies of neuropsychological functions in OCD have documented deficits in several cognitive domains, particularly with regard to visuospatial abilities, executive functioning, and motor speed. The objective of the present study was to investigate systematically the cognitive functioning of OCD patients who were free of medication and comorbid psychiatric disorders. In the present study, 72 OCD patients were compared with 54 healthy controls on their performance in a comprehensive neuropsychological battery. The Yale-Brown Obsessive Compulsive Scale and the Hamilton Depression Rating Scale were administered to the patients, and a semistructured interview form was used to evaluate the demographic features of the patients and control subjects. Overall, widespread statistically significant differences were found in tests related to verbal memory, global attention and psychomotor speed, and visuospatial and executive functions indicating a poorer performance of the OCD group. A closer scrutiny of these results suggests that the OCD group has difficulty in using an effective learning strategy that might be partly explained by their insufficient mental flexibility and somewhat poor planning abilities.     

Attention-deficit/hyperactivity disorder in childhood epilepsy: a neuropsychological and functional imaging study

Purpose: Children with epilepsy have a significant risk for attention‐deficit/hyperactivity disorder (ADHD), which is often accompanied by deficits in working memory performance. However, it is not yet clear whether there are specific differences in the underlying mechanisms of working memory capability between children with epilepsy‐related ADHD and those with developmental ADHD. There is evidence that methylphenidate can improve the behavioral difficulties in children with developmental ADHD. Whether this medication has the same effect on ADHD symptoms in patients with epilepsy is not yet well understood. The aim of the present study is, therefore, to evaluate whether boys with epilepsy‐related ADHD and developmental ADHD share a common behavioral, pharmacoresponsive, and neurofunctional pathophysiology. Methods: Seventeen boys with diagnosed combined epilepsy/ADHD, 15 boys with developmental ADHD, and 15 healthy controls (aged 8–14 years) performed on working memory tasks (N‐back) while brain activation was recorded using functional magnetic resonance imaging. Each patient was tested twice: once after the intake of methylphenidate and once without in a counterbalanced order. Key Findings: On a behavioral level, we show that boys with epilepsy‐related ADHD as well as those with developmental ADHD performed similarly poorly on tasks with high cognitive load when compared to healthy controls, and that intake of methylphenidate improved performance almost to normal levels in both ADHD groups. On the functional level, both patient groups showed similar reductions of activation in all relevant parts of the functional network of working memory when compared to controls. Of interest, intake of methylphenidate did not significantly alter this activity pattern. Significance: Our data show strong similarities between epilepsy‐related and developmental ADHD on the behavioral, pharmacoresponsive, and neural level, favoring the view that ADHD with and without epilepsy shares a common underlying neurobehavioral pathophysiology.     

Functional magnetic resonance imaging evidence for abnormalities in response selection in attention deficit hyperactivity disorder: differences in activation associated with response inhibition but not habitual motor response

Impaired response inhibition is thought to be a core deficit in attention deficit hyperactivity disorder (ADHD). Prior imaging studies investigating response inhibition in children with ADHD have used tasks involving different cognitive resources, thereby complicating the interpretation of their findings. In this study, a classical go/no-go task with a well-ingrained stimulus-response association (green = go; red = no-go) was used in order to minimize extraneous cognitive demands. Twenty-five children with ADHD and 25 typically developing (TD) children between the ages of 8 and 13 years and group-matched for IQ and performance on the go/no-go task were studied using event-related functional magnetic resonance imaging (fMRI). Analyses were used to examine differences in activation between the ADHD and TD groups for "go" (habitual motor response) and "no-go" (requiring inhibition of the motor response) events. Region-of-interest analyses revealed no between-group difference in activation in association with "go" events. For "no-go" events, the children with ADHD demonstrated significantly less activation than did TD controls within a network important for inhibiting a motor response to a visual stimulus, with frontal differences localized to the pre-supplementary motor area. Although blood oxygenation level-dependent fMRI data show no differences between children with ADHD and TD children in association with a habituated motor "go" response, during "no-go" events, which require selecting not to respond, children with ADHD show diminished recruitment of networks important for response inhibition. The findings suggest that abnormalities in circuits important for motor response selection contribute to deficits in response inhibition in children with ADHD and lend support to the growing awareness of ADHD-associated anomalies in medial frontal regions important for the control of voluntary actions.     

Neuropsychological deficits in adolescent-onset schizophrenia compared with attention deficit hyperactivity disorder.

OBJECTIVE: Impaired neuropsychological performance involving abstraction-flexibility, memory, motor function, and attention has frequently been reported in schizophrenia as well as in attention deficit hyperactivity disorder (ADHD). This study represents an attempt to compare groups of adolescents with schizophrenia and ADHD on a comprehensive neuropsychological test battery. Such a comparison affords the opportunity to ascertain differences in the degree, profile, and specificity of impairments. METHOD: The performance of 19 adolescents with schizophrenia, 20 adolescents with ADHD, and 30 normal adolescents on a broad battery of cognitive tests was compared. RESULTS: The schizophrenic group showed the most pronounced deficits on tests of abstraction, visual memory, and motor function in comparison with the subjects with ADHD, while the ADHD subjects had the most pronounced deficits on measures of attention, verbal memory, and learning. CONCLUSIONS: The subjects with schizophrenia appeared to have a more general pattern of brain dysfunction, whereas the impairment of the ADHD subjects seemed to be relatively specific to tests associated with frontal lobe function.     

Oculomotor abnormalities in boys with tourette syndrome with and without ADHD.

OBJECTIVE: To assess saccadic eye movements in boys with Tourette syndrome (TS) with and without attention-deficit hyperactivity disorder (ADHD), comparing performance with that of an age-matched group of male controls. METHOD: Three different saccade tasks (prosaccades, antisaccades, and memory-guided saccades) were used to examine functions necessary for the planning and execution of eye movements, including motor response preparation, response inhibition, and working memory. The study included 14 boys with TS without ADHD (TS-only), 11 boys with TS and ADHD (TS+ADHD), and 10 male controls. RESULTS: Latency of prosaccades was prolonged in boys with TS (both with and without ADHD) compared with controls. Variability in prosaccade latency was greater in the groups of boys with TS+ADHD compared with both the TS-only and control groups. Response inhibition errors on both the antisaccade task (directional errors) and memory-guided saccade task (anticipatory errors) were increased in boys with TS+ADHD compared with those with TS-only. There were no significant differences among the three groups in accuracy of memory-guided saccades. CONCLUSIONS: Oculomotor findings suggest that TS is associated with delay in initiation of motor response as evidenced by excessive latency on prosaccades. Signs of impaired response inhibition and variability in motor response appear to be associated with the presence of ADHD.     

Cognitive performance in early Parkinson''s disease

The cognitive, memory and psychomotor performance of 67 patients with Parkinson's disease who had not received any antiparkinson medication was compared with the performance of 43 healthy subjects matched by age and education. The principal impairments in the patients were motor ones, evident in various tests such as general motor slowness and delayed initiation of movement, and they correlated with clinical rigidity and hypokinesia but not with tremor. The performance of the patients was inferior to that of the controls in memory tests involving the processing of information and learning (logical memory, associative learning) but not in less demanding tasks such as the retrieval of numbers. The total disability was due to a combined effect of aging and disease. A decrease of about 15% in the psychomotor and cognitive performance, related to aging alone, can be expected to occur between the ages of 50 and 70. The performance of the patients in memory tests and other tests evaluating cognitive capacity did not correlate either with their motor disability or with their mood. A possibility therefore exists that biological processes behind the cognitive decline and the motor disability are separate, even if they may occur simultaneously.     

Neuropsychological performance in childhood OCD: A preliminary study

Background: Neuropsychological deficits have often been found in studies of adults with obsessive compulsive disorder (OCD). However, few studies have examined such impairment in children with OCD and of those studies published, the results are mixed. Methods: In the present study, 14 OCD children were compared to 24 healthy developing children of similar age and intellectual ability on a series of neuropsychological tests that assess response inhibition, abstract reasoning and problem solving, planning ability, verbal and nonverbal fluency, working memory, attention and information processing speed, and visual and verbal memory and learning. Results: No significant differences emerged between the children with OCD and healthy controls for working memory, verbal fluency, attention, information processing speed, concept formation/abstraction, and response inhibition. We observed some deficits and a trend toward performance differences between the groups for psychomotor speed and attention, cognitive flexibility, nonverbal fluency, planning ability, and verbal memory and learning. Results are partially consistent with those found in adults with OCD. Findings were not related to depressive symptoms or self‐report feeling of anxiety. Conclusions: This preliminary survey indicates that OCD children may have deficits for cognitive flexibility and planning ability and differ from adults with OCD in not presenting with poor response inhibition or memory deficits. Larger, multi‐site studies are warranted to help delineate the neurocognitive deficits associated with childhood OCD. Depression and Anxiety, 2010. © 2009 Wiley‐Liss, Inc.     

Motor persistence and inhibition in autism and ADHD.

The present study compared performance of children with Attention-Deficit/Hyperactivity Disorder (ADHD) and high functioning autism (HFA) with that of controls on 4 tasks assessing 2 components of motor control: motor response inhibition and motor persistence. A total of 136 children (52 ADHD, 24 HFA, 60 controls) ages 7 to 13 years completed 2 measures of motor inhibition (Conflicting Motor Response and Contralateral Motor Response Tasks) and 2 measures of motor persistence (Lateral Gaze Fixation and NEPSY Statue). After controlling for age, IQ, gender, and basic motor speed, children with ADHD performed significantly more poorly than controls on the Conflicting Motor Response and Contralateral Motor Response Tasks, as well as on Statue. In contrast, children with HFA achieved lower scores than controls only on measures of motor persistence, with no concomitant impairment on either motor inhibition task. These results are consistent with prior research that has demonstrated relatively spared motor inhibition in autism. The findings highlight the utility of brief assessments of motor control in delineating the unique neurobehavioral phenotypes of ADHD and HFA.