Emerging support for a role of exercise in attention-deficit/hyperactivity disorder intervention planning.

Recent years have seen an expansion of interest in non-pharmacological interventions for attention-deficit/hyperactivity disorder (ADHD). Although considerable treatment development has focused on cognitive training programs, compelling evidence indicates that intense aerobic exercise enhances brain structure and function, and as such, might be beneficial to children with ADHD. This paper reviews evidence for a direct impact of exercise on neural functioning and preliminary evidence that exercise may have positive effects on children with ADHD. At present, data are promising and support the need for further study, but are insufficient to recommend widespread use of such interventions for children with ADHD.

Training Executive, Attention, and Motor Skills (TEAMS): a Preliminary Randomized Clinical Trial of Preschool Youth with ADHD.

This preliminary randomized controlled trial compared Training Executive, Attention and Motor Skills (TEAMS), a played-based intervention for preschool children with attention-deficit/hyperactivity disorder (ADHD), to an active comparison intervention consisting of parent education and support (ClinicalTrials.gov Identifier: NCT01462032). The primary aims were to gauge preliminary efficacy and assist in further development of TEAMS. Four- and 5-year-old children with ADHD were randomly assigned to receive TEAMS (N = 26) or the comparison intervention (N = 26) with blinded assessments by parents, teachers and clinicians ascertained pretreatment, post-treatment, and 1- and 3-months post-treatment. Changes in ADHD severity, impairment, parenting factors, and neuropsychological functioning over time as a function of treatment condition were assessed using the PROC MIXED procedure in SAS. Across most measures, significant main effects for Time emerged; both treatments were associated with reduced ADHD symptoms that persisted for three months post-treatment. There were no significant Treatment effects or Time x Treatment interactions on symptom and impairment measures, suggesting that the magnitude of improvement did not differ between the two interventions. However, significant correlations emerged between the magnitude of behavioral change, as assessed by parents and clinicians, and the amount of time families engaged in TEAMS-related activities during treatment. Across a wide array of parenting and neuropsychological measures, there were few significant group differences over time. TEAMS and other psychosocial interventions appear to provide similar levels of benefit. Play-based interventions like TEAMS represent a potentially viable alternative/addition to current ADHD treatments, particularly for young children, but more research and further development of techniques are necessary.

Prefrontal and parietal correlates of cognitive control related to the adult outcome of attention-deficit/hyperactivity disorder diagnosed in childhood.

The protracted and highly variable development of prefrontal cortex regions that support cognitive control has been purported to shape the adult outcome of attention-deficit/hyperactivity disorder (ADHD). This neurodevelopmental model was tested in a prospectively followed sample of 27 adult probands who were diagnosed with ADHD in childhood and 28 carefully matched comparison subjects aged 21-28 years. Probands were classified with persistent ADHD or remitted ADHD. Behavioral and neural responses to the Stimulus and Response Conflict Task (SRCT) performed during functional magnetic resonance imaging (fMRI) were compared in probands and comparison subjects and in probands with persistent and remitted ADHD. Response speed and accuracy for stimulus, response, and combined conflicts did not differ across groups. Orbitofrontal, inferior frontal and parietal activation was lower in probands than comparison subjects, but only for combined conflicts, when demand for cognitive control was highest. Reduced activation for combined conflicts in probands was almost wholly attributable to the persistence of ADHD; orbitofrontal, inferior frontal, anterior cingulate and parietal activation was lower in probands with persistent ADHD than both probands with remitted ADHD and comparison subjects, but did not differ between probands with remitted ADHD and comparison subjects. These data provide the first evidence that prefrontal and parietal activation during cognitive control parallels the adult outcome of ADHD diagnosed in childhood, with persistence of symptoms linked to reduced activation and symptom recovery associated with activation indistinguishable from adults with no history of ADHD.

Neuropsychological correlates of ADHD symptoms in preschoolers.

The authors examined the neuropsychological status of 22 preschoolers at risk for attention-deficit/hyperactivity disorder (ADHD) and 50 matched control children, using measures of nonverbal working memory, perceptual and motor inhibition, and memory for relative time. All tasks included paired control conditions, which allowed for the isolation of discrete executive function constructs. Group differences were evident on several measures of neuropsychological functioning; however, after accounting for nonexecutive abilities, no deficits could be attributed to specific functions targeted by the tasks. Performance on executive measures was not related to objective indices of activity level or ratings of ADHD symptoms. Yet, the fact that at-risk preschoolers were highly symptomatic casts doubt on whether executive function deficits and/or frontostriatal networks contribute etiologically to early behavioral manifestations of ADHD.

Self-report and objective measures of ADHD-related behaviors in parents of preschool children at risk for ADHD.

OBJECTIVE: Few studies have used a combination of objective and self-report measures to examine neuropsychological and behavioral functioning in parents of children with attention-deficit/hyperactivity disorder (ADHD). This study examined attention and inhibitory control in the parents of preschool children who were rated as "at risk" for developing ADHD as compared with parents of controls. METHODS: Preschool children (N=53) were divided into at risk for ADHD and control groups based on parent and teacher ratings of Diagnostic and Statistical Manual of Mental Disorders, Fourth Edition ADHD symptoms. One parent of each child was administered an identical pairs Continuous Performance Test (CPT-IP), a Go/No-Go task, and the Brown Attention-Deficit Disorder Scale for Adults. RESULTS: Parents of preschoolers at risk for ADHD showed a pattern of responding on measures of vigilance characterized by slower reaction times and increased commission errors as compared with parents of controls. There were no significant group differences on self-report measures on the Brown Attention-Deficit Disorder Scale for Adults. CONCLUSION: Parents of preschoolers at risk for ADHD appear to exhibit cognitive processing deficits that may not be evident using self-report measures. Further research is needed to more clearly identify the specific nature of these neuropsychological deficits and to determine whether they have a negative impact on their children.

Healthy body, healthy mind?: the effectiveness of physical activity to treat ADHD in children.

Data from animal studies provide convincing evidence that physical exercise enhances brain development and neurobehavioral functioning in areas believed to be impaired in children with attention-deficit/hyperactivity disorder (ADHD). To a lesser but still compelling extent, results from studies in typically developing children and adults indicate beneficial effects of exercise on many of the neurocognitive functions that have been shown to be impaired in children with ADHD. Together, these data provide a strong rationale for why a program of structured physical exercise might serve as an effective intervention for children with ADHD.

Preliminary evidence for reduced posterror reaction time slowing in hyperactive/inattentive preschool children.

BACKGROUND: Attention deficit/hyperactivity disorder (ADHD) has been associated with deficits in self-regulatory cognitive processes, some of which are thought to lie at the heart of the disorder. Slowing of reaction times (RTs) for correct responses following errors made during decision tasks has been interpreted as an indication of intact self-regulatory functioning and has been shown to be attenuated in school-aged children with ADHD. This study attempted to examine whether ADHD symptoms are associated with an early-emerging deficit in posterror slowing. METHOD: A computerized two-choice RT task was administered to an ethnically diverse sample of preschool-aged children classified as either "control" (n = 120) or "hyperactive/inattentive" (HI; n = 148) using parent- and teacher-rated ADHD symptoms. Analyses were conducted to determine whether HI preschoolers exhibit a deficit in this self-regulatory ability. RESULTS: HI children exhibited reduced posterror slowing relative to controls on the trials selected for analysis. Supplementary analyses indicated that this may have been due to a reduced proportion of trials following errors on which HI children slowed rather than due to a reduction in the absolute magnitude of slowing on all trials following errors. CONCLUSIONS: High levels of ADHD symptoms in preschoolers may be associated with a deficit in error processing as indicated by posterror slowing. The results of supplementary analyses suggest that this deficit is perhaps more a result of failures to perceive errors than of difficulties with executive control.

Thalamo-cortical activation and connectivity during response preparation in adults with persistent and remitted ADHD.

OBJECTIVE: The neural correlates of stimulus-driven processes, such as response preparation, have been posited to be associated with the onset of attention deficit hyperactivity disorder (ADHD) while being distinct from the neural mechanisms associated with recovery. The authors tested this hypothesis in adults with remitted and persistent ADHD. METHOD: Thirty-eight young adults who were diagnosed with combined-type ADHD in childhood (probands) and 32 carefully matched comparison subjects were followed longitudinally and scanned with functional MRI while performing an event-related cued reaction time task. Probands were characterized as individuals with persistent or remitted ADHD. Differences in thalamo-cortical activation and functional connectivity during response preparation between comparison subjects and probands and between individuals with persistent ADHD and those with remitted ADHD were assessed by contrasting neural activation and functional connectivity during cue or noncue events. RESULTS: Probands exhibited less cue-related activation than comparison subjects in the thalamus, anterior cingulate cortex, supplementary motor area, inferior parietal lobe, and dorsolateral prefrontal cortex despite similar overall patterns of activation. There were no differences in activation between individuals in the remitted ADHD group and those in the persistent ADHD group in any hypothesized regions. However, cue-related functional connectivity between the right thalamus and brainstem was greater in comparison subjects relative to probands, and cue-related connectivity was greater between the right thalamus and prefrontal regions in individuals with remitted ADHD relative to those with persistent ADHD. CONCLUSIONS: Decreased thalamo-cortical activation during response preparation was present in adults diagnosed with ADHD in childhood regardless of symptom remission in adulthood, and may be partly driven by less functional coordination between the brainstem and thalamus. Greater functional integration of the thalamo-cortical network might parallel symptom recovery.

Brief report: Television viewing and risk for attention problems in preschool children.

OBJECTIVES: This study examined whether high levels of television viewing are associated with attention problems and hyperactivity in preschool children. METHODS: Parent and teacher ratings of inattention, hyperactivity and impulsivity, objectively measured activity level, and parental estimation of early television exposure were collected for a sample of preschool children. Separate linear regression analyses were conducted with parent and teacher behavioral ratings and objectively assessed activity level as outcome variables. RESULTS: Results indicated that after controlling for demographic factors (i.e., age, sex, and SES), television exposure accounted for a significant proportion of the variance in teacher ratings of inattentive/hyperactive behaviors, as well as objectively measured activity level. CONCLUSIONS: These findings partially replicate those from a recent, highly publicized study indicating a correlation between television exposure and attention-deficit/hyperactivity disorder (ADHD)-associated behaviors. However, it remains unclear as to whether elevated levels of television viewing are the cause or result of ADHD symptoms.

Sustained attention and response inhibition in young children at risk for Attention Deficit/Hyperactivity Disorder.

BACKGROUND: Studies of school-aged children, adolescents, and adults with Attention Deficit/Hyperactivity Disorder (ADHD) have variably shown ADHD-related impairment in both inhibitory control and sustained attention. However, few studies have examined ADHD-associated patterns of performance on these tasks among younger children (below age 7 years). METHODS: A combined continuous performance test and go/no-go task (CPT/GNG) and the Day-Night Stroop Task (DNST) were administered to an ethnically diverse sample of 3.44- to 6.95-year-old children rated by parents and teachers as being either high risk or low risk for ADHD. All children performed the DNST (N = 71) and a subset of the sample (N = 44) performed the CPT/GNG. Analyses assessed task validity as well as the effects of age and risk status. RESULTS: Significant main effects for age and risk status were found on all tasks. In addition, age x condition interactions were found for the CPT and DNST, which suggest that the tasks were sensitive to age-related changes in sustained attention and inhibitory control respectively. No significant risk status x condition interactions were found, suggesting that young children at risk for ADHD do not exhibit specific deficits in either inhibitory control or sustained attention. The most consistent effect related to risk status across tasks was the greater number of errors and longer and more variable reaction times on the part of children at risk for ADHD irrespective of condition. CONCLUSIONS: ADHD-associated decrements in performance on these tasks appear to be attributable either to generalized behavioral dysregulation or poor state regulation rather than to deficient inhibitory control.