Effect of methylphenidate on Stroop Color-Word task performance in children with attention deficit hyperactivity disorder

Harvard University, Cambridge, Massachusetts, United States
Psychiatry Research (Impact Factor: 2.68). 04/2006; 141(3):315-20. DOI: 10.1016/j.psychres.2005.09.007
Source: PubMed

ABSTRACT Attention deficit hyperactivity disorder (ADHD) is a neuropsychiatric syndrome common in the pediatric population. It is associated with multiple nonspecific deficits on neuropsychological tests of executive function, and a beneficial response to pharmacotherapy with methylphenidate (MPH) and other psychostimulants. The Stroop Color-Word task is used empirically as an aid in diagnosis and treatment monitoring of ADHD; however, data on the sensitivity of the Stroop interference score to the effects of MPH are limited. To address this issue, we studied Stroop performance in a cohort of 18 MPH-treated prepubescent boys with ADHD and six healthy controls on and off MPH treatment conditions. MPH significantly improved performance in both groups, with the ADHD participants consistently displaying worse scores than those of controls both on and off MPH. These results suggest that though the diagnostic value of the Stroop task in ADHD remains controversial, it has heuristic value for monitoring clinical responses to MPH treatment. More research is needed to ascertain the clinical significance of our findings and to replicate this relatively small effect in a larger cohort, to determine whether MPH effects on Stroop performance are specific to ADHD symptoms or they generalize to other forms of symptomatology.

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    ABSTRACT: Methamphetamine (MA) dependence is associated with cognitive deficits. Methylphenidate (MPH) has been shown to improve inhibitory control in healthy and cocaine-dependent subjects. This study aimed to understand the neurophysiological effects before and after acute MPH administration in active MA-dependent and control subjects. Fifteen MA-dependent and 18 control subjects aged 18-46 years were scanned using functional magnetic resonance imaging before and after either a single oral dose of MPH (18 mg) or placebo while performing a color-word Stroop task. Baseline accuracy was lower (p = 0.026) and response time (RT) was longer (p < 0.0001) for the incongruent compared to congruent condition, demonstrating the task probed cognitive control. Increased activation of the dorsolateral prefrontal cortex (DLPFC) and parietal cortex during the incongruent and Stroop effect conditions, respectively was observed in MA-dependent compared to control subjects (p < 0.05), suggesting the need to recruit neural resources within these regions for conflict resolution. Post- compared to pre-MPH treatment, increased RT and DLPFC activation for the Stroop effect were observed in MA-dependent subjects (p < 0.05). In comparison to MPH-treated controls and placebo-treated MA-dependent subjects, MPH-treated MA-dependent subjects showed decreased activation of parietal and occipital regions during the incongruent and Stroop effect conditions (p < 0.05). These findings suggest that in MA-dependent subjects, MPH facilitated increased recruitment of the DLPFC for Stroop conflict resolution, and a decreased need for recruitment of neural resources in parietal and occipital regions compared to the other groups, while maintaining a comparable level of task performance to that achieved pre-drug administration. Due to the small sample size, the results from this study are preliminary; however, they inform us about the effects of MPH on the neural correlates of cognitive control in active MA-dependent subjects.
    Frontiers in Psychiatry 07/2014; 5:20. DOI:10.3389/fpsyt.2014.00020
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    ABSTRACT: Long-acting medications have been developed and approved for use in the treatment of attention-deficit hyperactivity disorder (ADHD). These compounds are intended to optimize and maintain symptoms control throughout the day. We tested prolonged effects of osmotic-release oral system methylphenidate on both attention and inhibition, in the late afternoon. A double-blind, randomized, placebo-controlled study was conducted in 36 boys (7-12 years) with ADHD and 40 typically developing children. The ADHD children received an individualized dose of placebo or osmotic-release oral system methylphenidate. They were tested about 8 hours after taking with 2 continuous performance tests (continuous performance test–X [CPT-X] and continuous performance test–AX [CPT-AX]) and a counting Stroop. A positive effect of osmotic-release oral system methylphenidate was present in CPT-AX with faster and less variable reaction times under osmotic-release oral system methylphenidate than under placebo, and no difference with typically developing children. In the counting Stroop, we found a decreased interference with osmotic-release oral system methylphenidate but no difference between children with ADHD under placebo and typically developing children.
    Journal of Child Neurology 10/2014; DOI:10.1177/0883073814550498 · 1.67 Impact Factor
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    ABSTRACT: Operant conditioning of the electroencephalographic rhythm (EEG biofeedback) is argued to be an effective method for treating children with ADHD. This study was designed to evaluate whether this method, compared to methylphenidate, achieves an equally effective outcome. Participants were 39 children aged between 7 -12 years. Thirteen children with attention-deficit/hyperactivity disorder (ADHD) were trained to enhance the amplitude of the beta1 activity (15 -18 Hz) and decrease the amplitude of the theta activity (4 -8 Hz), and 13 of which were treated with methylphenidate alone. Thirteen healthy children did not receive intervention. Several behavioral, neuropsychological and experimental tests were administered before and after intervention. While behavioral measures were improved by both types of method, methylphenidate was significantly more effective than EEG biofeedback. Response inhibition was improved only by EEG biofeedback. Both EEG biofeedback and methylphenidate were associated with improvements on the variability and accuracy measures of computerized tests. Intellectual ability increased also by both methods. Although averaged effect size for methylphenidate seems to be greater than for EEG biofeedback, the difference was not significant. In conjunction with other studies, these findings demonstrate that EEG biofeedback can significantly improve several be-havioral and cognitive functions in children with ADHD, and it might be an alternative treatment for non-responders or incomplete responders to medication as well as for those their parents favor a non-pharmacological treatment.


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