Methylphenidate restores visual memory, but not working memory function in attention deficit-hyperkinetic disorder

Sinead M. Rhodes, David R. Coghill, Keith Matthews

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    85 Citations (Scopus)


    Rationale Dysfunction of executive neuropsychological performance, mediated by the prefrontal cortex, has been the central focus of recent attention deficit/hyperkinetic disorder (AD-HKD) research. The role of other potential neuropsychological risk factors, such as recognition memory, remains understudied. Further, the impact of methylphenidate (MPH) on key neuropsychological processes in AD-HKD remains poorly understood. Objectives To compare the performance of boys with AD-HKD on a spatial working memory (SWM) task and on two non-working memory tasks [a simultaneous and delayed matching-to-sample task (DMtS) and a pattern-recognition task] with that of healthy boys, and to investigate the impact of acute and chronic MPH on performance of these tasks. Methods Baseline performance of 75 stimulant-naive boys with AD-HKD was compared with that of 70 healthy boys. The AD-HKD boys were then re-tested following the administration of acute and chronic challenges with MPH (0.3 mg/kg and 0.6 mg/kg) under randomised double-blind placebo controlled conditions. Results Compared with healthy boys, the AD-HKD boys demonstrated performance deficits on all neuropsychological tasks. A single dose of MPH restored performance on the DMtS task but had no impact on the SWM or pattern-recognition tasks. Chronic MPH administration did not alter performance on the SWM task but did improve performance on both the pattern-recognition and DMtS tasks. However, the acute restorative effect of MPH on DMtS diminished with repeated administration. Conclusions Our results suggest that current conceptualisations of the neuropsychological basis of AD-HKD and the proposed therapeutic mechanisms of MPH require broadening.
    Original languageEnglish
    Pages (from-to)319-330
    Number of pages12
    Issue number3
    Publication statusPublished - Sept 2004


    • ADHD
    • Methylphenidate
    • CANTAB
    • Delayed matching to sample
    • Visual memory
    • Working memory
    • Tolerance
    • Attention deficit hyperactivity disorder (ADHD)


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