The specificity of the effects of stimulant medication on classroom learning-related measures of cognitive processing for Attention Deficit Disorder children

Abstract

There appear to be beneficial effects of stimulant medication on daily classroom measures of cognitive functioning for Attention Deficit Disorder (ADD) children, but the specificity and origin of such effects is unclear. Consistent with previous results, 0.3 mg/kg methylphenidate improved ADD children's performance on a classroom reading comprehension measure. Using the Posner letting-matching task and four additional measures of phonological processing, we attempted to isolate the effects of methylphenidate to parameter estimates of (a) selective attention, (b) the basic cognitive process of retrieving name codes from permanent memory, and (c) a constant term that represented nonspecific aspects of information processing. Responses to the letter-matching stimuli were faster and more accurate with medication compared to placebo. The improvement in performance was isolated to the parameter estimate that reflected nonspecific aspects of information processing. A lack of medication effect on the other measures of phonological processing supported the Posner task findings in indicating that methylphenidate appears to exert beneficial effects on academic processing through general rather than specific aspects of information processing.

The Effects of Methylphenidate on Word Decoding Accuracy in Boys With Attention-Deficit/Hyperactivity Disorder

“…14 In contrast, methylphenidate does not improve reading in children with pure reading disorder 15,16 and has no direct impact on phonological processing in ADHD. 17,18 In light of the above-mentioned findings that methylphenidate influences attention/control functions but not decoding functions per se, the use of methylphenidate in a group of ADHD+RD can shed light on the nature of the deficit involved in the reading performance.Our hypothesis was that in the comorbid group, reading functions are partially influenced by impairments of attention/control functions. Therefore, an expected improvement of attention/control functions after methylphenidate administration will lead to an improvement of written language functions.…”

“…14 In contrast, methylphenidate does not improve reading in children with pure reading disorder 15,16 and has no direct impact on phonological processing in ADHD. 17,18 In light of the above-mentioned findings that methylphenidate influences attention/control functions but not decoding functions per se, the use of methylphenidate in a group of ADHD+RD can shed light on the nature of the deficit involved in the reading performance.…”

Comparing treatments for children with ADHD and word reading difficulties: A randomized clinical trial.

“…This hypothesis has been supported by studies indicating that treatment with ADHD medications (including stimulants and non-stimulants) is associated with improved word reading outcomes in children ages 6 to 16 with ADHD/RD (Bental & Tirosh, 2008; Keulers et al, 2007; Shaywitz, Williams, Fox, & Wietecha, 2014; Sumner et al, 2009; Williamson, Murray, Damaraju, Ascher, & Starr, 2014). However, there is also evidence that ADHD medications do not improve phonological processes key to reading development in children ages 5 to 11 (Balthazor, Wagner, & Pelham, 1991; Bental & Tirosh, 2008); thus, medication treatments may not have lasting effects on RD. Children in these studies met DSM criteria for ADHD, but the definition of RD varied.…”

An evaluation of the pharmacokinetics of methylphenidate for the treatment of attention-deficit/ hyperactivity disorder

“…Effects on different neuropsychological functions could be demonstrated (e.g., visuospatial memory), but only partially, for example, no influence on phonological processing or simple storage of auditory-verbal information could be demonstrated [93] and general cognitive improvement is not achieved. Moreover robust cognitive and behavioral MPH response was achieved for children with significant neuropsychological baseline impairment, yet response remained poor for those with adequate neuropsychological function prior to treatment [94,95].…”