Anne Fleur Kortekaas-Rijlaarsdam

CHAPTER 7 138 positive effects of MPH. However, results from individual studies so far don’t support the potential of MPH to improve spelling (Bental & Tirosh, 2008; Douglas et al., 1986; Pelham et al., 1985) or writing (Lufi & Gai, 2007) in children with ADHD. Another explanation is that the observed improvements are mostly improvements in productivity. Perhaps reading and math allow for improved productivity more than subjects such as spelling and writing, in which accuracy is more relevant. In keeping with this explanation, math and reading abilities may be more sensitive to short-term (direct) effects of MPH, whereas improvements in for instance handwriting may be achieved only over the longer term as these are more skills based. For example, previous studies showed that handwriting not only depends on sustained attention, but also on fine-motor skills and visual-motor integration (Feder & Majnemer, 2007). With regard to the effects of MPH on reading abilities, results from our meta-analysis reveal that MPH has the potential to improve reading speed but not accuracy. Our experimental data do not support this view. This may be due to methodological differences between the two studies - in the meta-analysis reading comprehension tasks (reading in story format) were used, while we used a word-reading task in our RCT (technical reading). Although reported correlations between word-reading tasks and reading comprehension are generally high (Aarnoutse, Van Leeuwe, Voeten, Van Kan, & Oud, 1996; Riedel, 2007a), there is also a considerable number of children who show impaired reading comprehension but adequate reading fluency on word-reading tasks (Riedel, 2007b). Thus, measures of reading comprehension may be of most interest here, as reading comprehension is often seen as the ultimate goal for reading achievement (Good, Simmons, & Kame’enui, 2001). However, evidence from earlier studies into ADHD-related impairments in reading do not distinguish between word- reading and reading comprehension (Arnold, Hodgkins, Kahle, Madhoo, & Kewley, 2015; Frazier, Youngstrom, Glutting, & Watkins, 2007). Therefore, it remains unclear whether children with ADHD are more impaired in reading comprehension or word- reading. Taken together, although the increase in reading speed in story format is promising, current literature suggests that such improvements in productivity do not result in qualitative better reading on the short-term or long-term (Langberg & Becker, 2012). Overall, MPH related improvements in academic performance are small compared to the robust effects of this type of medication on ADHD symptoms (MTA-group, 1999b; Van der Oord et al., 2008). Our findings, combined with evidence relating to MPH effects on longer-term academic outcomes (Langberg & Becker, 2012), raise questions about the value of these MPH-related improvements in math and reading for