**4.2 Orthographic performance**

As noted in the previous section, children with ADHD in our patients seemed to have more trouble writing Chinese characters which consist of many strokes and thus are visually more complex. This may be due to the fact that ADHD patients do not have long attention span (Bellgrove et al. 2006; Manly et al. 2001). This observation may point to a potential cause of literacy learning difficulties among Japanese ADHD children.

Both ADHD patients and dyslexics seemed to have less trouble reading orthographically more complex characters. This may be due to the fact that visually more complex characters tend to have more orthographical subunits which could function as clues as to their pronunciation. The majority of Chinese characters are phonograms which consist of a phonetic subcomponent that provides information about the character's pronunciation and a semantic subcomponent that provides information about the character's meaning, though sometimes the combination between the pronunciation and the orthographic (sub)component is entirely arbitrary as we noted in the example of 言. For example, 時 ('time') has On/Chinese reading *ji,* has the same orthographic unit as its phonetic component 寺 ('temple') which has also the same On/Chinese reading *ji*. Children with ADHD and dyslexia may be resorting to the same method that beginner readers are said to use (Bowey, Vaughan, and Hansen 1998), namely orthographical analogy, whereby components of characters are used as clues as to their pronunciation. In fact, even among typically developing children, Grade 2 children, many of whom can probably be classified as beginner readers, they had less trouble reading orthographically more complex characters in Fig. 4.

#### **4.3 Phonological performance**

82 Learning Disabilities

Now we would like to examine each of the three main observations that we made in the

It was found that the children with dyslexia had trouble both with writing and with reading, whereas children with ADHD had trouble mainly with writing and showed little evidence of impaired reading. Our finding about dyslexics seems to accord fairly well with previous findings. On the other hand, our finding about ADHD patients should be treated with caution, given the frequent co-occurrence of ADHD with language-related learning problems. Though ADHD has been reported to co-occur with problems in writing more often than with problems with reading in accordance with our results, several independent studies have reported that ADHD patients have problems not just with writing, but also with both reading and writing when they have any language-related problems (Rucklidge and Tannock 2002; Willcutt et al. 2005). If a further study involving a larger number of ADHD patients confirms our finding, that will constitute new

As was particularly obvious in the overall performance of children with ADHD and with dyslexia at Grade 3 in Fig. 3, there was not always a difference in performance between ADHD patients and dyslexics, possibly because of the small sample size. At the moment, overall performance does not differentiate ADHD patients and dyslexics as reliably as

As noted in the previous section, children with ADHD in our patients seemed to have more trouble writing Chinese characters which consist of many strokes and thus are visually more complex. This may be due to the fact that ADHD patients do not have long attention span (Bellgrove et al. 2006; Manly et al. 2001). This observation may point to a potential cause of

Both ADHD patients and dyslexics seemed to have less trouble reading orthographically more complex characters. This may be due to the fact that visually more complex characters tend to have more orthographical subunits which could function as clues as to their pronunciation. The majority of Chinese characters are phonograms which consist of a phonetic subcomponent that provides information about the character's pronunciation and a semantic subcomponent that provides information about the character's meaning, though sometimes the combination between the pronunciation and the orthographic (sub)component is entirely arbitrary as we noted in the example of 言. For example, 時 ('time') has On/Chinese reading *ji,* has the same orthographic unit as its phonetic component 寺 ('temple') which has also the same On/Chinese reading *ji*. Children with ADHD and dyslexia may be resorting to the same method that beginner readers are said to use (Bowey, Vaughan, and Hansen 1998), namely orthographical analogy, whereby components of characters are used as clues as to their pronunciation. In fact, even among typically developing children, Grade 2 children, many of whom can probably be classified as beginner readers, they had less trouble reading

orthographic performance and phonological performance, to be discussed below.

literacy learning difficulties among Japanese ADHD children.

orthographically more complex characters in Fig. 4.

**4. Discussion** 

previous section.

**4.1 Overall performance** 

information about ADHD.

**4.2 Orthographic performance** 

Compared to children with ADHD, dyslexic children were found to have more trouble reading (if not writing) Chinese characters which have more than one possible pronunciation and are thus arguably phonologically more complex. This is consistent with the previous findings about dyslexia, but it is notable that ADHD patients did not show an analogous tendency. This observation indicates that the learning problems experienced by dyslexics and those experienced by ADHD patients are distinct from each other, possibly reflecting the difference in innate cognitive abilities between the two groups
