**2. Methods**

70 Learning Disabilities

aspects of reading and writing that a given child is having a problem with. Previous achievement tests in reading and writing were designed to detect children having difficulty with reading and writing, and to diagnose the magnitude of the difficulty. Consequently those tests did not allow for construction of a detailed profile of each child's disability.

More specifically, the most important feature of our new tests is that they consist of questions that are more suited to assessing a child's ability in phonological processing and questions that are more suited to assessing a child's ability in orthographic processing. Over the past decade, a growing body of research has shown that reading and writing involve orthographic processing and phonological processing both in alphabetical and in nonalphabetical languages (Afonso and Alvarez 2011; Kandel et al. 2009; Mousikou et al. 2010; Qu et al. 2011). Moreover, a longitudinal developmental study showed that both orthographical and phonological skills accounted for independent variance in later orthographic skills (Sprenger-Charolles et al. 2003). It has been also suggested that both the orthographic and phonological measures contribute to distinguishing various types of dyslexia (Berninger et al. 2008; Coltheart et al. 2001; Hultquist 1997; Plaut et al. 1996); although dyslexia has been strongly associated with a deficit in phonological processing (Ramus et al. 2003; Shaywitz and Shaywitz 2005), reading disabilities may also be linked to problems with orthographic processing. We thus incorporated both orthographical and phonological measures into our reading and writing tests, with the expectation that their inclusion might help us distinguish

To state the advantage of our tests in this regard in a more precise fashion, let us go into some details about the way Chinese characters are used in the Japanese language and the way they are taught at Japanese schools. The way Chinese characters are used in Japan is uniquely complicated, even compared to the way they are used in other Asian countries, such as China and Korea (Taylor and Taylor 1995). Whereas the relation between *Kana*, Japanese syllabary, and sounds is relatively transparent, the relation between *Kanji*, Chinese characters used in Japan, and sounds is sometimes opaque and not transparent. While in Chinese each Chinese character corresponds only to one sound in principle, most Chinese characters used in Japanese have two or more pronunciations, which are classified into On/Chinese pronunciations, which reflect the pronunciations that the characters originally had in Chinese, and Kun/Japanese pronunciations, which are sounds representing the Japanese morphemes that are felt to semantically correspond to the meaning of the Chinese characters. The pronunciation of a Chinese character used in a Japanese text often cannot be

About a thousand Chinese characters, which are roughly half of the Chinese characters that are commonly used among adults (Jo-yo Kanji), are taught at primary school in Japan, i.e. during Grade 1 through to Grade 6. Children in Grade 1 are taught 80 Chinese characters, those in Grade 2 are taught 160 and those in Grade 3 through to Grade 6 are taught about 200 in each academic year. The average number of strokes of a single character taught at each grade increases from about 5 strokes at Grade 1 to about 11 strokes by Grade 5, which corresponds to almost the same average number of strokes of one character in Jo-yo Kanji used among adults. When Japanese children of each grade are taught a fixed set of Chinese characters, they are typically taught only one of the possible pronunciations of those characters at first; more frequently used, thus more important pronunciations, are taught at earlier grades and other pronunciations are taught at later grades. For example, the Chinese

not only various types of dyslexia but also dyslexia and ADHD.

determined unless the context in which it is used is taken into account.

The content of our new tests and the way they were administered to ascertain their validity are presented in this section.

#### **2.1 Material**

In this experiment, participants were asked to read and write Chinese characters that were orthographically and phonologically either complex or simple. Orthographically complex characters are ones that are written with a relatively large number of strokes and orthographically simple characters are ones that are written with a relatively small number of strokes. More specifically, in the tests for second and third graders, the test for fourth graders and the tests for fifth and sixth graders, the orthographically complex characters consisted of approximately six strokes, 11 strokes and 12 strokes respectively on average and orthographically simple characters consisted of approximately three strokes, five strokes and six strokes respectively on average. Phonologically complex characters are ones for which the child (the participant) is expected to have already learned at school more than one pronunciation and phonologically simple characters are ones for which the child (the participant) is expected to have already learned at school only one pronunciation. In other words, participants were asked to read and write Chinese characters which fell into one of the following four categories:


All the words in the achievement tests had been taught at school for at least more than a year before the test, except those used in the tests for Grade 2 children. All the words consist

Assessing Orthographical and Phonological Impairments 73

The participants took a reading test and a writing test for 10 and 15 minutes respectively. The children with developmental disorders were allowed to extend the time if needed. The order of the tests was counterbalanced among the participants. Both the tests consisted of 24 words for second and third graders and 32 words for fourth to sixth graders which were formatted on B4-sized paper. The participants were asked to read (i.e. write the syllabic, non-Chinese letters representing the pronunciation of) or write one Chinese character of each word. In the test for writing, ruby characters, i.e. syllabic, non-Chinese letters indicating the way the Chinese character was to be pronounced, were

As the number of items in the achievement tests was not equal among different graders, the correct response rate for each grade was calculated as a proportion and hence the arc sine root transformation was applied to the correct response rates (Sheskin 2007). Since the number of children with developmental disorders was limited at each grade, we abandoned the analysis of variance using two levels of each independent variable. Instead, we created

Specifically, in order to examine the effect of orthographical demand (i.e. visual complexity), we averaged the correct response rate for (i) characters that consist of a small number of strokes and have only one pronunciation and (iii) characters that consist of a small number of strokes and have more than one pronunciation on one hand to create a variable representing the participants' performance for visually less complex characters, and averaged the correct response rate for (ii) characters that consist of many strokes and have only one pronunciation and (iv) characters that consist of many strokes and have more than one pronunciation on the other hand to create a variable representing the participants' performance for visually more complex characters. Two more variables representing their performance for phonologically less complex characters and their performance for phonologically more complex characters were created in a similar

The mean correct response rate for typically developing children at each grade was further analyzed using the statistical tests according to its distribution after the test for the homogeneity of variance and the test for the normality of distribution. Since the mean correct response rates were not significantly different between the gender groups of typically developing children at each grade according to the Mann Whitney U test, we calculated the mean and the standard deviation of the entire group, containing both girls and boys. Using this mean and the standard deviation as the basis, we then calculated the Zscores for children with developmental disorders at each grade, although the proportion of males and females was different between typically developing children and children with

The result of the experiment seems to support the following three statements:

new variables using the four categories of items mentioned above.

**2.3 Procedure** 

provided.

manner.

developmental disorders.

**3. Results** 

**2.4 Analysis** 

of two to four characters and at least one of the characters is a Chinese character. Words which have potentially problematic homophones were excluded.

Factors such as lexical meaning have been controlled by choosing similar words with respect to frequency, familiarity and imageability (that is, the extent to which the representation of a word's meaning has sensorimotor properties and thus evokes a strong image in any given observer (Strain, Patterson, and Seidenberg 1995)) using some of the standard Japanese corpora for both adults and children (Amano and Kondo 1999; Kai 2005; Sakuma et al. 2005).

#### **2.2 Participants**

Twelve Japanese dyslexic children (mean chronological age 10 years 3 months [SD 16.6 months], one female, two lefthanders), nine Japanese ADHD children (mean chronological age 11 years 2 months [SD 11.9 months], two females, one lefthander) and 479 control children participated in the achievement tests.

The children of the diagnostic group had been referred to the National Center Hospital of Neurology and Psychiatry, mostly because of learning, attention and/or behavioural problems. All the children of the diagnostic group in the study underwent clinical evaluations by two professional clinicians (certified paediatric neurologists). Their intelligence as measured by Wechsler Intelligence Test, the third edition (WISC-III) (Japanese WISC-III Publication Committee 1998) was within the normal range (mean FIQ 90.1 [SD 12.7] among dyslexic children and mean FIQ 92.7 [SD 6.3] among ADHD children). With regard to the intelligence scores, there was no significant difference between dyslexic and ADHD children. Other psychological evaluations involved a computerized continuous performance test (Inoue et al. 2008); rapid naming tests developed for the clinics (Kobayashi et al. in press), clinical observations of the child during the evaluation; a review of the child's records including school records from Grade 1 to the present, previous clinical evaluations and the child's developmental history. The psychiatric and paediatric evaluations involved a semi-structured interview with the guardians and with the child (including an assessment of the child's history and current symptoms), clinical observations of the child, a review of records and analysis of the questionnaires completed by the guardians for clinics. The diagnoses of dyslexia and ADHD were based on the criteria in the Diagnostic and Statistical Manual of Mental Disorders, Forth Edition, Text Revision (DSM-IV-TR) (American Psychiatric Association 2000). None of the children had psychosis, autism, bipolar disorder, significant hearing or visual loss, or other neurological impairments (such as cerebral palsy). All the experimental procedures were in accordance with the Helsinki Declaration of 1964, revised in 2002, and approved by the ethics committee in National Center of Neurology and Psychiatry.

The 479 control children, all typically developing Japanese children (mean chronological age 10 years 3 months [SD 17.1 months], 251 females, 35 lefthanders), came from 16 classes of a municipal primary school located in a suburban community of average socioeconomic status in the middle of Japan. They went to regular general education classrooms, had no known learning problems and do not receive special educational support concerning learning disabilities. They have no history of developmental disorders reported by the classroom teachers. The experimental procedure had been approved by the headmaster of the school.

#### **2.3 Procedure**

72 Learning Disabilities

of two to four characters and at least one of the characters is a Chinese character. Words

Factors such as lexical meaning have been controlled by choosing similar words with respect to frequency, familiarity and imageability (that is, the extent to which the representation of a word's meaning has sensorimotor properties and thus evokes a strong image in any given observer (Strain, Patterson, and Seidenberg 1995)) using some of the standard Japanese corpora for both adults and children (Amano and Kondo 1999; Kai 2005;

Twelve Japanese dyslexic children (mean chronological age 10 years 3 months [SD 16.6 months], one female, two lefthanders), nine Japanese ADHD children (mean chronological age 11 years 2 months [SD 11.9 months], two females, one lefthander) and 479 control

The children of the diagnostic group had been referred to the National Center Hospital of Neurology and Psychiatry, mostly because of learning, attention and/or behavioural problems. All the children of the diagnostic group in the study underwent clinical evaluations by two professional clinicians (certified paediatric neurologists). Their intelligence as measured by Wechsler Intelligence Test, the third edition (WISC-III) (Japanese WISC-III Publication Committee 1998) was within the normal range (mean FIQ 90.1 [SD 12.7] among dyslexic children and mean FIQ 92.7 [SD 6.3] among ADHD children). With regard to the intelligence scores, there was no significant difference between dyslexic and ADHD children. Other psychological evaluations involved a computerized continuous performance test (Inoue et al. 2008); rapid naming tests developed for the clinics (Kobayashi et al. in press), clinical observations of the child during the evaluation; a review of the child's records including school records from Grade 1 to the present, previous clinical evaluations and the child's developmental history. The psychiatric and paediatric evaluations involved a semi-structured interview with the guardians and with the child (including an assessment of the child's history and current symptoms), clinical observations of the child, a review of records and analysis of the questionnaires completed by the guardians for clinics. The diagnoses of dyslexia and ADHD were based on the criteria in the Diagnostic and Statistical Manual of Mental Disorders, Forth Edition, Text Revision (DSM-IV-TR) (American Psychiatric Association 2000). None of the children had psychosis, autism, bipolar disorder, significant hearing or visual loss, or other neurological impairments (such as cerebral palsy). All the experimental procedures were in accordance with the Helsinki Declaration of 1964, revised in 2002, and approved by the ethics committee in National Center of Neurology and

The 479 control children, all typically developing Japanese children (mean chronological age 10 years 3 months [SD 17.1 months], 251 females, 35 lefthanders), came from 16 classes of a municipal primary school located in a suburban community of average socioeconomic status in the middle of Japan. They went to regular general education classrooms, had no known learning problems and do not receive special educational support concerning learning disabilities. They have no history of developmental disorders reported by the classroom teachers. The experimental procedure had been approved by the headmaster of the school.

which have potentially problematic homophones were excluded.

Sakuma et al. 2005).

children participated in the achievement tests.

**2.2 Participants** 

Psychiatry.

The participants took a reading test and a writing test for 10 and 15 minutes respectively. The children with developmental disorders were allowed to extend the time if needed. The order of the tests was counterbalanced among the participants. Both the tests consisted of 24 words for second and third graders and 32 words for fourth to sixth graders which were formatted on B4-sized paper. The participants were asked to read (i.e. write the syllabic, non-Chinese letters representing the pronunciation of) or write one Chinese character of each word. In the test for writing, ruby characters, i.e. syllabic, non-Chinese letters indicating the way the Chinese character was to be pronounced, were provided.
