Logographic Kanji Research Articles

The influence of intelligence and cognitive abilities on the reading ability of Japanese students with developmental disorders

ObjectiveWe examined the differences in reading skills between Japanese students with developmental dyslexia (DD) having developmental disorders who had borderline IQ (BIQ) and those who had normal IQ (NIQ), and the influence of cognitive factors through subscale scores of the Wechsler Intelligence Scale for Children - Fourth Edition on the reading skills of all students with DD having developmental disorders. MethodsOne-way analysis of variance revealed differences in reading scores among the four groups (DD with NIQ, DD with BIQ, as well as non-DD with NIQ and non-DD with BIQ as control groups). To examine the influence of cognitive factors, we used multiple regression analysis for all participants, and then for participants with DD. ResultsRegarding hiragana nonword fluency reading, no difference was observed between the two DD groups, and cognitive factors did not affect the performance of all participants with DD. Concerning hiragana word fluency reading, DD with NIQ group performed better than DD group with BIQ, and working memory index affected reading skills of participants with DD. Regarding kanji accuracy reading, DD with NIQ group performed better than DD with BIQ group, and processing speed index affected performance of participants with DD. ConclusionsThe results of hiragana reading suggest that the two DD groups shared similar weak sub-lexical route processing, while the acquisition of lexical route processing was hindered by lower IQ and weak phonological working memory in transparent phonographic hiragana reading. For kanji reading, lower IQ and weak visuomotor processing ability hampered the learning of visually complex logographic kanji characters.

Association Between Resting-State Functional Connectivity and Reading in Two Writing Systems in Japanese Children With and Without Developmental Dyslexia.

Introduction: Japanese is unique, as it features two distinct writing systems that share the same sound and meaning: syllabic Hiragana and logographic Kanji scripts. Acquired reading difficulties in Hiragana and Kanji have been examined in older patients with brain lesions. However, the precise mechanisms underlying deficits in developmental dyslexia (DD) remain unclear.Materials and Methods: The neural signatures of Japanese children with DD were examined by using resting-state functional magnetic resonance imaging. We examined 22 dyslexic and 46 typically developing (TD) children, aged 7–14 years.Results: Reading performance in each writing system was correlated with neural connectivity in TD children. In contrast, in children with DD, weak associations between neural connectivity and reading performance were observed. In TD children, Hiragana-reading fluency was positively correlated with the left fusiform gyrus network. No significant correlations between Hiragana fluency and neural connectivity were observed in children with DD. Correspondingly, there were fewer correlations between Kanji accuracy and strength of reading-related connectivity in children with DD, whereas positive correlations with the bilateral fronto-parietal network and negative correlations with the left fusiform network were found in TD children.Discussion: These data suggest that positive and negative coupling with neural connectivity is associated with developing Japanese reading skills. Further, different neural connectivity correlations between Hiragana fluency and Kanji accuracy were detected in TD children but less in children with DD.Conclusion: The two writing systems may exert differential effects and deficits on reading in healthy children and in children with DD, respectively.Impact statementThis is the first study of the precise neurobiological characteristics of dyslexia in Japanese children. Because the Japanese language uniquely features two writing systems and there is a low prevalence of dyslexia among Japanese children, our results from an examination of this population provided unique insights into the neural bases of dyslexia. Using resting-state functional magnetic resonance imaging, we determined possible networks that may be implicated in the reading deficits present in these and other children who suffer from dyslexia.

Altered visual character and object recognition in Japanese-speaking adolescents with developmental dyslexia

Many studies have confirmed a brain dysfunction in people with developmental dyslexia (DD) in certain brain regions, including the left superior temporal gyrus and the left fusiform gyrus. However, the neurobiological substrates in Japanese-speaking people with dyslexia are not fully understood, mostly due to the uniqueness of the orthographic systems. Since a substantial part of the written Japanese includes the logographic Kanji as well as the phonographic Kana systems, the reading disability might be caused not only by a dysfunction in the phonological system, but also by a dysfunction in the visual recognition system. Previous studies reported altered hierarchical visual word form processing in the left occipitotemporal cortex; however, it remains unclear whether the altered hierarchical visual processing is language stimuli-specific. Therefore, we aimed to investigate whether (a) Japanese-speaking individuals with DD exhibit atypical hierarchical visual processing, and if so, (b) whether the altered hierarchical visual processing is language stimuli-specific or not. The present study investigated the brain activation pattern for the hierarchical component of the Kanji characters and object stimuli in typically developing (TD) adolescents and adolescents with DD using functional magnetic resonance imaging. For the Kanji characters, adolescents with DD showed a greater activation in the left occipital gyrus and right occipital fusiform gyrus, and this hyperactivity was also found for pseudo and artificial Kanji characters. These results imply reliance on an early visual system in Kanji reading in Japanese-speaking adolescents with DD. Additionally, we also investigated the brain activity for object stimuli, and adolescents with DD showed a greater activation in the bilateral occipital gyri compared with the TD adolescents. These results imply an altered hierarchical visual processing characterized by overactivation in the early visual areas, which is a not restricted to language stimulus only.

Use of internet and online language tools for teaching reading comprehension to Italian learners of Japanese

Japanese is considered one of the most difficult foreign languages. A major factor is the complex Japanese orthography consisting of thousands of logographic kanji (adapted Chinese characters) and 105 phonetic kana (subdivided into hiragana and katakana). This situation leads to hardships in learning to read Japanese, discouraging students from tackling authentic texts full of unknown kanji symbols. Online language tools might assist and encourage learners to read authentic texts, reducing reading anxiety. To evaluate the potential of this learning support, an experimental study was conducted. Twelve Italian college students with elementary Japanese proficiency participated. They completed two homework reading tasks with the use of online language tools, taking a post-task survey. Three findings emerge from the data: 1) using online tools enables students to read authentic texts; 2) using more tools makes it easier and faster to comprehend texts; 3) students strongly feel that the use of online tools helps to read Japanese texts and reduces their psychological block, willing to continue to use them. Overall, the results show the positive effects of using the tools on both reading performance and psychology, suggesting the potential effectiveness of the use of online language resources for learning to read Japanese texts.

Single and compound logographic Kanji words elicit distinct early neurophysiological responses: ERP evidence from fluent and naïve Kanji readers

Abstract While the N170 to printed words in alphabetic scripts is consistently left-lateralized, the available evidence on logographic scripts is much less consistent. Here, we examined the extent to which use of single-character (e.g.,目) versus compound-character (e.g., 目玉) words in a logographic script could account for differences in the laterality of early neural responses in fluent readers. Participants included both fluent Kanji readers (n = 17) as well as naive Kanji readers (n = 19), in order to separate out differences due to low-level physical differences between stimuli. While fluent Kanji readers showed a larger amplitude N170 overall relative to naive readers, this expertise effect was bilateral, rather than left-lateralized as is common with alphabetic scripts. Trend-level differences in laterality were observed at the earlier P1 response, which has not been extensively examined in previous studies of logographic script reading, with naive readers only tending to show right-lateralization across both single- and compound-character Kanji words. Both participant groups differentiated single and compound Kanji words, but contrary to predictions these effects were bilateral and evident during different stages of processing in each group. Among naive readers, compound Kanji elicited a larger amplitude P1, suggesting influence on early perceptual processing, whereas among fluent readers, these differences were not apparent until the later N170. Taken together, findings from the present study indicate that low-level visual characteristics and perceptual expertise interact during the specialization of neural circuits for print, with implications for theories of lateralization of neural circuits for print.

A cross-linguistic evaluation of script-specific effects on fMRI lateralization in late second language readers.

Behavioral and neuroimaging studies have provided evidence that reading is strongly left lateralized, and the degree of this pattern of functional lateralization can be indicative of reading competence. However, it remains unclear whether functional lateralization differs between the first (L1) and second (L2) languages in bilingual L2 readers. This question is particularly important when the particular script, or orthography, learned by the L2 readers is markedly different from their L1 script. In this study, we quantified functional lateralization in brain regions involved in visual word recognition for participants' L1 and L2 scripts, with a particular focus on the effects of L1–L2 script differences in the visual complexity and orthographic depth of the script. Two different groups of late L2 learners participated in an fMRI experiment using a visual one-back matching task: L1 readers of Japanese who learnt to read alphabetic English and L1 readers of English who learnt to read both Japanese syllabic Kana and logographic Kanji. The results showed weaker leftward lateralization in the posterior lateral occipital complex (pLOC) for logographic Kanji compared with syllabic and alphabetic scripts in both L1 and L2 readers of Kanji. When both L1 and L2 scripts were non-logographic, where symbols are mapped onto sounds, functional lateralization did not significantly differ between L1 and L2 scripts in any region, in any group. Our findings indicate that weaker leftward lateralization for logographic reading reflects greater requirement of the right hemisphere for processing visually complex logographic Kanji symbols, irrespective of whether Kanji is the readers' L1 or L2, rather than characterizing additional cognitive efforts of L2 readers. Finally, brain-behavior analysis revealed that functional lateralization for L2 visual word processing predicted L2 reading competency.

Developmental Reading Disorders in Japan—Prevalence, Profiles, and Possible Mechanisms

Japan has been considered dyslexia-free because of the nature of the orthography, which consists of the visually simple kana syllabary and some thousands of visually complex, logographic kanji characters. It is true that few children struggle with learning kana, which provide consistent mappings between symbols and their pronunciation. Indeed, most children can read most of the kana by age 6. However, many Japanese children struggle with reading the kanji, which represent most of the content words in a text; in addition to their visual complexity and impoverished or nonexistent phonological information, kanji are difficult because they typically have several pronunciations and multiple meanings, depending on the context. Because kanji must be learned semantically rather than phonologically, many people believe that Japanese dyslexia is due to visuospatial rather than phonological processing impairments. We sketch the complex psycholinguistic demands of retrieving the correct pronunciations for kanji, especially in kanji compound words. Some individuals have extreme difficulty in learning the correspondences between these symbols and their sounds; whether these difficulties are visual, phonological, or both is an urgent topic for further research. After introducing Japanese orthography, we present 2 case studies. The first is a profile of a boy we observed from ages 7 to 20 years with difficulties in learning both kana and kanji. The second is a case study of using an interactive reading intervention for a fifth-grade boy with dyslexia. This program was designed to reduce decoding and fluency problems by teaching the meanings and pronunciations in phrasal context rather than in vocabulary lists. We propose that some of the dyslexias in Japanese may not be the same as any type of dyslexia that has been reported for learners of alphabetic writing systems. In addition, we emphasize the need for SLPs in Japan to establish new policies that support collaborative relationships with teachers and other professionals so that they can work in schools to identify and help children with spoken and written language problems.

Development of text reading in Japanese: an eye movement study

This study examined age-group differences in eye movements among third-grade, fifth-grade, and adult Japanese readers. In Experiment 1, Japanese children, but not adults, showed a longer fixation time on logographic kanji words than on phonologically transparent hiragana words. Further, an age-group difference was found in the first fixation duration on hiragana words but not on kanji words, suggesting character-type-dependent reading development in Japanese children. Examination of the distributions of saccade landing positions revealed that, like adults, both third and fifth graders fixated more on kanji than on hiragana characters, which suggests that even young children utilize the same oculomotor control strategy (the kanji targeting strategy) as Japanese adults. In Experiment 2, we examined whether the proportion of kanji characters in a text affected adult reading performance. Japanese adults made more refixations and regressions in texts with a high proportion of hiragana characters. The results of both experiments suggest that differences between kanji and kana affect the reading efficiency of school-age children and that maturation of reading skills allows adults to optimize their strategy in reading kanji and kana mixed texts.

Recognition of Japanese Phonographic Kana (Hiragana) and Logographic Kanji Characters by Passive Finger Tracing

The present study assessed the ability of normal Japanese adults to recognize kanji and hiragana characters through passive finger tracing without visual cues. We tested fifty-six right-handed Japanese university students using the left or right hand. Participants recognized approximately 50% of 44 kanji characters, regardless of the hand they used. The results are consistent with previous findings in Chinese speakers. In contrast, the average correct response to the 44 hiragana was almost 80%, again irrespective of hand. The results are discussed in terms of differential processing systems for Japanese writing and of differential cerebral hemispheric specializations.

Functional MRI evidence for the importance of visual short‐term memory in logographic reading

Logographic symbols are visually complex, and thus children's abilities for visual short-term memory (VSTM) predict their reading competence in logographic systems. In the present study, we investigated the importance of VSTM in logographic reading in adults, both behaviorally and by means of fMRI. Outside the scanner, VSTM predicted logographic Kanji reading in native Japanese adults (n=45), a finding consistent with previous observations in Japanese children. In the scanner, participants (n=15) were asked to perform a visual one-back task. For this fMRI experiment, we took advantage of the unique linguistic characteristic of the Japanese writing system, whereby syllabic Kana and logographic Kanji can share the same sound and meaning, but differ only in the complexity of their visual features. Kanji elicited greater activation than Kana in the cerebellum and two regions associated with VSTM, the lateral occipital complex and the superior intraparietal sulcus, bilaterally. The same regions elicited the highest activation during the control condition (an unfamiliar, unpronounceable script to the participants), presumably due to the increased VSTM demands for processing the control script. In addition, individual differences in VSTM performance (outside the scanner) significantly predicted blood oxygen level-dependent signal changes in the identified VSTM regions, during the Kanji and control conditions, but not during the Kana condition. VSTM appears to play an important role in reading logographic words, even in skilled adults, as evidenced at the behavioral and neural level, most likely due to the increased VSTM/visual attention demands necessary for processing complex visual features inherent in logographic symbols.

Logographic Kanji versus Phonographic Kana in Literacy Acquisition

It is well-established that phonological skills are important for literacy acquisition in all scripts. However, the role of visual skills is less well understood. For logographic scripts in which a symbol represents a whole word or a meaningful unit, the importance of visual memory in literacy acquisition might be expected to be high because of the visual complexity of logographic characters, but in fact its role remains poorly understood. The Japanese writing system uses both phonographic "Kana" and logographic "Kanji" scripts concurrently and thus allows for the assessment of the contribution of phonological and visual processing to literacy acquisition in these two different scripts in the same language. We tested 74 Japanese children (39 second graders and 35 fourth graders) on a range of literacy, sensory, and cognitive tasks. We found that Kana literacy performance was significantly predicted by low-level sensory processing (both auditory frequency modulation sensitivity and visual motion sensitivity) as well as phonological awareness, but not by visual memory. This result is largely consistent with previous studies in other phonographic scripts such as English. In contrast, Kanji literacy performance was strongly predicted by visual memory (particularly visual long-term memory), but not by either low-level sensory processing or phonological awareness. Our results show differences in the skills that predict literacy performance in phonographic Kana and logographic Kanji, as well as providing experimental evidence that visual memory is important when learning Kanji. Therefore, children's literacy problems and remediation programs should be considered in the context of the script in which children are learning to read and write.

Left-lateralized N170 Effects of Visual Expertise in Reading: Evidence from Japanese Syllabic and Logographic Scripts

The N170 component of the event-related potential (ERP) reflects experience-dependent neural changes in several forms of visual expertise, including expertise for visual words. Readers skilled in writing systems that link characters to phonemes (i.e., alphabetic writing) typically produce a left-lateralized N170 to visual word forms. This study examined the N170 in three Japanese scripts that link characters to larger phonological units. Participants were monolingual English speakers (EL1) and native Japanese speakers (JL1) who were also proficient in English. ERPs were collected using a 129-channel array, as participants performed a series of experiments viewing words or novel control stimuli in a repetition detection task. The N170 was strongly left-lateralized for all three Japanese scripts (including logographic Kanji characters) in JL1 participants, but bilateral in EL1 participants viewing these same stimuli. This demonstrates that left-lateralization of the N170 is dependent on specific reading expertise and is not limited to alphabetic scripts. Additional contrasts within the moraic Katakana script revealed equivalent N170 responses in JL1 speakers for familiar Katakana words and for Kanji words transcribed into novel Katakana words, suggesting that the N170 expertise effect is driven by script familiarity rather than familiarity with particular visual word forms. Finally, for English words and novel symbol string stimuli, both EL1 and JL1 subjects produced equivalent responses for the novel symbols, and more left-lateralized N170 responses for the English words, indicating that such effects are not limited to the first language. Taken together, these cross-linguistic results suggest that similar neural processes underlie visual expertise for print in very different writing systems.

Similar brain activation patterns for writing logographic and phonetic symbols in Chinese

This event-related functional MRI study examined the neural correlates for Chinese writing, by comparing the writing of logographic characters and that of pinyin, a phonetic notation system for Chinese characters. The temporal profile of the activations indicated that the middle frontal gyrus, superior parietal lobule, and posterior inferior temporal gyrus reflected more central processes for writing. Although pinyin writing elicited greater activity overall than character writing, the critical finding is that the two types of symbols recruited essentially the same brain regions. The results were compared with studies in Japanese showing dissociation between logographic kanji and phonetic kana writing and frequency of use was suggested to be an important factor in accounting for result differences across the two writing systems.

Japanese Kanji as a Semantically Based Orthography

14 Japanese college students were requested to judge as quickly and as accurately as possible whether two Japanese words, one written in syllabic hiragana and the other written in logographic kanji, were pronounced the same or not. More errors and longer latencies were observed when two words were phonologically different but semantically related than when they were phonologically different and semantically unrelated. This finding is interpreted as demonstrating that the connection between kanji and meaning is stronger than that between kanji and phonology.

Effects of Concurrent Articulation on Reading Japanese Kanji and Kana Words

In written Japanese, there are two types of scripts: logographic kanji and syllabic kana. Three experiments investigated effects of concurrent articulation on decisions about words that are normally written in kanji either presented in kanji or transcribed in kana. Concurrent articulation disrupted rhyme decisions and homophone decisions for the kanji condition more than for the kana-transcribed condition (Experiments 1 and 2) and did not disrupt lexical decisions in either the kanji condition or the kana-transcribed condition (Experiment 3). The results were interpreted as indicating that concurrent articulation does not disrupt the generation of assembled phonology in Japanese, consistent with findings using English materials.