Predicting the reading skill of Japanese children

Influence of cognitive abilities on literacy skills in a Korean–Japanese bilingual child with developmental dyslexia

Some individuals with developmental dyslexia show dissociation in reading skills between languages. The occurrence of dissociation depends on differences in the orthographic characteristics and cognitive demands of languages. This article reports on a Korean–Japanese bilingual and biliterate boy, SJ, with developmental dyslexia (aged 11 years), who displayed dissociation between Korean and Japanese in reading and writing accuracy. This study aimed to discuss possible accounts for the profile of his literacy skills from orthographic and cognitive perspectives. To accomplish this aim, we measured SJ’s literacy skills, receptive vocabulary, and cognitive abilities (i.e., phonological skills, naming speed, and visual skills) in both Korean and Japanese. Then, we compared his skills to those of monolingual and bilingual children. In terms of accuracy, his reading skills in Korean did not differ significantly from those of bilinguals, although they were lower than Korean monolinguals. His spelling skills were within the average range for Korean monolinguals and bilinguals. In contrast, his reading and writing accuracy levels in Japanese were low compared to both Japanese monolinguals and bilinguals. Moreover, his reading and writing deficits were more remarkable in Japanese kanji. However, his cognitive profile was similar between languages. Specifically, he showed deficits in phonological skills and naming speed in both languages, as well as deficits in visual skills. These results were explained by the facts that visual skills are one of the significant predictors of reading and writing accuracy in Japanese but not in Korean, and that visual skills are a key in learning kanji. Thus, our case, SJ, supports the cognitive account, namely, the idea that different cognitive demands on the development of literacy skills can cause dissociation in literacy skills (especially in terms of accuracy) in bilingual children.

Segmentation of Rhythmic Units in Word Speech by Japanese Infants and Toddlers

When infants and toddlers are confronted with sequences of sounds, they are required to segment the sounds into meaningful units to achieve sufficient understanding. Rhythm has been regarded as a crucial cue for segmentation of speech sounds. Although previous intermodal methods indicated that infants and toddlers could detect differences in speech sounds based on stress-timed and syllable-timed units, these methods could not clearly indicate how infants and toddlers perform sound segmentation. Thus, the present study examined whether Japanese infants and toddlers could segment word speech sounds comprising basic morae (i.e., rhythm units similar to syllables), on the basis of concurrent basic mora units within syllable units, using the new intermodal matching procedure. The results indicated that, regardless of their ages and linguistic abilities, Japanese infants and toddlers aged 6-25 months tended to segment Japanese words comprising basic morae sounds on the basis of concurrent basic mora units within syllable units. This implies that infants' and toddlers' use of syllable units for segmentation of speech sounds at an early age could be evident among many infants and toddlers learning various languages. Although this finding should be interpreted carefully, the present study demonstrated the utility of the new intermodal matching procedure for examining segmentation of speech sounds and word sounds by infants and toddlers, on the basis of specific rhythm units.

Intelligence test at preschool-age predicts reading difficulty among school-aged very low birth weight infants in Japan

OBJECTIVE

To elucidate whether the results of an intelligence test at preschool age are predictive of reading difficulty (RD) at school age among very low birth weight infants (VLBWI).

METHODS

Subjects were 48 Japanese children whose birth weight was <1500 g and who regularly visited a follow-up clinic. All subjects completed the Wechsler Intelligence Scale for Children-III (WISC-III) during the last grade of kindergarten, and four reading tasks during the second to fourth grade of elementary school. All participants had a full-scale intelligence quotient score of 85 or higher. Subjects with a standard deviation reading time score greater than 2.0 in two or more tasks were considered to have RD. We evaluated the associations between each WISC-III score and RD using logistic regression analyses. Furthermore, we performed receiver operating characteristic (ROC) analysis to determine a cutoff WISC-III score predictive of RD.

RESULTS

In the mutually-adjusted model, the adjusted odds ratio per 1 score increase of freedom from distractibility (FD) was 0.832 (95% confidence interval: 0.720-0.962). In the ROC analysis, an FD score of <95.5 was chosen as the cutoff value for predicting RD (sensitivity, 0.77; specificity, 0.74).

CONCLUSION

The present study indicated that a lower FD score at preschool age, which was associated with deficits in verbal working memory and attention, is a risk factor for RD at school age among Japanese VLBWI. Further investigation is desired to clarify the cognitive deficits underlying RD in Japanese-speaking preterm children, and to establish appropriate interventions for these children.