Four hundred and ninety-five Japanese primary-school children aged from 8 (Grade-2) to 12 (Grade-6) were tested for their abilities to read/write in Hiragana, Katakana, and Kanji, for their size of vocabulary and for other cognitive abilities including arithmetic, visuo-spatial and phonological processing. Percentages of the children whose reading/writing scores fell below the −1.5SD cut-off differ according to the scripts-Hiragana: 0.2% for reading and 1.6% for writing, Katakana: 1.4% and 3.8%, and Kanji: 6.9% and 6%, respectively. Further, for the normal children, the older the age, the better they performed on cognitive tasks, while the reading/writing disability (RWD) group (below −1.5SD) showed a weaker relationship between the age and the performance level. It was also revealed that for A. Uno the normal children, the "vocabulary size" was the most potent predictor variable in accounting for Kanji word reading performance for all grades except Grade-6, for whom nonword reading/repetition were also significant predictor variables. In contrast, for Kanji word writing, generally other writing related variables were better predictor variables. The RWD group however showed different patterns of results. Thus the data from the normal and RWD children in the current cohort were discussed in terms of the current theories of reading, and developmental dyslexia.

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Abstract:We investigated the typical development of reading fluency by measuring the speed of reading aloud, and the factors responsible for reading fluency. The participants for

The p3-Alcα is a metabolic fragment of Alcadeinα (Alcα). Like Alzheimer's amyloid β-protein precursor (AβPP) to generate p3 fragment, Alcα is cleaved by α-and γ-secretases to secrete p3-Alcα peptides in the cerebrospinal fluid (CSF). The p3-Alcα are also detected in the plasma as is amyloid-β (Aβ) which is a metabolic fragment of AβPP cleaved by an amyloidogenic β-and γ-secretases. Because p3-Alcα is a non-aggregatable and stable peptide, unlike aggregatable Aβ and metabolically labile p3 of AβPP, the changes of p3-Alcα in quality and/or quantity in CSF and plasma are expected as a marker for assessing alteration of substrate cleavage by γ-secretase such as Aβ generation from AβPP. The present study describes a sandwich enzyme-linked immunosorbent assay (sELISA) for quantifying levels of p3-Alcα35, the major form of the p3-Alcα species, and examines levels of p3-Alcα35 in the plasma of three independent Japanese cohorts. In two of the three cohorts, the p3-Alcα35 levels were significantly increased with a concomitant decrease in the mini mental state examination (MMSE) score, or in clinically diagnosed AD patients, when compared with age-matched non-demented subjects. The values were significantly lower in AD subjects who were administered donepezil, when compared to AD subjects without donepezil treatment. The increase in plasma p3-Alcα35 levels may indicate an endophenotype in subjects in whom AD is due to a progressing cognitive impairment in subjects with a γ-secretase malfunction, or a disorder of the clearance of peptides.