Establishing Methods for Early Identification and Intervention of Developmental Dyslexia Based on the Evaluation of Implicit Letter Knowledge in Preschoolers

2018 Fiscal Year Final Research Report

• Project/Area Number: 15K13259
• Research Category: Grant-in-Aid for Challenging Exploratory Research
• Allocation Type: Multi-year Fund
• Research Field: Special needs education
• Research Institution: The University of Tokyo (2018); National Center of Neurology and Psychiatry (2015-2017)
• Principal Investigator: Okumura Yasuko 東京大学, 高大接続研究開発センター, 特任研究員 (60749860)
• Project Period (FY): 2015-04-01 – 2019-03-31
• Keywords: 未就学児 / 文字学習 / 発達性ディスレクシア / 読み発達 / 早期支援 / 事象関連電位

Outline of Final Research Achievements

Japanese-native preschoolers (age 5-6) were able to identify Hiragana that matches words even before they became able to read aloud, which indicated the existence of implicit letter knowledge. In addition, the result of longitudinal survey showed that preschoolers with weaker letter recognition exhibited reading problems, such as decreased fluency and accuracy, in early elementary grades. For such children, early intervention to facilitate natural exposure to letters may be of particular importance. Regarding the evaluation based on measuring brain function, early visual components of event-related brain potentials were shown to be useful for examining the state of letter recognition, as well as for identifying the intervention-related changes in neural substrates. Further sophistication of the early identification and intervention methods are necessary for mitigating and preventing difficulties related to developmental dyslexia.

Free Research Field

特別支援教育、認知神経科学、生理心理学

Academic Significance and Societal Importance of the Research Achievements

本研究の成果は，ひらがなの読みに関わる従来の研究が読める（音読できる）・読めないの二値的な区分で進められていたのに対し，読める前にも認識が成立しているという新しい見方を確立した点に大きな学術的意義がある。社会的意義としては，そうした「読める前の文字認識」に着目することで，発達性ディスレクシアの早期発見および介入が促進され得ることを示した点が上げられ，小学校入学後のつまずきを予防・軽減するための方策として就学前教育（幼稚園・保育園）や保幼小連携の中に取り入れられていくことが望まれる。