香港大學腦與認知科學國家重點實驗室 香港大學語言學系 蕭慧婷 博士 助理教授

1. A structural-functional basis for dyslexia in the cortex of Chinese readers 中文閱讀障礙患者 大腦皮層的結構與功能基礎 有關研究的論文於 “ 美國國家科學院院刊” (Proceedings of the National Academy of Sciences) (PNAS) 四月八日刊載 香港大學腦與認知科學國家重點實驗室 香港大學語言學系 蕭慧婷博士助理教授

2. 字義 Fluent reading is characterized by the coherent and dynamic activity of several mental processors: Orthographic, Phonologic, and Meaning. 字形 字音 Learning to Read English: (1) Learn letter-sound conversion rules (cat - /kat/) (2) Phonemic awareness Learning to Read Chinese: By rote memorization

3. Developmental dyslexia (閱讀障礙): Individuals with normal to high intelligence have severe reading problems. Incidence of dyslexia among Chinese and English speakers: English speakers: 10-15% dyslexia Chinese speakers: 2-9% dyslexia The most recent US National test results (National Assessment of Educational Progress, 2001) indicate that 33% of the nation’s 4th graders, 36% of 8th graders, and 57% of 12th graders read below basic reading achievement level.

4. Reading in alphabetic languages Pugh et al., 2005 3 systems Turkeltaub et al., 2003, English Paulesu et al., 2000, English & Italian Posterior temporoparietal regions (左腦後部顳頂區): Letter-sound conversion Phonological sensitivity

5. Recent functional neuroimaging findings of dyslexia in alphabetic languages Flower et al. (1991) Rumsey et al. (1992) Paulseu et al. (1996) Parietal Rumsey et al. (1997) Frontal Horwitz et al. (1998) Shaywitz et al. (1998) Occipital Brunswick et al. (1999) Paulesu et al. (2001) Temporal Temple et al. (2001) Shaywitz et al. (2002) Eden et al. (2004) Hoeft et al. (2007)

6. What causes the dysfunction of the three brain systems? --different reading strategies --brain structure problems 左腦前部額下回區 左腦後部顳頂區 左腦後部顳枕區

7. Cell body: 細胞體 Axon: 神經細胞之軸索

8. Brain structure anomaly: Gray matter volume is larger in temporoparietal regions in normal controls relative to dyslexics (Hoeft et al., PNAS, 2007) Regions showing structural abnormalities Regions showing functional abnormalities 結構異常腦區 功能異常腦區

9. Summary of past studies of alphabetic languages: Regions of structural abnormalities in dyslexia : left temporoparietal and occipitotemporal regions 先前的腦成像研究顯示，使用以字母為基礎的拼音語言（如英語）的閱讀障礙患者，左腦後部顳頂區和顳枕區的灰質體積比正常人小

10. Prior study of Chinese dyslexic reading Functional deficits Experimental: Homophone Decision Baseline: Font Size Judgment

11. Present study of Chinese dyslexia 第一部分：對大腦微觀结構的分析 對16名閱讀障礙的兒童及16名正常兒童大腦結構進行高分辨率的磁力共震掃描，之後以像素形態分析方法（voxel-based morphometry），分析這些高解像的3D影像，從而測量他們腦部的灰質數量。這些研究對象乃北京的小學生，平均年齡為十一歲，全以普通話為母語。 Firstly, voxel-based morphometry, an established whole-brain gray-matter assessment technique, was used to analyze the high-resolution 3D anatomical images acquired with magnetic resonance images (MRIs) from 16 Chinese dyslexic subjects and 16 age-matched normal children as controls. The children, who were studying in Beijing primary schools, were all native speakers of Putonghua, on average aged 11, and all strongly right-handed.

12. 患有閱讀障礙兒童的左腦前部的額中回區（left middle frontal gyrus）的灰質數量，顯著少於正常學童。這一腦區的功能是協調認知資源和負責工作記憶，早前研究亦已證明這一腦區與中文的讀寫能力有很大關連。有趣的是，這些中文閱讀障礙兒童的左腦後部灰質數量則沒有減少跡象，與英文閱讀障礙患者的大腦灰質異常的情況有重要區別。

13. 第二部分：對大腦功能的研究 研究人員為兩組學童之中各12人進行功能性大腦磁力共震掃描。研究人員向每名學童同時呈現兩個漢字，要求他們判斷兩字的發音是否相同，並時觀察完成這一任務時的大腦活動。 A functional MRI experiment was conducted on a subset of 12 of each of the dyslexics and control groups. They were asked to decide whether two Chinese characters viewed simultaneously rhymed with each other. The rhyme judgment task involves phonological processing which would reflect in activation of some regions in the brain. .

14. a. Normal reader 正常學童的左腦額中回（left middle frontal gyrus）的活動，較閱讀障礙患者強烈得多。與此同時，兒童的左腦後部反應不大。在使用英語者中，左腦後部與閱讀活動有很大關連 b. Dyslexic reader c. Normal – dyslexic

15. 第三部分：對大腦结構和大腦功能的相關分析 A correlation analysis of gray matter volume and brain activity level in the left middle frontal gyrus

16. 閱讀中文與閱讀西方書面語言的失讀症患者，在腦部不同部分出現結構性病變和異常的功能活動，顯示在這兩大文化體系中，閱讀障礙可能屬於兩種不同的腦部發育失調。閱讀中文與閱讀西方書面語言的失讀症患者，在腦部不同部分出現結構性病變和異常的功能活動，顯示在這兩大文化體系中，閱讀障礙可能屬於兩種不同的腦部發育失調。 The fact that Chinese and Western dyslexics show structural abnormalities in different brain regions suggests that dyslexia may even be two different brain disorders in the two streams of culture.

17. Educational intervention: 左腦額中回（left middle frontal gyrus）主管工作記憶，並與負責動作的大腦運動皮層位置相近；而左腦後部則關乎字母與聲音的轉換，並與負責聲音的大腦聽覺皮層位置相近。 The left middle frontal gyrus is responsible for working memory and is spatially close to the motor cortex, whereas the left posterior brain areas are involved in letter-to-sound mappings and are spatially close to the auditory cortex.

19. premotor Chinese English auditory

20. 對患有閱讀障礙的華人兒童而言，側重於工作記憶和感覺運動機能的訓練，可能是更有效的矯正治療方法。而現時普遍應用於英文閱讀障礙兒童的治療策略，已經集中在字母與聲音的轉換和提升聲音辨識方面。對患有閱讀障礙的華人兒童而言，側重於工作記憶和感覺運動機能的訓練，可能是更有效的矯正治療方法。而現時普遍應用於英文閱讀障礙兒童的治療策略，已經集中在字母與聲音的轉換和提升聲音辨識方面。 Educational intervention for Chinese dyslexia may involve working memory and sensorimotor tasks. Current treatments of English dyslexia already use the aspects of letter-sound conversions and phonological awareness

21. 左腦額中回的灰質數量是預測中文閱讀能力的神經生物學指標。左腦額中回的灰質數量是預測中文閱讀能力的神經生物學指標。 The gray matter volume in the left middle frontal gyrus is a neurobiological marker of reading ability and reading disorders.

22. 患有中文閱讀障礙的兒童能否有效地學習英文? 患有英文閱讀障礙的兒童能否有效地學習中文? 有可能, 因為不同的腦區主管两種语言. 但是,學習方法亦非常重要. Is it possible that a person who is dyslexic in Chinese could read normally in English, and vice versa? Yes, it is possible, because different brain regions are involved in dissimilar languages. But, the learning method is also very important.