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DYSLEXIA and the BRAIN

DYSLEXIA and the BRAIN. Diagnosis and Intervention from Pre-school through Third Grade By Linda Weide. What is Dyslexia?. The International Dyslexia Association defines it as a specific learning disability that is neurobiological in origin.

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DYSLEXIA and the BRAIN

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  1. DYSLEXIA and the BRAIN Diagnosis and Intervention from Pre-school through Third Grade By Linda Weide

  2. What is Dyslexia? • The International Dyslexia Association defines it as a specific learning disability that is neurobiological in origin. • It is characterized by specific difficulties with accurate and/or fluent word recognition and by poor spelling or decoding. • People with dyslexia are of average or above average intelligence. • Dyslexia is defined within the context of having good classroom instruction.

  3. History of Dyslexia • 1872--Dr. Adolf Kussman of Germany reported a case in which he named “wortblindheit” or word blindness.A condition which he traced to lesions around the left angular gyrus. • 1896--Dr. Morgan of England wrote about a 14 year old boy. He was the first to appreciate that word-blindness was a developmental disorder occurring in otherwise healthy children. • Early 1900s--Dylsexia increasingly reported in Europe and several European countries. • 1905--First reported in US by Dr. W.E. Brunner an ophthalmologist. • 1987--Dr. Sally Shaywitz asked to care for children with reading difficulties. Which led her to begin the Connecticut Longitudinal Study.

  4. Prevalence of Dyslexia • Reading disability affects about 1 in 5 children according to Connecticut L.S. • Reading disability is estimated to account for 80 percent of all LD. • 78% of 8th grade students whose parents graduated high school read below proficiency levels • 55% of 8th grade students whose parents graduated college read below proficiency levels. • Prevalence in girls has been underreported. Is the same as in boys. Boys just more easily identified because of behavior. • In developed countries dyslexia affects about 5 to 9 out of 100 people. • Dyslexia is found all over the globe, but the rates and severity depend on the language system.

  5. Speaking vs. Reading • Linguists claim human spoken language goes back as far as 50 to 100 thousand years so the brain has had time to specialize areas for this function. • Written words are about 5000 years old so the brain has to borrow areas from speech to do reading tasks.

  6. First Clues • Delay in speaking. --First words should be around age of one, may be around 15 months --First phrases about 18 months, may be around a year. --Word retrieval difficulties Mispronouncing words --Leaving off sounds in beginning,middle or end --Difficulties pronouncing long or new words --Inverting sounds Rhyming words --They don’t get spoken rhymes, songs

  7. Diagnosis of Dyslexia • Diagnosis: • --Reading disability unexpected by intelligence, age, level of education • --Family history of dyslexia Gather Evidence --Is reading program good? --Is disability unexpected? --Is there evidence of phonological weakness? How does one do this? --Use reading test that measures how well child reads words and understands what they have read. Oral reading necessary. --WCJ III and WCJ Reading Master --WCJ III Spelling subtest of Test of Written Spelling

  8. Diagnosis cont. • Look for following signs: --Difficulty reading single words. --Particular difficulty decoding nonsense or unfamiliar words. --Reading comprehension often superior to decoding individual words. --Inaccurate and labored reading of oral passages. --Trouble reading small “function words” --that, is, an, for --Slow reading --Poor spelling Comprehensive test of Phonological Processing.

  9. Reading in Normal Brain • Spoken language is learned automatically. • Brain uses 3 key areas in left hemisphere to read. --Left inferior frontal gyrus for producing phonemes (Broca’s area) --Left parieto-temporal area for analyzing words --Left occipito-temporal area is the automatic detector

  10. Beginning vs. Skilled Readers Beginning Readers --Uses the inferior frontal gyrus to say words aloud and analyze the phonemes found in some words. --The parieto-temporal area to analyze words more thoroughly and pull apart sounds. Skilled Readers --Uses the occipito-temporal area more because he has stored a lot of words in this area, which he is able to retrieve rapidly.

  11. Dyslexic Readers • Beginning Readers --Underactivation of the left parieto-temporal area (the word analyzer) and --The left occipito-temporal area (the automatic detector) • Older Readers --increasingly use the left inferior frontal gyrus to sound out words which slows them down. --Right inferior frontal gyrus which is a manual system rather than an automatic

  12. Early Brains Dyslexic & Normal Reader

  13. More fMRIs

  14. Brain Size Abnormalities in Dyslexic People Study by Casanova, Araque, Giedd, Rumsey • Brain size of dyslexics significantly smaller than controls. • Brain gyrification significantly less in dyslexics than controls • Posit minicolumnar abnormality in dyslexia. • Minicolumns considered primary evolutionary change to increase brain size. • Suggests an early gestational defect, within weeks 8 to 12. • Larger gyrification index can affect the brains ability to generalize information, longer connections,but slower response time.

  15. Brain Gyrification

  16. Graph of Gyrification

  17. Interventions for Dyslexic Readers • Early identification • High intensity quality instruction of sufficient duration to reach fluency --May take as much as 150 to 300 hours (at least 90 min. a day over 3 years) of intensive instruction to reach fluency • Groups of no more than 3 or 4, 5 days a week • Taught by highly skilled teacher

  18. Reading Program for Dyslexics • Systematic and direct instruction in: • --Phonemic awareness--noticing, identifying and manipulating sounds of spoken lang. • --Phonics--how letters and groups represent sounds • --Sounding out words (decoding) • --Spelling • --Reading sight words • --Vocabulary and concepts • --Reading comprehension strategies • Practice applying these skills in reading and writing • Fluency training • Enriched language experiences,listening to, talking about and telling stories

  19. Video Series Children of the Code • http://www.childrenofthecode.org/Tour/previews/phonemes.htm

  20. Reading and RTI • Tier 1-Universal level • Preschool screening and then screening from kindergarten through grades 4 and new students. --Advocate for good reading instruction --Point teachers, administrators to good programs Tier 2--Have reading teachers and classroom teachers give appropriate additional instruction to children with dyslexia Tier 3--Here is where children with more severe forms of dyslexia and children with additional cognitive, behavioral and emotional issues would be. Treat the other symptoms as well.

  21. References • Casanova, M.F., Araque, J., Giedd, J., & Rumsey, J. (2004). Reduced brain size and gyrification in the brains of dyslexic patients. Journal of Child Neurobiology, 19, 275-281. • D’Arcangelo, M. (2003). On the mind of a child. Educational Leadership, 60, 6-11. • Gorman, C., Cuadros, P., Land, Scully, S., & Song, S. (2003) The New science of dyslexia. Time South Pacific (Australia/New Zealand edition), 29, 54-61. • Grigorenko, E. L. (2005). A conservative meta-analysis of linkage and linkage-association studies of developmental dyslexia. Scientific Studies of Reading, 9, 285-316.

  22. References continued • Joseph, J., Noble, K., & Eden, G. (2001). The Neurobiological basis of reading. Journal of Learning Disabilities, 34, 566-579. • Misra, M., Katzir, T., Wolf, M., & Poldrack, R.A. (2004). Neural systems for rapid automized naming in skilled readers: Unraveling the RAN—reading relationship. Scientific Studies of Reading, 8, 245-256. • Schatschneider, C., Torgesen, J.K. (2004). Using our current understanding of dyslexia to support early identification and intervention. Journal of Child Neurology, 19, 759-765. • Shaywitz, S. (2003). Overcoming dyslexia: a new and complete science-based program for reading problems at any level. New York: Alfred A. Knopf. • .

  23. References continued • Simos, P.G., Fletcher, J.M., Foorman, B. R., Francis, D.J., Castillo, E. M., Davis, R. N., et al. (2002). Brain activation profiles during the early stages of reading acquisition. Journal of Child Neurology, 17, 159-164. • Voeller, K.K.S. (2004). Dyslexia. Journal of Child Neurology, 19, 740-744

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