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.

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.

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.

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.

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.

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

Diagnosis of Dyslexia Diagnosis:

--Reading disability unexpected by intelligence, age, level of education

--Family history of dyslexiaGather 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

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.

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

Beginning vs. Skilled ReadersBeginning 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.

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

Early Brains Dyslexic & Normal Reader

More fMRIs

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.

Brain Gyrification

Graph of Gyrification

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

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

Video Series Children of the Code http://www.childrenofthecode.org/Tour/p

reviews/phonemes.htm

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 programsTier 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.

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.

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.

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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