Defining and Addressing Dyslexia in Young Children

Transcription

1 1 Session Goal: 2 Defining and Addressing Dyslexia in Young Children Salli Forbes, Director Debra Rich, Assistant Director Jacobson Center for Comprehensive Literacy University of Northern Iowa Framing the issues around the term dyslexia Identifying the definitions and research findings about dyslexia from different disciplines Looking to the future with caveats and a call for future research 3 u children are born wired for language, but print is an optional accessory that must be painstakingly bolted on. (Pinker, 1997 in Norton & Wolf, 2012) 4 u each child must develop reading skills using brain areas that have developed for other purposes, such as language, vision, and attention. (Norton & Wolf, 2012, p. 429)

2 5 Reasons for Differences Between Disciplines 6 u Developed understandings separately u Have unique research methodologies u Have unique terminology and definitions Different disciplines view dyslexia through different lenses. 7 8 Adolph Kussmaul (1878) Rudolf Berlin (1887) Word Blindness Vortblindheit Dyslexia Eine besondere Art der Wortblindheit (Dyslexie)

3 9 Dr. W. Pringle Morgan (1896) Dr. Samuel T. Orton (1925) A case of congenital word blindness British Medical Journal Strephosymbolia Recent History from the Fields of Literacy and Special Education Stanovich (1986) Matthew Effects Reciprocal causation 10 Phonological awareness and early reading acquisition (limited) Ease/speed of word recognition and comprehension Reading ability and vocabulary knowledge Vocabulary knowledge and comprehension Reading skill level and volume of reading Reading skill level and effective instruction 11 Recent History from the Fields of Literacy and Special Education 12 Clay (1987) - Learning to be learning disabled Reading disability for most - not an organic cause Reading disability for most - instructional cause Effective instruction significantly reduces the number of children with reading disability Identification using IQ-achievement discrepancy not valid

4 Recent History from the Fields of Literacy and Special Education 13 Cognitive/Medical Perspective Definition of Dyslexia 14 Stanovich (1991) Challenge to discrepancy definition for identification Vellutino (1996) Identification through response to instruction Dyslexia is a specific learning disability that is neurobiological in origin. It is characterized by difficulties with accurate and/or fluent word recognition and by poor spelling and decoding abilities. These difficulties typically result from a deficit in the phonological component of language that is often unexpected in relation to other cognitive abilities and the provision of effective classroom instruction. p.2 Lyon, G.R., Shaywitz, S.E., & Shaywitz, B.A. (2003). Defining dyslexia, comorbidity, teachers knowledge of language and reading. Annals of Dyslexia, 53, Phonological Processing (Bradley & Bryant, 1978; Lieberman, et al 1989; Ramus, 2003; Snowling, Goulandris & Defty, 1996; Wagner & Torgesen, 1987) u Refers to the child s ability to use the sound structure of oral language in service of processing oral and written language u Debate: Is it language-specific or sound-general?

5 fmri Imaging Activations for Phonological Processing Tasks Gabrieli, J. (2009). Dyslexia: A new synergy between education and cognitive neuroscience. Science, 325, DTI Imaging Activations for Phonological Processing 19 T D P P Rhyme Letters Match Letters Match Lines Phonological Processing Non-phonological Task Non-letter Baseline Rapid Automatized Naming (RAN) 20 (Ackerman & Dykman, 1993; Badian, 1995; Bowers, Steffy & Tate, 1988; Katzir, Kim, Wolf, Morris, & Lovett, 2008; Scarborough, 1998) u Speed with which a series of familiar stimuli can be named aloud, reflecting efficient visual-verbal connections Gabrieli, J. (2009). Dyslexia: A new synergy between education and cognitive neuroscience. Science, 325, Norton, E., & Wolf, M. (2012). Rapid automatized naming (RAN) and reading fluency: implications for understanding and treatment of reading disabilities. Annual Review of Psychology 63,

6 Double-Deficit Hypothesis (Wolf & Bowers, 1999) 21 Double-Deficit Hypothesis 22 u Deficits in phonologic or naming-speed processes can impeded reading acquisition u Naming speed cannot be subsumed under phonology u Phonological and naming-speed processes make unique contributions to reading Norton, E., Black, J., Stanley, L., Tanaka, H., Gabrieli, J., Sawyer, C., & Hoeft, F. (2014). Functional neuroanatomical evidence for the double-deficit hypothesis of developmental dyslexia. Neuropsychologia, 61, Additional Theories 23 Additional Theories 24 u Rapid auditory processing theory (Tallal, 1980, 2000; Tallal et al, 1993) u General impairment in the ability to adequately process brief sounds u Not generally supported u Magnocellular Theory (Galaburda et al, 1994; Livingstone et al, 1991; Stein, 2003: Stein and Walsh, 1997) u Unifying theory of visual, auditory, and cerebellar theories u Assumes sensory and motor deficits in dyslexia u Research does not support this model u Cerebellar Deficit Model (Nicolson and Fawcett, 1990; Nicolson et al, 2001) u Deficit in motor system related to task automaticity u Not consistently supported u Genetic Theories u Rare chromosomal translocations have been identified in familial studies u Three genes associated with white matter volume have been identified, which may influence reading ability

7 25 Theoretical Deficit Frameworks for Dyslexia Cerebellar Magnocellular Anchoring 26 Is the spotlight of attention shining on the right issues? Level: Neuro Level: Cognitive Level: Behavioral Motor Visual Auditory Phonological Memory Rhythmic Processing Phonology Rapid Temporal Processing Phonological Awareness Perceptual Learning Single word Reading Difficulty Rapid Naming Processing Speed? Naming Speed 27 Instructional Approaches 28 Can Dyslexia be Treated? Fast Forward Children fmri studies have shown that lefthemisphere brain regions that are typically under activated in dyslexia exhibit a gain in activation after effective intervention Lindamood Bell Adults

8 There is no behavioral research to demonstrate increased reading achievement of children with Dyslexia with these or any other educational programs Promising Research: The Compensation Brain Hyper activation in the left and right prefrontal cortex Increases in age in dyslexic children, not in typically reading children Hoeft, F., McCandliss, B., Black, J., Gantman, A., Zakerani, N, Hulme, C, Lyytinen, H., Whitfield-Gabrieli, S., Glover, G., Reiss, A., & Gabrieli, J. (2011), Neural systems predicting long-term outcome in dyslexia. Proceedings of the National Academy of Science, 1081)), Recommendations u Dyslexic children who overcome their reading difficulties somehow bypass regions normally used for reading u This finding encourages consideration of intervention approaches that capitalize on alternative reading strategies in addition to current interventions that build on typical reading instruction Hoeft, F., McCandliss, B., Black, J., Gantman, A., Zakerani, N, Hulme, C, Lyytinen, H., Whitfield-Gabrieli, S., Glover, G., Reiss, A., & Gabrieli, J. (2011), Neural systems predicting long-term outcome in dyslexia. Proceedings of the National Academy of Science, 1081)), Manuel Casanova, professor of psychiatry at the University of Louisville, says the study s most important contribution is revealing that the behavioral and intelligence measures commonly used to evaluate a dyslexic child s chances of improvement such as IQ tests and standardized reading tests are not reliable. The conventional wisdom until now has been behavioral measurements, says Casanova. I am blown away by the fact that IQ is not predictive of the ability to improve. 32

9 Areas for further research 33 What personalized interventions will improve the reading achievement of individual children with dyslexia? Caveats for Moving Forward: Each discipline has somewhat unique research methodologies Each discipline has unique terminology and definitions - dyslexia, reading disability, learning disability Each discipline has different methods of identification of people with dyslexia fmri, DTI & EEG, CTOPP & RAN, DSM-5, RtI 34 Compensation? Normalization? 35 There is no single test and no absolute criteria for diagnosing dyslexia. 36 Different disciplines view dyslexia through different lenses. (Norton & Wolf, 2012, p. 430)

10 In the 2013 edition of the DSM-5 from the American Psychiatric Association, dyslexia is listed in the category of specific learning disorder. The DSM-5 Neurodevelopmental Work Group concluded that the many definitions of dyslexia and dysgraphia meant those terms would not be useful as disorder names or in the diagnostic criteria. 37 DSM-5 Diagnosis of Disorder (Learning Disability) (F81.0) With impairment in reading: o Word reading accuracy o Reading rate or fluency o Reading comprehension 38 o Note: Dyslexia is an alternative term used to refer to a pattern of learning difficulties characterized by problems with accurate or fluent word recognition, poor decoding, and poor spelling abilities. If dyslexia is used to specify this particular pattern of difficulties, it is important also to specify any additional difficulties that are present, such as difficulties with reading comprehension or math reasoning. More than 100 years of research into developmental reading difficulties has yet to reveal anything resembling one single explanation for all the symptoms of dyslexia. (Norton & Wolf, 2012, p. 430) 39 Caveats for Moving Forward: There is still much more research that needs to be completed before we have a clear understanding of dyslexia, and effective instructional practices for people with dyslexia 40

11 The relative mass and proximity of existing research related to other individual differences in reading As yet, there is no certifiable best method for teaching children who experience reading difficulty (Mathes et al, 2005). Therefore, the ILA research advisory committee has called for a research agenda for determining evidence-based methods for teaching students with dyslexia. 41 The possible powerful interactions between affective, conative, and cognitive individual differences ILA Research Advisory on Dyslexia the nature and causes of dyslexia, and even the utility of the concept, are still under investigation. Although genetics and neurology appear to play a role in reading difficulties, environment and instruction moderate that role.

12 ILA Research Advisory on Dyslexia 45 ILA Research Advisory on Dyslexia 46 Research indicates that most students who experience literacy problems in their early years do not ultimately have long-term difficulties when appropriate instruction and intervention are provided. In fact, interventions that are appropriately responsive to individual needs have shown to reduce the number of children with continuing difficulties in reading to below 2% of the population (Vellutino et al, 2000) Reviews of research focusing solely on decoding interventions have shown either small to moderate or variable effects that rarely persist over time, and little to no effects on more global reading skills. ILA Research Advisory on Dyslexia 47 Rather students classified as dyslexic have varying strengths and challenges, and teaching them is too complex a task for a scripted, one-size-fits-all program (Coyne et al, 2013; Phillips & Smith, 1997; Simmons, 2015). Optimal instruction calls for teachers professional expertise and responsiveness, and the freedom to act on the basis of that professionalism.