Language, Reading and Dyslexia Brain, Mind and Education.

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Language, Reading and Dyslexia Brain, Mind and Education

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  • Language, Reading and Dyslexia

    Brain, Mind and Education

  • Outline of the SessionSpoken languageWritten language? Studies of the normal reading processBrain differences in atypical readersWhat causes dyslexia?

  • The brain basis of spoken languageIs spoken language innate?

    There is much debate about how innate e.g. nativists such as Chomsky, Pinker (evolutionary instinct) versus connectionists/neuroconstructivists say experiences specialise us

    Language in babies? Dehaene & Dehaene-Lambertz (2006) scanned 3 month old babies while they were listening to speech (asleep!). Activation was found in regions associated with language (e.g. Brocas area and superior temporal regions) similar language areas to adults

  • The brain basis of spoken languageBabies come into the world able to distinguish between all speech sounds.

    Some of this ability is lost by 6 months the child can only distinguish sounds he/she has been exposed to. The brain does not seem to treat the differences as significant and behaviourally, we do not experience the differences a sensitive language window. (Kuhl et al., 1992)

  • Speech 2 classic regions (Brocas and Wernickes)We have known for a long time that spoken language appears to be handled by the left-hemisphere of the brain - in most people.Paul Broca, a C19th neuoanatomist first linked speech difficulties to damage to the inferior frontal gyrus (IFG) of the L-hemisphere (case of Tan) Brocas area.Damage to this area can cause dysfluent speech

  • Brocas Area is near relevant motor cortexAuthor: OpenStax College, Creative Commons Attribution 3.0 Unported license.Primary Motor Cortex (BA 4) Was a bee / Wikimedia Commons /CC-BY-SA 2.1

  • Speech & understandingA little later, a German neurologist, Carl Wernike, studied brain-damaged patients who could speak but not understand language.Damage to the posterior region (Wernickes area) of the (left) superior temporal gyrus can result in fluent language that is meaningless.

  • Dryke. GNU Free ocumentation License, Version 1.2 or any later version published by the Free Software Foundation;

    Wernickes Area is near auditory cortexPrimary Auditory Cortex (BA 41,42)

  • Modern imaging techniques show a much wider range of regions involved with producing meaningful speech: (Poeppel et al, 2008)Parieto-temporal (left)Auditory-Motor mapping Sensori-motor input/output linksInferior Frontal Gyrus (left)Articulatory Speech Codes(speech movements)Middle Temporal GyrusInferior Temporal Gyrus (left)Sound-meaning, lexical activation(Identifying a word and its meaning)Superior Temporal Gyrus (bilateral)Acoustic-phonetic mapping = t links to sound of tSpeech

  • Reading studies of normal readersUntil quite recently, no brain data on normal reading acquisition process.

    Scanning children now possible, using fMRI techniques (see also EEG).

    Turkeltaub et al. (2003) have begun to look at the brain activity of children of different ages during a reading task.

  • Some termsGrapheme unit in a written language e.g. alphabet

    Orthography spelling

    Phoneme unit in spoken language

    Lexicon whole set/list of units (orthographic, phonological, etc)

  • Dual-route model of reading wordsColtheart (2001)Direct supposedly more used by skilled readersIndirect phonologically mediated access supposedly slower

  • But..Phonological processing appears very rapid as demonstrated by studies of parafoveal* preview in which attention momentarily shifts to phonological information later in sentence (Polletsek et al. 1992)And.this is also true for skilled readers (see also Ashby refs below)

    * Parafoveal vision = off centre but not quite peripheral

  • -> Triangle model of reading- from connectionists artificial neural networksPhonological ProcessorSemantic ProcessorOrthographic Processor

  • Orthographic processingPhonological processingSemantic processing So reading systems are distributed, and contain redundancyDiagram interpreted from Ashby(2012)Visual word form areaReadingWernickes/angular gyrusNetworks for reading are closely related to those for speech

  • Studies of the normal reading process (Turkeltaub et al., 2003)41 participants (6-22 years).Carried out a feature detection (implicit word processing) task in the scanner:Shown a series of words and false font stringsPress the button in right hand if stimulus has an ascender (tall letter), left hand if notsaucealarmnoyes

  • Studies of the normal reading processThis procedure controls for brain processes not specific to decoding processes (e.g. spatial processing, motor planning).When the activity associated with words was compared with that for the false font strings, the areas of brain activation that were specific to words were:Left posterior temporal cortex Left inferior frontal cortex Right inferior parietal cortex

  • Studies of the normal reading processReading ability also measured, to study brain activity in relation to reading level.Measures of phonological skills were also taken:Phonological WM (digit span)Phonological awarenessPhonological naming (RAN)

  • Studies of the normal reading processFindings indicate that:Temporoparietal cortex activity (including the left superior temporal sulcus, Wernickes area - see above) matures early and continues to be involved in reading throughout adulthood.Superior temporal sulcus is implicated in cross-modal integration (e.g. mapping print to sound) - early predictor of reading outcome?This area was correlated with phonological awareness skill.

  • a left region linked to reading/phonological skillsLeft temporal language area visual word form areaContralateral to left temporal language area non-phonological memory used by dyslexicsPosterior Fusiform Non-lexical (i.e. not words) visual pattern recognitionLEFTRIGHT Interpretation of (Turkeltaub et al., 2003)

  • Studies of the normal reading processFindings indicate:A progressive disengagement of right visual cortex over the course of reading acquisition.Supports a behavioural model of moving from relying more on visual features of each letter (right fusiform), to a phoneme-grapheme stage (left IFG), then lexical processing (visual word form area) i.e. whole words & using known whole words to identify new ones.

    LogographicstageAlphabeticstageOrthographicstage

  • Studies of the normal reading process

    Weird but true: Turkeltaub et al.s study provides support for ideas about reading that were proposed in 1925 by the American neurologist Samuel Orton.

    Orton suggested that, in the course of learning to read, children need disengage posterior RH visual representations that interfere with proper word identification.

  • Studies of the normal reading process in different languagesDifferent languages engage the brain areas differentially depending on the regularity of the orthography (e.g. Italian vs. English) Paulesu et al. (2001)Regular languages rely more on the middle parts of the brain, while irregular languages use the area at the back of the brain to a greater extent why might this be?

  • Individuals with dyslexiaThe study of differences in the brains of individuals with dyslexia has a long history (e.g. Orton)However, it is still a very contentious area of researchBrain differences in atypical readers

  • Brain differences in atypical readersIndividuals with dyslexia (see Beaton (2005) Pugh (2001), Shaywitz (2001))

    Brain differences have been found in, for example:Activity in the language areas of the left hemisphere (reduced) and in the right hemisphere (increased).Reduced activity in the left insular region (a bridge between the different language processing areas).Left Planum temporale (the superior temporal gyrus) larger (i.e. PT is symmetrical).Differences in the corpus callosum.Reduced activation in the cerebellum.Magnocellular system deficits (Visual motion sensed by special set of visual nerve cells: magnocellular system that controls visual attention and eye movements - system responsible for timing visual events when reading, auditory magnocellular system would influence phonological acqusition)

  • Causes of DyslexiaBiological differences cited aboveFor some recent biological theories see Beaton, A.A. (2005)These theories include:Phonological delay/deficitTemporal (time) processingVisual problems

  • Causal Modelling how should we think about cause?Brain

    Mind

    Behaviour

  • Model 1PhonologicalDelay/deficite.g. Clay 1987"You have hissed all my mystery lectures and tasted a whole worm. Genetic differenceBrain differencePhonological processing deficitGrapheme-phoneme system not learnerEnglish orthographySpoonerisms difficultPhonological tasks difficultProblems with namingLearning to read difficultbraincognitionbehaviourENVIRONMENT

  • Model 2Temporal ProcessingTallal et al. (1997)English orthographyMagnocellular abnormalitySlow temporal processingAuditory deficitPoor speech developmentVisual deficitPoor motion detectionPoor tone discriminationbraincognitionbehaviourENVIRONMENTPhonological processing problemsLearning to read difficultGrapheme-phoneme system not learnedSpoonerisms difficultPhonological tasks difficultProblems with naming

  • Model 3Skill Automization Nicholson and Fawcett (1990)

    English orthographyPhonological processing problemsLearning to read difficultGrapheme-phoneme system not learnedSpoonerisms difficultPhonological tasks difficultProblems with namingbraincognitionbehaviourGenetic differencecerebellum differenceSpeech motor areasPoor skill automizationtimingfine manual dexterityTime estimationBalance problemsENVIRONMENT

  • Model 4Visual Damagee.g. Stein (94) problems with binocular vision convergence

    No phonological processing problemsLearning to read difficultGrapheme-phoneme system not learnedSpoonerisms not difficultPhonological tasks not difficultNo problems with namingbraincognitionbehaviourENVIRONMENTGenetic differenceSpecific damage to visual systemVisual performance problems

  • Interventions for educationDoes any of this knowledge have implications for education?

    Possibly.

    A number of interventions have been developed which map onto the neurological evidence related to reading and reading disorders

  • Fast ForWordAn intervention aimed at remediating impairments in the temporal processing deficits (found in children with speech and reading problems).

  • ...software adapts to individual skill levels and responses, adjusting the learner's content exposure and targeting correct responses approximately 80% of the time, which maintains challenge and motivates success.

    ....Develops memory, attention, processing and sequencing, the underlying cognitive processes required for reading and learning. ....learning techniques based on decades of neuroscience research. ...to get results in as little as 3-6 weeks! (...30 minutes each day, five days a week, for 3 - 6 weeks )

  • Does it work?Evidence for behavioural and neural remediation (e.g. Temple et al. 2003)

    A lot of initial enthusiasm but negative reviews are beginning to come through too (e.g. Borman (2009)Dyslexic children increased activation in areas ringed in red

  • Other interventions have also remediated reading and brain activityPhonologically-targeted training (Eden et al., 2004): Dyslexic adults were given a programme of training involving: sound awareness, establishment of the rules for letter-sound organisation, sensory stimulation, and articulatory feedback The trained group showed improvements at the behavioural level, plus changes (increases) in task-related brain activity (left hemisphere parietal cortex and some RH regions)See also Shaywitz(2004) for more remediation of reading difficulties and their neural correlates

  • Will brain imaging become part of technology design?Graphogame is a non-commercial system developed at the University of Jyvskyl (Finland)

    Introduces association of graphemes and phonemes according to frequency and consistency of grapheme in a given language

    Onine algorithms analyze a childs performance and rewrite the lesson plans on the fly depending on which specific confusions the learner shows

  • Brem et al. (2010)fMRI and EEG together (spatial and temporal resolution):practise with the game initiates print-sensitive activation in a critical component of the mature reading network located in the left occipitotemporal cortex - visual word-form.If this occipito-temporal print sensitivity established during the earliest reading acquisition, suggests crucial later reading network first adopts a role in print:sound mapping. Such results provide insight into how the software succeeds in supporting literacy, how/when it should be implemented and how neuroscience can be used to inform TEL design.Brem, S., S. Bach, et al. (2010). "Brain sensitivity to print emerges when children learn letter-speech sound correspondences." Proceedings of the National Academy of Sciences of the United States of America 107(17): 7939-7944.

  • and does dyslexia exist anyway?!Prof. Julian Elliot (Durham):

    1. Is dyslexia a clinically or educationally meaningful term for differentiating between children with reading difficulties?2. To what extent would the dyslexic diagnosis guide the educator in devising appropriate forms of intervention?3. To what extent should the dyslexic diagnosis result in the differential allocation of resources or other forms of special arrangement?Elliott, J. G., & Gibbs, S. (2008). Does dyslexia exist? Journal of Philosophy of Education, 42(3-4), 475-491.

    *Ghislaine Dehaene-Lambertz, Lucie Hertz-Pannier, Jessica Dubois, Sbastien Mriaux, Alexis Roche, Mariano Sigman, and Stanislas Dehaene Functional organization of perisylvian activation during presentation of sentences in preverbal infants PNAS 2006 103: 14240-14245; published online before print September 12 2006

    *LINGUISTIC EXPERIENCE ALTERS PHONETIC PERCEPTION IN INFANTS BY 6 MONTHS OF AGE Author(s):KUHL PK, WILLIAMS KA, LACERDA F, STEVENS KN, LINDBLOM B Source:SCIENCE 255 (5044): 606-608 JAN 31 1992 Poeppel, D., Idsardi, W. J., & van Wassenhove, V. (2008). Speech perception at the interface of neurobiology and linguistics. Philosophical Transactions of the Royal Society B: Biological Sciences, 363(1493), 1071-1086.**Turkeltaub, P.E., Gareau, L., Flowers, D.L., Zeffiro, T.A., & Eden, G.F. (2003). Development of neural mechanisms for reading. Nature Neuroscience, 6, 767-773.

    Coltheart, M., Rastle, K., Perry, C., Langdon, R. & Ziegler, J. (2001). DRC: A dual route cascaded model of visual word recognition and reading aloud. Psychological Review, 108, 204-256.Polletsek,A., Lesch, M., Morris, R. K., & Rayner, K. (1992). Phonological codes are used in integrating information across saccades in word identification and reading. Journal of Experimental Psychology: Human Perception and Performance, 18, 148-162.Ashby, J., & Rayner, K. (2004). Representing syllable information during silent reading: Evidence from eye movements. Language and Cognitive Processes, 19, 391426.Ashby, J., Martin, A. E. (2008). Prosodic phonological representations early in visual word recognition. Journal of Experimental Psychology: Human Perception & Performance, 34, 224-236.Ashby, J., Treiman, R., Kessler, B., & Rayner, K. (2006). Vowel processing during silent reading: Evidence from eye movements. Journal of Experimental Psychology: Learning, Memory, and Cognition, 32, 416-424.Ashby and Rayner (to be published in "Educational Neuroscience: The Good, the Bad and the Ugly" (CUP)) BBD downloadable library**E. Paulesu, J.-F. Dmonet, F. Fazio, E. McCrory, V. Chanoine, N. Brunswick, S. F. Cappa, G. Cossu, M. Habib, C. D. Frith, and U. Frith (2001) Dyslexia: Cultural Diversity and Biological Unity Science 16 March 2001: 2165-2167.

    *Pugh, K.R., Mencl, W.E., Jenner, A.R., Katz, L., Frost, S.J., Lee, J.R., Shaywitz, S.E. & Shaywitz, B.A. (2001). Neurobiological studies of reading and reading disability. Journal of Communications Disorders, 34, 479-492.

    Beaton, A.A. (2005). The neurobiology of dyslexia. In M. Turner & J. Rack (Eds.) The Study of Dyslexia. New York: Kluwer.Shaywitz, B.A., Shaywitz, S.E., Pugh, K.R., Fulbright, R.K., Mencl, W.E., Constable, R.T., Skudlarski, P., Fletcher, J.M., Lyon, G.R., & Gore, J.C. (2001). The neurobiology of dyslexia. Clinical Neuroscience Research, 1, 292-299.

    * NB Visual motion is sensed by a special set of visual nerve cells, the magnocellular system, that plays the main part in controlling visual attention and eye movements following the letters when reading. *Beaton, A.A. (2005). The neurobiology of dyslexia. In M. Turner & J. Rack (Eds.) The Study of Dyslexia. New York: Kluwer.

    Morton, John (2004) Understanding Developmental Disorders: A Causal Modelling Approach, Blackwell.**Clay, M.M. (1987) Learning to be learning disabled, New Zealand Journal of Educational Studies, 22, 155-72*Tallal, P., Miller, S., Jenkins, B., Merzenich, M. (1997): The role of temporal processing in developmental language-based learning disorcers: research and clinical implications. In B. Blachman (ed.), foundations of Reading Acquisition and Dyslexia, Mahwah, NJ: Lawrence Erlbaum Associates, 49-66.

    *Nicholson, R. and Fawcett, A. (1990) Dyslexia is more than a phonological disability. Dyslexia, 1, 19-36.Stein, J.F. (1994) Developmental dyslexia, neural timing and hemispheric lateralisation, International Journal of Psychophysiology, 18, 241-9.

    **Veale, T.K. (1999). Targeting temporal processing deficits through Fast ForWord: Language therapy with a new twist. Language, Speech and Hearing Services in Schools, 30, 353-362.

    Temple, E., Deutsch, G. K., Poldrack, R. A., Miller, S. L., Tallal, P., Merzenich, M. M., et al. (2003). Neural deficits in children with dyslexia ameliorated by behavioral remediation: Evidence from functional MRI. Proceedings of the National Academy of Sciences, 100(5), 2860-2865.Borman, G. D., Benson, J. G., & Overman, L. (2009). A randomized field trial of the Fast ForWord language computer-based training program. Educatioal Evaluation and Policy Analysis, 31, 82.

    **Eden, G.F., Jones, K.M., Cappell, K., Gareau, L., Wood, F.B., Zeffiro, T.A., Dietz, N.A.E., Agnew, J.A., & Flowers, D.L. (2004). Neural changes following remediation in adult developmental dyslexia. Neuron, 44, 411-422.Shaywitz, B. A., Shaywitz, S. E., Blachman, B. A., Pugh, K. R., Fullbright, R. K.,Skudlarski, P., Mencl, W. E., Constable, R. T., Holahan, J. M., Marchione, K. E.,Fletcher, J. M., Lyon, G. R. and Gore, J. C. (2004) Development of left occipitotemporalsystems for skilled reading in children after a phonologically-based intervention.Biological Psychiatry, 55, 926933.

    Elliott, J. G., & Gibbs, S. (2008). Does dyslexia exist? Journal of Philosophy of Education, 42(3-4), 475-491.*