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Neurobiological perspectives on reading:

Implications for assessment and intervention across the lifespan

DePaul WSHA 2016

Objectives

1. Understand that a reading disorder is not a unitary disorder

2. Understand fundamental neurobiologic principles underlying reading

3. Develop optimal assessment and intervention for reading disorders across the lifespan

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This can get complicated…

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Obj. 1: Reading disorder is not a unitary disorder

DePaul WSHA 2016

Aphasia Literature“what you do about aphasia depends on what you think aphasia is”

Schuell p. 138, 1974b

“to locate the damage which destroys speech and to locate speech are two different things” Jackson, 1874

Unitary condition = General language deficit crossing all language modalities

• No localization

• Severity based

• Language associations, networks

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Before one can read…Word production models remind us how words are mapped and accessedPapathanasiou, et al., 2013, p. 133

Discrete (left side) Interactive model (right side)

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Before one can read…Interactive Activation (IA) Model Papathanasiou, et al., 2013, p. 138 (from Dell & O’Seaghdha, 1992)

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Shows reading as a series of modulesbut dependent on oral language…

Papathanasiou, et al., 2013, p. 158

Dual Route Reading Model

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How do you decode the visual input?

• Visual pathway but remember …

• VISUAL SYMBOL ACCESSES A LANGUAGE SYSTEM

• VISUAL COMPREHENSION• Silent reading

• ORAL READING IS A PRODUCTION TASK

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Obj.: 2. Understand fundamental neurobiologic principles underlying reading

• Neurology of reading

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Language: Reading is visual comprehension

• Linguistic symbols…

• visual input MUST cross corpus callosum to dominant (left) language area

• right hemisphere homologues

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• Right occipital lobe input, needs to cross-over to left dominant language areas• corpus callosum

• angular gyrus• serves as the connection between the language

centers and the visual cortex

• Damage • typically results alexia and

agraphia • Posterior Cerebral Artery (PCA) territory

Assumptions and perhaps too simplistic

DePaul WSHA 2016

Developmental Reading Areas Shaywitz sourceshttp://soundprinciples4literacy.com/index.php/2010/11/26/neural-systems-for-reading/

A. Broca’s area:beginning reading

B. Parieto-temporal area (PTA): word analysis area beginning reading

C. Occipito-temporal area (OTA): visual word form area developed reading

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Occipito-temporal area [OTA] = (visual)word form area(VWFA)Fusiform gyrus: Cortical territory evolved for object and face recognition

Left hemisphere Right hemisphere

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Important role of VWFA in reading developmenthttp://journal.frontiersin.org/article/10.3389/fpsyg.2014.00703/full Paper talks about developmental process

Visual Word Form Area* [VWFA] OTA

Note the varied inputs to developing VWFA eventual result is fluent reading.

MULTIPLE domains in action

*VWFA, fusiform gyrus, occipito-temporal

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Neural connections for association: Arcuate fasciculus

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Geschwind territory and language, another pathway

Inferior parietal lobule (IFP)• lies below horizontal portion of the

intraparietal sulcus• behind the lower part of the postcentral

sulcus• inferior parietal lobule:

• supramarginal gyrus• arches over the upturned end of the lateral

fissure; it is continuous in front with the postcentral gyrus, and behind with the superior temporal gyrus

• angular gyrus• arches over the posterior end of the superior

temporal sulcus, behind which it is continuous with the middle temporal gyrus

• Arcuate fasciculus W → Br• Geschwind territory parallel pathway

• age 5-7 years

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Why Geschwind territory is important …http://thebrain.mcgill.ca/flash/i/i_10/i_10_cr/i_10_cr_lan/i_10_cr_lan.html

1. Massive connection at the junction of the auditory, visual, and somatosensory cortices

2. Neurons in this lobule are multimodal: process different kinds of stimuli (auditory, visual, sensorimotor, etc.) simultaneously capturing multiple properties of spoken and written words: their sound, their appearance, their function, etc.

3. This lobule may thus help the brain to classify and label things, which is a prerequisite for forming concepts and thinking abstractly.

4. Developed late in human brain evolution (rudimentary form in the brains of other primates)

Implication: language may have evolved through changes in existing neural networks, rather than through the emergence of completely new structures in the brain.

5. Inferior parietal lobule is also one of the last structures to mature in human children, and there are reasons to believe that it may play a key role in the acquisition of language.

Implication: late maturation of this structure would explain, among other things, why children cannot begin to read and write until they are 5 or 6 years old.

DePaul WSHA 2016

Developmental reading: What might go wrong?

• Assume misconnection or faulty connections

• Genetic programming error (classic dyslexia)

Phonologic analysis errors

↓

Phonologic impairment interferes with spoken and written language development

Depends on the degree of faulty network: might expect a continuum of problems in spoken and written language varying degrees of severity (in this case, reading difficulty) e.g., many children with RD have dysnomia/anomia

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Reading Brain Areas: Key Points

Brain areas and neural network interplay:

• Developing skill = PTA area (language acquisition) →→→OTA

• More skilled and fast = OTA (anatomic location =fusiform gyrus)(functional area = visual word form area)

• Less skilled and slow = PTA

• Compensatory and/or redundant = (anatomic location = IFG, i.e., Broca’s area)

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On the fast track to reading development...Goal:

Develop rapid decoding from language association area PTA (word analysis area)

↓

rapid word recognition in the OTA/VWFA

[fusiform gyrus located in the inferior temporal gyrus (ITG)]

As skill develops… see a word

• More activation in VWFA• Less than 150ms when see a word• No analysis• Instantaneous whole word pattern• Automatically identified on sight

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Compare Acquired vs. Developmental Reading Disorders

Acquired reading disorder (aphasic alexia)

• Adult can read, adult has stroke, adult cannot read

• Brain circuitry that worked, now is disrupted, an incomplete circuit

• Result: reading power outage

Developmental reading disorder (dyslexia)

• Child learns to read, fails to develop typically, circuitry not making connections, faulty blueprint

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Distinction between acquired-developmental RD

Consider:

• not cutting the circuitry as in the adult power outage

• but wiring not laid down correctly in first place – glitch in fetal development when brain is hard-wired for language

• thousands of neurons carrying phonologic messages for language doesn’t connect to some network for skilled reading to develop

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Acquired reading disorders: Alexia subtypes (informs developmental

reading) Papathanasiou, et. al. 2013

Clinical Features

Locus of Damage↓

Syndrome↓

Word lengthshort>long

Spelling regularityreg>irreg

Frequency (F)HF>LF

Imageability (I)/ConcretenessHI>LI

Word ClassNouns>Functors

Inability to read nonwords

SemanticErrors

Access to orthographic input lexicon

Letter-by-letter readingPure alexia

√

Orthographic input lexicon

Surface alexia

√ √

Sublexical (Letter-to sound) procedures

Phonological alexia

√ √ √ √

Semantics and letter-to-sound conversion

Deep alexia √ √ √ √ √

Access to phonological output lexicon

Surface Alexia

√ √

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Importance of the subcategories in acquired RD

• Treatment might be influenced by subcategories

• Insight to brain mechanisms

Example:

• Pure alexia or alexia w/o agraphia

• Multiple oral rereading = repeated reading aloud of a text facilitating whole word (vs letter by letter) reading. See Beeson, for example on MOR Rx

• Rerouting idea: access to orthographic input lexicon decrease letter by letter

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What is the path to effective reading intervention?

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Developmental Reading Areas – Improve activationhttp://soundprinciples4literacy.com/index.php/2010/11/26/neural-systems-for-reading/

Brain areas and neural network interplay:

• Developing skill = PTA →→→OTA

• More skilled and fast = OTA (anatomic location =fusiform gyrus)(functional area = visual word form area)

• Less skilled and slow = PTA

• Compensatory and/or redundant = (anatomic location = IFG, i.e., Broca’s area)

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Neurorehabilitation

Principles

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Brain and language…let’s get it in order!

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What is your underlying assumption about language intervention?

• Neural plasticity is the basic neural mechanism supporting functional improvement be it for recovery or compensation

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Compare restore or compensateEtiology and Relationship to Behavioral ChangeDevelopmental

Classic dyslexia (genetic basis)

• Wired differently reading system

• Higher verbal abilities

• Compensatory – accurate but slow

Experiential/environmental dyslexia

• Poor reading instruction

• Disadvantaged home environment

• Wiring map laid down genetically but never activated appropriately

• (UW) Pollak study: JAMA pediatrics

Acquired

• Adventitious or degenerative

• Reperfusion• Restoration

• Failure to reperfuse; hypofuse, poor activation

DePaul, WSHA 2016

Treatment principles: Restitution or Compensation

• Functional Restitution = reorganization of the brain (plasticity to regain functional ability)

– may require sparing of a minimum proportion of cells/connections

(Sabel estimates 10-20%)

• Compensation = using other intact brain regions or external aids to recovery functional abilities

Refer to this lecture for next 3 slides: http://www.utm.utoronto.ca/~w3psy393/Lec11_rehab.pdf

DePaul, WSHA 2016

Clinical Case Example: Prosopagnosia (facial recognition impairment)

Problem:After his stroke, this man can no longer recognize people by their faces, not even his wife: he may well pass her by on the street, unknowingly. This distresses him (and her).

What to do?

• Rx Restoration: Try to improve the operation of his face recognition system so that it can recognize faces again, at least for faces that were highly familiar. (Direct processing treatment)

• Rx Compensation: Propose that she buy a very distinctive pair of spectacles and always wear them; he can then use this as a cue for identifying his wife. (Indirect task-oriented treatment)

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Basic mechanisms of RecoveryCells that fire together, wire together

Donald Hebb (1949) Hebbian Learning • Integrate behavioral and biological levels of

analysis • Cells that fire together, wire together

• (Long term potentiation LTP)

• When cells fire apart … wires depart• (Long term Depression LTD)

Merzenich: brain was constructed to change • Cortical Plasticity: use-dependent allocation

of cortical area • Experiments demonstrating reorganization of

somatosensory cortex in monkeys following peripheral nerve damage/amputation

• https://www.ted.com/talks/michael_merzenich_on_the_elastic_brain?language=en

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This is critically important…

• Does stimulation improve brain function?

• Do we treat the language impairment directly, or teach use of alternative strategies?• Target disordered executive functions (reestablish

internal executive control) or• Redesign the environment (use external aids to help

maintain executive control)

What are the outcomes?

• Neural resources to overcome deficit may not be lost completely just difficult to access…

• May be inhibited by other parts of the brain• Not stimulated enough for the connections to

reestablish• Improvement not possible in all cases

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Aphasia treatment inherent decisions and planning…Is this a horse? Or what is this?

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Intervention Principles: Connectionist model (Nadeau)

Patterns are formed with practice

Connections reinforced

Repeated practice and experience

• Reinforce

• Deep imprinting

• Explicit

• Specificity

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Parallel Distributed ProcessingPDP models applied to brain maps

Roth HL, Nadeau SE, Hollingsworth AL, Cimino-Knight AM, Heilman KM. Naming Concepts: Evidence of Two Routes. Neurocase 2006;12:61-70.

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Reminder evidence base for language recoveryWhat happens is stroke recovery? Compensation/Restitution Connections!Dynamics of language reorganization after strokeDorothee Saur, Rüdiger Lange, Annette Baumgaertner, Valeska Schraknepper, Klaus Willmes, Michel Rijntjes, Cornelius WeillerDOI: http://dx.doi.org/10.1093/brain/awl090 1371-1384 First published online: 25 April 2006

What are the dynamics of reorganization in the language system?

Repeated functional MRI (fMRI) examinationsparallel language testing from the acute to the chronic stagen=14 persons with aphasia L. MCAage-matched control group

DePaul, WSHA 2016

Brain reorganization during language recovery proceeds in three phases Saur, et al., 2006; Hillis, 2015 ASHA Enticing the Brain to Behave (after stroke)

Subacute phase (mean:

12.1 dps)

Chronic phase (mean: 321 dps)

Acute phase (mean: 1.8

dps):

Chronic recovery of post-stroke aphasia can be augmented by neuromodulation with language intervention (Hillis)

REPERFUSION

Little, early activation of

infarcted left-hemispheric

language structures

Increased activation in the

bilateral language

network with peak activation in the right Broca-

homologue (Bho)

Normalization of activation with a re-shift of peak

activation to left-hemispheric

language areas, associated with

further language improvement.

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What are the components of language treatment for reading?What is the dose?

• Explicit and direct instruction

• Practice:• Frequency

• Intensity

• What is the optimal or practical dosage?

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What happens over time? Possible outcomes w/ or w/o treatmentShaywitz source

Goal: Strong activation posteriorly and less activation anteriorly

Individuals with RDs tend to:

• Activate back AND front of brain

• Underactivation of posterior region has net effect• difficulty analyzing words → transform letters into

sounds remains slow – not fluent readers

Over time with age:

• Dyslexia - increased activation in frontal regions by adolescence • Pattern of activation in Broca’s region

• Result: Compensation for a deficient neural network

• Behavioral patterns in dyslexic readers: subvocalize as read (moving lips) activates Broca’s area – production

• Why? Helps with awareness of sound structure by physically forming words → slow

Outcome: Slow but accurate using secondary pathways

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Over time: Patterns of underactivation

Adult readers with history of dyslexia:

• Draining and exhausting

• Accurate but slow readers

• Disruption of left posterior system

• Prevents rapid, automatic word recognition

• Ancillary systems right and left frontal system allow for accurate albeit slow reading

What if they were provided reading (language) intervention as children?

If so, what was the nature of the intervention?

What happens if acquired (aphasic) alexia is superimposed?

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Stretch break

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Obj. 3: Develop optimal assessment and intervention for reading disorders across the lifespan

DePaul, WSHA 2016

Obj. 3: Develop optimal assessment and intervention for reading disorders across the lifespan

“what you do about aphasia a reading disorder depends on what you think aphasia a reading disorder is”

What’s your destination?

What is your road map?

How did you get to the Dells?

• Direct – get there faster

• Indirect• accurate slow• inaccurate slow

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Two adult subjects post CVA

• Posterior cerebral artery (PCA) lesion = fluent, alexia w/o agraphia

• Middle cerebral artery (MCA) lesion = more typical, non-fluent

• What are intervention approach possibilities?

Adult (vs children)

• What is the purpose for communication ADL?• Functional outcomes

• Processing treatment

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Subject: Alexia w/o agraphia and Anomia (L. PCA) lesion Anomia, alexia, visual agnosia, visual field cut, not agraphic

Anomia Grapheme recognition

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• Video 1 • Video 2

Alexia lesion site….what about anomia?

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Subject: (L. MCA) lesion

Conversation Cookie theft description

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• Video 1 • Video 2

GOALSWill use phoneme-grapheme knowledge to self-cue oral reading of words

• Adapted explicit instruction (Orton-Gillingham)

• Single word reading (or is it naming the written word)

Problem list: Refer to Papathanasiou, et. al. 2013, Fig 7.2

• Can generally write a word, but cannot read what she wrote

• Word recognition is 100%,

Assumption: Primary phonological impairment because naming 100% with phonemic cues

• Reading depends on lexical semantic strategy, orthography activates semantic system

Plan: Phonological treatments strengthen letter to sound relations written and spoken

(and likely will have affect on naming – Kendall and Nadeau’s work)

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Treatment Sample

Pre-Treatment Multi-modality Probes Treatment: Grapheme phoneme

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• Video 3 • Video 4

Steps in Subject 2 Treatment Plan

Modified O-G/PhonomotorPhase 1

• Key words for word and initial letter to sound recognition

Phase 2

• Grapheme card sets visual

• Train phoneme• Use articulation (motor) approach for placement

(called OM cue in my scoring system)

Phase 3

• Grapheme to phoneme conversion

• Produce a word

Phase 4

• Produce a word

• Extract initial phoneme

Naming Probes

• Confrontation naming

• Generative naming

Recent confrontation naming data:

n =30

57% Spontaneous20% OM coaching23% PC

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Evidence Base

Impaired phonological processing associated with phonological alexia and agraphia [Beeson, et al., 2010]

Impaired lexical/semantics and phonology resulting in anomia [Kendall, et al., 2015 – Phase II clinical trial]

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Reading is not a unitary phenomenonRefer to : Word Retrieval Abilities in 26 Individuals With Chronic Aphasia: An Open Trial: Kendall, et.al. (2015) JSHR

1. Purpose: The ultimate goal of aphasia therapy should be to achieve gains in function that generalize to untrained exemplars and daily conversation.Principle: Generalization

2. Anomia is one of the most disabling features of aphasia. Model: Lexical network is disturbed (refer to Figure 7.2 from Pathanasiou et. al., 2013, p.138)Question: Do children with RD have word finding difficulties?

3. The predominantly lexical/semantic approaches used to treat anomia have low potential for generalization due to the orthogonality of semantic and phonologic representations; this has been borne out in a meta-analysis of treatment studies. Model: Consider the phonologic network (refer to Figure 7.2 from Pathanasiou et. al., 2013, p.138 and Nadeau model)

4. The intensive, neurally distributed, phonologic therapy reported here can, in principle, generalize to untrained phonologic sequences because of extant regularities in phonologic sequence knowledge and should, in principle, generalize to production of words trained as well as those untrained.Model: PDP models demonstrate connectionism in neural network models (remember Geschwind, Nadeau, model)

5. Method: Twenty-six persons with chronic aphasia due to stroke were treated, in a staggered (immediate vs. delayed treatment) open trial design, with 60 hrs. of intensive, multimodal therapy designed to enhance access to and efficiency of phonemes and phonologic sequences.Principle: Evidence based practice and the importance of clinical trials – for treatment “dosage” to achieve generalization

6. Results: There was an absolute increase of 5% in confrontation naming of “untrained” nouns at 3 months, and there were 9% to 10% increases on measures of generalization of phonologic processes.Principle: Language network is activated (refer to Figure 7.2 from Pathanasiou et. al., 2013, p.138). Treat underlying phonologic impairment and generalizable results in lexical network (naming) and in reading (refer to Kendall paper and Brookshire papers)

7. Conclusion: The results of this trial demonstrate generalization of training effects on laboratory measures, which were sustained at 3 months, and provide support for the theories that motivated the treatment.Implications: May be feasible and efficacious treatment for anomia, reading and possibly AOS.

DePaul, WSHA 2016

Time to recap and…

DePaul, WSHA 2016

Developmental Reading Areas – Improve activationhttp://soundprinciples4literacy.com/index.php/2010/11/26/neural-systems-for-reading/

Brain areas and neural network interplay:

• Developing skill = PTA →→→OTA

• More skilled and fast = OTA (anatomic location =fusiform gyrus)(functional area = visual word form area)

• Less skilled and slow = PTA

• Compensatory and/or redundant = (anatomic location = IFG, i.e., Broca’s area)

DePaul, WSHA 2016

Summarize

What are the essentials of reading intervention that will alter brain?

• Specific and explicit instruction

• Repeated practice and experience: frequency and intensity

Increasing efficiency

• Activating an underused path

• Reactivating/reinstating a path

• Bypassing a path

DePaul, WSHA 2016

Next steps for reading disordersDevelopmental RD

1. Epidemiology studies

Next generation of longitudinal studies IPP model

2. Gene-brain data

3. IPP

4. Study comorbidities, cross-linguistic studies

5. Study talents and strengths

6. Higher education cross-disciplinary training

7. Common measures… common nomenclature

Acquired RD

1. Phase three studiesKendall et al. team

2. Work-up across all language modalities• Reading (input) as facilitator for word

access (output)

• Schuell concepts adapted for current time

(Schuell meets Geschwind)

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DePaul, WSHA 2016