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Brunsdon & Coltheart, 2005

Assessment and Treatment of Reading Disorders:

A Cognitive Neuropsychological Perspective

DeCog Research Unit (Developmental Cognitive Neuropsychology Research Unit)

MACCS, Macquarie University

Rehabilitation and Psychology Departments, The Children’s Hospital at Westmead


Overview

! Assessment of reading! Diagnosis of reading impairment ! Treatment of reading difficulties

Print

LetterIdentification

SUBLEXICAL

Visual Word Recognition

LEXICAL

Spoken Word Production

Speech

Letter to Sound ConversionSemantics


Dual Route Model of Reading

! Skilled readers use two main procedures for reading aloud

• Lexical Reading Route• relies on whole-word recognition and allows successful

and efficient processing of words that are familiar to the reader

• Sublexical Reading Route• involves rule-based letter to sound conversion and allows

the skilled reader to ‘sound-out’ unfamiliar words and nonwords.


Developmental Dyslexia


Developmental Dyslexia

! Developmental Dyslexia is heterogeneous

! Main Subtypes

• Phonological• Surface• Mixed


Developmental Dyslexia - Subtypes

! Phonological Dyslexia• children who have difficulty acquiring skills

for converting letters into sounds


Phonological Dyslexia

! Phonological Dyslexia

• Difficulty with the Sublexical Reading Route • the route that relies on letter to sound correspondences

to assemble a pronunciation.

• Over-reliance on the Lexical Reading Route• the route that relies on whole word recognition

• where the reader gains access to an internal store of the visual representations of familiar words

Print

SUBLEXICAL



LEXICAL


Speech



PhonologicalDyslexia

! Phonological Dyslexia:

• good reading of familiar words• Poor nonword reading• Difficulty reading unfamiliar word• Nonword reading errors

• visual similar real words• eg. tapple → table


Developmental Dyslexia - Subtypes

! Surface Dyslexia• children who have difficulty learning to

recognise words as whole units


Surface Dyslexia

! Surface Dyslexia

• Difficulties with Lexical Reading Route• the route that relies on whole word recognition

• Over-reliance on the Sublexical Reading Route

• the route that relies on letter to sound correspondences to assemble a pronunciation.

Print


LEXICAL

SUB LEXICAL



Speech



Surface Dyslexia

! Surface Dyslexia:

• good nonword reading• good reading of regular words (e.g., little)• poor reading of irregular words (eg. quay)• regularisation errors when reading

• eg. quay → “kway”colonel → “kollonell”


Assessment


Assessment

! Assessment of phonological, surface and mixed dyslexia in children:

• Standardised word reading tasks inadequate (eg. WRAT, WIAT)

• Only diagnose delay in general reading development

• Do not detect specific types of dyslexia


Assessment

! Cognitive Neuropsychological Assessment

• Structured according to existing models of normal reading

• to determine which subprocesses are intact and which are not


Assessment

! Core assessment Tools

• PALPA - Psycholinguistic assessment of language processing in aphasia

Kay, Lesser & Coltheart (1992).

• Word/Nonword list Coltheart & Leahy (1996)

• Graded Nonword Reading TestSnowling, Stothard, & McLean (1996).

Print


SUBLEXICAL

LEXICAL



Speech



Assessment

• Sublexical Reading

• intact if nonword reading is age appropriate• Word/Nonword list (Coltheart & Leahy, 1996)

• Graded Nonword Reading Test (Snowling, Stothard, & McLean, 1996)


Assessment

• Lexical Reading

• intact if irregular word reading is age appropriate• Word/Nonword list (Coltheart & Leahy, 1996)


Assessment

• But, if impaired:• why is the child having difficulties with the lexical

and/or sublexical processing routes?• How do we treat the problem?

• Each process relies on the intact functioning of a number of subprocesses each of which may be dysfunctional

• We now need to assess each subcomponent of Lexical and Sublexical Route