University of Edinburgh
 

Deaf Plus: Teaching Deaf Children who are Dyslexic

Thursday 3 May 2007

Identification of Dyslexia in Deaf Readers

Ros Herman & Penny Roy, City University, London

Content

Background on reading and deafness
Problems in identification of dyslexia among poor deaf readers
Issues of measurement & interpretation
Case study
Implications?

Background

Deafness: some background statistics (Périer 1987; Leybaert 2006)

  • Frequency of profound hearing loss (91 dB>)
    • 1 /2,500 healthy FT newborns
    • 1 /1,000 premature births
    • 1 /100 neonatal pathology
  • 40% additional problems (eg; visual, learning)
  • About 50% genetic origin, 50% acquired
  • Because high % due to recessive genes/non genetic factors about 90-95% of deaf children are born to parents with normal hearing.

How do deaf children learn to read? (Goldwin-Meadow & Mayberry 2001)

  • Reading requires two related but separable capabilities:
    • Familiarity with a language
    • Understanding the mapping between that language and the printed word
  • Profoundly deaf children (DC) are disadvantaged on both counts
  • Some DC are fluent readers - why?
  • Are they ‘simply the smartest of the crop?’

Simple view of reading (Gough & Tunmer 1986)

Reading involves:

  • Text decoding +
    mappings between letters and speech sounds (the alphabetic principle)
  • Language comprehension
    understanding words and sentences
    integrating meanings of sentences within texts and making inferences

Word recognition: beyond decoding

Term ‘decoding’ in the literature used loosely to refer to either basic single word reading skills or to translation of letter strings to phonological codes.

Sometimes term used more widely: to decipher word by whatever means including use of contextual information on an item by item basis (Share 1995).

Disambiguation of words (eg; bow cannot rest on phonological decoding alone)

Share (1995) described the alphabetic principle as a ‘self-teaching device’:
"every successful decoding encounter with an unfamiliar word provides an opportunity to acquire word-specific orthographic information that is critical to the development of skilled word recognition".

Early predictors of reading ability (Scarborough, 1998)

early predictors of reading ability

Higher level processes involved in reading (Grigorkenko 2001)

Reading is complex and involves many higher level processes:

  • Phonemic awareness
  • Phonological decoding
  • Ability to process stimuli rapidly and autotmatize this process
  • Memory
  • Ability to recognise words

Areas of reading instruction recommended by the National Reading Panel in USA

  • Phonics
    The understanding that there is a predictable relationship between phonemes and graphemes
  • Phonological awareness (PA)
  • Fluency
  • Vocabulary
  • Comprehension

Role of environmental factors

Social class counts for a substantial amount of variation in growth of reading skills between grades 1-4 even when effects of IQ and PA in kindergarten are taken in account. (Hecht, Burgess, Torgesen, Wagner & Rashotte 2000)

Exposure to print particularly important with opaque systems such as English. Print exposure accounts for variation even once PA controlled for. (Cunningham & Stanovich 1991) 

Reading problems more frequent in opaque languages.

3 types of phonological processing (Wagner & Torgesen 1987)

  • Phonological awareness
    Awareness of phonological information
  • Lexical access of phonological information
    eg; naming, rapid naming
  • Working memory involvement
    Memory span, digit span, non-word repetition

Phonological awareness

PA is a metalinguistic skill. It requires children to reflect on phonological segments of spoken words and manipulate them in systematic ways

PA comprises 2 component skills (Muter, Hulme, Snowling & Taylor 1998)

  • Segmentation: high loadings on syllable and phoneme tasks
  • Rhyme: rhyme detection and rhyme production

What is the role of phonological awareness in reading acquisition?

  • Precursor (Bradley & Bryant 1983; Olofson & Lundberg 1985)
  • Result of learning to read (Morias, Alegria & Content 1987; Brady & Shankweiler 1991)
  • Interactive relationship (Morais 1991)
  • Debate ongoing (Castles & Coltheart 2004; Hulme, Snowling, Caravolas & Carroll 2005)
  • PA in the absence of letter knowledge (orthographic awareness) may be insufficient.

Early findings

  • A landmark study (Conrad 1979)
    300 deaf school leavers(15.5-16.5years)
    Median reading age (RA) 9 years
  • Recent studies have confirmed findings (Chamberlain & Mayberry 2000; Traxler 2000)
  • But ... a minority (5/205 teenagers - Conrad 1979) at reading level expected for age
  • Why?

'Good' deaf readers (Conrad 1979)

  • 'Good' DRs were 'phonological coders' vs 'visual coders'
    Phonological coders made more errors on rhyming word memory list
    Visual coders made more errors on visually similar non-rhyming words
  • Phonological coders had a 2-year advantage in reading comprehension vs 'visual coders'
  • Conrad argued phonological code essential for development of reading, even in deaf youngsters.

Phonological representations in DC

  • It is impossible to translate literally a sign language into an oral language.
  • Phonological representations are not necessarily acoustic, they are ‘meaningless units out of which meaning units are formed’.
  • But for DRs in general, phonological representations are poorer and less precise than those of hearing children.

A study of ‘good’ deaf readers (Gravenstede 2005 unpub)

  • 20 profoundly deaf adolescent ‘good’ DRs
  • Mean age; 13 years, SD=12 months
  • Attended school for high achieving deaf youngsters with potential to achieve at least 5 grade A-C at GCSE
  • School had oral/aural philosophy

PhAB: Non-reading subscale (Frederickson, Frith & Reason 1997)

  • examples of one-syllable items
    pim fot chog
  • examples of two-syllable items
    yutmip cromgat shendon

Word and non-word reading scores

  • The mean group reading score was average (98.6)
  • Overall nonword reading levels were significantly higher (mean=113.6)
  • Non-word reading scores were significantly related to reading scores

reading scores

PhAB: Rhyme, spoonerisms and naming speed tests

  • Rhyme Test
    I am going to say some words and I want you to tell me which two sound the same at the end
    Listen – sail boot nail
  • Naming Speed Test
    The child is required to name a random sequence of 50 stimuli (consisting either of line drawings of 5 common objects or of single digit numbers) as quickly as possible.

PhAB: Rhyme, spoonerisms and naming speed tests

  • Spoonerisms Test
    We are going to play a game with words and sounds. Listen – cat with a /f/ gives fat
    red with a /b/ gives …? (bed)
  • Here is our next game. This time I will say two words. Listen, King John gives ..Jing Kon. You see, you swap over the first sound from each word so King John gives…
    Riding boot gives …? (biding root)

Phonological awareness scores of ‘good’ DRs

phonological awareness scores

PhAB: Verbal fluency test

  • Semantic test
    I’m going to ask you to tell me as many words as you can in a short time. When I say "start", tell me lots of things to eat / animals, as fast as you can (30secs)
  • Alliteration test
    ..words that start with /k/ and /b/
  • Rhyme test
    ..words that rhyme with /more/ and /whip/

Phonological awareness scores of ‘good’ DRs: verbal fluency

phonological awareness scores

Phonological awareness scores of ‘good’ DRs

  • Performance on phonological awareness tasks showed considerable variability both within and between tasks.
  • Performance on rhyming identification was poorest and overall scores were below average.
  • Reading scores were significantly associated with rhyme identification, rhyme fluency and spoonerisms but not naming tasks or semantic fluency.

Factors associated with outcome

  • Speech intelligibility was not associated with reading levels.
  • Phonological skills and phonological awareness were significantly associated with reading outcomes.
  • In the absence of longitudinal data it is not possible to determine the direction of relationships.
  • Nevertheless the substantially higher performance on non-word reading, indicative of well developed knowledge of grapheme/phoneme correspondence, is striking.

The relative contribution of phonological awareness and decoding and rapid automatized naming – RAN (Dyer et al 2003)

  • 49 deaf students:
    mean age 13 yrs, RA 7yrs
  • Although phonological awareness and decoding poor, they correlated with RA.
  • RAN (tested in sign/speech) was much faster in DR compared with RA matched controls.
  • RAN showed no direct relation to reading level or delay in DR.

Comparison of good and poor readers (Harris et al 1998, 2004, 2006)

  • DC can develop PA before learning to read, but less precisely than HC
  • Variations in PA predicted early reading in DC and HC
  • Development of phonemic knowledge boosted more by learning to read in DC vs HC
  • Speech intelligibility unrelated
  • Speech reading, vocabulary and hearing loss related to reading
  • Speech reading necessary but not sufficient – some poor readers were also good speech readers
  • Individual differences in profiles.

Limitations of Speech Reading (Leybaert 2006)

  • Speech reading
    Because of numerous ambiguities only part of the message can be conveyed by speech reading
    Effective use of speech reading requires a good knowledge of oral language (Bernstein, Demorest & Tucker 1998)
  • Cued speech is a system of hand shapes and placements
    Aim is to disambiguate consonant and vowels
    Convey explicit phonemic information in the visual modality

Cued Speech (Leybaert 2006)

  • French speaking children exposed to Cued Speech at home and school from an early age (<3years) demonstrated phonological abilities and written language skills comparable to hearing peers.
  • Children exposed late to Cued Speech and children educated with sign language showed impairments of reading development.
    Concluded the development of phonological systems not entirely dependent on acoustic input but
    can develop from linguistically relevant contrasts presented in the visual modality as well.

Visual phonics (Trezek & Wang 2006)

  • 13 children aged 5;5 to 7;11 received a year of phonics based reading curriculum supplemented by Visual Phonics (a system similar to Cued Speech)
  • Improvements found in:
    Word reading
    Pseudoword decoding
    Reading comprehension

Fingerspelling & ‘lexicalised’ finger spelling (Haptonstall-Nykaza & Schick 2007)

  • 21 deaf signers (aged 4-14 years) trained on unknown English vocabulary with:
    lexicalised fingerspelling
    neutral fingerspelling
    ASL signs
  • Lexicalised fingerspelling improved ability to recognise, write and fingerspell words.

The relationship between signs neutral fingerspelling and orthography (Haptonstall-Nykaza & Schick 2007)

diagram

The relationship between signs lexicalised fingerspelling and orthography (Haptonstall-Nykaza & Schick 2007)

diagram

Exposure to sign language

  • Earlier evidence that DoD children who used ASL read better and achieved higher academic levels than DoH who did not know ASL.
  • Early exposure likely to have positive effect on linguistic and intellectual development and other cognitive skills (eg; verbal and nonverbal memory) which in turn promote reading comprehension.
  • But ... a significant relationship found between finger-spelling/ initialised signs and reading levels amongst ASL users (Padden & Ramsey 2000).

Phonological representations in DC with cochlear implants (Burkholder & Pisoni)

  • Most DC who receive a cochlear implant have been deprived of auditory input for one or more years. (Kirk 2002)
  • Direct links between working memory and development of speech and language skills have been found in deaf and hearing children.
  • Non-word repetition skills poor overall in DC with CI.
  • Children who used oral communication received higher ratings on non-word repetition than children who used total communication.
  • Lack of early experiences with auditory and linguistic input had profound effects on
    Speech perception and sensory encoding,
    Ability to encode, rehearse, and recall sequential information.

Acquisition of spoken language phonology in DC

  • Hearing children’s acquisition of phonology is determined by experience with audiovisual speech. (Campbell, Dodd & Burnham 1998; Leybaert 2000)
  • DC acquisition of spoken-language phonological units is largely influenced by visual experiences
    Speech reading and Cued Speech
    Finger spelling
    Reading
  • Some evidence that early experiences are important in the development of phonological representations.

Dyslexia

Identifying dyslexia

  • Definition of dyslexia
  • Genetic component
  • Decoding and phonological problems

Definition of dyslexia (International Dyslexia Association 1994; USA)
"Dyslexia is one of several distinct learning disabilities. It is a specific language–based disorder of constitutional origin characterised by difficulties in single word decoding, usually reflecting insufficient phonological processing abilities. These difficulties in single-word decoding are often unexpected in relation to age or other cognitive abilities, they are not the result of generalized developmental disability or sensory impairment. Dyslexia is manifested by a variable difficulty with different forms of language, including, in addition to a problem with reading, a conspicuous problem with acquiring proficiency in writing and spelling"

Complexity of dyslexia (Grigorenko 2001)

  • Reading is a complex hierarchical system encompassing, eg; visual recognition; symbol mapping; phonological, lexical, semantic & syntactic processing, memory and vocabulary for starters.
  • Dyslexia as a part of continuum or categorically different?
  • Frequency varies by:
    Language and culture
    Age

Genetic basis of dyslexia

"Dyslexia (…is an) etiologically complex disorder with a strong genetic basis. Genetic influences on reading disability appear most marked for cases that:
involve phonological impairments;
are out of keeping with other cognitive skills;
are relatively severe."
(Bishop & Snowling 2004)

A causal model of dyslexia (Frith 1997)

causal model of dyslexia

Dyslexia & verbal fluency: more evidence for a phonological deficit (Frith, Landerl & Frith 1995)

  • 19 twelve year-old dyslexic children were compared with 19 typically developing children
  • Matched in terms of:
    CA
    Verbal IQ (BPVS)
    Nonverbal IQ (Ravens CPM)
  • Differed in terms of:
    BAS reading age (8.3 vs. 13.5)
    BAS spelling age (8.2 vs. 12.1)
    WISC digit span (7.3 vs. 10.5)

Verbal fluency: time to produce 1st ten words according to category

  • Dyslexic children took significantly longer to generate words from phonemic cues than typically developing children.
  • No group differences were found for words from semantic cues.

verbal fluency

A hearing child with dyslexia
Dyslexia in a hearing child: A case study (Snowling, Stackhouse & Rack 1986)

JM - Early history

  • C.A:3 years, referred to SALT
  • ‘Late talker’, first words around 2 years
  • Speech delayed and phonologically disordered, comprehension good, vocabulary development normal.

Dyslexia in a hearing child: JM

  • C.A: 7 yrs EP referral for poor reading
  • IQ high, WISC full scale 123
  • Reading and spelling ages significantly below expected levels
  • Problem learning common sequences, eg; days of the week, months of the year and alphabet.
  • Diagnosed as dyslexic, with clear cut profile of strengths and weaknesses.
    high on non verbal tests of visuo-spatial skills
    strikingly poor on digit span, a test of verbal STM.

Dyslexia in a hearing child: JM Scores on nonverbal subscales

dyslexia scores

Dyslexia in a hearing child: JM

  • Reading totally reliant on sight vocabulary, and heavily dependent on context.
  • Very poor auditory skills, poor auditory discrimination.
  • Could segment words, could not analyse them at phonemic level.
  • Word finding difficulties
  • Very poor at non-word reading and repetition of non-words
    very severe problems at all levels of ‘phonological representation’.

Dyslexia in a hearing child: JM

Could JM compensate for deficits with his strong visual memory and/or semantic ‘bootstrapping’?

CA:15;0yrs, RA 10;0 yrs

  • Very poor non-word reading persisted.
  • Read irregular words as well as regular.
  • Despite severe and persisting phonological difficulties and persistent problem with spelling, graduated with Psychology degree.

Dyslexia in deaf children?

Issues of measurement & interpretation

  • Most tests measure bottom up skills only.
  • Lack of tests developed for deaf children.
  • Lack of deaf norms.

Case study: X, aged 12 when referred for poor literacy.

  • Deafness identified at 3 years.
  • Auditory neuropathy: inconsistent auditory responses to PTA, inability to process complex linguistic information.
  • No longer wears hearing aids.
  • Only deaf family member.

Early development

  • Early development other than communication within normal limits.
  • History of challenging behaviour.
  • Initial query of autism.
  • Family history of dyslexia: mother, sister

Communication and education

  • Introduced to BSL at age 4
  • Communicated using a mixture of BSL and Sign Supported English (SSE)
  • BSL/SSE used at home
  • Attended a resource for hearing impaired children
  • The only deaf child in his class, supported by CSWs and TOD
  • Uneven SATs profile - English 1A, Maths 3A, Science 5C

BSL Test Scores

BSL Receptive Skills Test (Herman et al 1999) 112 Within normal limits for 9-11 year olds
BSL Production Test
(Herman et al 2004)
   
Narrative Content 25th centile Low average for 9-11 year olds
Narrative Structure 50th centile Average for 9-11 year olds
BSL Grammar 10th centile Below average for 9-11 year olds

Profile on psychometric tests - dyslexia?

  • CA: 12 yrs
  • IQ high: WISC-IIIUK nonverbal 123
  • Reading and spelling significantly below expected level (<6;0 – 6;9)
  • Problem learning common sequences
  • Immediate and delayed spatial recall of visual material excellent
  • But immediate verbal recall of same material significantly weaker

Scores on non-verbal subscales - dyslexia?

nonverbal scores

Verbal fluency scores: X and ‘good’ deaf readers

  • NB and ‘good’ DRs achieved average scores for semantically cued words.
  • Fluency scores for phonologically cued words were lower.
  • NB’s scores for phonologically cued words were lower than the average scores for ’good’ DRs.

verbal fluency scores

Positive indicators of dyslexia

  • Genetic background: dyslexia in first degree relatives
  • Good visuo-spatial skills
  • Poor phonological skills and phonological awareness
  • Selective impairment in verbal fluency

But…

  • Wide variability in these skills even amongst ‘good’ deaf readers

Intervention studies with hearing children & identification of dyslexia (Velluntino et al 1996)

  • Longitudinal study of 118 poor readers followed from kindergarten to 4th grade
  • Tutored daily (1 to1) for half a year in grade 1
  • 2/3 tutored children in normal range after half a year of remediation
  • 15% made very poor progress
  • ‘Dyslexic’ children vs those who improved
    Poor phonological skills: poor verbal STM, poor PA and rapid naming skills but
    IQ, semantic processing, visual skills, attention and planning did not differ.

Diagnosis of dyslexia in DC – implications?

  • Identification
  • Resources
  • Intervention
  • Research

Dyslexia support for NB

  • Input from a literacy specialist.
  • Opportunities for repetition.
  • Access to computerised/multi-sensory literacy programmes.
  • Feedback on his progress (visual).
  • Opportunities to consider the benefits to himself of improving his literacy skill.
  • Signer-writer support in class and in examinations so he can convey his knowledge fully.