Early Identification and Intervention for Children with Reading Difficulties. Deborah Knight CHERI Conference September, 2005

Transcription

1 Early Identification and Intervention for Children with Reading Difficulties Deborah Knight CHERI Conference September, 2005

2 The Case for Early Intervention! Chronicity probability that a Year 1 reader will remain a poor reader in Year 4 =.88 (Juel, 1988)! Increasingly restricted access to the curriculum - ramifications for broader knowledge base and associated cognitive skills! Elevated risk for development of emotional and behavioural difficulties

3 Prediction- Historical Overview Efforts to identify predictive variables driven by available, often disparate theoretical ideas. Broad based perceptual difficulties: Smith (1928) ability to match letters in early Year 1 predicted word reading skills in late Year 1 Monroe (1935) pre-reading battery included measures of oculomotor control, attention, motor skills, auditory discrimination, vocabulary Visual perceptual difficulties: Bond & Dykstra (1967) familiarity with print, auditory visual discrimination Frostig battery visual closure, figure ground discrimination

4 Early neuropsychological models: Satz et al (1978): visual perceptual skills, vocabulary, alphabet recitation, SES Silver & Hagin (1975): auditory & visual discrimination, finger agnosia, praxis, right-left discrimination Ill defined constructs, batteries proved to have limited predictive validity.

5 Phonological Processing Deficits Reading and spelling difficulties exist on the continuum of developmental language disorders. Primary difficulty arises from weaknesses in encoding and processing the phonological or speech sounds of the child s language. Compromises child s ability to efficiently convert letters or groups of letters into the speech codes they represent.

6 Phonological Processing Deficits Affected children experience difficulties forming and maintaining clear representations of speech sounds. Phonological codes (cognitive structures that aid in the perception and production of speech sounds) - fuzzy, indistinct or unstable. Sluggish and inaccurate processing of speech sounds difficulties in developing an awareness of the sound structure of words and in establishing reliable and easily accessible links between written and spoken language ie cracking the alphabetic code.

7 Lexical Restructuring Hypothesis (Metsala & Walley,1998) Input Output Phonological Representations Rapid growth in vocabulary increasing pressure during early childhood for sound structure of words to be represented in ways that make words readily distinguishable. whole word - shallow levels normally develops during syllable preschool years via natural language onset rime experiences phoneme - deeper levels - develops through exposure to text and instruction

8 Poorly specified phonological codes Poor phonological awareness: capacity to reflect on and manipulate (segment & blend) sounds within words Slow naming speed & laboured retrieval of sounds: Phonological codes activated too slowly to permit efficient encoding of letter combinations found in words. Constrains reading fluency due to slower individual word recognition. Verbal working memory deficits: Laboured access to speech codes poor blending skills and difficulties assembling sound units in words. Difficulties in speech perception and production

9 Early Identification Studies Unselected samples At risk samples: Children with speech and language difficulties -at a 4 to 5 fold risk of developing reading difficulties vs unaffected children Children with a family history of reading difficulties around a 40-50% risk for the child Model: administer measures prior to start of formal instruction and track reading progress over time.

10 Skills that underpin normal reading development are also the best predictors of impaired development. Phonological Awareness: assumes predictive power in late preschool period; continuity found in development from shallow (word, syllable, onset-rime segmentation) to phonemic sensitivity. Tasks: rhyme oddity detection (boat, snail, nail) alliteration oddity detection (car, cat, sun) blending syllables & phonemes elision (say a word then delete syllable or phoneme)

11 Letter Name Knowledge in late preschool/early K a potent predictor of reading competence in Year 1. Assists learning of letter sounds and associated development of phonemic sensitivity. Naming speed RAN digits. Provides an index of the child s capacity to quickly retrieve sound based material from memory. Oral language skills vocabulary level, syntactic and narrative skills.

12 RAN task o a s d p a o s p d s d a p d o a p s o a o s p s d p o d a d a p o d s a s o p o a d s d p o a p s

13 Does prediction change over time? Late preschool: oral language measures exert a sizeable effect (around 25-40% variance) on later (Y1) reading competence. : letter name knowledge : phonological awareness combined provide substantial predictive relevance (approx. 50% variance in K & Year 1 decoding skills)

14 Kindergarten: 3 skill areas consistently shown to have strong predictive relevance for Year 1 and Year 2 word recognition and reading comprehension skills.! Phonological awareness! Letter name knowledge (early K) Letter sound knowledge (late K)! Letter naming speed Together explain between 40 60% variance in Year 1 reading. Predictive power diminishes over time - 30% in Year 2. No significant contribution found for IQ, non-verbal skills or print concept knowledge.

15 Oral language (vocabulary and syntactic) skills reemerge as again predictive around Year 3 with increased demands on more complex text comprehension. Current measures administered in Kindergarten tend to yield high rate of false positives. Difficulties offset by early introduction of code-based instruction and regular monitoring of the children s progress throughout the course of instruction.

16 Prediction for at risk children Children with speech and language difficulties at inflated risk of literacy problems. Evident for both receptive and expressive domains. Reduced vocabulary early on impedes development of finer representational codes and later understanding of more complex text; expressive difficulties compromise formation of stable and distinct phonological codes and ease of access to these codes. Identified markers for speech and language impaired children in K similar to those in randomly selected samples. - letter identification, phonological awareness, rapid naming, sentence imitation. Probability equation including above variables plus maternal education level yielded 93.3% hit rate in identifying Y2 reading difficulties from K administered measures (Catts et al, 2001).

17 Scarborough (1990) Children at genetic risk 32 2 year olds, family history of RD vs control children At age 8 years - 65% (20 children) exhibited RD at 30 months - more speech production errors - poorer syntax at 36 & 42 months - less well developed vocabulary - persistent syntactic difficulties at 5 years - poorer letter knowledge - poorly developed phonological awareness - expressive naming difficulties

18 Preschool (2-4 years) - poor speech production - weak vocabulary - syntactic weaknesses Late Preschool Early Schooling (4-6 years) - letter name knowledge - phonological awareness - naming speed - speech perception & production - vocabulary Family risk continuity (Byrne et al, 1997; Locke et al, 1997; Elbro et al, 1998; Gallagher et al, 2000; Pennington & Lefly, 2001; Lyytinen et al, 2001; Molfese et al, 2001; Snowling et al, 2003)

19 At risk markers: Family history of reading difficulties Delayed speech and language development slow vocabulary development, poor expressive language, weak syntax Persistent problems with sound processing, inconsistent speech production Problems mastering production of new words Poor phonological sensitivity Evident naming, word retrieval difficulties Difficulty learning the alphabet Poor invented spelling

20 Early ID Measures - articulation accuracy - phoneme identification & deletion - naming speed tasks - repetition of non-words - letter name /letter sound knowledge Available tests: DIBELS CTOPP (Pro-Ed) PhAB (ACER) SPAT -R

21 Intervention Lundberg s work (1988)- phonological awareness training for K children, oral based Bryant & Bradley (1985) training in pa integrated with letter-sound correspondences; sound categorisation skills Byrne et al (1989, 1990) Preschool children. Taught articulatory cues for production of sounds; phoneme identity training, letter-sound mappings. Ball & Blachman (1991) Say It & Move It, lettersound training together with explicit training in segmentation strategies

22 Programs vary in level of phonological sensitivity addressed, whether phoneme-grapheme connections are taught, degree to which decoding strategies are included. Evidence for young children (preschool, early K) training of phonological awareness can significantly enhance children s phonemic sensitivity (av. effect size.86); longer term effects on word reading ability (decoding skills) evident through primary schooling. (Byrne & Fielding-Barnsley,2000; Elbro & Petersen, 2004)

23 Indicators: training at phoneme level more effective vs rhyme identity & production :better outcomes when letter-sound mappings are trained : inclusion of articulatory cueing probably beneficial : group instruction for young children as effective as individual training Not a guaranteed innoculation effect, particularly for at risk children. Proportion of children who show limited or no improvement in pa. Identified predictors - pretraining pronunciation quality and phoneme discrimination.

24 School-aged samples: Substantial evidence supporting efficacy of explicit training in letter sound knowledge, phonological awareness and phonemic decoding strategies for promoting reading development. (Vellutino et al, 1996; Foorman et al, 1998; Torgesen, 1999, 2000). Direct code instruction (teaches letter-sound correspondences, phonemic awareness, blending skills, provides practice with phonetically controlled text, writing) produces stronger reading growth for children with phonological weaknesses vs indirect, text level instruction

25 Instruction should commence early to minimise effects on fluency of reduced successful exposure to text. Improved decoding skills promote development of text comprehension Outcomes support efficacy of a range of instructional contexts: whole class, small group, individualised What about the treatment resisters? Typically between 2-6% of children.

26 Remediation vs Prevention Remediation Prevention Y3 Y6 (67.5 hours) mid K Y2 (88 hours) Pre 2yr FU Y2 Y4 Text Rate Text Accuracy Word Attack Word Ident