Speech Sound Disorders: Red Flags for Literacy Problems

transcript

Speech Sound Disorders: Red Flags

for Literacy Problems

Jonathan Preston Mary Louise EdwardsHaskins Laboratories Syracuse University

preston@haskins.yale.edu mledward@syr.edu

Outline

• Defining speech sound disorders (SSD), phonological processing, literacy

• Known risk factors: Which children with SSD are likely to have literacy problems?

• Types of speech errors

• Relating speech errors to phonological processing in preschoolers with SSD

• Summary

Outline

Speech Sound Disorders (SSDs)

• Difficulty producing and/or using the sounds of the adult language, in comparison to peers.

• Includes both “articulation” and “phonology,” as well as possible cases of CAS.

• Does not include (in this study) SSDs with a clear etiology.

Prevalence of SSDs

• Approximately 32% of all communication disorders are SSDs (Slater, 1992).

• 2% ‐ 6 % of school‐age children have SSDs.

• Many children with SSDs also have language problems; estimates from 35 ‐ 50% (Tyler, 2002) to 75% ‐ 85% (Shriberg & Kwiatkowski, 1988).

SSDs and Literacy

• Phonologically‐based reading and spelling skills are often lower for individuals with a histories of SSDs (Lewis & Freebairn, 1992).

• 50‐75% of children with SSDs have been found to have long‐term academic problems (Lewis et al., 2006).

Some Early Predictors of Literacy Acquisition

• Phonological awareness

• Phonological (short‐term) memory

• Phonological recoding in lexical access

Phonological Processing

Phonological Awareness

Phonological Memory Rapid Naming

Literacy

Phonological Awareness

• The awareness of speech sounds and the ability to reflect on and manipulate them (Tunmer, Pratt & Herriman, 1984).

• Involves abilities such as rhyming, segmenting, blending, and manipulating sounds (e.g., moving or reversing sounds).

Phonological Awareness and Literacy

• Phonological awareness is a critical skill for literacy development.

• Performance on phonological awareness tasks is a good predictor of future reading ability (Webster & Plante, 1992).

• 2/3 of children with SSDs between the ages of 3;6 and 16 have low PA (Broomfield & Dodd, 2005).

Phonological (Short‐Term) Memory

• Temporary storage/retention of speech sound information (Baddeley, 2003).

• Assessed by tasks such as repetition of syllables or nonwords.

Phonological Recoding in Lexical Access

• Often referred to as Rapid Naming (RN)

• Assessed by tasks that involve rapidly naming pictures of familiar objects, letters, etc.

• Relationship with reading skills, especially reading fluency

Outline

Syllable/Rhyme-Level Awareness

Phoneme-Level Awareness

Reading/Spelling

Which children with SSD are most likely to have literacy problems?

• Co‐occurring Language Impairment– Robust evidence suggesting SSD + LI = increased

risk for literacy problems (Catts, 1993; Lewis et al., 2004; Nathan et al., 2004)

Reading/Spelling

Syllable/ RhymeLevel Awareness

PhonemeLevel

Awareness

Syllable/ Rhyme-Level

Awareness

Phoneme-Level Awareness

Reading/Spelling

Which Language Skills?

• Much research indicating that, for children with SSD, language skills predict additional variance in phonological processing and literacy scores

• Semantics• Receptive vocabulary explains ~25% of variance in PA in preschoolers (Rvachew & Grawburg, 2006; Preston & Edwards, in press)

• Age 5‐6 semantics composite score significantly predicts age 7‐9 literacy and PA (Peterson et al. 2009)

Which Language Skills?

• Morphosyntax• Age 4 ½ MLU strong predictor of age 8 ½ reading (Bishop &

Adams, 1990)

• Age 5‐6 Expressive Syntax score explains significant variance in 7‐9 yr PA and reading skills; speech skills only weakly predicted PA (Peterson et al., 2009)

• CELF Word Structure and Recalling Sentence scores related to Reading Recognition & Reading Comp in children grades K‐2 (r>.57) (Bernhardt & Major 2005)

Which Children with SSD are most likely to have literacy problems?

• Nonverbal Cognition– Nonverbal IQ found to relate to reading outcomes in children with SSD (Bird et al., 1995; Peterson et al., 2009)

– Index of general developmental delay?

Which Children with SSD are most likely to have literacy problems?

• Speech perception – Preschool speech perception (as assessed by SAILS) predicted kindergarten PA (Rvachew, 2006)

– Perception problems poor phonological representations?

• Persisting Speech Problems– Case Studies (e.g., Stackhouse, 1997)

– Lower PA scores for children ~6 yrs who still have a SSD vs. those whose SSD normalized (Nathan et al., 2004; Raitano et al., 2004)

– Children ages 10‐14 with residual rhotic errors showed deficits in phonological awareness, phonological memory, and rapid naming (Preston & Edwards, 2007, 2009)

• Childhood Apraxia of Speech– A neurological childhood (pediatric) speech sound disorder in which the precision and consistency of movements underlying speech are impaired in the absence of neuromuscular deficits (e.g., abnormal reflexes, abnormal tone) (ASHA, 2007)

• Clinical and theoretically important– Motor‐based disorder resulting in problems with phonological bases of literacy

• Childhood Apraxia of Speech– Children ages 6‐11 with CAS below controls on reading and spelling (Stackhouse, 1982)

– Preschoolers with SSD followed to ages 8‐9. CAS < S+LI < S only on spelling and reading comprehension (Lewis et al., 2004)

• Severity– Inconsistent Findings: not strongly predictive of phonological awareness or literacy skills if speech is measured using standardized tests or PCC (Peterson et al., 2009; Preston, 2008; Rvachew, 2006, 2007; Smith et al., 2005)

– Is this a measurement issue?

SSD Severity and PASTUDY AGES N SPEECH MEASURE PA MEASURE Correlation

rPreston & Edwards (in press)

4-5 yr 43 GFTA-2 standard score PA Principal Component (.15)PCC (.22)

Bird & Bishop (1992) 5-6 yr 14 Percent distinctive features correct Onset identification .60Onset segmentation and matching

Rhyme judgment (.35)Rhyme generation (.42)

Major & Bernhardt (1998)

3-4 yr 19 PCC-R Metaphonology composite ρ=.57Cons Matches ρ= .47

ρ=.64Percent Vowels CorrectWord shape match ρ=.62CVC matches ρ=.52CVCV matches (<.47)

Nijland (2009) 21 PCCPercent Vowels Correct

Rhyme judgment ρ=.48ρ=.54

Smith et al (2005) 5-8 yr 187 GFTA cons errors Phonological Awareness Principal Component

-.31zPCC-R .10Speech1 (log odds of SSD, composite of 7 variables) -.09Speech2 (probability of SSD, composite of 7 variables) -.11

Rvachew (2006) Pre-K Kinder.

47 GFTA-2 cons errors (Pre-K) Phonological Awareness Test –Pre-K

GFTA-2 cons errors (Kinder.)

GFTA-2 cons errors (Pre-K)

Phonological Awareness Test–Kinder.Phonological Awareness Test–Kinder.

-.54(-.38)

Rvachew (2007) Pre-K Gr.1 68 GFTA-2 cons errors (Pre-K) Phonological Awareness Test –First Grade

Rvachew et al (2004) 3-4 yr 34 GFTA-2 cons errors Phonological Awareness Test (-.23)Webster & Plante (1992) 6-8 yr 22

(11 SSD)Number of intelligible words Pseudoword segmentation

Word-syllable segmentationWord-phoneme segmentation

.62(.32).77

Correlation Coefficients: Severity and PA

00.10.20.30.40.50.60.70.80.9

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26

SSD Severity and Literacy

STUDY AGES N SPEECH MEASURE LITERACY MEASURE

CORR.r

Catts (1993) Kinder. Gr.1 56 GFTA consonant errors Word Attack (<.29)

Word Identification (<.29)Stein et al (2004) Pre-K SSD &

siblings177 PCC in conversation Word Attack .18

Word Identification .12188 GFTA percentile Word Attack .13

Word Identification .19Rvachew (2007) Pre-K Gr.1 68 GFTA-2 errors (Pre-K)

PCC (Pre-K)First Gr sight word reading

(-.16) (.10)

GFTA-2 errors (Pre-K)PCC (Pre-K)

First Gr nonword reading -.39.30

Lewis et al 2002 ~9 yrs 52 GFTA percentile Test of Written Spelling 3TotalPredictibleUnpredictible

Webster & Plante(1992)

6-8 yrs 22 (11 SSD)

Number of intelligible words

Printed word recognition (.35)

Correlation Coefficients: SSD Severity and Literacy

00.10.20.30.40.50.60.70.80.9

1 2 3 4 5 6 7 8 9 10 11 12 13 14

Theoretical Argument

Is there a common mechanism that underlies speech sound production and (pre)literacy?

One possibility: Accuracy of Phonological Representations (Bird et al., 1995; Rvachew et al., 2003, 2004; Rvachew & Grawburg, 2006; Senechal et al., 2004; Sutherland & Gillon, 2005)

In production, poorly specified phonological representations may be indicated by atypical(unusual) speech sound errors

Outline

• Summary

Types of Speech Sound Errors

• In the present study speech sound errors are classified as:

– Typical error patterns

– Atypical error patterns

– Distortions 31

Typical Error Patterns

• Common in typical phonological development, e.g.,

‐ Final Consonant Deletion

‐ Cluster Reduction

‐ Velar Fronting

‐ Stopping of Fricatives

‐ Gliding of Liquids

Atypical Error Patterns

• Unusual or not commonly observed in typical phonological development, e.g.,

‐ Initial Consonant Deletion

‐ Cluster Production

‐ Backing to Velars

‐ Glottal Replacement

Distortions

• Errors that are within the correct phoneme category (sub‐phonemic), e.g.,

‐ Dentalization

‐ Lateralization

‐ Labialization

‐ Derhotacization (of /r/)

Research on Types of Speech Sound Errors & PA

• Mixed results re: phonological processing & error types– Trend for 6 yr olds with SSD & low PA to produce more

“atypical”/unusual errors (Leitao et al. 1997)

– no statistics, just observations

– Children with more atypical errors at 6 yrs scored lower on phonological processing at 12‐13 yrs (Leitao et al., 2004)

– n= 7 per group, did not consider vocabulary differences

• Preschoolers with low PA had more “typical” omissions than preschoolers with normal PA (Rvachew et al., 2007)

• Kindergarteners with low PA had more “atypical” substitutions than peers with normal PA (Rvachew et al., 2007)

Outline

• Summary, Questions

The Current Study

• Is the relative occurrence of different types of speech sound errors related to phonological processing in preschoolers with SSD? – Considers both the frequency and types.

• Theoretical assumption: poorer performance on phonological processing tasks and less precise speech sound output both reflect weaker phonological representations

Participants

• Monolingual English speaking children with SSD of unknown origin– Primarily clinical referrals

• Ages 4 – 5

• Not yet in kindergarten

Part I: Screening, n=51

• Speech Sound Production– Goldman‐Fristoe Test of Articulation‐2 <90

• Oral Mechanism Screening, Hearing Screening

• Receptive Language (met at least 2 of 3 criteria)

– Peabody Picture Vocabulary Test‐4 >80– Clinical Evaluation of Language Fundamentals: Preschool‐2

• Sentence Structure subtest >6• Concepts & Following Directions subtest >6

• Nonverbal Cognition– Differential Ability Scales Pattern Construction Subtest T score >37

Part II: Experimental Measures,n=43

• Speech sound production– 125 word picture naming task (480 consonants) – Digitally recorded, phonetically transcribed

• Analysis of speech sound errors: • Percent Consonants Correct (PCC)

and• Frequency of Different Types of Errors

– Distortions per consonant– Typical sound changes per consonant– Atypical sound changes per consonant

Experimental Measures: Part II

Phonological Awareness– Adapted from previous research (Bird et al., 1995; Rvachew

& Grawburg, 2006)

– All early predictors of later literacy– All require nonverbal responses– Tasks assess:

• Rhyme• Onset Matching• Onset Segmentation & Matching• Blending

• 16 items

Onset Segmentation and Matching

10 items

Onset Matching

10 items

Blending

• 12 items:

– 6 items spoken in two parts (onset‐rhyme): C – VC

– 6 items spoken in three parts: C ‐ V ‐ C

Phonological Memory

• Syllable Repetition Task (Shriberg et al., 2006, 2009)

– 2 ‐ 4 syllable sequences• Included /ba, na, da, ma/

– Example• /naba, daba, nada, maba/

Rapid Naming

• Monosyllabic: 5 pictures repeated 6 times in different sequences

• Disyllabic: 5 pictures repeated 6 times in different sequences

Example

Data Analysis

• Correlational design to examine concurrentrelationships between speech sound production and phonological processing

RESULTS: Summary of PA tasks

• Principal Component Analysis summarized four Phonological Awareness Tasks

Phonological Awareness Composite (Principal Component)

Sound Error Types per Consonant

Results: PA

DistortionsTypical Sound Changes

Atypical Sound Changes

Correlation with PAnsns

r = -0.36

Results: PA

• Types of errors that reflect weak phonological representations will predict variance in PA beyond receptive vocabulary and age

Variance in Phonological Awareness

Note: values are adjusted R2

Results: PA

Typical Sound Changes

Distortions

Atypical Sound Changes Age & Vocab33%

Results: PA

Distortions

Age & Vocab33%

Results: PA

• Types of errors that reflect weak phonological representations will better explain variance in PA than will PCC.

Age & Vocab33%*

PCC = 0% change

Variance in Phonological Memory

(Syllable RepetitionTask)

Results: Phonological Memory

• An analysis that considers three types of sound changes will predict variance in phonological memory beyond age and receptive vocabulary.

Distortions

Age & Vocab (nonsig)

Distortions

Age & Vocab (nonsig)

30.8%*

Results: Rapid Naming

• An analysis that considers three types of sound changes will predict variance in rapid naming beyond age and receptive vocabulary.

Variance inRapid Naming

Distortions

Age & Vocab (nonsig.)

Distortions

Age & Vocab (nonsig.)

5.3%9.9% *

Outline

• Summary

Summary

• More atypical sound changes associated with lower performance in 3 phonological processing domains (phonological awareness, phonological memory, rapid naming)

– Implications for early literacy problems

– May be diagnostically useful for SLPs

– May help to explain some inconsistencies reported in other studies relating SSD and phonological processing

• Distortions and typical sound changes were notassociated with phonological processing

• Caveat: Still assess phonological processing in ALL preschoolers with SSD

Overall Summary• Based on existing literature, children with SSD most at risk for (pre)literacy problems would include:

– Co‐existing language impairment

– Childhood Apraxia of Speech

– Persisting speech problems (~6 yrs and beyond)

– Low Nonverbal IQ

– Speech perception deficits

– Severity?

– Many Atypical errors 70

Where do we go next?

• SSD and literacy problems: Etiological similarities and differences

• Better measurement and classification of SSD– Error patterns can be informative

• Neural phenotypes: what can the brain tell us about how these cognitive skills are related or how subgroups might be defined? Can neural characteristics help predict outcomes?

Acknowledgements

• American Speech‐Language Hearing Foundation Student Grant in Early Childhood Language Development

• NIH Training Grant to Haskins Laboratories (C. Fowler, PI) T32 HD 7548‐8

Thank You!

Questions?

Speech Sound Disorders: Red Flags for Literacy Problems

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