Non-Word Repetition (NWR) - Is it a linguistic marker of SLI



Non-Word Repetition (NWR) - Is it a linguistic marker of SLI?

Reading: Graf Estes, K. Evans, J. & Else-Quest, N. 2007. Differences in the Nonword Repetition: Performance of Children With and Without Specific Language Impairment: A Meta-Analysis. Journal of Speech, Language and Hearing Research, 5,177-195

Children with Specific Language Impairment show difficulties in repeating multisyllabic non-words (Bishop, North, & Donlan, 1996; Dollaghan & Campbell’ 1998; Edwards & Lahey, 1998; Ellis Weismer et al., 2000; Gathercole & Baddeley, 1990; Montgomery, 1995), with a significant chromosome linkage (The SLI Consortium 2002, 2004)

What is a Non-Word Repetition task?

In a non-word repetition task the child in asked to repeat non-words on 1-5 syllables, with or without a cluster at the onset, middle or coda.

Sample words for English (from GAPS - GRAMMAR AND PHONOLOGY SCREENING TEST, van der Lely): dep, pif, dremp, klest, tobilf, difimp, bademper, fakester, padrepper, difrimple

What contributes to the complexity of these words? Are they English like? Could they be used as is in a Hebrew test? Which considerations should apply?

What is NWR testing?

Phonological working memory (phonological loop)

“Working memory (WM) according to Baddeley (1986) is a multicomponent, capacity-limited system that comprises a controlling ‘‘central executive’’ and that includes an articulatory loop system. The central executive ... is thought to regulate information flow within WM, retrieval of information from other memory systems, and the processing and storage of information. The articulatory loop … includes a capacity-limited phonological short-term store and an articulatory control process … that acts to refresh and maintain speech material in the store for a brief period. The articulatory loop’s function is to store verbal input temporarily, especially novel phonological input (Baddeley, Gathercole, & Papagno, 1998), while other cognitive tasks such as auditory comprehension take place. The ability to temporarily store novel material also allows the listener the opportunity to create long-term phonological representations of that material (Baddeley et al1998).” (Montgomery 2003, p. 222)

Digit Span

Gray, S. 2003. Diagnostic accuracy and test-retest reliability of nonword repetition and digit span tasks administered to preschool children with specific language impairment. Journal of Communication disorders 36, 129-151

| |Digit Span |NWR [N=20] |

| |Mean |S.D. |

|# of words |40 |16 |

|# of Syllable |2-5 |1-4 |

|Clusters |+ |- (CV structure, no late acquired phonemes) |

|Weak syllable with reduced vowels (hampent) |+ |- (acoustically salient only) |

|Lexical components (morphemes) |+ |- |

|Prosodic pattern |Natural for English |Equal stress on each syllable |

|Score |Online (correct/incorrect) |From transcription (percentage of correct phoneme) |

|Test |Morpho/Lexical abilities + …. |Basic phonological processing or memory skills |

Hypothesis:

If ____________________________________

then ______________________________________

0-Hypothesis:

If ____________________________________

then ______________________________________

Archibald, L. M. D. & Gathercole, S. E. 2006. Nonword repetition: A comparison of tests. Journal of Speech, Language and Hearing Research, 49:5, 970-983.

Subjects: 36 native speakers: 12 SLI (9;8), 12 TD age (9;9), 12 TD language (6;1). Same SES

Scores on standardized test:

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Findings

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Within group: CNRep is easier than NRT

Across group: The gap is more significant on CNRep

What influences these results?

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What do the findings tell us about the predictions?

Graf Estes, K. Evans, J. & Else-Quest, N. 2007. Differences in the Nonword Repetition: Performance of Children With and Without Specific Language Impairment:A Meta-Analysis. Journal of Speech, Language and Hearing Research, 5,177-195

1. Are all versions of the nonword repetition task interchangeable?

2. Are there age differences in the magnitude of the nonword repetition deficit in children with SLI?

3. Are there circumstances under which the nonword repetition skills of children with SLI are comparable to those of children with NL?

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• Dissimilar effect sizes for the nonword repetition deficit in SLI >> “design characteristics of the measures affect performance and indicate that the measures are not interchangeable gauges of the same deficit.” (p.182)

• Similar magnitude effect sizes >> “despite differences in the characteristics of the measures such as wordlikeness, complexity, and nonword length, the magnitude of the difference between children with and without SLI is robust.” (p 182)

Effect size (d), is the difference between the scores of control group (children with NL) and children with SLI, divided by the pooled/mean standard deviation for both groups.

d = (Mean Control – Mean SLI) / Mean SD (within group)

Positive effect sizes indicate higher performance by control group children (d = 1.0 indicates that children with NL performed one standard deviation better than children with SLI).

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The magnitude of this deficit varied significantly across studies. Children with SLI performed between 0.62 (Washington&Craig, 2004) and 4.34 standard deviations (Gathercole & Baddeley, 1990) below children with NL.

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1) Measures of nonword repetition are not interchangeable. The CNRep and the NRT yielded the most extreme effect sizes.

2) No significant relation between effect size and the age of children in the SLI samples.

3) Children with SLI were impaired at all nonword lengths, with significantly greater deficits for longer nonwords (three and four syllables) than for shorter nonwords (one and two syllables).

“The CNRep may differentiate some groups of children with and without SLI to a greater degree than the NRT. The CNRep could tap subtle articulation difficulties and a lack of support from lexical or sublexical mediation, in addition to problems with phonological memory resources ... It suggests that measures that compound influences on performance promote the largest differences in performance between children with and without language impairments.” (p. 193)

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