Working memory and novel word learning in children with hearing impairment and children with specific language impairment

Speech and language development in a population of Swedish hearing-impaired pre-school children, a cross-sectional study

OBJECTIVE

There is little information on speech and language development in pre-school children with mild, moderate or severe hearing impairment. The primary aim of the study is to establish a reference material for clinical use covering various aspects of speech and language functions and to relate test values to pure tone audiograms and parents' judgement of their children's hearing and language abilities.

METHODS

Nine speech and language tests were applied or modified, both classical tests and newly developed tests. Ninety-seven children with normal hearing and 156 with hearing impairment were tested. Hearing was 80 dB HL PTA or better in the best ear. Swedish was their strongest language. None had any additional diagnosed major handicaps. The children were 4-6 years of age. The material was divided into 10 categories of hearing impairment, 5 conductive and 5 sensorineural: unilateral; bilateral 0-20; 21-40; 41-60; 61-80 dB HL PTA. The tests, selected on the basis of a three component language model, are phoneme discrimination; rhyme matching; Peabody Picture Vocabulary Test (PPVT-III, word perception); Test for Reception of Grammar (TROG, grammar perception); prosodic phrase focus; rhyme construction; Word Finding Vocabulary Test (word production); Action Picture Test (grammar production); oral motor test.

RESULTS

Only categories with sensorineural loss showed significant differences from normal. Word production showed the most marked delay for 21-40 dB HL: 5 and 6 years p<0.01; for 41-60 dB: 4 years p<0.01 and 6 years p<0.01 and 61-80 dB: 5 years p<0.05. Phoneme discrimination 21-40 dB HL: 6 years p<0.05; 41-60 dB: 4 years p<0.01; 61-80 dB: 4 years p<0.001, 5 years p<0.001. Rhyme matching: no significant difference as compared to normal data. Word perception: sensorineural 41-60 dB HL: 6 years p<0.05; 61-80 dB: 4 years p<0.05; 5 years p<0.01. Grammar perception: sensorineural 41-60 dB HL: 6 years p<0.05; 61-80 dB: 5 years p<0.05. Prosodic phrase focus: 41-60 dB HL: 5 years p<0.01. Rhyme construction: 41-60 dB HL: 4 years p<0.05. Grammar production: 61-80 dB HL: 5 years p<0.01. Oral motor function: no differences. The Word production test showed a 1.5-2 years delay for sensorineural impairment 41-80 dB HL through 4-6 years of age. There were no differences between hearing-impaired boys and girls. Extended data for the screening test [E. Borg, A. Risberg, B. McAllister, B.M. Undemar, G. Edquist, A.C. Reinholdsson, et al., Language development in hearing-impaired children. Establishment of a reference material for a "Language test for hearing-impaired children", Int. J. Pediatr. Otorhinolaryngol. 65 (2002) 15-26] are presented.

CONCLUSIONS

Reference values for expected speech and language development are presented that cover nearly 60% of the studied population. The effect of the peripheral hearing impairment is compensated for in many children with hearing impairment up to 60 dB HL. Above that degree of impairment, language delay is more pronounced, probably due to a loss of acuity. The importance of central cognitive functions, speech reading and signing for compensation of peripheral limitations is pointed out.

Working memory involvement in stuttering: exploring the evidence and research implications

Several studies of utterance planning and attention processes in stuttering have raised the prospect of working memory involvement in the disorder. In this paper, potential connections between stuttering and two elements of Baddeley's [Baddeley, A. D. (2003). Working memory: Looking back and looking forward. Neuroscience, 4, 829-839] working memory model, phonological memory and central executive, are posited. Empirical evidence is drawn from studies on phonological memory and dual-task performance among children and adults who stutter to examine support for the posited connections. Implications for research to examine working memory as one of the psycholinguistic bases of stuttering are presented.

EDUCATIONAL OBJECTIVES

The reader will learn about and be able to: (1) appraise potential relationships between working memory and stuttering; (2) evaluate empirical evidence that suggests the possibility of working memory involvement in stuttering; and (3) identify research directions to explore the role of working memory in stuttering.

Clinical markers for specific language impairment in Italian: The contribution of clitics and non-word repetition

BACKGROUND

The discovery of clinical markers for specific language impairment (SLI) in children can assist in the accurate identification of children with this disorder, and in a description of the disorder's phenotype for genetic study. One challenge to this type of research is the fact that languages vary in the most salient symptoms of SLI. This study focuses on Italian.

AIMS

To determine whether three measures--the use of third-person plural inflections, the use of direct-object clitics and non-word repetition--are successful in distinguishing Italian-speaking children with SLI from their typically developing peers.

METHODS & PROCEDURES

Eleven preschool-aged children with SLI, 11 same-age typically developing peers and 11 younger typically developing children participated in the study. The third-person plural inflection and direct-object clitic tasks required the children to describe drawings in response to prompts provided by the examiner. In the non-word repetition task, the children repeated non-words ranging from one to four syllables in length.

OUTCOMES & RESULTS

All three measures proved successful either singly or in combination, with direct-object clitics and non-word repetition showing the highest sensitivity and specificity.

CONCLUSIONS

Additional research should be pursued to replicate and extend these findings. Along with the potential clinical value of the findings, the results suggest that difficulties with non-final weak syllables--a problem that would adversely affect all three measures--may be an important part of the SLI profile in Italian.

Nonword repetition and sentence repetition as clinical markers of specific language impairment: the case of Cantonese

PURPOSE

Recent research suggests that nonword repetition (NWR) and sentence repetition (SR) tasks can be used to discriminate between children with SLI and their typically developing age-matched (TDAM) and younger (TDY) peers.

METHOD

Fourteen Cantonese-speaking children with SLI and 30 of their TDAM and TDY peers were compared on NWR and SR tasks. NWR of IN nonwords (CV combinations attested in the language) and OUT nonwords (CV combinations unattested in the language) were compared. SR performance was compared using 4 different scoring methods.

RESULTS

The SLI group did not score significantly lower than the TDAM group on the test of NWR (overall results were TDAM = SLI > TDY). There were nonsignificant group differences on IN syllables but not on OUT syllables. The results do not suggest a limitation in phonological working memory in Cantonese-speaking children with SLI. The SR task discriminated between children and their TDAM peers but not between children with SLI and their TDY peers matched for mean length of utterance.

CONCLUSIONS

SR but not NWR discriminates between children with SLI and their TDAM peers. Poorer NWR for English-speaking children with SLI might be attributable to weaker use of the redintegration strategy in word repetition. Further cross-linguistic investigations of processing strategies are required.

Genetic influences on language impairment and phonological short-term memory

It has been known for some years that specific language impairment (SLI), an unexpected failure to acquire age-appropriate language skills, is highly heritable. However, molecular genetic studies have been hampered by the heterogeneity of the disorder and the predominant lack of clear genotype-phenotype relationships. We review recent studies suggesting that a better understanding of the genetics of SLI might emerge if we move away from clinical criteria for diagnosis to look instead at a theoretically based quantitative and cognitive measure of the phenotype: a test of phonological short-term memory (STM). Deficient phonological STM has been linked to specific genetic loci, and might play a role in determining some types of reading impairment as well as SLI. Identifying those cognitive deficits that work best as indices of heritable phenotypes will help us to uncover the aetiology of developmental disorders.