Nonspecific Language Impairment Research Articles

Causal Pathways for Specific Language Impairment: Lessons From Studies of Twins.

PurposeThis review article summarizes a program of longitudinal investigation of twins' language acquisition with a focus on causal pathways for specific language impairment (SLI) and nonspecific language impairment in children at 4 and 6 years with known history at 2 years.MethodThe context of the overview is established by legacy scientific papers in genetics, language, and SLI. Five recent studies of twins are summarized, from 2 to 16 years of age, with a longitudinal perspective of heritability over multiple speech, language, and cognitive phenotypes.ResultsReplicated moderate-to-high heritability is reported across ages, phenotypes, full population estimates, and estimates for clinical groups. Key outcomes are documentation of a twinning effect of risk for late language acquisition in twins that persists through 6 years of age, greater for monozygotic than dizygotic twins (although zygosity effects disappear at 6 years); heritability is greater for grammar and morphosyntax than other linguistic dimensions, from age 2 years through age 16 years, replicated within twin samples at subsequent age levels and across twin samples at age 16 years.ConclusionThere is consistent support for legacy models of genetic influences on language acquisition, updated with a more precise growth signaling disruption model supported by twin data, as well as singleton data of children with SLI and nonspecific language impairment.Presentation Video https://doi.org/10.23641/asha.13063727

Heritability of Specific Language Impairment and Nonspecific Language Impairment at Ages 4 and 6 Years Across Phenotypes of Speech, Language, and Nonverbal Cognition.

Purpose Early language and speech acquisition can be delayed in twin children, a twinning effect that diminishes between 4 and 6 years of age in a population-based sample. The purposes of this study were to examine how twinning effects influence the identification of children with language impairments at 4 and 6 years of age, comparing children with specific language impairment (SLI) and nonspecific language impairment (NLI); the likelihood that affectedness will be shared within monozygotic versus dizygotic twin pairs; and estimated levels of heritability for SLI and NLI. Twinning effects are predicted to result in elevated rates of language impairments in twins. Method The population-based twin sample included 1,354 children from 677 twin pairs, 214 monozygotic and 463 dizygotic, enrolled in a longitudinal study. Nine phenotypes from the same comprehensive direct behavioral assessment protocol were investigated at 4 and 6 years of age. Twinning effects were estimated for each phenotype at each age using structural equation models estimated via diagonally weighted least squares. Heritabilities were calculated for SLI and NLI. Results As predicted, the twinning effect increased the percentage of affected children in both groups across multiple language phenotypes, an effect that diminished with age yet was still not aligned to singleton age peers. Substantial heritability estimates replicated across language phenotypes and increased with age, even with the most lenient definition of affectedness, at -1 SD. Patterns of outcomes differed between SLI and NLI groups. Conclusions Nonverbal IQ is not on the same causal pathway as language impairments. Twinning effects on language acquisition affect classification of 4- and 6-year-old children as SLI and NLI, and heritability is most consistent in the SLI group. Clinical practice requires monitoring language acquisition of twins to avoid misdiagnosis when young or a missed diagnosis of language impairments at school entry.

Memory and language in middle childhood in individuals with a history of specific language impairment.

This study reports on the sensitivity of sentence repetition as a marker of specific language impairment (SLI) in different subgroups of children in middle childhood and examines the role of memory and grammatical knowledge in the performance of children with and without language difficulties on this task. Eleven year old children, 197 with a history of SLI and 75 typically developing (TD) peers were administered sentence repetition, phonological short term memory (PSTM) and grammatical morphology tasks. Children with a history of SLI were divided into four subgroups: specific language impairment, non-specific language impairment, low cognition with resolved language and resolved. Performance on the sentence repetition task was significantly impaired in all four subgroups of children with a history of SLI when compared to their age peers. Regression analyses revealed grammatical knowledge was predictive of performance for TD children and children with a history of SLI. However, memory abilities were significantly predictive of sentence repetition task performance for children with a history of SLI only. Processes involved in sentence repetition are more taxing of PSTM for individuals with a history of SLI in middle childhood in a way that does not appear to be the case for TD children.

A comparison of oral narratives in children with specific language and non-specific language impairment

This research investigated whether children with specific language impairment (SLI) and non-specific language impairment (NLI) could be differentiated by their oral narrative characteristics. Oral narrative samples were collected from 69 children and comparisons were made among four groups of participants. The two language impairment groups (SLI and NLI), aged 4;11–6;03, were matched for age and their linguistics skills. Their oral narratives were compared between these diagnostic groups and with age-matched and language-matched control groups. Measures of narrative structure, cohesion, and information did not significantly differentiate the SLI and NLI groups, suggesting that the influence of their similar linguistic skills on oral narrative measures was stronger than the influence of their differing non-verbal cognition. The SLI group produced significantly more complex and informative oral narratives than the language-matched group, while the NLI group differed from the language-matched group on fewer measures. Interactions among linguistic, cognitive, maturational, and task factors are discussed.

Modeling Developmental Language Difficulties From School Entry Into Adulthood: Literacy, Mental Health, and Employment Outcomes

Understanding the long-term outcomes of developmental language difficulties is key to knowing what significance to attach to them. To date, most prognostic studies have tended to be clinical rather than population-based, which necessarily affects the interpretation. This study sought to address this issue using data from a U.K. birth cohort of 17,196 children, following them from school entry to adulthood, examining literacy, mental health, and employment at 34 years of age. The study compared groups with specific language impairment (SLI), nonspecific language impairment (N-SLI), and typically developing language (TL). Secondary data analysis of the imputed 5-year and 34-year data was carried using multivariate logistic regressions. The results show strong associations for demographic and biological risk for both impairment groups. The associations are consistent for the N-SLI group but rather more mixed for the SLI group. The data indicate that both SLI and N-SLI represent significant risk factors for all the outcomes identified. There is a strong case for the identification of these children and the development of appropriate interventions. The results are discussed in terms of the measures used and the implications for practice.

Grammatical morpheme effects on sentence processing by school-aged adolescents with specific language impairment

Sixteen-year-olds with specific language impairment (SLI), nonspecific language impairment (NLI), and those showing typical language development (TD) responded to target words in sentences that were either grammatical or contained a grammatical error immediately before the target word. The TD participants showed the expected slower response times (RTs) when errors preceded the target word, regardless of error type. The SLI and NLI groups also showed the expected slowing, except when the error type involved the omission of a tense/agreement inflection. This response pattern mirrored an early developmental period of alternating between using and omitting tense/agreement inflections that is characteristic of SLI and NLI. The findings could not be readily attributed to factors such as insensitivity to omissions in general or insensitivity to the particular phonetic forms used to mark tense/agreement. The observed response pattern may represent continued difficulty with tense/agreement morphology that persists in subtle form into adolescence.

Syntactic Development in Adolescents With a History of Language Impairments: A Follow-Up Investigation

Syntactic development in adolescents was examined using a spoken discourse task and standardized testing. The primary goal was to determine whether adolescents with a history of language impairments would differ from those with a history of typical language development (TLD). This is a companion study to one that examined these same adolescents 2 years earlier (M. A. Nippold, T. C. Mansfield, J. L. Billow, & J. B. Tomblin, 2008). The participants were 15-year-old adolescents with a history of specific language impairment (SLI; n = 102), nonspecific language impairment (NLI; n = 77), or TLD (n = 247). A sample of spoken discourse was elicited using a Peer Conflict Resolution (PCR) task and analyzed for mean length of T-unit, clausal density, and subordinate clause use. In addition, 2 subtests from the Clinical Evaluation of Language Fundamentals, Third Edition (E. Semel, E. H. Wiig, & W. A. Secord, 1995), Concepts and Directions and Recalling Sentences, were administered. On the PCR task, the TLD group outperformed the SLI and NLI groups on mean length of T-unit, clausal density, and nominal clause use, and the TLD group outperformed the NLI group on relative clause use. On the standardized testing, the TLD group outperformed the SLI and NLI groups, and the SLI group outperformed the NLI group. Correlation coefficients calculated between the nonstandardized and standardized measures of syntax were statistically significant and positive. Speech-language pathologists may wish to employ the PCR task to examine syntactic development in adolescents as a supplement to standardized testing.

Expository Discourse in Adolescents With Language Impairments: Examining Syntactic Development

This study examined syntactic development in a large cohort of adolescents. At kindergarten, each participant had been identified as having specific language impairment (SLI), nonspecific language impairment (NLI), or typical language development (TLD). The participants (n = 444) had a mean age of 13;11 (years;months; range = 12;10-15;5). Language samples were elicited in 2 genres, conversational and expository, and analyzed for mean length of T-unit and subordinate clause production. Mean length of T-unit and the use of nominal, relative, and adverbial clauses were greater during the expository task than the conversational task for all groups. Thus, even the SLI and NLI groups produced longer sentences containing greater amounts of subordination when speaking in the expository genre than in the conversational genre. No group differences were revealed by the conversational task. However, on the expository task, the TLD group outperformed both the SLI and NLI groups on mean length of T-unit, and the TLD group outperformed the NLI group on relative clause use. Speech-language pathologists may wish to employ expository discourse tasks rather than conversational tasks to examine syntactic development in adolescents.

Grammaticality judgements in adolescents with and without language impairment

Existing evidence suggests that young children with specific language impairment have unusual difficulty in detecting omissions of obligatory tense-marking morphemes, but little is known about adolescents' sensitivity to such violations. The study investigated whether limitations in receptive morphosyntax (as measured by grammaticality judgements) were present at age 16 years, and, if so, whether participants' profiles showed less sensitivity to omissions of tense and agreement morphemes than to (1) inappropriate uses (intrusions) of these same morphemes, and (2) omissions of morphemes that do not encode tense and agreement. The study also compared adolescents with language impairment and non-verbal IQ more than 1 standard deviation (SD) below the mean (nonspecific language impairment) to adolescents with specific language impairment. Adolescents with specific language impairment (n = 48), adolescents with non-specific language impairment (n = 25), and adolescents with normal language development (n = 108) performed speeded grammaticality judgements of sentences presented over headphones. Half the sentences were ungrammatical. They included omissions of non-tense morphemes (-ing and possessive -s), omissions of tense morphemes (-ed and third-person singular present -s), and intrusions of the same tense morphemes. The A' statistic was used as the dependent variable for comparisons across groups and item types. Overall, the normal language development group was more sensitive to grammatical violations than the specific language impairment and non-specific language impairment groups, and there was no significant interaction of group and item type. Post-hoc analyses showed that the specific language impairment group was less sensitive to violations than the normal language development group on each item type, and the specific language impairment and non-specific language impairment groups did not differ. Across groups, performance on omission of past tense -ed was lowest, and properties of the items that may have contributed to this difference were explored. The adolescents with language impairment in this study showed evidence of reduced sensitivity to morphological errors, including both tense-marking and non-tense-marking morphemes, but no evidence of any extraordinary difficulty in detecting the omission of tense-marking morphemes, in contrast to results from other research on younger children with specific language impairment. Participants whose non-verbal IQ score was too low to meet the criteria for specific language impairment performed similarly to their peers with specific language impairment. Grammatical competence is compromised in these adolescents with specific language impairment and non-specific language impairment. Neither researchers nor clinicians can assume that adolescents with language impairment have fully mastered grammatical morphology.

Literacy and Children with Specific Language Impairment

The purpose of this article is to summarize the literacy outcomes for children with specific language impairment and to consider principles and approaches for literacy intervention with preschool and early school-age children with language impairments. Initially, specific language impairment is defined and differentiated from nonspecific language impairment. In addressing intervention considerations, we first consider the application of best practice principles and then specifically focus on intervention with preschool children and intervention with early school-age children. Consideration of evidence-based treatment approaches is guided by the developmental literature and by the intervention literature.

Response Time in 14-Year-Olds With Language Impairment

To determine whether children with language impairment were slower than typically developing peers at age 14, and whether slowing, if present, was similar across task domains; whether differences in response time (RT) across domains were the same for children with specific language impairment (SLI) and nonspecific language impairment (NLI); and whether RT performance at age 9 predicted performance at age 14. Fourteen-year-old children with SLI (n = 20), NLI (n = 15), and typical development (NLD; n = 31) were administered several linguistic and nonlinguistic speeded tasks. The children had received the same tasks at age 9. RT performance was examined. Both the SLI and the NLI groups were significantly slower than the NLD group in motor, nonverbal cognitive, and language task domains, and there was no significant difference among domains. Individual analyses showed that most, but not all, children with SLI and NLI were slower than the NLD group mean. Slowing at age 9 and age 14 were moderately correlated. The results suggest that slow RT is a persistent characteristic of many children with language impairment; however, the nature of the relationship between RT and language performance requires further investigation.

Pronominal reference skills of second and fourth grade children with language impairment

Pronominal referencing was evaluated in a sample of 569 children comprising four diagnostic subgroups: typical language (TL), specific language impairment (SLI), nonspecific language impairment (NLI), and typical language with low nonverbal IQ (LNIQ). Participants generated oral narratives in second grade and again in fourth grade. The narratives of the females in the TL group included a significantly higher rate of pronominal references than the narratives of both the males in the TL group and the females in the NLI group. A higher percentage of complete pronominal references was found in the TL group compared to the SLI group. These findings suggest that pronominal referencing measures are not sensitive enough to differentiate school-aged children with typical language development from those with language impairment. Learning outcomes The reader will: (1) become familiar with narrative language measures and (2) learn how groups of children with varying language and cognitive profiles perform on measures of referential cohesion.

Genetic Influences on Specific Versus Nonspecific Language Impairment in 4-Year-Old Twins

The present study addresses the distinction between specific (SLI) and nonspecific (NLI) language impairment at an etiological level by estimating the relative genetic and environmental contributions to language impairment in children with SLI and NLI. Drawing on a large longitudinal twin study, we tested a sample of 356 four-and-a-half-year-old children with low language ability and their twin partners at home on a range of language and nonverbal measures. For children whose language and nonverbal abilities were both low (NLI), genetic influence on language impairment was moderate and shared environmental influence was substantial. A similar pattern emerged for children whose language difficulties occurred in apparent isolation (SLI), although there was a trend for the genetic effects to be smaller for SLI than for NLI: Group heritability was .18 for SLI and .52 for NLI. Probandwise cross-concordances were suggestive of some genetic overlap between these two groups, but not with a subgroup of children with more severe cognitive delay.

Oral and Written Story Composition Skills of Children With Language Impairment

In this study 538 children composed 1 oral and 1 written fictional story in both 2nd and 4th grades. Each child represented 1 of 4 diagnostic groups: typical language (TL), specific language impairment (SLI), nonspecific language impairment (NLI), or low nonverbal IQ (LNIQ). The stories of the TL group had more different words, more grammatical complexity, fewer errors, and more overall quality than either language-impaired group at either grade. Stories of the SLI and LNIQ groups were consistently stronger than were those of the NLI group. Kindergarten children with language impairment (LI) whose standardized test performance suggested normalization by 2nd grade also appeared to have recovered in storytelling abilities at that point. By 4th grade, however, these children's stories were less like the children with TL and more like those of children with persistent LI than they had been in 2nd grade. Oral stories were better than written stories in both grades, although the greatest gains from 2nd to 4th grade were generally made on written stories. Girls told stronger stories than did boys at both grades, regardless of group placement. It is concluded that story composition tasks are educationally relevant and should play a significant role in the evaluation of children with developmental LI.

A longitudinal investigation of reading outcomes in children with language impairments.

This investigation examined the reading outcomes of children with language impairments (LI). A large subsample of children who participated in an epidemiologic study of language impairments in kindergarten (J. B. Tomblin, N. Records, P. Buckwalter, X. Zhang, E. Smith, & M. O'Brien, 1997) was followed into second and fourth grades. Participants' language, reading, and nonverbal cognitive abilities were assessed. Results indicated that children with LI in kindergarten were at a high risk for reading disabilities in second and fourth grades. This risk was higher for children with a nonspecific language impairment (nonverbal and language deficits) than for those with a specific language impairment (deficits in language alone). Children with LI in kindergarten who had improved in spoken language abilities by second and fourth grades had better reading outcomes than those with persistent language impairments. Also, children's literacy knowledge/ experience in kindergarten and their initial reading achievement in second grade were good predictors of subsequent reading outcomes.

Genetics and the development of language disabilities and abilities

Genetic research has been slow to come to the field of language development, but during the past decade it has begun to make up for lost time. Research suggests that language disabilities in children are among the most highly heritable disorders, fuelling optimism for finding specific genes. Research has gone beyond merely demonstrating heritability in three ways. First, there are strong genetic links between language disabilities and abilities: what we see as language problems may be the extremes of dimensions (abilities) rather than aetiologically distinct disorders (disabilities). Second, multivariate genetic research suggests that about half of the genetic effects on language disability overlap with non-verbal cognitive disability and about half of the genetic effects are specific, providing support for non-specific language impairment as well as for specific language impairment. Third, specific genes are being identified which will be used to address such issues with much greater precision.

Speed of processing in children with specific language impairment.

The aim of the present study was to investigate the speed with which children with specific language impairment (SLI) respond on a range of tasks. Seventy-seven third-grade children participated in 10 different tasks (involving a total of 41 conditions), including nonlinguistic and linguistic activities. Mean response times (RTs) of children with SLI (n = 29) increased as a function of mean RTs of children with normal language (NLD, n = 29) under each of three different regression models; children with SLI responded more slowly across all task conditions, and also when linguistic and nonlinguistic tasks were analyzed separately. Children with nonspecific language impairment (NLI) were also included (n = 19). The results were similar to those for children with SLI, but the degree of slowing was greater. The results of the group analyses support the hypothesis that speed of processing in children with SLI is generally slower than that of children with normal language. However, some children with SLI do not appear to show deficits of this type.