Verbal working memory and sentence comprehension in children with specific language impairment.

In this study we examined the influence of verbal working memory on sentence comprehension in children with SLI. Twelve children with SLI, 12 normally developing children matched for age (CA), and 12 children matched for receptive vocabulary (VM) completed two tasks. In the verbal working memory task, children recalled as many real words as possible under three processing load conditions (i.e., no-load condition; single-load condition, where words were recalled according to physical size of word referents; and dual-load condition, where words were recalled by semantic category and physical size of word referents). In the sentence comprehension task, children listened to linguistically nonredundant (shorter) and linguistically redundant (longer) sentences. Results of the memory task showed that the children with SLI recalled fewer words in the dual-load condition than their CA peers, who showed no condition effect. The SLI and VM groups performed similarly overall, but both groups showed poorer recall in the dual-load condition than in the other conditions. On the sentence comprehension task, children with SLI comprehended fewer sentences of both types than the CA children and fewer redundant sentences relative to themselves and to the VM children. Results were interpreted to suggest that children with SLI (a) have less functional verbal working memory capacity (i.e., ability to coordinate both storage and processing functions) than their CA peers and (b) have greater difficulty managing both their working memory abilities and general processing resources than both age peers and younger children when performing a "complex" off-line sentence processing task.     

Beyond capacity limitations: determinants of word recall performance on verbal working memory span tasks in children with SLI.

Reduced verbal working memory capacity has been proposed as a possible account of language impairments in specific language impairment (SLI). Studies have shown, however, that differences in strength of linguistic representations in the form of word frequency affect list recall and performance on verbal working memory tasks. This suggests that verbal memory capacity and long-term linguistic knowledge may not be distinct constructs. It has been suggested that linguistic representations in SLI are weak in ways that result in a breakdown in language processing on tasks that require manipulation of unfamiliar material. In this study, the effects of word frequency, long-term linguistic knowledge, and serial order position on recall performance in the competing language processing task (CLPT) were investigated in 10 children with SLI and 10 age-matched peers (age 8 years 6 months to 12 years 4 months). The children with SLI recalled significantly fewer target words on the CLPT as compared with their age-matched controls. The SLI group did not differ, however, in their ability to recall target words having high word frequency but were significantly poorer in their ability to recall words on the CLPT having low word frequency. Differences in receptive and expressive language abilities also appeared closely related to performance on the CLPT, suggesting that working memory capacity is not distinct from language knowledge and that degraded linguistic representations may have an effect on performance on verbal working memory span tasks in children with SLI.     

An examination of verbal working memory capacity in children with specific language impairment.

This study investigated verbal working memory capacity in children with specific language impairment (SLI). The task employed in this study was the Competing Language Processing Task (CLPT) developed by Gaulin and Campbell (1994). A total of 40 school-age children participated in this investigation, including 20 with SLI and 20 normal language (NL) age-matched controls. Results indicated that the SLI and NL groups performed similarly in terms of true/false comprehension items, but that the children with SLI evidenced significantly poorer word recall than the NL controls, even when differences in nonverbal cognitive scores were statistically controlled. Distinct patterns of word-recall errors were observed for the SLI and NL groups, as well as different patterns of associations between CLPT word recall and performance on nonverbal cognitive and language measures. The findings are interpreted within the framework of a limited-capacity model of language processing.     

Sustained selective attention skills of preschool children with specific language impairment: evidence for separate attentional capacities.

PURPOSE: The present study was designed to investigate the performance of preschool children with specific language impairment (SLI) and their typically developing (TD) peers on sustained selective attention tasks. METHOD: This study included 23 children diagnosed with SLI and 23 TD children matched for age, gender, and maternal education level. The children's sustained selective attention skills were assessed with different types of stimuli (visual, nonverbal-auditory, linguistic) under 2 attentional load conditions (high, low) using computerized tasks. A mixed design was used to compare children across groups and performance across tasks. RESULTS: The SLI participants exhibited poorer performance than their peers on the sustained selective attention tasks presented in the auditory modality (linguistic and nonverbal-auditory) under the high attentional load conditions. Performance was comparable with their peers under the low attentional load conditions. The SLI group exhibited similar performance to their peers on the visual tasks regardless of attentional load. CONCLUSION: These results support the notion of attention difficulties in preschool children with SLI and suggest separate attentional capacities for different stimulus modalities.     

Factors that influence lexical and semantic fast mapping of young children with specific language impairment.

PURPOSE: This purpose of this study was to investigate the lexical and semantic fast mapping ability of young children with specific language impairment (SLI) and normal language (NL), with a specific emphasis on the influence of phonological factors. METHOD: The study included 46 children (mean age 58 months), half with SLI and half with NL. Children were asked to fast map visual information only, visual-plus-nonlinguistic-auditory information, and visual-plus-linguistic-auditory information. A mixed design was used to compare children across and within groups. RESULTS: Children with SLI performed worse than children with NL overall. The SLI group showed specific deficits in semantic fast mapping when they saw visual information only. This condition may have disrupted encoding because it varied from the expected auditory and visual pattern. The children with SLI also performed poorly when they were asked to map phonotactically infrequent linguistic information and when the difficulty of the task increased. A nonword repetition task was correlated with both semantic and lexical fast mapping. CONCLUSIONS: The findings are discussed in the light of their support for a limited capacity model of processing, as well as the impact of phonology on word learning.     

Lexical activation during sentence comprehension in adolescents with history of Specific Language Impairment

One remarkable characteristic of speech comprehension in typically developing (TD) children and adults is the speed with which the listener can integrate information across multiple lexical items to anticipate upcoming referents. Although children with Specific Language Impairment (SLI) show lexical deficits (Sheng & McGregor, 2010) and slower speed of processing (Leonard et al., 2007), relatively little is known about how these deficits manifest in real-time sentence comprehension. In this study, we examine lexical activation in the comprehension of simple transitive sentences in adolescents with a history of SLI and age-matched, TD peers. Participants listened to sentences that consisted of the form, Article-Agent-Action-Article-Theme, (e.g., The pirate chases the ship) while viewing pictures of four objects that varied in their relationship to the Agent and Action of the sentence (e.g., Target, Agent-Related, Action-Related, and Unrelated). Adolescents with SLI were as fast as their TD peers to fixate on the sentence's final item (the Target) but differed in their post-action onset visual fixations to the Action-Related item. Additional exploratory analyses of the spatial distribution of their visual fixations revealed that the SLI group had a qualitatively different pattern of fixations to object images than did the control group. The findings indicate that adolescents with SLI integrate lexical information across words to anticipate likely or expected meanings with the same relative fluency and speed as do their TD peers. However, the failure of the SLI group to show increased fixations to Action-Related items after the onset of the action suggests lexical integration deficits that result in failure to consider alternate sentence interpretations.Learning outcomes: As a result of this paper, the reader will be able to describe several benefits of using eye-tracking methods to study populations with language disorders. They should also recognize several potential explanations for lexical deficits in SLI, including possible reduced speed of processing, and degraded lexical representations. Finally, they should recall the main outcomes of this study, including that adolescents with SLI show different timing and location of eye-fixations while interpreting sentences than their age-matched peers.     

Working memory and comprehension in children with specific language impairment: what we know so far

Many children with specific language impairments (SLI) demonstrate deficits in the areas of verbal working memory and language learning/processing. In this article, evidence is reviewed suggesting that the lexical/morphological learning and sentence comprehension/processing problems of many of these children are associated with their deficient working memory functioning. Evidence is also reviewed for the possibility that deficient working memory provides a clinical marker of SLI. A number of potentially useful assessment and intervention techniques are offered, as well as several directions for future research.The reader will be introduced to two prominent models of verbal working memory (phonological working memory model, functional working memory) and how each model potentially relates to (a) various language abilities in typically developing children, (b) the morphological and lexical learning abilities in children with specific language impairment (SLI), and (c) the sentence comprehension of children with SLI. The reader will also be provided a variety of clinical suggestions on how to assess and treat the working memory and language processing problems of children with SLI. Finally, some suggestions for future research will also be offered.     

The comprehension of wh-questions in children with specific language impairment.

Current theories of specific language impairment (SLI) in children fall into 2 general classes: those that attribute SLI to processing limitations and those that attribute the disorder to deficits in grammatical knowledge. In this study, the authors examined children's comprehension of subject and object Wh-questions because they offer the means of determining the relative contribution to performance of knowledge and of processing. Comprehension of subject and object Wh-questions presumably requires knowledge of grammatical movement. However, through manipulation of the length of the questions, it is also possible to vary the processing demands of the questions. If a simple deficit in knowledge of movement is involved, children should show poorer comprehension on object questions than on subject questions, regardless of sentence length. However, if processing limitations are involved, length should affect comprehension of object questions but not subject questions. Children with SLI and typically developing (TD) children matched on receptive vocabulary test scores participated in a comprehension task consisting of short and long subject and object Wh-questions. The two groups performed similarly on short questions, each showing high accuracy in both subject and object conditions. However, the children with SLI showed poorer performance on long object questions compared to long subject questions. They were also less accurate on long object questions than were children in the TD group. We argue that demands on linguistic processing abilities play an important role in the difficulties experienced by children with SLI.     

Visuospatial immediate memory in specific language impairment.

PURPOSE: Investigations of the cognitive processes underlying specific language impairment (SLI) have implicated deficits in verbal short-term and working memory and in particular the storage and processing of phonological information. This study investigated short-term and working memory for visuospatial material for a group of children with SLI, to test whether the verbal memory impairments already established extend to the visuospatial domain. METHOD: Fifteen children with SLI and control groups of children matched on chronological age and language age completed tests of visuospatial short-term and working memory. RESULTS: The SLI group performed comparably with age-matched control children on all measures and at a higher level than the language-age control group on several measures. CONCLUSIONS: The visuospatial short-term and working memory abilities were at age-appropriate levels in this SLI group. This contrasts markedly with their impairments on tests of verbal short-term and working memory.     

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.     

Vocal/verbal response times of normal-hearing and hearing-impaired children

A series of experiments are reported that contrast vocal/verbal reaction-time measures from 16 normal-hearing and 25 hearing-impaired children 7 to 14 years old. Sixteen of the hearing-impaired children were enrolled in a residential school, 9 in a day school. Vocal reaction time of the children in response to visually presented stimuli was measured in four tasks: phonating "uh", saying the word "one", counting to digits, and naming digits. No significant differences were found between the response latencies of the two hearing-impaired groups on any task. Nor were differences found between the normal and hearing-impaired groups when the task was simply phonating "uh". Differences between these groups began to emerge when the word "one" was spoken. These differences increased systematically with the phonetic complexity of the task. Hearing level, latency in the counting responses, and magnitude of a ratio between phonating and digit counting latencies were identified as major predictors of speech intelligibility. The results suggest that central phonetic processing functions may be related to the quality of speech production by hearing-impaired talkers.     

Arithmetic calculation, short-term memory, and language performance in children with specific language impairment: a 5-year follow-up.

A 5-year follow-up of the arithmetic calculation abilities of low-income children with specific language impairment (SLI) is reported. The performance of fourth- and fifth-grade children with SLI was compared with that of typically developing low-income peers and with younger, typically developing low-income children. Short-term memory, language, and arithmetic calculation abilities were assessed. Compared to their age-matched peers, the SLI group exhibited low scores on a number recall task, a marked difficulty with mathematical calculation under timed conditions, and numerous errors when retrieving rote math facts such as 7 x 6 =. Although children with SLI made more written calculation errors than their age-matched peers, they did not differ in the type of errors made. However, strategies used to solve written calculation differed among the groups. Rather than use automatic math fact retrieval, children with SLI were more likely to use counting strategies to solve calculation problems. These findings offer further evidence that children with SLI have difficulty with rote memory. The findings also document the real-world consequences of slow, inefficient memory retrieval in children with SLI.     

Memory scanning speed in language-disordered children

Twelve students from classrooms for children with severe language disorders and 12 age-matched controls were evaluated for short-term memory scanning speed using the Sternberg task. Sets of two, three, and four digits were presented via earphones as memory sets, followed by single-probe digits. Reaction time was measured for a verbal response of "yes" or "no" indicating whether the probe was a member of the initial set. Average per-item scanning speed for the normal children was 66 ms, which was significantly different from the 253-ms average scanning speed of the language-disordered group. Many similarities were noted in the performance of the two groups on the memory scanning task. No differences were found in estimates of encoding and response speed, in percentage of errors or in serial or numerical position effects across groups. Results indicate that children with developmental language disorders may demonstrate reduced processing speed or memory retrieval time, which could contribute to linguistic deficits.     

Is processing speed related to severity of language impairment?

Children with specific language impairment (SLI) typically respond more slowly on many tasks than do their typically developing peers. This paper addresses the question of whether speed of response is linearly related to severity of language impairment as measured by standardized test score. To address this question, we performed post hoc analyses of data from a study on lexical processing involving 66 children with SLI (mean age 6 years 9 months) and 66 typically developing children matched for age and nonverbal IQ. Response times derived from a series of tasks were correlated with language test scores. None of the Pearson correlations reached significance when corrected for number of correlations run, nor did a canonical correlation analysis reach significance. If these results are replicated in other studies, then they suggest that there is no direct linear relation between speed of processing and severity of language impairment as it is estimated from scores on standardized tests of language.     

Morpheme learning of children with specific language impairment under controlled instructional conditions.

Three groups of children were exposed to instances of a novel morpheme under controlled experimental conditions. The performance of 32 children with specific language impairment (SLI), aged 5:0 to 7:0 years (years:months), was compared to that of 24 normally developing children matched for age and nonverbal ability and 20 younger normally developing children matched for language development and nonverbal ability. The children were taught under two instructional conditions that differed only in whether the child was asked to imitate the new language form after each instance (imitation) or just to observe its use (modeling). Consistent with past research (Connell, 1987b), the children with SLI performed significantly better under the imitation condition than under modeling, but the age-matched controls showed no difference in response to instruction. The performance of the language-matched controls was similar to that of the age-matched controls, suggesting that the instruction-specific effect for the children with SLI is not merely a function of general language immaturity. Although the superiority of the imitation condition for the children with SLI was evident for test trials requiring production of the new morpheme (as in past research), no such effect was evident for comprehension trials. This differing effect of output demands suggests that the SLI-specific response to instruction is not a matter of different mastery of the new rule but rather is specific to the need to access the newly induced rule on production trials. The accessing of phonological representations as a possible explanation for the effect is discussed.     

Language-specific effects of task demands on the manifestation of specific language impairment: a comparison of English and Icelandic

PURPOSE: Previous research has indicated that the manifestation of specific language impairment (SLI) varies according to factors such as language, age, and task. This study examined the effect of task demands on language production in children with SLI cross-linguistically. METHOD: Icelandic- and English-speaking school-age children with SLI and normal language (NL) peers (n = 42) were administered measures of verbal working memory. Spontaneous language samples were collected in contexts that vary in task demands: conversation, narration, and expository discourse. The effect of the context-related task demands on the accuracy of grammatical inflections was examined. RESULTS: Children with SLI in both language groups scored significantly lower than their NL peers in verbal working memory. Nonword repetition scores correlated with morphological accuracy. In both languages, mean length of utterance (MLU) varied systematically across sampling contexts. Context exerted a significant effect on the accuracy of grammatical inflection in English only. Error rates were higher overall in English than in Icelandic, but whether the difference was significant depended on the sampling context. Errors in Icelandic involved verb and noun phrase inflection to a similar extent. CONCLUSIONS: The production of grammatical morphology appears to be more taxing for children with SLI who speak English than for those who speak Icelandic. Thus, whereas children with SLI in both language groups evidence deficits in language processing, cross-linguistic differences are seen in which linguistic structures are vulnerable when processing load is increased. Future research should carefully consider the effect of context on children's language performance.     

Neurophysiological indices of language impairment in children

Recent investigations of children with specific language impairment (SLI) have found deviant anatomical asymmetry of the perisylvian cortex. These studies argue that this deviant anatomical asymmetry is linked to the language disorders of SLI children. To date no studies have examined whether deviant functional asymmetry underlies the processing of spoken language in these children. In the current study, brain-electrical activity was recorded from 31 scalp sites while children with SLI listened to auditorally presented stories and two different nonsense contexts. Electrical activity was time-locked to the grammatical word "the" in these contexts. The SLI children showed reversed asymmetry compared to control children from 200 ms to 400 ms in processing "the" in all contexts. More specifically, they showed depressed processing at the left temporal scalp site (T7) and enhanced processing at the right temporal site (T8). The second spatial derivative (the Laplacian) of the voltage activity was calculated to remove constant voltage potential and uniform changes in voltage potential across the scalp. The Laplacian analysis indicated that the sources of the positive electrical activity seen at the temporal electrode sites T7 and T8 are the lateral surfaces of the temporal cortices. A comparison of the scalp topography of the voltage potentials and Laplacian also suggests that children with SLI lack some contribution from a deep neural generator, possibly in the hippocampus or basal ganglia. This investigation is the first to demonstrate a direct link between deviant neurophysiological asymmetry and the processing of spoken language in children with SLI.     

The effect of temporal adverbials on past tense production by children with specific language impairment.

PURPOSE: Children with specific language impairment (SLI) often fail to produce past tense forms in obligatory contexts, although the factors affecting such inconsistency are not well understood. This study examined the influence of accompanying temporal adverbials (e.g., just, already) on the past tense production of these children. METHOD: Fifteen preschool-aged children with SLI, 15 typically developing children matched for age (TD-A) and 15 younger typically developing children matched for mean length of utterance (TD-MLU) participated in the study. The children responded to probes that obligated the use of past tense forms. The verbal context provided by the experimenter for half of the items included a temporal adverbial. RESULTS: Overall, the SLI and TD-MLU groups produced past tense less frequently than the children in the TD-A group, and there were no significant differences between the SLI and the TD-MLU groups. However, both the SLI and the TD-MLU participants produced past tense forms less frequently when temporal adverbials were included than when they were absent. CONCLUSIONS: These findings suggest that the tendency to use past tense by the children with SLI and their younger MLU-matched peers may not have been independent of other types of temporal information.     

Association between language development and auditory processing disorders

IntroductionIt is crucial to understand the complex processing of acoustic stimuli along the auditory pathway; comprehension of this complex processing can facilitate our understanding of the processes that underlie normal and altered human communication.AimTo investigate the performance and lateralization effects on auditory processing assessment in children with specific language impairment (SLI), relating these findings to those obtained in children with auditory processing disorder (APD) and typical development (TD).Material and methodsProspective study. Seventy-five children, aged 6-12 years, were separated in three groups: 25 children with SLI, 25 children with APD, and 25 children with TD. All went through the following tests: speech-in-noise test, Dichotic Digit test and Pitch Pattern Sequencing test.ResultsThe effects of lateralization were observed only in the SLI group, with the left ear presenting much lower scores than those presented to the right ear. The inter-group analysis has shown that in all tests children from APD and SLI groups had significantly poorer performance compared to TD group. Moreover, SLI group presented worse results than APD group.ConclusionThis study has shown, in children with SLI, an inefficient processing of essential sound components and an effect of lateralization. These findings may indicate that neural processes (required for auditory processing) are different between auditory processing and speech disorders.     

Neurophysiological Indices of Language Impairment in Children

Recent investigations of children with specific language impairment (SLI) have found deviant anatomical asymmetry of the perisylvian cortex. These studies argue that this deviant anatomical asymmetry is linked to the language disorders of SLI children. To date no studies have examined whether deviant functional asymmetry underlies the processing of spoken language in these children. In the current study, brain-electrical activity was recorded from 31 scalp sites while children with SLI listened to auditorally presented stories and two different nonsense contexts. Electrical activity was time-locked to the grammatical word ''the'' in these contexts. The SLI children showed reversed asymmetry compared to control children from 200 ms to 400 ms in processing ''the'' in all contexts. More specifically, they showed depressed processing at the left temporal scalp site (T7) and enhanced processing at the right temporal site (T8). The second spatial derivative (the Laplacian) of the voltage activity was calculated to remove constant voltage potential and uniform changes in voltage potential across the scalp. The Laplacian analysis indicated that the sources of the positive electrical activity seen at the temporal electrode sites T7 and T8 are the lateral surfaces of the temporal cortices. A comparison of the scalp topography of the voltage potentials and Laplacian also suggests that children with SLI lack some contribution from a deep neural generator, possibly in the hippocampus or basal ganglia. This investigation is the first to demonstrate a direct link between deviant neurophysiological asymmetry and the processing of spoken language in children with SLI.