Grammar predicts procedural learning and consolidation deficits in children with Specific Language Impairment

The Procedural Deficit Hypothesis (PDH) posits that Specific Language Impairment (SLI) can be largely explained by abnormalities of brain structures that subserve procedural memory. The PDH predicts impairments of procedural memory itself, and that such impairments underlie the grammatical deficits observed in the disorder. Previous studies have indeed reported procedural learning impairments in SLI, and have found that these are associated with grammatical difficulties. The present study extends this research by examining consolidation and longer-term procedural sequence learning in children with SLI. The Alternating Serial Reaction Time (ASRT) task was given to children with SLI and typically developing (TD) children in an initial learning session and an average of three days later to test for consolidation and longer-term learning. Although both groups showed evidence of initial sequence learning, only the TD children showed clear signs of consolidation, even though the two groups did not differ in longer-term learning. When the children were re-categorized on the basis of grammar deficits rather than broader language deficits, a clearer pattern emerged. Whereas both the grammar impaired and normal grammar groups showed evidence of initial sequence learning, only those with normal grammar showed consolidation and longer-term learning. Indeed, the grammar-impaired group appeared to lose any sequence knowledge gained during the initial testing session. These findings held even when controlling for vocabulary or a broad non-grammatical language measure, neither of which were associated with procedural memory. When grammar was examined as a continuous variable over all children, the same relationships between procedural memory and grammar, but not vocabulary or the broader language measure, were observed. Overall, the findings support and further specify the PDH. They suggest that consolidation and longer-term procedural learning are impaired in SLI, but that these impairments are specifically tied to the grammatical deficits in the disorder. The possibility that consolidation and longer-term learning are problematic in the disorder suggests a locus of potential study for therapeutic approaches. In sum, this study clarifies our understanding of the underlying deficits in SLI, and suggests avenues for further research.     

Working, declarative and procedural memory in specific language impairment

According to the Procedural Deficit Hypothesis (PDH), abnormalities of brain structures underlying procedural memory largely explain the language deficits in children with specific language impairment (SLI). These abnormalities are posited to result in core deficits of procedural memory, which in turn explain the grammar problems in the disorder. The abnormalities are also likely to lead to problems with other, non-procedural functions, such as working memory, that rely at least partly on the affected brain structures. In contrast, declarative memory is expected to remain largely intact, and should play an important compensatory role for grammar. These claims were tested by examining measures of working, declarative and procedural memory in 51 children with SLI and 51 matched typically-developing (TD) children (mean age 10). Working memory was assessed with the Working Memory Test Battery for Children, declarative memory with the Children's Memory Scale, and procedural memory with a visuo-spatial Serial Reaction Time task. As compared to the TD children, the children with SLI were impaired at procedural memory, even when holding working memory constant. In contrast, they were spared at declarative memory for visual information, and at declarative memory in the verbal domain after controlling for working memory and language. Visuo-spatial short-term memory was intact, whereas verbal working memory was impaired, even when language deficits were held constant. Correlation analyses showed neither visuo-spatial nor verbal working memory was associated with either lexical or grammatical abilities in either the SLI or TD children. Declarative memory correlated with lexical abilities in both groups of children. Finally, grammatical abilities were associated with procedural memory in the TD children, but with declarative memory in the children with SLI. These findings replicate and extend previous studies of working, declarative and procedural memory in SLI. Overall, we suggest that the evidence largely supports the predictions of the PDH.     

Intact procedural motor sequence learning in developmental coordination disorder

The purpose of the present study was to explore the possibility of a procedural learning deficit among children with developmental coordination disorder (DCD). We tested 34 children aged 6–12 years with and without DCD using the serial reaction time task, in which the standard keyboard was replaced by a touch screen in order to minimize the impact of perceptuomotor coordination difficulties that characterize this disorder. The results showed that children with DCD succeed as well as control children at the procedural sequence learning task. These findings challenge the hypothesis that a procedural learning impairment underlies the difficulties of DCD children in acquiring and automatizing daily activities. We suggest that the previously reported impairment of children with DCD on the serial reaction time task is not due to a sequence learning deficit per se, but rather due to methodological factors such as the response mode used in these studies.     

Sequence learning in Parkinson's disease: a comparison of spatial-attention and number-response sequences

The serial reaction time (SRT) task has been frequently used to assess procedural learning of sequences. Patients with Parkinson's disease (PD) have been reported to show deficits on this task, but it is as yet unclear whether this impairment reflects a general sequencing deficit or a deficit in the sequencing of motor-output responses. In order to examine this issue, PD patients and controls were administered an SRT task which allowed the simultaneous and independent assessment of the procedural learning of spatial regularities and the learning of motor-response regularities. PD patients were unimpaired at learning a sequence of spatial locations, but showed a deficit at learning a stimulus-to-motor-response sequence. The results suggest that sequencing impairments in PD are not general, but specific to the type of sequential information inherent in a task.     

List intonation in pre-schoolers with normal and disordered language development

The principal aim of this study was to evaluate pre-schoolers’ expressive intonation in light of current debates about the underlying nature of language impairment (LI). Children with LI typically have deficits in grammar, a component of language that is phonologically represented on the segmental level. The hypothesis is that children with LI do not have deficits of this type when grammar is conveyed by intonation, a pitch-based component of language that is phonologically represented on the suprasegmental level. This study focused on the richly diversified suprasegmental patterns of sentences in which the speaker produces a series of items in a list. To address the hypothesis, list intonation in the speech of 4-year-olds with and without LI was acoustically analysed. Lists produced by children with LI were comparable to those produced by children with normal language development (NL). The results do not support the claim that LI stems from a poor understanding of grammatical principles. Rather, LI reflects an underlying impairment of segmental information processing. The discussion focuses on two characteristics of pitch contours which may account for the resilience of intonation in children with LI. Namely, steady state versus transient signals and universal symbol meanings versus arbitrary relationships between form and function.     

Word and pseudoword reading in children with specific speech and language impairment

Children with specific language impairment frequently encounter difficulties in learning to read and in particular, in word recognition. The present study set out to determine the precise impact of language impairment on word reading skills. We investigated single-word reading in 27 French children with specific speech and language impairment (2SLI). Precise quantification of reading levels in the 2SLI group showed an average delay of 3.5 years. Approximately 90% of these children were affected by a reading disorder, whereas for the remaining 10%, reading performance was within normal limits. Word reading procedures are analyzed using the so-called ‘dual route model’, which proposes that reading is achieved through two processes, the phonological and the orthographic procedures. Group comparison analyses of 27 reading level-matched control children, revealed an increased lexicality effect in the 2SLI group, indicating a specific deficit in the phonological procedure. Moreover, multiple case analyses revealed interindividual differences among the children with 2SLI, with four reading subtypes. Approximately 60% of these children reached the standard levels expected of younger children with identical reading levels (delayed reading profile) in both procedures. Twenty percent displayed qualitatively different reading mechanisms, with a greater deficit in the phonological procedure (phonological profile). These children showed a severe impairment in language production at the phonological level. Ten percent exhibited a greater orthographic deficit (surface profile) and 10% had normal reading skills (normal profile). Further research is required to improve our understanding of the relationships between 2SLI or specific language impairment and reading acquisition. The present results suggest that in clinical practice, both reading procedures should be exercised, with emphasis on the phonological procedure for children with more severe deficits in phonological production.     

Impaired implicit sequence learning in children with developmental dyslexia

It has been proposed that an impairment of procedural memory underlies a range of linguistic, cognitive and motor impairments observed in developmental dyslexia (DD). However, studies designed to test this hypothesis using the implicit sequence learning paradigm have yielded inconsistent results. A fundamental aspect of procedural learning is that it takes place over an extended time-period that may be divided into distinct stages based on both behavioural characteristics and neural correlates of performance. Yet, no study of implicit sequence learning in children with DD has included learning stages beyond a single practice session. The present study was designed to fill this important gap by extending the investigation to include the effects of overnight consolidation as well as those of further practice on a subsequent day. The results suggest that the most pronounced procedural learning impairment in DD may emerge only after extended practice, in learning stages beyond a single practice session.     

Do phonologic and rapid automatized naming deficits differentially affect dyslexic children with and without a history of language delay? A study of Italian dyslexic children.

OBJECTIVE: The study aims to verify whether phonologic and rapid automatized naming (RAN) deficits are present and associated in Italian dyslexic children and whether they differentially affect dyslexics with and without a history of previous language delay (LD). BACKGROUND: According to the phonologic core deficit hypothesis, dyslexia may stem from impairment of the representation and manipulation of phonemes and may be closely associated with oral language deficits. However, deficits in tasks not requiring fine-grained phonologic representations, such as RAN, have also been described in dyslexic children. METHODS: Thirty-seven children were selected on the basis of a reading deficit and were assigned to 2 groups according to whether or not they had a history of early LD as determined retrospectively by parental report. A battery of reading and writing, verbal working memory, metaphonologic, RAN, and visual search tests were administered. RESULTS: RAN deficits were shared by most dyslexics (with and without a history of LD), whereas phonologic deficits were mainly associated with a previous LD. This last condition did not result in a more profound impairment of reading and writing decoding skills. CONCLUSION: In a shallow orthography such as Italian, RAN, not phonologic deficits, may represent the main cognitive marker of developmental dyslexia.     

Grammatical impairment in developmental aphasia.

The language production of a 23 year old patient with developmental aphasia caused by birth injury was analyzed in detail within the framework of Chomsky's generative grammar. It was shown that different stages of grammatical development occur simultaneously, without the predominance of those grammatical forms which are identical with or close to adult grammar. Thus the language of this patient with developmental aphasia is quite comparable to the language of children from 3 to 6, and shares many features with grammatical impairment well known from agrammatism and paragrammatism in adult aphasia. It was suggested that in developmental aphasia incomplete linguistic generalizations are related to an incomplete maturation of inhibitory functions during language acquisition, whereas in adult aphasia comparable forms of less advanced grammars are set free by dissolution of function.     

The influence of the frequency of functional markers on repetitive imitation of syntactic constructions in children with specific language impairment,from their own language productions

Several studies provide considerable insight into the role that frequency plays in language development. However, no study has investigated the direct relationship between frequency and grammatical acquisition in children with specific language impairment (SLI). In this study, we focus specifically on the influence of the frequency of functional words on the ability of children with SLI to produce grammatical constructions based on the children's own previous production but containing previously unused functional words. To test our hypothesis, the children were administered an imitative repetition task, tailored to their current level of language development. Results showed that children with SLI performed more poorly than language-matched children with typical language development. The difference between the two groups was more marked when the previously unused functional words were infrequent rather than frequent. Consequently, it would seem that the token frequency of functional words influences grammatical acquisition in children with SLI. The results and their implications for linguistic theories are discussed.     

Phonological memory and word learning deficits in children with specific language impairment: A role for perceptual context?

BackgroundSensitivity to perceptual context (anchoring) has been suggested to contribute to the development of both oral- and written-language skills, but studies of this idea in children have been rare.AimsTo determine whether deficient anchoring contributes to the phonological memory and word learning deficits of children with specific language impairment (SLI).Methods and procedures84 preschool children with and without SLI participated in the study. Anchoring to repeated items was evaluated in two tasks – a phonological memory task and a pseudo-word learning task.Outcomes and resultsCompared to children with typical development, children with SLI had poorer phonological memory spans and learned fewer words during the word learning task. In both tasks the poorer performance of children with SLI reflected a smaller effect of anchoring that was manifested in a smaller effect of item repetition on performance. Furthermore, across the entire sample anchoring was significantly correlated with performance in vocabulary and grammar tasks.Conclusions and implicationsThese findings are consistent with the hypothesis that anchoring contributes to language skills and that children with SLI have impaired anchoring, although further studies are required to determine the role of anchoring in language development.     

The Use of Grammatical Morphemes by Mandarin-Speaking Children with High Functioning Autism

The present study investigated the production of grammatical morphemes by Mandarin-speaking children with high functioning autism. Previous research found that a subgroup of English-speaking children with autism exhibit deficits in the use of grammatical morphemes that mark tense. In order to see whether this impairment in grammatical morphology can be generalised to children with autism from other languages, the present study examined whether or not high-functioning Mandarin-speaking children with autism also exhibit deficits in using grammatical morphemes that mark aspect. The results show that Mandarin-speaking children with autism produced grammatical morphemes significantly less often than age-matched and IQ-matched TD peers as well as MLU-matched TD peers. The implications of these findings for understanding the grammatical abilities of children with autism were discussed.     

Grammatical case-marking in Japanese children with SLI

ABSTRACT

The purpose of this study was to investigate whether or not Japanese children with specific language impairment (henceforth; SLI) would in fact experience difficulty with grammatical case-marking. The participants were 10 Japanese children with SLI, aged 7;7 to 11;4, and 25 Japanese children with typical language development (henceforth; TLD), aged 8;11 to 9;11. In this study, a sentence completion task was used, which involved both active and passive sentences with canonical and scrambled word order. The children with SLI were significantly less accurate than those with TLD with the use of grammatical case-markers. Moreover, the majority of the errors that the children with SLI made with case-marking consisted of canonical case-marking patterns. These results suggest that Japanese children with SLI do in fact appear to experience difficulty with grammatical case-marking and furthermore that they seem to rely on canonical case-marking patterns to compensate for their deficits.     

Intact first- and second-order false belief reasoning in a patient with severely impaired grammar

The retention of first-order theory of mind (ToM) despite severe loss of grammar has been reported in two patients with left hemisphere brain damage (Varley & Siegal, 2000; Varley, Siegal, & Want, 2001). We report a third, and more detailed, case study. Patient PH shows significant general language impairment, and severe grammatical impairment similar to that reported in previous studies. In addition we were able to show that PH's impairment extends to grammatical constructions most closely related to ToM in studies of children (embedded complement clauses and relative clauses). Despite this, PH performed almost perfectly on first-order false belief tasks and on a novel nonverbal second-order false belief task. PH was also successful on a novel test of "ToM semantics" that required evaluation of the certainty implied by different mental state terms. The data strongly suggest that grammar is not a necessary source of structure for explicit ToM reasoning in adults, but do not rule out a critical role for "ToM semantics." In turn this suggests that the relationship observed between grammar and ToM in studies of children is the result of an exclusively developmental process.     

Implicit learning deficit in children with developmental dyslexia

Several neuropsychological deficits have been reported as characteristic of the cognitive profile of dyslexic children. Phonological and visual processing are often impaired as well as auditory processing, attention and information processing speed. We investigated whether implicit learning, is impaired in dyslexic children and adolescents. Tests of implicit and declarative learning were administered to 18 clinically defined dyslexics and 18 similar age controls. Dyslexics showed a reduced learning rate in the implicit but not in the declarative task, suggesting a specific deficit of implicit learning. Although alternative hypothesis cannot be ruled out, considering that implicit learning is a cognitive function primarily processed by the cerebellum and that recent neurological and physiological data suggest a cerebellar dysfunction in dyslexia, the present results suggest an impairment of cerebellar system in reading disabilities.     

When artificial grammar acquisition in Parkinson's disease is impaired: the case of learning via trial-by-trial feedback

Although there is strong evidence that human category learning is mediated by qualitatively distinct systems, the neural substrates of procedural category learning remain largely unclear. The present research sought to investigate the role of the basal ganglia in the acquisition of categorical knowledge via an examination of the ability of people with Parkinson's disease (PD) to learn an artificial grammar (AG) system in a format akin to habit learning tasks such as probabilistic classification learning. Eighteen nondemented patients with PD were compared with 22 matched controls on a task modified so that participants' grammar learning depended on making use of feedback provided on each trial. Results showed that patients with PD exhibited abnormal AG learning, with the deficit more pronounced early in the task. Impaired categorisation performance in patients was not related to declarative knowledge obtained during the test and was independent of frontal functioning. The findings presented here indicate that prior inconsistencies across category learning tasks in PD performance may be explained, at least in part, by whether the task necessitates the formation of associations between stimulus cues and categorical responses, and support the hypothesis that the basal ganglia play a specific role in procedural learning in complex feedback-based categorisation tasks.     

Dissociation between the procedural learning of letter names and motor sequences in developmental dyslexia

Motor sequence learning has been studied extensively in Developmental dyslexia (DD). The purpose of the present research was to examine procedural learning of letter names and motor sequences in individuals with DD and control groups. Both groups completed the Serial Search Task which enabled the assessment of learning of letter names and motor sequences independently of each other. Control participants learned both the letter names as well as the motor sequence. In contrast, individuals with DD were impaired in learning of the letter names sequence and showed a reliable transfer of the motor sequence. Previous studies proved that motor sequence learning is impaired in DD. The present study demonstrated that this deficit is more pronounced when the task to be learned involves linguistic units. This result implies that the procedural learning system of language is more deficient than the motor procedural learning system in individuals with DD. The dissociation between motor and letter names sequence learning in those with DD also implies that the systems underlying these two tasks are separable.     

Behavioral and Imaging Studies of Infant Artificial Grammar Learning

Artificial grammar learning (AGL) paradigms have proven to be productive and useful to investigate how young infants break into the grammar of their native language(s). The question of when infants first show the ability to learn abstract grammatical rules has been central to theoretical debates about the innate vs. learned nature of grammar. The presence of this ability early in development, that is, before considerable experience with language, has been argued to provide evidence for a biologically endowed ability to acquire language. Artificial grammar learning tasks also allow infant populations to be readily compared with adults and non‐human animals. Artificial grammar learning paradigms with infants have been used to investigate a number of linguistic phenomena and learning tasks, from word segmentation to phonotactics and morphosyntax. In this review, we focus on AGL studies testing infants’ ability to learn grammatical/structural properties of language. Specifically, we discuss the results of AGL studies focusing on repetition‐based regularities, the categorization of functors, adjacent and non‐adjacent dependencies, and word order. We discuss the implications of the results for a general theory of language acquisition, and we outline some of the open questions and challenges.     

What we can learn from naming errors of children with language impairment at preschool age

Naming is a complex, multi-level process. It is composed of distinct semantic and phonological levels. Children with naming deficits produce different error types when failing to retrieve the target word. This study explored the error characteristics of children with language impairment compared to those with typical language development. 46 preschool children were tested on a naming test: 16 with language impairment and a naming deficit and 30 with typical language development. The analysis compared types of error in both groups. In a group level, children with language impairment produced different error patterns compared to the control group. Based on naming error analysis and performance on other language tests, two case studies of contrasting profiles suggest different sources for lexical retrieval difficulties in children. The findings reveal differences between the two groups in naming scores and naming errors, and support a qualitative impairment in early development of children with naming deficits. The differing profiles of naming deficits emphasise the importance of including error analysis in the diagnosis.     

The comprehension of verb agreement morphology by English-speaking children with specific language impairment

English-speaking children with specific language impairment (SLI) have well-documented difficulties with the production of grammatical morphemes related to agreement, as compared to both same-age and younger normally developing peers. However, comprehension of agreement-related morphemes has not been well studied in children with SLI, especially during the pre-school years. In two experiments, pre-schoolers with SLI and their normally developing peers were compared on their comprehension of third person singular, copula, and noun plural forms. The results showed that the children with SLI had poorer overall comprehension. Furthermore, the children with SLI appeared to rely primarily on the number cues that were present in the subject rather than on the verb agreement morphology. The findings are examined in light of several current accounts of the grammatical deficits found in children with SLI.