Working, Declarative, and Procedural Memory in Children With Developmental Language Disorder

Implicit and Explicit Sequence Learning in Adults With Developmental Language Disorder

PURPOSE

Developmental language disorder (DLD) is a neurodevelopmental disorder that impacts approximately 7% of the population and is characterized by unexplained deficits in expressive and/or receptive components of language. A common procedural learning task, serial reaction time (SRT), has been used to develop models of the basis of DLD. However, paradigms involve differing levels of implicit and explicit learning during this task, muddying interpretations of the data. Here, we tested adults with DLD on implicit and explicit SRT tasks to better understand implicit and explicit procedural learning in this population. We hypothesized that adults with DLD would demonstrate reduced learning on only the implicit SRT task, as alternate explicit neural mechanisms could lead to equivalent performance on the explicit task.

METHOD

Fifty participants (25 with DLD and 25 with typical language) completed implicit and explicit SRT tasks, measuring their ability to learn visually presented 10-element sequences. Group differences were evaluated on sequence learning, error rates, and explicit recall of the sequence after learning.

RESULTS

Sequence learning was the same between the groups on both tasks. However, individuals with DLD showed increased errors and significantly worse recall of the explicitly learned sequence.

CONCLUSIONS

Results suggest that sequence learning may be intact in this population, while aspects of explicit learning and motoric responses are impaired. Results are interpreted in light of a neurobiological model of DLD.

SUPPLEMENTAL MATERIAL

https://doi.org/10.23641/asha.26210651.

Retrieval Practice and Word Learning by Children With Developmental Language Disorder: Does Expanding Retrieval Provide Additional Benefit?

PURPOSE

The word learning of preschool-age children with developmental language disorder (DLD) is improved when spaced retrieval practice is incorporated into the learning sessions. In this preregistered study, we compared two types of spacing-an expanding retrieval practice schedule and an equally spaced schedule-to determine if one of these approaches yields better word learning outcomes for the children.

METHOD

Fourteen children with DLD aged 4-5 years and 14 same-age children with typical language development (TD) learned eight novel nouns over two sessions. Spacing for half of the novel words was expanded gradually during learning; for the remaining novel words, greater spacing remained at the same level throughout learning. Immediately after the second session and 1 week later, the children's recall of the words was tested.

RESULTS

The children with TD recalled more novel words than the children with DLD, although this difference could be accounted for by differences in the children's standardized receptive vocabulary test scores. The two groups were similar in their ability to retain the words over 1 week. Initially, the shorter spacing in the expanding schedule resulted in greater retrieval success than the corresponding (longer spaced) retrieval trials in the equally spaced schedule. These early shorter spaced trials also seemed to benefit retrieval of the trials with greater spacing that immediately followed. However, as the learning period progressed, the accuracy levels for the two conditions converged and were likewise similar during final testing.

CONCLUSION

We need a greater understanding of how and when short spacing can be helpful to children's word learning, with the recognition that early gains might give a misleading picture of the benefits that short spacing can provide to longer term retention.

SUPPLEMENTAL MATERIAL

https://doi.org/10.23641/asha.25537696.

Quantifying the effects of practicing a semantic task according to subclinical schizotypy

The learning ability of individuals within the schizophrenia spectrum is crucial for their psychosocial rehabilitation. When selecting a treatment, it is thus essential to consider the impact of medications on practice effects, an important type of learning ability. To achieve this end goal, a pre-treatment test has to be developed and tested in healthy participants first. This is the aim of the current work, which takes advantage of the schizotypal traits present in these participants to preliminary assess the test's validity for use among patients. In this study, 47 healthy participants completed the Schizotypal Personality Questionnaire (SPQ) and performed a semantic categorization task twice, with a 1.5-hour gap between sessions. Practice was found to reduce reaction times (RTs) in both low- and high-SPQ scorers. Additionally, practice decreased the amplitudes of the N400 event-related brain potentials elicited by semantically matching words in low SPQ scorers only, which shows the sensitivity of the task to schizotypy. Across the two sessions, both RTs and N400 amplitudes had good test-retest reliability. This task could thus be a valuable tool. Ongoing studies are currently evaluating the impact of fully deceptive placebos and of real antipsychotic medications on these practice effects. This round of research should subsequently assist psychiatrists in making informed decisions about selecting the most suitable medication for the psychosocial rehabilitation of a patient.

Replication of a single-case design cross-situational statistically based word learning treatment for late talking children

PURPOSE

Late talking children are at risk of ongoing language impairment. This intervention study replicated and extended research based on cross-situational statistical learning principles.

METHOD

Three late talking children (age 24-32 months) were enrolled into the concurrent multiple baseline single-case experimental intervention study. The intervention consisted of 16 sessions over eight/nine weeks, including 10-11 pairs of target and control words (three per session). Children heard the target words a minimum of 64 times per session, in sentences with high linguistic variability in varied play activities.

RESULT

All children increased production of target words and expressive vocabulary, with statistically significant differences between word acquisition in baseline and intervention phases. One of the three children learnt statistically significantly more target words than control words.

CONCLUSION

The results replicated the findings of previous research for some but not all of the participants, providing individual evidence that this approach has promise as a therapy technique for late talking children.

Less Versus More: The Effect of Recast Length in Treatment of Grammatical Errors

PURPOSE

Although conversational recast treatment is generally efficacious, there are many ways in which the individual components of the treatment can be delivered. Some of these are known to enhance treatment, others appear to interfere with learning, and still others appear to have no impact at all. This study tests the potential effect of clinicians' recast length on child learning during a recast treatment.

METHOD

Twenty-six preschool children were treated for grammatical errors using Enhanced Conversational Recast Treatment. Half heard recasts of four or fewer words (Short Recast condition), and half heard recasts of five or more words (Extended Recast condition). Outcome measures included generalization of the treated grammatical form, spontaneous use of these forms, change in mean length of utterances in words, and the number of children in each condition who showed a clinically meaningful response.

RESULTS

There was strong evidence of improvements in the use of grammatical forms targeted by the treatment compared with forms that were tracked but not treated. Twenty children (11 in the Short Recast condition and nine in the Extended Recast condition) showed a clinically meaningful response. There was minimal support for the hypothesis that the length of clinician utterance influenced either progress on a grammatical form targeted by the treatment or on the child's mean length of utterance in words.

CONCLUSIONS

The study adds to the evidence for the efficacy of Enhanced Conversational Recast Treatment. However, there is little evidence that clinicians need to regulate the length of the recast they provide to children.

SUPPLEMENTAL MATERIAL

https://doi.org/10.23641/asha.24653613.

Selective short-term memory impairment for verbalizable visual objects in children with Developmental Language Disorder

BACKGROUND

Developmental language disorder (DLD) affects the ability to acquire and make use of native language. Possible underlying cognitive mechanisms are related to memory functions.

AIMS

The aim was examination of the relationship between visual short-term memory of objects as well as audiovisual short-term memory, and particular nonverbal and language abilities.

METHODS AND PROCEDURES

The study included 7-9-year-old children with DLD and matched control group. Participants completed the Language Development Test, the Stanford-Binet IQ scale (SB5), and two short-term memory tasks: immediate recall of the visually presented pictograms and immediate recall of audiovisually presented sequences of syllables.

OUTCOMES AND RESULTS

The results revealed diminished levels of short-term visual memory for objects as well as audiovisual memory in children with DLD. However, there were no group differences in the control task of WM.

CONCLUSIONS AND IMPLICATIONS

Results supported the idea of diminished abilities in children with DLD to perform mental operations on verbalizable visual objects. Importantly non-verbal working memory ability, which cannot easily be supported by verbal representations, is at typical levels. This suggests that verbalization ability should be taken into account in the assessment of seemingly non-verbal cognitive functions among children with DLD.

A Role for Visual Memory in Vocabulary Development: A Systematic Review and Meta-Analysis

Although attention and early associative learning in preverbal children is predominantly driven by rapid eye-movements in response to moving visual stimuli and sounds/words (e.g., associating the word "bottle" with the object), the literature examining the role of visual attention and memory in ongoing vocabulary development across childhood is limited. Thus, this systematic review and meta-analysis examined the association between visual memory and vocabulary development, including moderators such as age and task selection, in neurotypical children aged 2-to-12 years, from the brain-based perspective of cognitive neuroscience. Visual memory tasks were classified according to the visual characteristics of the stimuli and the neural networks known to preferentially process such information, including consideration of the distinction between the ventral visual stream (processing more static visuo-perceptual details, such as form or colour) and the more dynamic dorsal visual stream (processing spatial temporal action-driven information). Final classifications included spatio-temporal span tasks, visuo-perceptual or spatial concurrent array tasks, and executive judgment tasks. Visuo-perceptual concurrent array tasks, reliant on ventral stream processing, were moderately associated with vocabulary, while tasks measuring spatio-temporal spans, associated with dorsal stream processing, and executive judgment tasks (central executive), showed only weak correlations with vocabulary. These findings have important implications for health professionals and researchers interested in language, as they advocate for the development of more targeted language learning interventions that include specific and relevant aspects of visual processing and memory, such as ventral stream visuo-perceptual details (i.e., shape or colour).

Quantitative MRI reveals differences in striatal myelin in children with DLD

Developmental language disorder (DLD) is a common neurodevelopmental disorder characterised by receptive or expressive language difficulties or both. While theoretical frameworks and empirical studies support the idea that there may be neural correlates of DLD in frontostriatal loops, findings are inconsistent across studies. Here, we use a novel semiquantitative imaging protocol - multi-parameter mapping (MPM) - to investigate microstructural neural differences in children with DLD. The MPM protocol allows us to reproducibly map specific indices of tissue microstructure. In 56 typically developing children and 33 children with DLD, we derived maps of (1) longitudinal relaxation rate R1 (1/T1), (2) transverse relaxation rate R2* (1/T2*), and (3) Magnetization Transfer saturation (MTsat). R1 and MTsat predominantly index myelin, while R2* is sensitive to iron content. Children with DLD showed reductions in MTsat values in the caudate nucleus bilaterally, as well as in the left ventral sensorimotor cortex and Heschl's gyrus. They also had globally lower R1 values. No group differences were noted in R2* maps. Differences in MTsat and R1 were coincident in the caudate nucleus bilaterally. These findings support our hypothesis of corticostriatal abnormalities in DLD and indicate abnormal levels of myelin in the dorsal striatum in children with DLD.

A Short and Engaging Adaptive Working-Memory Intervention for Children with Developmental Language Disorder: Effects on Language and Working Memory

Recent research has suggested that working-memory training interventions may benefit children with developmental language disorder (DLD). The current study investigated a short and engaging adaptive working-memory intervention that targeted executive skills and aimed to improve both language comprehension and working-memory abilities in children with DLD. Forty-seven 6- to 10-year-old children with DLD were randomly allocated to an executive working-memory training intervention (n = 24) or an active control group (n = 23). A pre-test/intervention/post-test/9-month-follow-up design was used. Outcome measures included assessments of language (to evaluate far transfer of the training) and working memory (to evaluate near transfer of the training). Hierarchical multiple regression analyses controlling for pre-intervention performance and age found the group to be a significant predictor of sentence comprehension and of performance on six untrained working-memory measures at post-intervention and 9-month follow-up. Children in the intervention group showed significantly higher language comprehension and working-memory scores at both time points than children in the active control group. The intervention programme showed the potential to improve working memory and language comprehension in children with DLD and demonstrated several advantages: it involved short sessions over a short period, caused little disruption in the school day, and was enjoyed by children.

A longitudinal study of the phonological organisation of novel word forms in children with developmental language disorder

Purpose: Deficits in the production of novel words, such as in nonword repetition tasks, are one of the early hallmarks of developmental language disorder (DLD). In children with DLD, the production of novel nonwords is characterised by speech sound inaccuracy. The focus of the present study is on the stable organisation of phonological sequences. Specifically, we aimed to identify the persistence of deficits in accuracy and in variability in sound sequencing in novel word production from pre-school to the early school years.Method: Children with and without DLD produced a set of six nonwords 12 times each, initially collected when children were 4- to 5-years old. Children repeated this task over the course of two years. Analyses included phonetic accuracy as well as network science indices of sound sequence organisation.Result: Children with DLD were less accurate than their peers with typical language at each timepoint, and their productions were markedly variable, as revealed by network science metrics; these children never converged with their peers with typical language.Conclusion: The findings suggest a unique deficit in phonological sequence production that persists beyond the pre-school years. These results offer new theoretical and clinical insights into mechanisms that underlie deficits in novel word form learning.

Phonological characteristics of novel gesture production in children with developmental language disorder: Longitudinal findings

Children with developmental language disorder (DLD; aka specific language impairment) are characterized based on deficits in language, especially morphosyntax, in the absence of other explanatory conditions. However, deficits in speech production, as well as fine and gross motor skill, have also been observed, implicating both the linguistic and motor systems. Situated at the intersection of these domains, and providing insight into both, is manual gesture. In the current work, we asked whether children with DLD showed phonological deficits in the production of novel gestures and whether gesture production at 4 years of age is related to language and motor outcomes two years later. Twenty-eight children (14 with DLD) participated in a two-year longitudinal novel gesture production study. At the first and final time points, language and fine motor skills were measured and gestures were analyzed for phonological feature accuracy, including handshape, path, and orientation. Results indicated that, while early deficits in phonological accuracy did not persist for children with DLD, all children struggled with orientation while handshape was the most accurate. Early handshape and orientation accuracy were also predictive of later language skill, but only for the children with DLD. Theoretical and clinical implications of these findings are discussed.