Klara Marton

Visuo‐spatial processing and executive functions in children with specific language impairment

BACKGROUND Individual differences in complex working memory tasks reflect simultaneous processing, executive functions, and attention control. Children with specific language impairment (SLI) show a deficit in verbal working memory tasks that involve simultaneous processing of information. AIMS The purpose of the study was to examine executive functions and visuospatial processing and working memory in children with SLI and in their typically developing peers (TLD). Experiment 1 included 40 children with SLI (age = 5; 3-6;10) and 40 children with TLD (age = 5; 3-6;7); Experiment 2 included 25 children with SLI (age = 8;2-11; 2) and 25 children with TLD (age = 8; 3-11; 0). It was examined whether the difficulties that children with SLI show in verbal working memory tasks are also present in visuo-spatial working memory. METHODS & PROCEDURES In Experiment 1, childrens performance was measured with three visuo-spatial processing tasks: space visualization, position in space, and design copying. The stimuli in Experiment 2 were two widely used neuropsychological tests: the Wisconsin Card Sorting Test-64 (WCST-64) and the Tower of London test (TOL). OUTCOMES & RESULTS In Experiment 1, children with SLI performed more poorly than their age-matched peers in all visuo-spatial working memory tasks. There was a subgroup within the SLI group that included children whose parents and teachers reported a weakness in the childs attention control. These children showed particular difficulties in the tasks of Experiment 1. The results support Engles attention control theory: individuals need good attention control to perform well in visuo-spatial working memory tasks. In Experiment 2, the children with SLI produced more perseverative errors and more rule violations than their peers. CONCLUSIONS Executive functions have a great impact on SLI childrens working memory performance, regardless of domain. Tasks that require an increased amount of attention control and executive functions are more difficult for the children with SLI than for their peers. Most children with SLI scored either below average or in the low average range on the neuropsychological tests that measured executive functions.

Effect of Sentence Length and Complexity on Working Memory Performance in Hungarian Children with Specific Language Impairment (SLI): A Cross-Linguistic Comparison.

BACKGROUND English-speaking children with specific language impairment (SLI) perform more poorly than their typically developing peers in verbal working memory tasks where processing and storage are simultaneously required. Hungarian is a language with a relatively free word order and a rich agglutinative morphology. AIMS To examine the effect of linguistic structure on working memory performance. It was examined whether syntactic complexity has a larger impact on working memory performance than sentence length in Hungarian-speaking children, similar to the findings in English speaking children. METHODS & PROCEDURES In Experiment 1, performance accuracy was measured with two linguistic span tasks that included stimuli with varying sentence length and syntactic complexity. Experiment 2 examined the impact of sentence length and morphological complexity on working memory performance. OUTCOMES & RESULTS Children with SLI performed more poorly than their age-matched peers in all working memory tasks. Their error patterns differed from those of children with typical language development. Children with SLI produced a high number of interference errors that indicate poor executive functions. The findings were compared with previous results of English-speaking children. Complexity affected working memory performance accuracy differently across languages. In English, it was the increase of syntactic complexity that resulted in a decrease in performance accuracy, whereas in Hungarian, it was the morphological complexity that had a large impact on working memory performance. CONCLUSIONS Working memory performance depends on the linguistic characteristics of the language tested. In both English- and Hungarian-speaking children, complexity has a larger effect on verbal working memory performance than the length of the stimuli. However, complexity affects working memory performance accuracy differently across languages.

Positive effects of a computerised working memory and executive function training on sentence comprehension in aphasia

ABSTRACT Aphasia, the language disorder following brain damage, is frequently accompanied by deficits of working memory (WM) and executive functions (EFs). Recent studies suggest that WM, together with certain EFs, can play a role in sentence comprehension in individuals with aphasia (IWA), and that WM can be enhanced with intensive practice. Our aim was to investigate whether a combined WM and EF training improves the understanding of spoken sentences in IWA. We used a pre–post-test case control design. Three individuals with chronic aphasia practised an adaptive training task (a modified n-back task) three to four times a week for a month. Their performance was assessed before and after the training on outcome measures related to WM and spoken sentence comprehension. One participant showed significant improvement on the training task, another showed a tendency for improvement, and both of them improved significantly in spoken sentence comprehension. The third participant did not improve on the training task, however, she showed improvement on one measure of spoken sentence comprehension. Compared to controls, two individuals improved at least in one condition of the WM outcome measures. Thus, our results suggest that a combined WM and EF training can be beneficial for IWA.

THE EFFECT OF PLAUSIBILITY ON SENTENCE COMPREHENSION AMONG OLDER ADULTS AND ITS RELATION TO COGNITIVE FUNCTIONS

Background/Study Context: Older adults show age-related decline in complex-sentence comprehension. This has been attributed to a decrease in cognitive abilities that may support language processing, such as working memory (e.g., Caplan, DeDe, Waters, & Michaud, 2011,Psychology and Aging, 26, 439–450). The authors examined whether older adults have difficulty comprehending semantically implausible sentences and whether specific executive functions contribute to their comprehension performance. Methods: Forty-two younger adults (aged 18–35) and 42 older adults (aged 55–75) were tested on two experimental tasks: a multiple negative comprehension task and an information processing battery. Results: Both groups, older and younger adults, showed poorer performance for implausible sentences than for plausible sentences; however, no interaction was found between plausibility and age group. A regression analysis revealed that inhibition efficiency, as measured by a task that required resistance to proactive interference, predicted comprehension of implausible sentences in older adults only. Consistent with the compensation hypothesis, the older adults with better inhibition skills showed better comprehension than those with poor inhibition skills. Conclusion: The findings suggest that semantic implausibility, along with syntactic complexity, increases linguistic and cognitive processing loads on auditory sentence comprehension. Moreover, the contribution of inhibitory control to the processing of semantic plausibility, particularly among older adults, suggests that the relationship between cognitive ability and language comprehension is strongly influenced by age.

Verbal strategies and nonverbal cues in school-age children with and without specific language impairment (SLI)

BACKGROUND Considerable evidence suggests that performance across a variety of cognitive tasks is effectively supported by the use of verbal and nonverbal strategies. Studies exploring the usefulness of such strategies in children with specific language impairment (SLI) are scarce and report inconsistent findings. AIMS To examine the effects of induced labelling and auditory cues on the performance of children with and without SLI during a categorization task. METHODS & PROCEDURES Sixty-six school-age children (22 with SLI, 22 age-matched controls, 22 language-matched controls) completed three versions of a computer-based categorization task: one baseline, one requiring overt labelling and one with auditory cues (tones) on randomized trial blocks. OUTCOMES & RESULTS Labelling had no effect on performance for typically developing children but resulted in lower accuracy and longer reaction time in children with SLI. The presence of tones had no effect on accuracy but resulted in faster reaction time and post-error slowing across groups. CONCLUSIONS & IMPLICATIONS Verbal strategy use was ineffective for typically developing children and negatively affected children with SLI. All children showed faster performance and increased performance monitoring as a result of tones. Overall, effects of strategy use in children appear to vary based on task demands, strategy domain, age and language ability. Results suggest that children with SLI may benefit from auditory cues in their clinical intervention but that further research is needed to determine when and how verbal strategies might similarly support performance in this population.

The Influence of Phonotactic Probability on Word Recognition in Toddlers.

This study examined the influence of phonotactic probability on word recognition in English-speaking toddlers. Typically developing toddlers completed a preferential looking paradigm using familiar words, which consisted of either high or low phonotactic probability sound sequences. The participants’ looking behavior was recorded in response to correctly-produced and incorrectly-produced forms of familiar words. Results indicate that toddlers were more sensitive to mispronunciations of high probability words as compared to low probability words. Toddlers’ word recognition skills were more closely related to the frequency with which they have heard and produced phonological sequences, rather than word familiarity. These findings are discussed in terms of toddlers with expressive language delay.

Information Level and Young Children's Phonological Accuracy.

The influence of information level on the production accuracy of 20 children (22 to 28 months) was examined. The data were childrens productions of nouns in sets of utterances referring to triplets of pictures representing noun-verb-noun utterances. In each triplet one noun remained the same, thus decreasing in information value from the first to the third picture (new, moderately old, and old information). Words representing new information were produced more accurately than words representing old information. The types of errors did not differ. Further evidence of this effect was provided by an examination of the duration of new versus old word productions by 12 of the children. Productions encoding new information were consistently longer on average than those encoding old information. The result provide experimental evidence of an effect observed in adults that indicates early sensitivity to information level. However, because of the childrens young age, the effects are characterized as a speaker-internal process that only serendipitously corresponds to listener needs.

Does Working Memory Enhance or Interfere With Speech Fluency in Adults Who Do and Do Not Stutter? Evidence From a Dual-Task Paradigm

PURPOSE The present study examined whether engaging working memory in a secondary task benefits speech fluency. Effects of dual-task conditions on speech fluency, rate, and errors were examined with respect to predictions derived from three related theoretical accounts of disfluencies. METHOD Nineteen adults who stutter and twenty adults who do not stutter participated in the study. All participants completed 2 baseline tasks: a continuous-speaking task and a working-memory (WM) task involving manipulations of domain, load, and interstimulus interval. In the dual-task portion of the experiment, participants simultaneously performed the speaking task with each unique combination of WM conditions. RESULTS All speakers showed similar fluency benefits and decrements in WM accuracy as a result of dual-task conditions. Fluency effects were specific to atypical forms of disfluency and were comparable across WM-task manipulations. Changes in fluency were accompanied by reductions in speaking rate but not by corresponding changes in overt errors. CONCLUSIONS Findings suggest that WM contributes to disfluencies regardless of stuttering status and that engaging WM resources while speaking enhances fluency. Further research is needed to verify the cognitive mechanism involved in this effect and to determine how these findings can best inform clinical intervention.

Cognitive Flexibility in Preschool Children with and without Stuttering Disorders

PURPOSE Multifactorial explanations of developmental stuttering suggest that difficulties in self-regulation and weak attentional flexibility contribute to persisting stuttering. We tested this prediction by examining whether preschool-age children who stutter (CWS) shift their attention less flexibly than children who do not stutter (CWNS) during a modified version of the Dimension Card Change Sort (DCCS), a reliable measure of attention switching for young children. METHODS Sixteen CWS (12 males) and 30 children CWNS (11 males) participated in the study. Groups were matched on age (CWS: M=49.63, SD=10.34, range=38-80months; CWNS: M=50.63, SD=9.82, range=37-74months), cognitive ability, and language skills. All children completed a computer-based variation of the DCCS, in which they matched on-screen bivalent stimuli to response buttons based on rules that switched mid-task. RESULTS Results showed increased slowing for CWS compared to controls during the postswitch phase, as well as contrasting patterns of speed-accuracy tradeoff for CWS and CWNS as they moved from the preswitch to postswitch phase of the task. CONCLUSIONS Group differences in performance suggest that early stuttering may be associated with difficulty shifting attention efficiently and greater concern about errors. Findings are consistent with a growing literature indicating links between weak attentional control and persisting developmental stuttering.

Working Memory and Interference Control in Children with Specific Language Impairment

Language and communication disorders are often associated with deficits in working memory (WM) and interference control. WM studies involving children with specific language impairment (SLI) have traditionally been framed using either resource theories or decay accounts, particularly Baddeleys model. Although significant interference problems in children with SLI are apparent in error analysis data from WM and language tasks, interference theories and paradigms have not been widely used in the SLI literature. A primary goal of the present paper is to provide an overview of interference deficits in children with SLI. Review of the extant literature on interference control shows deficits in this population; however, the source and the nature of the deficit remain unclear. Thus, a second key aim in our review is to demonstrate the need for theoretically driven experimental paradigms in order to better understand individual variations associated with interference weaknesses in children with SLI.