Ferenc Kemény

Domain-general sequence learning deficit in specific language impairment.

OBJECTIVE Grammar-specific accounts of specific language impairment (SLI) have been challenged by recent claims that language problems are a consequence of impairments in domain-general mechanisms of learning that also play a key role in the process of language acquisition. Our studies were designed to test the generality and nature of this learning deficit by focusing on both sequential and nonsequential, and on verbal and nonverbal, domains. METHOD Twenty-nine children with SLI were compared with age-matched typically developing (TD) control children using (a) a serial reaction time task (SRT), testing the learning of motor sequences; (b) an artificial grammar learning (AGL) task, testing the extraction of regularities from auditory sequences; and (c) a weather prediction task (WP), testing probabilistic category learning in a nonsequential task. RESULTS For the 2 sequence learning tasks, a significantly smaller proportion of children showed evidence of learning in the SLI than in the TD group (χ2 tests, p < .001 for the SRT task, p < .05 for the AGL task), whereas the proportion of learners on the WP task was the same in the 2 groups. The level of learning for SLI learners was comparable with that of TD children on all tasks (with great individual variation). CONCLUSIONS Taken together, these findings suggest that domain-general processes of implicit sequence learning tend to be impaired in SLI. Further research is needed to clarify the relationship of deficits in implicit learning and language.

Executive functions and the contribution of short-term memory span in children with specific language impairment.

OBJECTIVE An increasing number of results show that specific language impairment (SLI) is often associated with impairments in executive functions (EF), but the nature, extent, and generality of these deficits is yet unclear. The aim of the paper is to present results from verbal and nonverbal tasks examining EF in children with SLI and their age-matched typically developing (TD) peers. METHOD 31 children with SLI were tested on verbal and nonverbal versions of simple and complex span, fluency, N-back, and Stroop tasks. Their performance was compared with 31 TD children matched on age and nonverbal IQ. The design allows us to examine whether executive functions are similarly affected in SLI in verbal and nonverbal tasks. RESULTS The SLI group showed difficulties in verbal versions of complex span (listening span task) and fluency but not in inhibition (Stroop tasks) relative to TD age-matched children. Including simple verbal span (digit span) as a covariate eliminated group differences on both verbal tasks. CONCLUSIONS Children with SLI were found to be impaired on several verbal measures of EF, but these differences were largely due to more fundamental deficits in verbal short-term span.

Learning and Overnight Retention in Declarative Memory in Specific Language Impairment

We examined learning and retention in nonverbal and verbal declarative memory in Hungarian children with (n = 21) and without (n = 21) SLI. Recognition memory was tested both 10 minutes and one day after encoding. On nonverbal items, only the children with SLI improved overnight, with no resulting group differences in performance. In the verbal domain, the children with SLI consistently showed worse performance than the typically-developing children, but the two groups showed similar overnight changes. The findings suggest the possibility of spared or even enhanced declarative memory consolidation in SLI.

Visuo-spatial cueing in children with differential reading and spelling profiles

Dyslexia has been claimed to be causally related to deficits in visuo-spatial attention. In particular, inefficient shifting of visual attention during spatial cueing paradigms is assumed to be associated with problems in graphemic parsing during sublexical reading. The current study investigated visuo-spatial attention performance in an exogenous cueing paradigm in a large sample (N = 191) of third and fourth graders with different reading and spelling profiles (controls, isolated reading deficit, isolated spelling deficit, combined deficit in reading and spelling). Once individual variability in reaction times was taken into account by means of z-transformation, a cueing deficit (i.e. no significant difference between valid and invalid trials) was found for children with combined deficits in reading and spelling. However, poor readers without spelling problems showed a cueing effect comparable to controls, but exhibited a particularly strong right-over-left advantage (position effect). Isolated poor spellers showed a significant cueing effect, but no position effect. While we replicated earlier findings of a reduced cueing effect among poor nonword readers (indicating deficits in sublexical processing), we also found a reduced cueing effect among children with particularly poor orthographic spelling (indicating deficits in lexical processing). Thus, earlier claims of a specific association with nonword reading could not be confirmed. Controlling for ADHD-symptoms reported in a parental questionnaire did not impact on the statistical analysis, indicating that cueing deficits are not caused by more general attentional limitations. Between 31 and 48% of participants in the three reading and/or spelling deficit groups as well as 32% of the control group showed reduced spatial cueing. These findings indicate a significant, but moderate association between certain aspects of visuo-spatial attention and subcomponents of written language processing, the causal status of which is yet unclear.

Sleep-independent off-line enhancement and time of the day effects in three forms of skill learning.

The role of sleep in memory and skill-learning processes is an important and widely debated issue. The current study explores the nature of the relationship between sleep and off-line improvement in three tasks for measuring different aspects of skill learning: the serial reaction time (SRT) task, which is a motor sequence learning task; the artificial grammar learning (AGL) task, testing abstract verbal sequence learning; and the weather prediction (WP) task, which is a non-sequential categorization task. Each participant was tested on one of the three tasks twice, either in a Wake condition (with a 12-h off-line period without sleep), or in a Sleep condition (with sleep). Results showed no sleep-related off-line improvement throughout the three tasks in a two-session re-learning design, but a sleep-independent time-based effect was found on the SRT task. No performance boost was observed in the WP and AGL tasks. Performance on the SRT showed a time of the day effect: the Sleep group outperforming the Wake group; however, this effect was restricted to overall response latencies. Taken together, no evidence was found in favor of sleep-dependent off-line enhancement in skill learning, but methodological concerns warrant further investigations.

Multimodal sequence learning.

While sequence learning research models complex phenomena, previous studies have mostly focused on unimodal sequences. The goal of the current experiment is to put implicit sequence learning into a multimodal context: to test whether it can operate across different modalities. We used the Task Sequence Learning paradigm to test whether sequence learning varies across modalities, and whether participants are able to learn multimodal sequences. Our results show that implicit sequence learning is very similar regardless of the source modality. However, the presence of correlated task and response sequences was required for learning to take place. The experiment provides new evidence for implicit sequence learning of abstract conceptual representations. In general, the results suggest that correlated sequences are necessary for implicit sequence learning to occur. Moreover, they show that elements from different modalities can be automatically integrated into one unitary multimodal sequence.

Visual attention span performance in German-speaking children with differential reading and spelling profiles: No evidence of group differences

An impairment in the visual attention span (VAS) has been suggested to hamper reading performance of individuals with dyslexia. It is not clear, however, if the very nature of the deficit is visual or verbal and, importantly, if it affects spelling skills as well. The current study investigated VAS by means of forced choice tasks with letters and symbols in a sample of third and fourth graders with age-adequate reading and spelling skills (n = 43), a typical dyslexia profile with combined reading and spelling deficits (n = 26) and isolated spelling deficits (n = 32). The task was devised to contain low phonological short-term memory load and to overcome the limitations of oral reports. Notably, eye-movements were monitored to control that children fixated the center of the display when stimuli were presented. Results yielded no main effect of group as well as no group-related interactions, thus showing that children with dyslexia and isolated spelling deficits did not manifest a VAS deficit for letters or symbols once certain methodological aspects were controlled for. The present results could not replicate previous evidence for the involvement of VAS in reading and dyslexia.

Impaired sequential and partially compensated probabilistic skill learning in Parkinson's disease

The striatal dopaminergic dysfunction in Parkinsons disease (PD) has been associated with deficits in skill learning in numerous studies, but some of the findings remain controversial. Our aim was to explore the generality of the learning deficit using two widely reported skill learning tasks in the same group of Parkinsons patients. Thirty‐four patients with PD (mean age: 62.83 years, SD: 7.67) were compared to age‐matched healthy adults. Two tasks were employed: the Serial Reaction Time Task (SRT), testing the learning of motor sequences, and the Weather Prediction (WP) task, testing non‐sequential probabilistic category learning. On the SRT task, patients with PD showed no significant evidence for sequence learning. These results support and also extend previous findings, suggesting that motor skill learning is vulnerable in PD. On the WP task, the PD group showed the same amount of learning as controls, but they exploited qualitatively different strategies in predicting the target categories. While controls typically combined probabilities from multiple predicting cues, patients with PD instead focused on individual cues. We also found moderate to high correlations between the different measures of skill learning. These findings support our hypothesis that skill learning is generally impaired in PD, and can in some cases be compensated by relying on alternative learning strategies.

Print-, sublexical and lexical processing in children with reading and/or spelling deficits: An ERP study

Findings on the neurophysiological correlates of developmental dyslexia are mixed, due to the differential conceptualization of the impairment. Studies differ on whether participants with developmental dyslexia are recruited based on reading skills only or reading as well as spelling skills. The current study contrasts the contribution of impaired reading and spelling to ERP correlates of print sensitivity, lexico-semantic access and sensitivity to orthographic regularities. Four groups of children were recruited: isolated reading deficit, isolated spelling deficit, combined reading and spelling deficit, and typically developing. Their neural correlates (EEG) of word, pseudohomophone, and pseudoword reading, as well as false font processing were compared. 1) All groups showed higher N1 amplitudes to letters than to false fonts. 2) Good spellers exhibited more negative N400 amplitudes for meaningless (pseudowords) than for meaningful stimuli (words and pseudohomophones). This effect was not observed in poor spellers. 3) Good readers showed sensitivity to orthographic regularities in a later time window (700-900 ms), whereas this was not the case for poor readers. 1) Print sensitivity is not affected by reading and/or spelling deficit in German-speaking 3rd graders. 2) Spelling deficits are associated with a reduced orthographic lexicon, 3) Reading deficits are associated with atypical use of sublexical information. As this effect was observed after lexico-semantic access, the results are discussed in terms of a possible orthographic reanalysis hypothesis.

THE EFFECT OF EMOTIONAL CUES ON EVENT-BASED PROSPECTIVE MEMORY PERFORMANCE IN OBSESSIVE COMPULSIVE DISORDER

Introduction Prospective memory (PM) is defined as the ability to formulate, retain and carry out intentions, plans and promises at the appropriate time or in the appropriate context. Previous studies found evidence that patients with obsessive compulsive disorder (OCD) beside the executive deficit manifest impairment in various PM tasks (Harris et al., 2010; Racsmany et al., 2011; Yang et al., 2015). Our aim with this study was to investigate the influence of emotional stimuli on event-based PM performance in OCD. Material And Methods Thirteen OCD patients took part in the study. An emotional event-based PM task was administered to each participant under two conditions: (1) a baseline condition in which no PM stimuli occurred and the ongoing trials were presented in three blocks based on the stimulus valence as positive, negative and neutral and a (2) PM condition in which beside the ongoing trials positive, negative and neutral PM stimuli also occurred. There were two arrows, pointing right and left, and one of them was black, the other was white. The order of colours varied randomly. Two pictures also appeared on the screen and were located at equal distances above and below the arrows. Participants in the baseline condition were asked to press the arrow key corresponding to the black arrow (ongoing task). In the PM condition the task was similar, except participants were told to press the up-arrow key if the two pictures above and below the fixation point were the same on any trial, this instruction served as a PM task. Results And Conclusions Based on our preliminary results and analysis it seems that the stimulus valence does not influence significantly the accuracy rate and reaction time scores on PM trials. The emotional cues have no beneficial effect on patients PM performance as suggested in previous findings. Further analysis and the recruitment of a healthy control group are under way.