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

Sequence learning in the human brain: a functional neuroanatomical meta-analysis of serial reaction time studies

Sequence learning underlies numerous motor, cognitive, and social skills. Previous models and empirical investigations of sequence learning in humans and non-human animals have implicated cortico-basal ganglia-cerebellar circuitry as well as other structures. To systematically examine the functional neuroanatomy of sequence learning in humans, we conducted a series of neuroanatomical meta-analyses. We focused on the serial reaction time (SRT) task. This task, which is the most widely used paradigm for probing sequence learning in humans, allows for the rigorous control of visual, motor, and other factors. Controlling for these factors (in sequence-random block contrasts), sequence learning yielded consistent activation only in the basal ganglia, across the striatum (anterior/mid caudate nucleus and putamen) and the globus pallidus. In contrast, when visual, motor, and other factors were not controlled for (in a global analysis with all sequence-baseline contrasts, not just sequence-random contrasts), premotor cortical and cerebellar activation were additionally observed. The study provides solid evidence that, at least as tested with the visuo-motor SRT task, sequence learning in humans relies on the basal ganglia, whereas cerebellar and premotor regions appear to contribute to aspects of the task not related to sequence learning itself. The findings have both basic research and translational implications

Priming vs. rhyming: orthographic and phonological representations in the left and right hemispheres

The right cerebral hemisphere has long been argued to lack phonological processing capacity. Recently, however, a sex difference in the cortical representation of phonology has been proposed, suggesting discrete left hemisphere lateralization in males and more distributed, bilateral representation of function in females. To evaluate this hypothesis and shed light on sex differences in the phonological processing capabilities of the left and right hemispheres, we conducted two experiments. Experiment 1 assessed phonological activation implicitly (masked homophone priming), testing 52 (M = 25, F = 27; mean age 19.23 years, SD 1.64 years) strongly right-handed participants. Experiment 2 subsequently assessed the explicit recruitment of phonology (rhyme judgement), testing 50 (M = 25, F = 25; mean age 19.67 years, SD 2.05 years) strongly right-handed participants. In both experiments the orthographic overlap between stimulus pairs was strictly controlled using DICE [Brew, C., &amp; McKelvie, D. (1996). Word-pair extraction for lexicography. In K. Oflazer &amp; H. Somers (Eds.), Proceedings of the second international conference on new methods in language processing (pp. 45&ndash;55). Ankara: VCH], such that pairs shared (a) high orthographic and phonological similarity (e.g., not&ndash;KNOT); (b) high orthographic and low phonological similarity (e.g., pint&ndash;HINT); (c) low orthographic and high phonological similarity (e.g., use&ndash;EWES); or (d) low orthographic and low phonological similarity (e.g., kind&ndash;DONE). As anticipated, high orthographic similarity facilitated both left and right hemisphere performance, whereas the left hemisphere showed greater facility when phonological similarity was high. This difference in hemispheric processing of phonological representations was especially pronounced in males, whereas female performance was far less sensitive to visual field of presentation across both implicit and explicit phonological tasks. As such, the findings offer behavioural evidence indicating that though both hemispheres are capable of orthographic analysis, phonological processing is discretely lateralised to the left hemisphere in males, but available in both the left and right hemisphere in females.<br /

Verbal declarative memory impairments in specific language impairment are related to working memory deficits

This study examined verbal declarative memory functioning in SLI and its relationship to working memory. Encoding, recall, and recognition of verbal information was examined in children with SLI who had below average working memory (SLILow WM), children with SLI who had average working memory (SLIAvg. WM) and, a group of non-language impaired children with average working memory (TDAvg. WM). The SLILow WM group was significantly worse than both the SLIAvg. WM and TDAvg. WM groups at encoding verbal information and at retrieving verbal information following a delay. In contrast, the SLIAvg. WM group showed no verbal declarative memory deficits. The study demonstrates that verbal declarative memory deficits in SLI only occur when verbal working memory is impaired. Thus SLI declarative memory is largely intact and deficits are likely to be related to working memory impairments

Sex differences in the prevalence of oppositional defiant disorder during middle childhood: a meta-analysis

This review provides a meta-analysed male:female prevalence ratio of oppositional defiant disorder (ODD) during middle childhood in non-referred children. It also analyses sex differences in prevalence across cultures and over time. A systematic search for studies via the following sources was conducted: PsycInfo, Web of Knowledge, Medline Complete, Scopus, EMBASE, InfoRMIT, Psychological and Behavioural Sciences Collection, Cochrane Library, PubMed and ProQuest Health. The studies presented in two previous systematic reviews were also added to the search results. Inclusion/exclusion criteria were then applied and final studies were appraised for their methodological quality. Nineteen independent effect sizes met full inclusion criteria (aggregated sample N&thinsp;=&thinsp;44,107). Overall, the prevalence of ODD was significantly higher in boys than girls (RR&thinsp;=&thinsp;1.59, 95&nbsp;% CI [1.36, 1.86], p&thinsp;&lt;&thinsp;0.001), with the male:female prevalence ratio found to be 1.59:1. Sex differences in prevalence were significant in Western (RR&thinsp;=&thinsp;1.80, 95&nbsp;% CI [1.55, 2.10], p&thinsp;&lt;&thinsp;0.001) but not non-Western cultures (RR&thinsp;=&thinsp;1.08, 95&nbsp;% CI [0.76-1.53], p&thinsp;&gt;&thinsp;0.05). Sex differences in prevalence were significant in studies published prior to and post the year 2000 (RR&thinsp;=&thinsp;1.57, 95&nbsp;% CI [1.22, 2.02], p&thinsp;&lt;&thinsp;0.001; RR&thinsp;=&thinsp;1.64, 95&nbsp;% CI [1.35, 2.00], p&thinsp;&lt;&thinsp;0.001), and were consistent between these two periods (Q, 1&thinsp;=&thinsp;0.36, p&thinsp;=&thinsp;&gt;&thinsp;0.05). The sex differences in ODD prevalence are discussed within the context of (i) predominant theories of sex differences in externalising behaviours, and (ii) departure from the sex-differences pattern found for other disruptive behavioural disorders

Statistical Learning in Specific Language Impairment and Autism Spectrum Disorder: A Meta-Analysis

Impairments in statistical learning might be a common deficit among individuals with Specific Language Impairment (SLI) and Autism Spectrum Disorder (ASD). Using meta-analysis, we examined statistical learning in SLI (14 studies, 15 comparisons) and ASD (13 studies, 20 comparisons) to evaluate this hypothesis. Effect sizes were examined as a function of diagnosis across multiple statistical learning tasks (Serial Reaction Time, Contextual Cueing, Artificial Grammar Learning, Speech Stream, Observational Learning, Probabilistic Classification). Individuals with SLI showed deficits in statistical learning relative to age-matched controls g = .47, 95% CI [.28, .66], p < .001. In contrast, statistical learning was intact in individuals with ASD relative to controls, g = –.13, 95% CI [–.34, .08], p = .22. Effect sizes did not vary as a function of task modality or participant age. Our findings inform debates about overlapping social-communicative difficulties in children with SLI and ASD by suggesting distinct underlying mechanisms. In line with the procedural deficit hypothesis (Ullman & Pierpont, 2005), impaired statistical learning may account for phonological and syntactic difficulties associated with SLI. In contrast, impaired statistical learning fails to account for the social-pragmatic difficulties associated with ASD