Monthly Archives: July 2011
Twelve- and 15-month-old infants who received simple verbal cues at encoding and retrieval exhibited superior representational flexibility on an imitation task compared to infants who did not receive those cues. Verbal cues can help early-verbal infants overcome perceptual dissimilarity and express knowledge in novel situations.
The Enigma of Number: Why Children Find the Meanings of Even Small Number Words Hard to Learn and How We Can Help Them Do Better
Although number words are common in everyday speech, learning their meanings is an arduous, drawn-out process for most children, and the source of this delay has long been the subject of inquiry. Children begin by identifying the few small numerosities that can be named without counting, and this has prompted further debate over whether there is a specific, capacity-limited system for representing these small sets, or whether smaller and larger sets are both represented by the same system. Here we present a formal, computational analysis of number learning that offers a possible solution to both puzzles. This analysis indicates that once the environment and the representational demands of the task of learning to identify sets are taken into consideration, a continuous system for learning, representing and discriminating set-sizes can give rise to effective discontinuities in processing. At the same time, our simulations illustrate how typical prenominal linguistic constructions (“there are three balls”) structure information in a way that is largely unhelpful for discrimination learning, while suggesting that postnominal constructions (“balls, there are three”) will facilitate such learning. A training-experiment with three-year olds confirms these predictions, demonstrating that rapid, significant gains in numerical understanding and competence are possible given appropriately structured postnominal input. Our simulations and results reveal how discrimination learning tunes children’s systems for representing small sets, and how its capacity-limits result naturally out of a mixture of the learning environment and the increasingly complex task of discriminating and representing ever-larger number sets. They also explain why children benefit so little from the training that parents and educators usually provide. Given the efficacy of our intervention, the ease with which it can be implemented, and the large body of research showing how early numerical ability predicts later educational outcomes, this simple discovery may have far-reaching consequences.
from PLoS ONE
Communicating without a functioning language system: Implications for the role of language in mentalizing
A debated issue in the relationship between language and thought is how our linguistic abilities are involved in understanding the intentions of others (’mentalizing’). The results of both theoretical and empirical work have been used to argue that linguistic, and more specifically, grammatical, abilities are crucial in representing the mental states of others. Here we contribute to this debate by investigating how damage to the language system influences the generation and understanding of intentional communicative behaviors. Four patients with pervasive language difficulties (severe global or agrammatic aphasia) engaged in an experimentally controlled non-verbal communication paradigm, which required signaling and understanding a communicative message. Despite their profound language problems they were able to engage in recipient design as well as intention recognition, showing similar indicators of mentalizing as have been observed in the neurologically healthy population. Our results show that aspects of the ability to communicate remain present even when core capacities of the language system are dysfunctional.
Electrophysiological auditory responses and language development in infants with periventricular leukomalacia
This study presents evidence suggesting that electrophysiological responses to language-related auditory stimuli recorded at 46 weeks postconceptional age (PCA) are associated with language development, particularly in infants with periventricular leukomalacia (PVL). In order to investigate this hypothesis, electrophysiological responses to a set of auditory stimuli consisting of series of syllables and tones were recorded from a population of infants with PVL at 46 weeks PCA. A communicative development inventory (i.e., parent report) was applied to this population during a follow-up study performed at 14 months of age. The results of this later test were analyzed with a statistical clustering procedure, which resulted in two well-defined groups identified as the high-score (HS) and low-score (LS) groups. The event-induced power of the EEG data recorded at 46 weeks PCA was analyzed using a dimensionality reduction approach, resulting in a new set of descriptive variables. The LS and HS groups formed well-separated clusters in the space spanned by these descriptive variables, which can therefore be used to predict whether a new subject will belong to either of these groups. A predictive classification rate of 80% was obtained by using a linear classifier that was trained with a leave-one-out cross-validation technique.
from Brain and Language
The effect of knowledge on memory generally is processing. However, both conceptual and empirical reasons exist to suspect that the organizational account is incomplete. Recently a revised version of that account has been proposed under the rubric of distinctiveness theory (Rawson & Van Overschelde, 2008). The goal of the experiments reported here was to extend the distinctiveness theory to the effect of knowledge on event-based as well as item-based memory. High and low knowledge individuals were shown two lists of items, each containing domain relevant items and control items. Various orienting tasks were performed across the experiments, which in conjunction with type of material and level of knowledge defined distinctive processing. The tests required recognition of items from the second of the two lists in the presence of lures drawn from the first list as well as novel items. For domain relevant material, hits and false alarms were a direct function of knowledge, the rates of which were predicted successfully by the distinctiveness theory. Most current theories attribute the effect of knowledge on memory to organizational processing. The results of these experiments illustrate the importance of item-specific processing to supplement organizational processing in order to adequately explain skilled memory.
from the Journal of Memory and Language
Improvements in speech-recognition performance resulting from the addition of low-frequency information to electric (or vocoded) signals have attracted considerable interest in recent years. An important question is whether these improvements reflect a form of constructive perceptual interaction—whereby acoustic cues enhance the perception of electric or vocoded signals—or whether they can be explained without assuming any interaction. To address this question, speech-recognition performance was measured in 24 normal-hearing listeners using lowpass-filtered, vocoded, and “combined” (lowpass + vocoded) words presented either in quiet or in a realistic background (cafeteria noise), for different signal-to-noise ratios, different lowpass-filter cutoff frequencies, and different numbers of vocoder bands. The results of these measures were then compared to the predictions of three models of cue combination, including a “probability-summation” model and two Gaussian signal detection theory (SDT) models—one (the “independent-noises” model) involving pre-combination noises, and the other (the “late-noise” model) involving post-combination noise. Consistent with previous findings, speech-recognition performance with combined stimulation was significantly higher than performance with vocoded or lowpass stimuli alone, and it was also higher than predicted by the probability-summation model. The two Gaussian-SDT models could account quantitatively for the data. Moreover, a Bayesian model-comparison procedure demonstrated that, given the data, these two models were far more likely than the probability-summation model. Since these models do not involve any constructive-interaction mechanism, this demonstrates that constructive interactions are not needed to explain the combined-stimulation benefits measured in this study. It will be important for future studies to investigate whether this conclusion generalizes to other test conditions, including real EAS, and to further test the assumptions of these different models of the combined-stimulation advantage.
from Hearing Research
Six-year-old children can judge a speaker’s feelings either from content or paralanguage but have difficulty switching the basis of their judgments when these cues conflict. This inflexibility may relate to a lexical bias in 6-year-olds’ judgments. Two experiments tested this claim. In Experiment 1, 6-year-olds (n = 40) were as inflexible when switching from paralanguage to content as when switching from content to paralanguage. In Experiment 2, 6-year-olds (n = 32) and adults (n = 32) had more difficulty when switching between conflicting emotion cues than conflicting nonemotional cues. Thus, 6-year-olds’ inflexibility appears to be tied to the presence of conflicting emotion cues in speech rather than a bias to judge a speaker’s feelings from content.
from Child Development
In the present study, genotype–phenotype correlations in eight Dutch DFNB8/10 families with compound heterozygous mutations in TMPRSS3 were addressed. We compared the phenotypes of the families by focusing on the mutation data. The compound heterozygous variants in the TMPRSS3 gene in the present families included one novel variant, p.Val199Met, and four previously described pathogenic variants, p.Ala306Thr, p.Thr70fs, p.Ala138Glu, and p.Cys107Xfs. In addition, the p.Ala426Thr variant, which had previously been reported as a possible polymorphism, was found in one family. All affected family members reported progressive bilateral hearing impairment, with variable onset ages and progression rates. In general, the hearing impairment affected the high frequencies first, and sooner or later, depending on the mutation, the low frequencies started to deteriorate, which eventually resulted in a flat audiogram configuration. The ski-slope audiogram configuration is suggestive for the involvement of TMPRSS3. Our data suggest that not only the protein truncating mutation p.T70fs has a severe effect but also the amino acid substitutions p.Ala306Thr and p.Val199Met. A combination of two of these three mutations causes prelingual profound hearing impairment. However, in combination with the p.Ala426Thr or p.Ala138Glu mutations, a milder phenotype with postlingual onset of the hearing impairment is seen. Therefore, the latter mutations are likely to be less detrimental for protein function. Further studies are needed to distinguish possible phenotypic differences between different TMPRSS3 mutations. Evaluation of performance of patients with a cochlear implant indicated that this is a good treatment option for patients with TMPRSS3 mutations as satisfactory speech reception was reached after implantation.
Children in a school that uses corporal punishment performed significantly worse in tasks involving “executive functioning” – psychological processes such as planning, abstract thinking, and delaying gratification – than those in a school relying on milder disciplinary measures such as time-outs, according to a new study involving two private schools in a West African country.
Touch devices — most notably the iPad — are revolutionizing the lives of children, adults and seniors with special needs. Rahman estimates some 40,000 apps have been developed for this demographic.
For those of us hoping to keep our brains fit and healthy well into middle age and beyond, the latest science offers some reassurance. Activity appears to be critical, though scientists have yet to prove that exercise can ward off serious problems like Alzheimer’s disease. But what about the more mundane, creeping memory loss that begins about the time our 30s recede, when car keys and people’s names evaporate? It’s not Alzheimer’s, but it’s worrying. Can activity ameliorate its slow advance — and maintain vocabulary retrieval skills, so that the word “ameliorate” leaps to mind when needed?
from The New York Times
A man with a medical condition which meant he heard his eyeballs move in their sockets has been cured.
from the BBC
Clinical researchers at The University of Nottingham have been studying how to improve the treatment of glue ear, a condition common in children during which mucus amasses behind the ear drum and impairs hearing. Typically, grommets are inserted for ventilation, but a considerable number of patients return with infections.
To directly combat this, the researchers developed biodegradable pellets that can be implanted during grommet surgery to deliver antibiotics right to where the infections happen.
The 2011 ASHA Convention, Nov. 17–19 in San Diego, will include a number of educational sessions specifically designed for or of interest to audiology and speech-language pathology assistants. This preliminary list of courses may prove helpful as assistants and supervisors plan their convention schedules. For more information on convention, including registration, visit ASHA’s Convention webpage.
from the ASHA Leader