Monthly Archives: January 2010
Enabling self-directed computer use for individuals with cerebral palsy: a systematic review of assistive devices and technologies
Aim The purpose of this study was to systematically review published evidence on the development, use, and effectiveness of devices and technologies that enable or enhance self-directed computer access by individuals with cerebral palsy (CP).Methods Nine electronic databases were searched using keywords ‘computer’, ‘software’, ‘spastic’, ‘athetoid’, and ‘cerebral palsy’; the reference lists of articles thus identified were also searched. Thirty articles were selected for review, with 23 reports of development and usability testing of devices and seven evaluations of algorithms to increase computer recognition of input and cursor movements.Results Twenty-four studies had fewer than 10 participants with CP, with a wide age range of 5 to 77 years. Computer task performance was usually tested, but only three groups sought participant feedback on ease and comfort of use. International standards exist to evaluate effectiveness of non-keyboard devices, but only one group undertook this testing. None of the study designs were higher than American Academy for Cerebral Palsy and Developmental Medicine level IV.Interpretation Access solutions for individuals with CP are in the early stages of development. Future work should include assessment of end-user comfort, effort, and performance as well as design features. Engaging users and therapists when designing and evaluating technologies to enhance computer access may increase acceptance and improve performance.
Discrimination of phonemic vowel length by Japanese infants.
Japanese has a vowel duration contrast as one component of its language-specific phonemic repertory to distinguish word meanings. It is not clear, however, how a sensitivity to vowel duration can develop in a linguistic context. In the present study, using the visual habituation–dishabituation method, the authors evaluated infants’ abilities to discriminate Japanese long and short vowels embedded in two-syllable words (/mana/ vs. /ma:na/). The results revealed that 4-month-old Japanese infants (n = 32) failed to discriminate the contrast (p = .676), whereas 9.5-month-olds (n = 33) showed the discrimination ability (p = .014). The 7.5-month-olds did not show positive evidence to discriminate the contrast either when the edited stimuli were used (n = 33; p = .275) or when naturally uttered stimuli were used (n = 33; p = .189). By contrast, the 4-month-olds (n = 24) showed sensitivity to a vowel quality change (/mana/ vs. /mina/; p = .034). These results indicate that Japanese infants acquire sensitivity to long–short vowel contrasts between 7.5 and 9.5 months of age and that the developmental course of the phonemic category by the durational changes is different from that by the quality change. (PsycINFO Database Record (c) 2009 APA, all rights reserved)
Exploring developmental differences in visual short-term memory and working memory.
Although visuospatial short-term memory tasks have been found to engage more executive resources than do their phonological counterparts, it remains unclear whether this is due to intrinsic differences between the tasks or differences in participants’ experience with them. The authors found 11-year-olds’ performances on both visual short-term and working memory tasks to be more greatly impaired by an executive suppression task (random number generation) than were those of 8-year-olds. Similar findings with adults (e.g., Kane & Engle, 2000) suggest that the imposition of a suppression task may have overloaded the older children’s executive resources, which would otherwise be used for deploying strategies for performing the primary tasks. Conversely, the younger children, who probably never had the capacity or know-how to engage these facilitative strategies in the first place, performed more poorly in the single task condition but were less affected in the dual task condition. These findings suggest that differences in the children’s ability to deploy task-relevant strategy are likely to account for at least part of the executive resource requirements of visual memory tasks. (PsycINFO Database Record (c) 2009 APA, all rights reserved)
The interaction of concreteness and phonological similarity in verbal working memory.
Although phonological representations have been a primary focus of verbal working memory research, lexical-semantic manipulations also influence performance. In the present study, the authors investigated whether a classic phenomenon in verbal working memory, the phonological similarity effect (PSE), is modulated by a lexical-semantic variable, word concreteness. Phonological overlap and concreteness were factorially manipulated in each of four experiments across which presentation modality (Experiments 1 and 2: visual presentation; Experiments 3 and 4: auditory presentation) and concurrent articulation (present in Experiments 2 and 4) were manipulated. In addition to main effects of each variable, results show a Phonological Overlap × Concreteness interaction whereby the magnitude of the PSE is greater for concrete word lists relative to abstract word lists. This effect is driven by superior item memory for nonoverlapping, concrete lists and is robust to the modality of presentation and concurrent articulation. These results demonstrate that in verbal working memory tasks, there are multiple routes to the phonological form of a word and that maintenance and retrieval occur over more than just a phonological level. (PsycINFO Database Record (c) 2009 APA, all rights reserved)
from Journal of Experimental Psychology: Learning, Memory, and Cognition
‘Sit in the corner and don’t eat the crayons’: postgraduates with dyslexia and the dominant ‘lexic’ discourse
The lack of cultural diversity in higher education is recognised by policy objectives and a current focus on the development of widening participation for a range of students, including those with disabilities. Amongst this group are those with dyslexia who might previously have been disenfranchised from formal education and under-represented within it. This paper explores the personal narratives and learner histories of six postgraduates and academics with dyslexia from their earliest memories of learning to their present experiences. It examines how literacy, as a dominant form of discourse, has defined concepts of academic ability resulting in the early exclusion of these learners from formal education. It is argued that this dominant discourse can be challenged by non-authorised, informal learning resulting in stories of resistance.
from Disability & Society
An fMRI study of multimodal semantic and phonological processing in reading disabled adolescents
Abstract Using functional magnetic resonance imaging, we investigated multimodal (visual and auditory) semantic and unimodal (visual only) phonological processing in reading disabled (RD) adolescents and non-impaired (NI) control participants. We found reduced activation for RD relative to NI in a number of left-hemisphere reading-related areas across all processing tasks regardless of task type (semantic vs. phonological) or modality (auditory vs. visual modality). Moreover, activation differences in these regions, which included the inferior frontal gyrus, the superior temporal gyrus, and the occipitotemporal region, were largely independent of in-scanner performance in our auditory semantic task. That is, although RD participants and NI participants differed in performance in visually presented conditions, they did not differ significantly in the auditory condition, yet similar patterns of reduced activation were observed in these regions across conditions. These findings indicate a neurobiological marker in RD that is independent of task, modality, or performance. These findings are discussed in the context of current neurobiological models of RD.
from the Annals of Dyslexia
‘Autistic’ Local Processing Bias also Found in Children Gifted in Realistic Drawing
Abstract We investigated whether typically-developing children with a gift for drawing realistically show the local processing bias seen in individuals with autism spectrum disorder (ASD). Twenty-seven 6–12 year-olds made an observational drawing (scored for level of realism) and completed three local processing tasks, and parents completed the Childhood Asperger Syndrome Test (CAST). Drawing score predicted local processing performance on all tasks independently of verbal IQ, age, and years of art lessons. Drawing score also predicted more frequent repetitive behaviors as assessed by the CAST. Thus, skill in realistic drawing is associated with a strong local processing bias and a tendency towards repetitive behaviors, showing that traits found in individuals with ASD irrespective of artistic talent are also found in typically developing children with artistic talent.
The role of motor learning in stuttering adaptation: repeated versus novel utterances in a practice-retention paradigm
Most individuals who stutter become more fluent during repeated oral readings of the same material. This adaptation effect may reflect motor learning associated with repeated practice of speech motor sequences. We tested this hypothesis with a paradigm that used two integrated approaches to identify the role of motor learning in stuttering adaptation: to distinguish practice effects from situation effects, the texts contained both repeated and novel sentences; to differentiate learning effects from temporary performance effects, stuttering frequency was determined for both the initial adaptation readings and retention tests after 2 and 24 hours. Average group data for 7 stuttering individuals who showed adaptation indicate that (a) both repeated and novel sentences resulted in decreased stuttering frequency across five readings in the initial session, but the decrease was larger for repeated than for novel sentences; (b) after 2 hours, stuttering frequency for both types of sentences was again similar, but with additional readings the repeated sentences once again showed larger improvements in fluency; (c) after 24 hours, prior fluency improvements for the novel sentences had dissipated whereas retention was observed for the repeated sentences. These findings–supporting the hypothesis that motor learning plays a role in stuttering adaptation–were representative for most, but not all, individual subjects. Subjects whose data did not follow the group trend and showed comparable retention for repeated and novel sentences may adapt primarily on the basis of non-motor mechanisms. Alternatively, those subjects may in fact show more substantial generalization of motor learning effects to previously unpracticed movement sequences.
Nonfluent aphasia and the evolution of proto-language
This paper briefly explores the relevance of patterns of related symptoms of nonfluent aphasia arising from left inferior frontal brain damage for the evolution of speech, language and gesture. I discuss aphasic lexical speech automatisms (LSAs) and their resolution with recovery into agrammatism with apraxia of speech and draw parallels between this recovery and the early evolution of language to protospeech and protosyntax. I focus attention on the most common forms of LSAs, expletives and the pronoun + modal/aux subtype, and propose that further research into these phenomena can contribute to the debate on the evolution of speech and language.
from the Journal of Neurolinguistics
Relationships amongst age, language and related skills in adults with Down syndrome
Studies into the effects of ageing on language in adults with Down syndrome (DS) have tended to rely on measures that lack sensitivity to change because they fail to explore across linguistic domains or rely on proxy reports. The study aim was to use measures of receptive and expressive language from studies of younger individuals with DS in exploring relationships across linguistic and associated skills, and age in young to older adults. Fifty-five adults (aged 19–58 years), 10 with a diagnosis of or signs of early stage Alzheimer’s Disease (AD), provided data on measures of functioning associated with AD, non-verbal cognition, receptive language (which provided a measure of mental age), receptive and expressive language, and short term auditory and visual memory. The first order correlation between the measure of AD and CA was significant; but not when the 10 participants with AD were removed from the analysis. Significant negative correlations were obtained between CA and all other measures; small to large significant positive correlations were found amongst the other measures. Partial correlations were conducted to remove the potential effects of AD and IQ (the latter measured by a test of non-verbal cognition). Remaining significant correlations were between auditory short term memory and all other included measures, expressive language and all other included measures, and CA and auditory short term memory and expressive language. The results indicate that deterioration with age in this cross-sectional study was accounted for largely by the presence of AD. The exceptions were for auditory short term memory and expressive language. The findings may reflect an underlying deficit in auditory short term memory for adults with DS, as has been found in previous research of children and adolescents. The implications are discussed in terms of the importance of including comprehensive measures of receptive and expressive language and the need to account for the presence of AD in studies of cognitive decline associated with ageing in DS.
Neural correlates of generating visual nouns and motor verbs in a minimal phrase context
The neural basis underlying the generation of nouns and verbs is still not completely understood. In classical generation tasks, specific features of the produced words can hardly be controlled. Therefore, the observed neural correlates of noun and verb production cannot be directly related to differences in specific features of the generated words. The present study seeks to address this issue by using a “minimal-phrase context” to elicit the activation of specific nouns and verbs. With this context, the to-be-generated words were highly constrained, and thus their semantic and other features (visual/action relatedness, word frequency, cloze probability, etc.) are well controlled. Thus, the present paradigm combines the advantages of classical word generation tasks (i.e., active semantic processing) with the advantages of tasks that allow for a high control of the experimental stimuli, such as passive viewing, reading, or lexical decision tasks. In an fMRI study, 17 participants generated verbs with strong motor and nouns with strong visual associations. Both noun and verb generation, compared to a rhyme generation baseline, elicited stronger activation in perisylvian language areas of the temporal and parietal cortex. In addition, stronger activation for nouns was found in the right middle/inferior temporal cortex. This activation supports the claim that noun generation is mediated by visual processing areas. Stronger activation for verb generation was found in the left superior temporal gyrus. Since this area is involved in motion perception, the results suggest that perceptual representations of movements mediate the generation of action verbs.
from Brain Research
Simultaneous interpreters as a model for neuronal adaptation in the domain of language processing
In the context of language processing, proficiency and age of acquisition have reliably been shown to have a strong influence on the functional and structural architecture of the human brain. The aim of the present EEG study was to examine the impact of language training as experienced by simultaneous interpreters (SI) on auditory word processing and to disentangle its influence from that of proficiency and age of acquisition. Eleven native German SI and controls matched in L2 proficiency and age of acquisition were asked to judge whether auditory presented disyllabic noun pairs both within and across the German (L1) and English (L2) languages were either semantically congruent or incongruent. We revealed enlarged N400 responses in SI while they detected incongruent trials both within the native (L1) and non-native (L2) language and also while they performed the task in the opposite direction as specifically trained (L1 to L2). These enlarged N400 responses in SI suggest a training-induced altered sensitivity to semantic processing within and across L1 and L2. The enlarged N400 responses we revealed in SI to congruent noun pairs during the German–English condition (L1 to L2) may indicate that SI could not benefit from an L1 prime when the target was a L2 word, suggesting additional processing resulting from long-term backwards (L2 to L1) training.
from Brain Research
Hearing Impairment in Childhood Bacterial Meningitis Is Little Relieved by Dexamethasone or Glycerol
CONCLUSIONS: With bacterial meningitis, the child’s presenting status and young age are the most important predictors of hearing impairment. Little relief is obtained from current adjuvant medications.
from Pediatrics
Dean of Libraries Starting a New Chapter
Dean Larry Sall is retiring this month after leading the university’s libraries through an era of dynamic growth in a career that included service under four UT Dallas presidents.
