Monthly Archives: January 2010

Right Hemisphere Dysfunction and Metaphor Comprehension in Young Adults with Asperger Syndrome

Abstract This study examined whether the known difficulties in metaphor comprehension exhibited by persons with Asperger syndrome (AS) can be explained by a dysfunctional right hemisphere (RH). Using the divided visual field paradigm, 27 AS participants and 36 matched controls were presented with word pairs of four types (literal, conventional metaphors, novel metaphors, and unrelated word pairs), and were asked to perform a semantic judgment task. The main hypothesis was that whereas the control group participants will show RH superiority for novel metaphor processing, no RH superiority will be found in the AS group. Results indeed indicate much less RH contribution to novel metaphor comprehension in AS, and are discussed in light of linguistic models and the neurobiology of autism.

from the Journal of Autism and Developmental Disorders

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Normal Hearing Is Required for the Emergence of Long-Lasting Inhibitory Potentiation in Cortex

Long-term synaptic plasticity is a putative mechanism for learning in adults. However, there is little understanding of how synaptic plasticity mechanisms develop or whether their maturation depends on experience. Since inhibitory synapses are particularly malleable to sensory stimulation, long-lasting potentiation of inhibitory synapses was characterized in auditory thalamocortical slices. Intracortical high-frequency electrical stimulation led to a 67% increase in inhibitory synaptic currents. In the absence of stimulation, inhibitory potentiation was induced by a brief exposure to exogenous brain-derived neurotrophic factor (BDNF). BDNF exposure occluded any additional potentiation by high-frequency afferent stimulation, suggesting that BDNF signaling is sufficient to account for inhibitory potentiation. Moreover, inhibitory potentiation was reduced significantly by extracellular application of a BDNF scavenger or by intracellular blockade of BDNF receptor [tropomyosin-related kinase B (TrkB)] signaling. In contrast, glutamatergic or GABAergic antagonists did not prevent the induction of inhibitory potentiation. Since BDNF and TrkB expression are influenced strongly by activity, we predicted that inhibitory potentiation would be diminished by manipulations that decrease central auditory activity, such as hearing loss. Two forms of hearing loss were examined: conductive hearing loss in which the cochleae are not damaged or sensorineural hearing loss in which both cochleae are removed. Both forms of hearing loss were found to reduce significantly the magnitude of inhibitory potentiation. These data indicate that early experience is necessary for the normal development of BDNF-mediated long-lasting inhibitory potentiation, which may be associated with perceptual deficits at later ages.

from the Journal of Neuroscience

Aging and the Perception of Emotion: Processing Vocal Expressions Alone and With Faces

Abstract
This study investigated whether the difficulties older adults experience when recognizing specific emotions from facial expressions also occur with vocal expressions of emotion presented in isolation or in combination with facial expressions. When matching vocal expressions of six emotions to emotion labels, older adults showed worse performance on sadness and anger. When matching vocal expressions to facial expressions, older adults showed worse performance on sadness, anger, happiness, and fear. Older adults’ poorer performance when matching faces to voices was independent of declines in fluid ability. Results are interpreted with reference to the neuropsychology of emotion recognition and the aging brain.

from Experimental Aging Research

Therapy to improve gestural expression in aphasia: a controlled clinical trial

Conclusions: In view of the limited generalization, gesture therapy should concentrate on gestures that are relevant for communication in daily living of the individual patients.

from Clinical Rehabilitation

Computer-assisted instruction to prevent early reading difficulties in students at risk for dyslexia: Outcomes from two instructional approaches

Abstract The relative effectiveness of two computer-assisted instructional programs designed to provide instruction and practice in foundational reading skills was examined. First-grade students at risk for reading disabilities received approximately 80 h of small-group instruction in four 50-min sessions per week from October through May. Approximately half of the instruction was delivered by specially trained teachers to prepare students for their work on the computer, and half was delivered by the computer programs. At the end of first grade, there were no differences in student reading performance between students assigned to the different intervention conditions, but the combined-intervention students performed significantly better than control students who had been exposed to their school’s normal reading program. Significant differences were obtained for phonemic awareness, phonemic decoding, reading accuracy, rapid automatic naming, and reading comprehension. A follow-up test at the end of second grade showed a similar pattern of differences, although only differences in phonemic awareness, phonemic decoding, and rapid naming remained statistically reliable.

from the Annals of Dyslexia

Dysphagia and dysphonia among persons with post-polio syndrome – a challenge in neurorehabilitation

Conclusions – Professionals need to be aware of the routine evaluation of dysphagia and dysphonia in patients with post-polio syndrome.

from Acta Neurologica Scandinavica

Topography and physiology of ascending streams in the auditory tectothalamic pathway

Auditory information is relayed from the cochlea along parallel pathways and reaches the inferior colliculus (IC) and the medial geniculate body (MGB) en route to the cortex. Although the ascending tectothalamic pathway to the ventral division of the MGB is regarded as a high-fidelity information-bearing channel, the roles of the pathways to the dorsal and medial divisions are more opaque. Here, we show fundamental differences between these ascending pathways using an in vitro slice preparation. Using photostimulation, we found three main patterns of input (excitatory, inhibitory, and mixed) that differed in each pathway. Furthermore, electrical stimulation of the central nucleus of the IC evoked a depressing response in the MGB with no metabotropic glutamate (mGlu) receptor component, whereas stimulation of the lateral cortex of the IC evoked a facilitating response with an mGlu receptor component. These data suggest that the ascending tectothalamic pathways are functionally distinct from one another.

from the Proceedings of the National Academy of Sciences of the United States of America

Feeding preterm infants milk with a higher dose of docosahexaenoic acid than that used in current practice does not influence language or behavior in early childhood: a follow-up study of a randomized controlled trial.

CONCLUSIONS: Feeding preterm infants milk containing 3 times the standard amount of DHA did not result in any clinically meaningful change to language development or behavior when assessed in early childhood. Whether longer-term effects of dietary DHA supplementation can be detected remains to be assessed. This trial was registered with the Australia and New Zealand Clinical Trial Registry at http://www.anzctr.org.au as 12606000327583.

from the American Journal of Clinical Nutrition

Influence of Cochlear Function on Auditory Temporal Resolution in Tinnitus Patients

Our aim was to analyze the influence of subtle cochlear damage on temporal auditory resolution in tinnitus patients. Forty-eight subjects (hearing threshold ≤25 dB HL) were assigned to one of two experimental groups: 28 without auditory complaints (mean age, 28.8 years) and 20 with tinnitus (mean age, 33.5 years). We analyzed distortion product otoacoustic emission growth functions (by threshold, slope, and estimated amplitude), extended high-frequency thresholds, and the Gaps-in-Noise test. There were differences between the groups, principally in the extended high-frequency thresholds and the Gaps-in-Noise test results. Our findings suggest that subtle peripheral hearing impairment affects temporal resolution in tinnitus, even when pure-tone thresholds as conventionally measured appear normal.

from Audiology & Neuro-Otology

A Review of Developmental and Applied Language Research on African American Children: From a Deficit to Difference Perspective on Dialect Differences

Conclusion: Research initiatives that can expand knowledge about this group are proposed.

from Language, Speech and Hearing Services in Schools

Advancing Research on Children With Speech-Language Impairment: An Introduction to the Early Childhood Longitudinal Study—Kindergarten Cohort

Conclusion: The comprehensive assessments, large subsamples of children with diagnosed disabilities, and detailed information about special education services makes the ECLS–K a useful resource for advancing the development of theory, effective classroom practices, and evidence-based policies that promote the well-being of children with special needs.

from Language, Speech and Hearing Services in Schools

Data Recycling: Using Existing Databases to Increase Research Capacity in Speech-Language Development and Disorders

Conclusion: Researchers invested in addressing basic and applied problems of relevance to speech and language services in schools can make use of a variety of extant databases to increase research capacity.

from Language, Speech and Hearing Services in Schools

Effects of a Supplemental Spanish Oral Language Program on Sentence Length, Complexity, and Grammaticality in Spanish-Speaking Children Attending English-Only Preschools

Discussion and Clinical Implications: The findings demonstrate that a daily short native language program has significant effects on sentence length in words and subordination index in English language learners who are attending English-only preschool programs.

from Language, Speech and Hearing Services in Schools

Genetic Influences on Language, Reading, and Mathematics Skills in a National Sample: An Analysis Using the National Longitudinal Survey of Youth

Conclusion: The present study provides additional support for significant genetic effects across low and wide ranges of specific achievement. Moreover, this study supports that genetic influences on reading, language, and mathematics are generalizable beyond twin and adoption studies.

from Language, Speech and Hearing Services in Schools

Home Literacy Experiences and Early Childhood Disability: A Descriptive Study Using the National Household Education Surveys (NHES) Program Database

Conclusions: These findings suggest the importance of considering the home literacy experiences and emergent literacy skills of young children with disabilities when making clinical recommendations.

from Language, Speech and Hearing Services in Schools