Monthly Archives: November 2009

Processing interaural cues in sound segregation by young and middle-aged brains.

CONCLUSIONS: We conclude that our findings reflect neurophysiologic differences between young and middle-aged adults for IPD processing in concurrent sound segregation.

from the Journal of the American Academy of Audiology

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Recovery function of the late auditory evoked potential in cochlear implant users and normal-hearing listeners.

CONCLUSIONS: Our interpretation of these findings is that the faster recovery of the LAEP in CI users is related to abnormal adaptation mechanisms and a less prominent role of the components with longer latencies in the LAEP of CI users. Other mechanisms such as the compromised inhibitory regulation in the auditory system and the aging effect in CI users might also play a role. More research needs to be done to determine whether the slope of the LAEP recovery function is correlated with speech-perception performance.

from the Journal of the American Academy of Audiology

Speech recognition and temporal processing in middle-aged women.

CONCLUSIONS: These results suggest that some middle-aged women with little or no pure-tone hearing loss experience listening difficulty in complex environments. Results also suggest a strong relationship between temporal processing and speech understanding in certain competing speech situations.

from the Journal of the American Academy of Audiology

Temporal integration of the contralateral acoustic reflex threshold for a 1000 hz tonal activator and its age-related changes.

CONCLUSION: Results contradict the findings for broadband noise.

from the Journal of the American Academy of Audiology

The time course of the amplitude and latency in the auditory late response evoked by repeated tone bursts.

CONCLUSIONS: The reduction of latency in the time course of the ALR might be related to the fact that neurons with shorter latencies had faster recovery speed from adaptation and/or refractoriness than those with longer latencies. This finding is meaningful in the context of future research to restore normal adaptation in abnormal hearing populations such as cochlear implant patients.

from the Journal of the Acoustical Society of America

In Utero Iron Status and Auditory Neural Maturation in Premature Infants as Evaluated by Auditory Brainstem Response

Conclusion
Premature infants with in utero latent iron deficiency have abnormal auditory neural maturation compared with infants with normal in utero iron status.

from the Journal of Pediatrics

Profiling Fragile X Syndrome in males: Strengths and weaknesses in cognitive abilities

The present study examined the cognitive profile in Fragile X Syndrome (FXS) males, and investigated whether cognitive profiles are similar for FXS males at different levels of intellectual functioning. Cognitive abilities in non-verbal, verbal, memory and executive functioning domains were contrasted to both a non-verbal and verbal mental age reference. Model-based cluster analyses revealed three distinct subgroups which differed in level of functioning, but showed similar cognitive profiles. Results showed that cognitive performance is particularly weak on measures of reasoning- and performal abilities confined to abstract item content, but relatively strong on measures of visuo-perceptual recognition and vocabulary. Further, a significant weakness was found for verbal short-term memory. Finally, these results indicated that the choice of an appropriate reference is critically important in examining cognitive profiles. The pattern of findings that emerged from the current cognitive profiling of FXS males was interpreted to suggest a fundamental deficit in executive control.

from Research in Developmental Disabilities

Between love and culture: Misunderstanding, textuality and the dialectics of ethnographic knowledge

This paper will explore the intertextual dialectics of understanding and misunderstanding in the negotiation of relations between consultants and the ethnographic fieldworker. The material for this essay draws on conversations with consultants from the Fort Apache Reservation. I will argue that the textual constructions of otherness through which consultants apprehend the social presence of the fieldworker are transformed in the fieldwork encounter. These transformations allow consultants to author relations with the ethnographer. I will also explore attempts by field consultants to understand the objective and limits of the ethnographic project by framing it in terms of locally constituted idioms of relationship. I will conclude by suggesting that the entextualizing practices of ethnography threaten to obscure the authority asserted by consultants in fieldwork conversations.

from Language & Communication

Entextualizing diversity: Semiotic incoherence in institutional discourse

This article examines processes by which diversity is differentially entextualized and partially circulated in higher education discourses. Diversity is entextualized most coherently among administrators, both academic and non-academic, where it is routinely construed as standardized, measurable units, i.e. persons. In these discourses, its spoken and written uses map neatly onto each other coherently with its uses in discourses of institutional advancement, where embodiments of diversity are coherent with neoliberal concepts of person. Its enregisterment across these fields is relatively coherent. By contrast, among faculty acting as faculty, diversity is variously conceptualized and entextualized in discipline-specific discourses, leading to less coherent enregisterment. This discrepancy plays an important role in the growing hegemony of a neoliberal interpretation of diversity.

from Language & Communication

Diagnostic challenges and safety considerations in cochlear implantation under the age of 12 months

Conclusion
Assessment of hearing in infancy is feasible with adequate reliability. If parental expectations are realistic and hearing aid trial unsuccessful, cochlear implantation can be performed in otherwise healthy infants, provided that the attending pediatric anesthesiologist is considerably experienced and appropriate facilities of pediatric perioperative care are readily available. A number of concerns, with regard to anatomic constraints, existing co-morbidities or additional disorders, tuning difficulties, and special phases of the developing child should be also taken into account. The present meta-analysis did not find an increased rate of anesthetic or surgical complications in infant implantees, although long-term follow-up and large numbers are lacking.

from the International Journal of Pediatric Otorhinolaryngology

The role of dyslipidemia in sensorineural hearing loss in children

Conclusions
Dyslipidemia seems to have no association with sensorineural hearing loss in 5–18 years old children according to this study.

from the International Journal of Pediatric Otorhinolaryngology

Vestibular changes after cochlear implantation in children

No abstract available.

from the International Journal of Pediatric Otorhinolaryngology

Functional But Not Structural Networks of the Human Laryngeal Motor Cortex Show Left Hemispheric Lateralization during Syllable But Not Breathing Production

The laryngeal motor cortex (LMC) is indispensible for the vocal motor control of speech and song production. Patients with bilateral lesions in this region are unable to speak and sing, although their nonverbal vocalizations, such as laughter and cry, are preserved. Despite the importance of the LMC in the control of voluntary voice production in humans, the literature describing its connections remains sparse. We used diffusion tensor probabilistic tractography and functional magnetic resonance imaging-based functional connectivity analysis to identify LMC networks controlling two tasks necessary for speech production: voluntary voice as repetition of two different syllables and voluntary breathing as controlled inspiration and expiration. Peaks of activation during all tasks were found in the bilateral ventral primary motor cortex in close proximity to each other. Functional networks of the LMC during voice production but not during controlled breathing showed significant left-hemispheric lateralization (p < 0.0005). However, structural networks of the LMC associated with both voluntary voice production and controlled breathing had bilateral hemispheric organization. Our findings indicate the presence of a common bilateral structural network of the LMC, upon which different functional networks are built to control various voluntary laryngeal tasks. Bilateral organization of functional LMC networks during controlled breathing supports its indispensible role in all types of laryngeal behaviors. Significant left-hemispheric lateralization of functional networks during simple but highly learned voice production suggests the readiness of the LMC network for production of a complex voluntary behavior, such as human speech.

from the Journal of Neuroscience

Sensitivity of Newborn Auditory Cortex to the Temporal Structure of Sounds

Understanding the rapidly developing building blocks of speech perception in infancy requires a close look at the auditory prerequisites for speech sound processing. Pioneering studies have demonstrated that hemispheric specializations for language processing are already present in early infancy. However, whether these computational asymmetries can be considered a function of linguistic attributes or a consequence of basic temporal signal properties is under debate. Several studies in adults link hemispheric specialization for certain aspects of speech perception to an asymmetry in cortical tuning and reveal that the auditory cortices are differentially sensitive to spectrotemporal features of speech. Applying concurrent electrophysiological (EEG) and hemodynamic (near-infrared spectroscopy) recording to newborn infants listening to temporally structured nonspeech signals, we provide evidence that newborns process nonlinguistic acoustic stimuli that share critical temporal features with language in a differential manner. The newborn brain preferentially processes temporal modulations especially relevant for phoneme perception. In line with multi-time-resolution conceptions, modulations on the time scale of phonemes elicit strong bilateral cortical responses. Our data furthermore suggest that responses to slow acoustic modulations are lateralized to the right hemisphere. That is, the newborn auditory cortex is sensitive to the temporal structure of the auditory input and shows an emerging tendency for functional asymmetry. Hence, our findings support the hypothesis that development of speech perception is linked to basic capacities in auditory processing. From birth, the brain is tuned to critical temporal properties of linguistic signals to facilitate one of the major needs of humans: to communicate.

from the Journal of Neuroscience

Evidence-based systematic review: Oropharyngeal dysphagia behavioral treatments. Part I–background and methodology

Summary: Evidence-based systematic reviews (EBSRs), in conjunction with clinical expertise and client values, are invaluable tools for speech-language pathologists and audiologists. This article provides an overview of the levels-of-evidence scheme used by the American Speech-Language-Hearing Association (ASHA) to conduct systematic reviews. The goal of ASHA reviews is to provide a tool to help clinicians determine the best treatment course for their clients. We present a collaborative project between ASHA’s National Center for Evidence-based Practice in Communication Disorders and the Department of Veterans Affairs (VA) that examined seven behavioral swallowing treatments for disordered and nondisordered populations. The methodology used in a series of reviews conducted by ASHA and the VA will be discussed, including the development of clinical questions, search parameters, inclusion/exclusion criteria, and literature search results. Findings from the series of reviews as well as the practical applications of EBSRs will be reported in subsequent articles in this series.

from the National Library for Health