Monthly Archives: December 2010
Voice discrimination in cochlear-implanted deaf subjects
The human voice is important for social communication because voices carry speech and other information such as a person’s physical characteristics and affective state. Further restricted temporal cortical regions are specifically involved in voice processing. In cochlear implanted deaf patients, the processor alters the spectral cues which are crucial for the perception of the paralinguistic information of human voices. The aim of this study was to assess the abilities of voice discrimination in cochlear-implant (CI) users and in normal-hearing subjects (NHS) using a CI simulation (vocoder). In NHS the performance in voice discrimination decreased when reducing the spectral information by decreasing the number of channels of the vocoder. In CI patients with different delays after implantation we observed a strong impairment in voice discrimination at time of activation of the neuroprosthesis. No significant improvement can be detected in patients after two years of experience of the implant while they have reached a higher level of recovery of speech perception, suggesting a dissociation in the dynamic of functional recuperation of speech and voice processing. In addition to the lack of spectral cues due to the implant processor, we hypothesized that the origin of such deficit could derive from a crossmodal reorganization of the temporal voice areas in CI patients.
from Hearing Research
Rare familial 16q21 microdeletions under a linkage peak implicate cadherin 8 (CDH8) in susceptibility to autism and learning disability
Conclusion Rare familial 16q21 microdeletions and expression analysis implicate CDH8 in susceptibility to autism and LD.
from the Journal of Medical Genetics
Preservation of Language in the Ataxic Infant in a Case of Cerebellar Agenesis
This article does not have an abstract.
Biomechanical Analysis of Hyoid Bone Displacement in Videofluoroscopy: A Systematic Review of Intervention Effects
This systematic review explores studies using biomechanical analysis of hyoid bone displacement in videofluoroscopy of swallowing as a spatial outcome parameter to evaluate intervention effects. Two authors independently carried out the literature search using the electronic databases Embase, PubMed, and Cochrane Library. Differences in their search findings were settled by discussion. The search was limited to publications in the English, German, French, Spanish, or Dutch language. MeSH terms were used, supplemented by free-text words to identify the most recent publications. In addition, reference lists were searched by hand. Only studies using videofluoroscopy to evaluate the biomechanical effects of swallowing interventions in dysphagic subjects were included in the review. While the body of literature on measuring hyoid bone displacement in videofluoroscopy has grown, only 12 studies met the inclusion criteria. Several of the 12 studies had methodological shortcomings. In general, the conclusions could not be compared across the studies because of their heterogeneous designs and outcome measures. Overall, several intervention effect studies reported significant results. In particular, bolus modification and swallowing maneuvers showed a greater range of hyoid bone displacement. In light of this review, further research on hyoid bone displacement as a spatial variable in well-defined patient populations using well-defined videofluoroscopic protocols to measure intervention effects is recommended.
from Dysphagia
Diet and gender influences on processing and discrimination of speech sounds in 3- and 6-month-old infants: a developmental ERP study
Early post-natal nutrition influences later development, but there are no studies comparing brain function in healthy infants as a function of dietary intake even though the major infant diets differ significantly in nutrient composition. We studied brain responses (event-related potentials; ERPs) to speech sounds for infants who were fed either breast milk (BF), milk-based formula (MF), or soy formula (SF) during the first 6 months of life. Two syllables presented in an oddball paradigm elicited a late positive wave (P350) from temporal and frontal brain regions involved in language processes. All groups showed significantly greater response amplitudes to the infrequent syllable across sites at 3 months and frontally at 6 months, but significant discrimination at temporal sites was only observed at 6 months in BF infants. Decreases in response amplitudes from 3 to 6 months were greater for the frequently presented syllable, most prominent in BF infants, and greater in females than males. The results indicate greater syllable discrimination in BF than formula-fed infants, but whether this can be attributed to dietary influences alone remains unclear. Feeding method and background factor differences between breastfed and formula-fed infants may also contribute to the observed differences. The general absence of differences between formula-fed groups is notable and suggests that milk-based formula and soy formula equally support brain development and function during the first post-natal 6 months. Finally, the results indicate gender differences in the development of neural and temporal processes involved in sensory discrimination, and suggest that at 6 months these processes are better developed in females.
Early Bifrontal Brain Injury: Disturbances in Cognitive Function Development
In conclusion, early frontal brain injury disorganizes the development of cognitive functions, and interactions exist between executive function and other cognitive functions during development.
Voluntary Versus Spontaneous Swallowing in Man
This review examines the evidence regarding the clinical and neurophysiological differences between voluntary and spontaneous swallows. From the clinical point of view, voluntary swallow (VS) occurs when a human has a desire to eat or drink during the awake and aware state. Spontaneous swallow (SS) is the result of accumulated saliva and/or food remnants in the mouth. It occurs without awareness while awake and also during sleep. VS is a part of eating behavior, while SS is a type of protective reflex action. In VS, there is harmonized and orderly activation of perioral, lingual, and submental striated muscles in the oral phase. In SS, the oral phase is bypassed in most cases, although there may be partial excitation. Following the oral phase, both VS and SS have a pharyngeal phase, which is a reflex phenomenon that protects the upper airway from any escape of food and direct the swallowed material into the esophagus. This reflexive phase of swallowing should not be confused with SS. VS and SS are similar regarding their dependence on the swallowing Central Pattern Generator (CPG) at the brainstem, which receives sensory feedback from the oropharynx. There are differences in the role of the corticobulbar input between VS and SS.
from Dysphagia
Phenotypic Overlap Between Core Diagnostic Features and Emotional/Behavioral Problems in Preschool Children with Autism Spectrum Disorder
This study examined the phenotypic overlap between core diagnostic features and emotional/behavioral problems in a sample of 335 preschool children with autism spectrum disorder (ASD). Results from principal component analysis (2 components; 49.70% variance explained) suggested substantial phenotypic overlap between core diagnostic features and emotional/behavioral problems. Component I, Emotional Behavioral Repetitive Problems, was independent of the children’s intellectual, adaptive functioning, and structural language abilities. Component II, Social Communication Deficits, was negatively related to the children’s intellectual, adaptive functioning, and structural language abilities. Both components were positively related to parental stress. This exploratory study contributes to our understanding of the ASD phenotype and provides further support for including emotional/behavioral problems as part of the clinical characterization of children with ASD.
Evidence of Key Tinnitus-Related Brain Regions Documented by a Unique Combination of Manganese-Enhanced MRI and Acoustic Startle Reflex Testing
Animal models continue to improve our understanding of tinnitus pathogenesis and aid in development of new treatments. However, there are no diagnostic biomarkers for tinnitus-related pathophysiology for use in awake, freely moving animals. To address this disparity, two complementary methods were combined to examine reliable tinnitus models (rats repeatedly administered salicylate or exposed to a single noise event): inhibition of acoustic startle and manganese-enhanced MRI. Salicylate-induced tinnitus resulted in wide spread supernormal manganese uptake compared to noise-induced tinnitus. Neither model demonstrated significant differences in the auditory cortex. Only in the dorsal cortex of the inferior colliculus (DCIC) did both models exhibit supernormal uptake. Therefore, abnormal membrane depolarization in the DCIC appears to be important in tinnitus-mediated activity. Our results provide the foundation for future studies correlating the severity and longevity of tinnitus with hearing loss and neuronal activity in specific brain regions and tools for evaluating treatment efficacy across paradigms.
from PLoS ONE
Longitudinal trends in aphasia in the United States
Conclusions: The occurrence of aphasia and demographic characteristics of individuals with aphasia has been generally consistent in the U.S. from 1997 to 2006. Future studies are needed to quantify direct and indirect costs of treating individuals with aphasia as well as other factors that determine the true impact of aphasia and other neurologically based disorders of communication.
from Neurorehabilitation
Diagnostic accuracy of acute vestibular syndrome at the bedside in a stroke unit
Acute vestibular syndrome may be due to vestibular neuritis (VN) or posterior circulation strokes. Bedside ocular motor testing performed by experts is superior to early MRI in excluding strokes. We sought to demonstrate that differentiation of strokes from VN in our stroke unit is reliable. During a prospective study at a tertiary hospital over 1 year, patients with AVS were evaluated in the emergency department (ED) and underwent admission with targeted examination: gait, gaze-holding, horizontal head impulse test (hHIT), testing for skew deviation (SD) and vertical smooth pursuit (vSP). Neuroimaging included CT, transcranial Doppler (TCD) and MRI with MR angiogram (MRA). VN was diagnosed with normal diffusion-weighted images (DWI) and absence of neurological deficits on follow-up. Acute strokes were confirmed with DWI. A total of 24 patients with AVS were enrolled and divided in two groups. In the pure vestibular group (n = 20), all VN (n = 10/10) had positive hHIT and unidirectional nystagmus, but 1 patient had SD and abnormal vertical smooth pursuit (SP). In all the strokes (n = 10/10), one of the following signs suggestive of central lesion was present: negative hHIT, central-type nystagmus, SD or abnormal vSP. Finding one of these was 100% sensitive and 90% specific for stroke. In the cochleovestibular group (n = 4) all had normal DWI, but 3 patients had central ocular motor signs (abnormal vertical SP and SD). Whilst the study is small, classification of AVS in our stroke unit is reliable. The sensitivity and specificity of bedside ocular motor testing are comparable to those previously reported by expert neuro-otologists. Acute cochleovestibular loss and normal DWI may signify a labyrinthine infarct but differentiating between different causes of inner ear dysfunction is not possible with bedside testing.
from the Journal of Neurology
Researchers Recommend ‘Watchful Waiting’ Over Antibiotic Treatment For Many Children With Ear Infections
The authors indicate that watchful waiting could substantially reduce the use of antibiotics in the treatment of AOM and play a major role in helping fight the development of treatment-resistant bacteria.
Reading to Newborns in Intensive Care a Boon for Parents
Parents who read to their newborns in the intensive care unit feel closer to their babies during this difficult time, a new study finds.
from HealthScout.com
Mother’s voice triggers language area in newborn brain, research suggests
Researchers in Quebec applied electrodes on the babies’ heads and found that hearing Mom’s voice can activate parts of the newborn’s brain responsible for language learning.
from MedBroadcast.com
Early intervention for children with autism improves I.Q., language and social skills
Early intervention for children with autism, as young as 6 months of age, may change the development trajectory for later symptoms of the disorder according to a research project being spearheaded by the MIND Institute at the University of California Davis Medical Center
from News-Medical.net
