Monthly Archives: October 2008
Response of vestibular-nerve afferents innervating utricle and saccule during passive and active translations
from the Journal of Neurosphysiology
The distinction between sensory inputs that are a consequence of our own actions from those that result from changes in the external world is essential for perceptual stability and accurate motor control. In this study, we investigated whether linear translations are encoded similarly during active and passive translations by the otolith system. Vestibular-nerve afferents innervating the saccule or utricle were recorded in alert macaques. Single unit responses were compared during passive whole body, passive head-on-body, and active head-on-body translations (vertical, fore-aft or lateral) to assess the relative influence of neck proprioceptive and efference copy related-signals on translational coding. The response dynamics of utricular and saccular afferents were comparable, and similarly encoded head translation during passive whole-body versus head-on-body translations. Furthermore, when monkeys produced active head-on-body translations with comparable dynamics, the responses of both regular and irregular afferents remained comparable to those recorded during passive movements. Our findings refute the proposal that neck proprioceptive and/or efference copy inputs coded by the efferent system function to modulate the responses of the otolith afferents during active movements. We conclude that the vestibular periphery provides faithful information about linear movements of the head in the space coordinates, regardless of whether they are self- or externally-generated.
Perceived competence and school adjustment of hearing impaired children in mainstream primary school settings
BACKGROUND: Although educational main streaming of children with special needs formally began in Iran since 1992 there is little information whether hearing impaired children feel competent in regular schools. METHODS: To determine the perceived competence and school adjustment of hearing impaired children in mainstream primary school settings, the self-perception profile was administered to 60 mainstreamed hard of hearing children and 60 classmates with normal hearing matched for gender by a single interviewer. The instrument comprised 28 items, 23 of which were similar to those of ‘adapted test Image for children with cochlear implants’ asking children about their feelings about their own cognitive, physical, socio-emotional and communication competence and school adjustment. The Cronbach alpha coefficient for the instrument was 0.93. RESULTS: Hard of hearing children rated their competence significantly poorer than their hearing classmates for all domains. Mean differences for the five domains ranged from 0.48 (for physical competence) to 0.90 (for school adjustment) on a scale of 1-4. There were no significant differences between girls’ and boys’ competence, in either the hearing or the hearing impaired groups. Classifying overall scores for perceived competence into four groups (‘poor competence’, ‘low competence’, ‘moderate competence’ and ‘high competence’), 23.4% of hearing impaired children but none of the hearing classmates rated themselves as having low or poor competence. On the other hand 85% of hearing children and only 18.3% of hearing impaired children rated themselves as highly competent. CONCLUSION: We suggest that periodical assessments of mainstreamed children might help to identify those children who are having difficulty adapting to their environment.
CONCLUSION. Gestational diabetes hinders expressive language in offspring into middle childhood. Genes are strongly associated with the risk of delays in infants of diabetic mothers, and offspring of educated mothers are less affected.
Conclusions: The surgical procedure for CI in infants is feasible and patient-related complications are usually minor and may be managed conservatively. Because most postoperative major problems are implant-related, improving cochlear implant technology can enhance the reliability of the devices and prevent untoward events that need for explantations and reimplantations. To reduce the risk of general anesthesia in infants we recommended the presence of pediatric anesthesiologist at surgery. Shortening time of surgery with using of nonmastoidectomy techniques for CI can reduce the time of bacterial exposure of the wound and prevent surgical complications related to the facial nerve and chorda tympani damage as well as electrode misplacement.
Conclusions: Air-bone gap(s) can be found in most ears with EVA if both air and bone conduction thresholds are properly tested. Normal tympanometry, presence of acoustic reflex and low threshold VEMP responses suggest that the air-bone gap in EVA is due to an inner ear anomaly, similar to the “third” labyrinthine window syndrome.
Conclusion: The absence of significant differences in hearing thresholds between the EIT + DXMb group and control ears in response to 0.5 to 4 kHz tones demonstrates that DXMb is as effective as the aqueous form of dexamethasone in conserving hearing against EIT-induced loss.
Discussion: Patients with substantial preoperative residual hearing can gain significant benefit from cochlear implantation. Although the degree of improvement in these individuals is somewhat more modest than for those patients without preoperative residual hearing, the outcomes are still excellent. That there were no significant differences between the patient groups suggests that having substantial residual hearing before implantation does not provide a measurable performance advantage for electrical stimulation. Patients with substantial residual hearing who are contemplating cochlear implantation should be counseled regarding a possible initial decline in speech perception performance.
Small Vestibular Schwannomas With No Hearing: Comparison of Functional Outcomes in Stereotactic Radiosurgery and Microsurgery.
Conclusions: In our study population, patients with small tumors and no serviceable hearing, these data suggest that MS results in comparable minimal morbidity with SRS, though posttreatment dysequilibrium is significantly decreased. While the authors recommend translabyrinthine resection of small VS with no hearing in patients able to tolerate surgery, the need for further prospective investigation is clear.
ABSTRACT—Recent findings in neuroscience challenge the view that the motor system is exclusively dedicated to the control of actions, and it has been suggested that it may contribute critically to conceptual processes such as those involved in language and number representation. The aim of this review is to address this issue by illustrating some interactions between the motor system and the processing of words and numbers. First, we detail functional brain imaging studies suggesting that motor circuits may be recruited to represent the meaning of action-related words. Second, we summarize a series of experiments demonstrating some interference between the size of grip used to grasp objects and the magnitude processing of words or numbers. Third, we report data suggestive of a common representation of numbers and finger movements in the adult brain, a possible trace of the finger-counting strategies used in childhood. Altogether, these studies indicate that the motor system interacts with several aspects of word and number representations. Future research should determine whether these findings reflect a causal role of the motor system in the organization of semantic knowledge.
ABSTRACT—Psychologists have known for over 20 years that infants begin learning the speech-sound categories of their language during the first 12 months of life. This fact has dominated researchers’ thinking about how language acquisition begins, although the relevance of this learning to the child’s progress in language acquisition has never been clear. Recently, views of the role of infancy in language acquisition have begun to change, with a new focus on the development of the vocabulary. Infants’ learning of speech-sound categories and infants’ abilities to extract regularities in the speech stream allow learning of the auditory forms of many words. These word forms then become the foundation of the early vocabulary, support children’s learning of the language’s phonological system, and contribute to the discovery of grammar.
Early treatment to prevent severe newborn jaundice in extremely early preterm infants reduces the infants’ rate of brain injury, according to a study in the October 30 issue of the New England Journal of Medicine.
Hundreds of British soldiers who have served in Afghanistan have had their hearing permanently damaged because of the noise of intense combat, a newspaper reported Thursday.
Syntactic and Prosodic Computations in the Resolution of Relative Clause Attachment Ambiguity by English-French Learners
This study investigates the manner in which syntax, prosody, and context interact when second- and fourth-semester college-level English-French learners process relative clause (RC) attachment to either the first noun phrase (NP1) or the second noun phrase (NP2) in complex nominal expressions such as le secrétaire du psychologue qui se promène (au centre ville) “the secretary of the psychologist who takes a walk (downtown).” Learners’ interpretations were affected by the length of the RC, specifically its phonological weight. Effects of intonation contour were found only in a subset of learners. In a response time (RT) experiment that manipulated contexts, fourth-semester learners showed a final bias for NP1 attachment in interpretation but an initial RT bias for NP2 attachment. Second-semester learners also produced a NP2 attachment bias in RTs, but no asymmetry in interpretation was found. We argue that the processing of RC attachment by English-French learners requires a task-specific algorithm that implicates autonomous syntactic and prosodic computations and specific interactions among them.
This article investigates the information structure of verb-second (V2) declaratives in Swedish, German, and nonnative German. Even though almost any type of element can occur in the so-called prefield, the clause-initial preverbal position of V2 declaratives, we have found language-specific patterns in native-speaker corpora: The frequencies of prefield constituent types differ substantially between German and Swedish, and Swedish postpones new (rhematic) information and instead fills the prefield with given (thematic) elements and elements of no or low informational value (e.g., expletives) to a far greater extent than German. We compare Swedish learners of German to native controls matched for age and genre (Bohnacker, 2005, 2006; Rosén, 2006). These learners master the syntactic properties of V2 but start their sentences in nonnative ways. They overapply the Swedish principle of rheme later in their second language German, indicating first language (L1) transfer at the interface of syntax and information structure, especially for structures that are frequent in the L1.
Results from a number of recent studies suggest that nativelike adult second language (L2) learners possess a high degree of language learning aptitude, the positive effects of which may have compensated for the negative effects of a critical period in these learners. According to the same studies, child learners seem to attain a nativelike command of the L2 regardless of high or low aptitude, which has led researchers to conclude that this factor plays no role in early acquisition. The present study investigates the L2 proficiency and language aptitude of 42 near-native L2 speakers of Swedish (i.e., individuals whom actual mother-tongue speakers of Swedish believe are native speakers). The results confirm previous research suggesting that a high degree of language aptitude is required if adult learners are to reach a L2 proficiency that is indistinguishable from that of native speakers. However, in contrast to previous studies, the present results also identify small yet significant aptitude effects in child SLA. Our findings lead us to the conclusions that the rare nativelike adult learners sometimes observed would all turn out to be exceptionally talented language learners with an unusual ability to compensate for maturational effects and, consequently, that their nativelikeness per se does not constitute a reason to reject the critical period hypothesis.