Auditory and language skills of children using hearing aids

IntroductionHearing loss may impair the development of a child. The rehabilitation process for individuals with hearing loss depends on effective interventions.ObjectiveTo describe the linguistic profile and the hearing skills of children using hearing aids, to characterize the rehabilitation process and to analyze its association with the children's degree of hearing loss.MethodsCross-sectional study with a non-probabilistic sample of 110 children using hearing aids (6–10 years of age) for mild to profound hearing loss. Tests of language, speech perception, phonemic discrimination, and school performance were performed. The associations were verified by the following tests: chi-squared for linear trend and Kruskal–Wallis.ResultsAbout 65% of the children had altered vocabulary, whereas 89% and 94% had altered phonology and inferior school performance, respectively. The degree of hearing loss was associated with differences in the median age of diagnosis; the age at which the hearing aids were adapted and at which speech therapy was started; and the performance on auditory tests and the type of communication used.ConclusionThe diagnosis of hearing loss and the clinical interventions occurred late, contributing to impairments in auditory and language development.     

Aphasia in stroke patients: early outcome following thrombolysis

Background: Data on the early course of stroke-related aphasia after thrombolysis are scant.

Aims: The aim of this study was to describe recovery patterns of aphasia after thrombolysis in a large sample of stroke patients.

Methods & Procedures: Clinical and radiological data of consecutive stroke patients treated with thrombolysis over a 5-year period were routinely entered into prospective registries at two stroke units. Recovery was evaluated using the National Institutes of Health Stroke Scale (NIHSS) at baseline, after 24 hr, and on day 7. Aphasia was defined as a score >0 on item 9 of the NIHSS (measurement of language skills), aphasia improvement as any decrease in the item-9 score, and aphasia resolution as an item-9 score of 0. To assess global motor and language impairments, we created a composite language score obtained by summing the scores for items 1b, 1c, and 9; and a composite motor score obtained by summing the scores for items 4, 5, and 6.

Outcomes & Results: Out of the 338 patients treated with thrombolysis, 137 (40.5%) had aphasia. In patients with both aphasia and motor deficits (n = 109), these two impairments showed similar recovery patterns. Aphasia recovered significantly better in patients without limb motor deficits (n = 28) than those with limb motor deficits (n = 109), both after 24 hr (p < 0.05) and after 7 days (p < 0.0001). These results were supported by findings from a group-based trajectory modelling methods (p < 0.005).

Conclusions: Language impairments and limb motor deficits show similar recovery after thrombolysis in a given patient. Aphasia recovery is significantly better in the absence of limb motor deficits.     

The contribution of working memory to language comprehension: differential effect of aphasia type

Background: Experimental studies of short-term memory and working memory (WM) in aphasia fail to discriminate cognitive impairments of different aphasia types—non-fluent, Broca-type aphasia and fluent, Wernicke-type aphasia. However, based on the varying fundamental features of these two aphasia syndromes, the potentially different underlying mechanisms of impairment and scant preliminary evidence of varying cognitive deficits, a differential relationship between cognitive function and language processing in these two groups can be predicted.

Aims: The current study investigates the hypothesis concerning the differential impact of cognitive impairments in individuals with fluent versus non-fluent aphasia types.

Methods & Procedures: Participants with fluent (n = 19) and non-fluent (n = 16) aphasia and participants without brain damage (n = 36) were presented with an eye-tracking WM task. Additionally, individuals with aphasia completed two language comprehension tasks.

Outcomes & Results: Results revealed significant decrease in WM capacity in individuals with aphasia compared with participants without brain damage. The two aphasia groups performed similarly on the WM and language tasks. Furthermore, for participants with non-fluent aphasia, it was revealed that WM makes a significant contribution to language comprehension, while for fluent individuals this relationship was not significant.

Conclusions: Overall, the present data support the claim that there are cognitive deficits in aphasia and that these cognitive deficits tend to exacerbate the language impairments of persons with non-fluent aphasia types. The results are discussed in the context of varying mechanisms of impairment in different types of aphasia. The present findings have important implications both for the assessment and the treatment of individuals with aphasia and for understanding the nature of aphasia.     

Exploring consequences of short- and long-term deafness on speech production: A lip-tube perturbation study

Studies have reported strong links between speech production and perception. We aimed to evaluate the role of long- and short-term auditory feedback alteration on speech production. Eleven adults with normal hearing (controls) and 17 cochlear implant (CI) users (7 pre-lingually deaf and 10 post-lingually deaf adults) were recruited. Short-term auditory feedback deprivation was induced by turning off the CI or by providing masking noise. Acoustic and articulatory measures were obtained during the production of /u/, with and without a tube inserted between the lips (perturbation), and with and without auditory feedback. F1 values were significantly different between the implant OFF and ON conditions for the pre-lingually deaf participants. In the absence of auditory feedback, the pre-lingually deaf participants moved the tongue more forward. Thus, a lack of normal auditory experience of speech may affect the internal representation of a vowel.     

Past tense –ed omissions by children with specific language impairment: The role of sonority and phonotactics

Children with Specific Language Impairment (SLI) frequently omit past tense –ed. Omission rates are subject to phonological context. Two phonological characteristics were manipulated; the sonority profile of the stem-final phoneme plus affix, and the phonotactic probability of the word-final phonemes (/i:pt/ in beeped). Seventeen children with SLI (mean age 6;7) and 21 language-matched children (mean age 4;8) repeated sentences containing regularly inflected verbs according to a 2 (sonority) by 2 (phonotactic legality) design. Affix omissions were analysed. There was a significant effect of sonority only, characterised by a difficulty with level-sonority clusters, and no interaction. Syllabic affixes, e.g. head-ed, were produced relatively accurately. It is argued that –ed omissions in SLI may reflect a low-level speech or articulation difficulty which surfaces in uniquely challenging clusters. This is not an alternative to morphosyntactic accounts; rather past tense omissions are best explained according to complexity in multiple domains; syntactic, morpho-syntactic and phonological.     

Cross-language differences in the brain network subserving intelligible speech

How is language processed in the brain by native speakers of different languages? Is there one brain system for all languages or are different languages subserved by different brain systems? The first view emphasizes commonality, whereas the second emphasizes specificity. We investigated the cortical dynamics involved in processing two very diverse languages: a tonal language (Chinese) and a nontonal language (English). We used functional MRI and dynamic causal modeling analysis to compute and compare brain network models exhaustively with all possible connections among nodes of language regions in temporal and frontal cortex and found that the information flow from the posterior to anterior portions of the temporal cortex was commonly shared by Chinese and English speakers during speech comprehension, whereas the inferior frontal gyrus received neural signals from the left posterior portion of the temporal cortex in English speakers and from the bilateral anterior portion of the temporal cortex in Chinese speakers. Our results revealed that, although speech processing is largely carried out in the common left hemisphere classical language areas (Broca’s and Wernicke’s areas) and anterior temporal cortex, speech comprehension across different language groups depends on how these brain regions interact with each other. Moreover, the right anterior temporal cortex, which is crucial for tone processing, is equally important as its left homolog, the left anterior temporal cortex, in modulating the cortical dynamics in tone language comprehension. The current study pinpoints the importance of the bilateral anterior temporal cortex in language comprehension that is downplayed or even ignored by popular contemporary models of speech comprehension.The brain of a newborn discriminates the various phonemic contrasts used in different languages (1) by recruiting distributed cortical regions (2); by 6–10 mo, it is preferentially tuned to the phonemes in native speech that they have been exposed to (3, 4). In adult humans, the key neural nodes that subserve speech comprehension are located in the superior temporal cortex (5, 6) and the inferior frontal cortex (7). Do these regions interact in different ways depending on the type of language that is being processed? Little is known about how information flows among these critical language nodes in native speakers of different languages.As one of the unique capacities of the human brain (8), the nature of compositional languages and their neural mechanisms have been the interests of scientific research for decades. There are more than 7,000 different spoken languages in the world today used for communication. By exploring the brain networks subserving universal properties across languages and specific differences within different languages, such research helps address the essential questions in neurolinguistics such as the constitution of knowledge of language, as well as how it is acquired (9). Although traditional universal grammar theory argues that functional components of linguistic ability are manifest without being taught (10), recent connectionist theory within a neural network approach emphasizes interactions among primary systems of neuronal processing units that support language acquisition and use, where the weights of connections among these units are gradually changed during learning and thus highly constrained by the unique feature of a given language (9, 11, 12). Related with connectionist views, the dual pathway model of language based on evidence from neuroimaging and anatomical studies was also framed to interpret the neural basis of language comprehension and production (13, 14), especially in speech comprehension.Intelligible speech is processed hierarchically in human neocortex, with the anterior temporal (13, 15, 16) and frontal cortices (Broca’s area) operating at a higher hierarchical level than the posterior region centered on superior temporal sulcus/gyrus (pSTS/pSTG, core of Wernicke’s area), which itself receives inputs from primary and secondary auditory cortices (17). In the dual ventral-dorsal pathway model, the dorsal-stream pathway of speech processing assumes primary processing begins in the posterior region of the temporal cortex and is then sent through the dorsal part to the temporal-parietal cortex before finally reaching the frontal cortex for a sound-motor projection. The ventral-stream pathway assumes processing starts on the ventral side of the temporal lobe and then proceeds to the anterior regions, before reaching the frontal cortex for a sound-meaning mapping (7, 18).The cortical regions that process speech are likely to be common across languages, but how these regions interact with each other in the cortical pathway may depend on the distinctive phonetic-linguistic characteristics in different languages. Based on the connectionist approach, previous cross-language studies investigated the behavioral consequence of processing different languages with a distinction such as pitch accent processing (19). The current study aims to explore the dynamic neural networks of processing intelligible speech in two different languages with a featured phonological-semantic variant: Mandarin Chinese and English. These two languages are the most widely spoken languages in the world, but differ in several aspects such as the use of lexical tones. In tonal languages like Mandarin Chinese, suprasegmental features, i.e., different pitch patterns, serve to distinguish lexical meaning, whereas in nontonal languages, pitch changes are less complex and do not convey lexical information. Except the lexical tone, Mandarin Chinese includes more homophones than English, which also makes the sound-meaning mapping in Mandarin dependent more on tone and context information during speech and thus may place higher demands on the ventral pathway of the related neural network. To test this hypothesis, we examined the cortical dynamics underlying speech comprehension for two groups of native speakers of English and Mandarin languages.We used functional MRI (fMRI) and dynamic causal modeling (DCM) (20) to first investigate the cortical dynamics among the left posterior region of superior temporal gyrus (pSTG), anterior region of superior temporal gyrus (aSTG), and inferior frontal gyrus (IFG) of native speakers in Chinese (a tonal language) compared with English (a nontonal language) with an identical experimental design. Thirty native Chinese speakers and 26 native English speakers with matched age, sex, and handedness (all right-handed) were scanned while presented with intelligible and unintelligible speech of their native languages (either Mandarin Chinese or English) in blocks, spoken by a male and a female. Subjects were instructed only to judge the gender of the speakers. The data of native English speakers were reanalyzed from a previous study (21). The brain activation of the intelligibility effect and the effective connectivity among the three left hemisphere brain regions were analyzed for both language groups under identical procedures and then put together for comparison.     

The prevalence of asthma risk and contributing factors in underserved Vietnamese children in Orange County,CA

Objectives: Vietnamese constitutes one of the fastest growing minority groups in America, with the largest concentration in Orange County (OC), CA. Yet, there are limited data on the prevalence of asthma in Vietnamese children. Our study evaluated the risk of asthma and key contributing factors among these children living in OC, CA. Method: Five elementary schools in OC that were predominantly Vietnamese with low socioeconomic status were selected for participation. Validated surveys were sent to parents of all students ages 3–12 in these schools with materials available in English, Vietnamese and Spanish. Surveys included questions to identify the risk of asthma and related key factors. Surveys were completed by parents and returned to schools. Results: There were 1530 participants eligible for analysis. Asthma risk was 30.4%, and of these, 22.6% had no prior diagnosis. Contributing factors to identification of those at risk were male gender (p?<?0.001), preferred use of the Vietnamese language (p?=?0.004), longer duration in the United States (p?=?0.019), and smoker in the household (p?=?0.015). Conclusions: The prevalence of asthma risk in our community of low socioeconomic status Vietnamese children was found to be higher than commonly appreciated. Furthermore, a considerable number of these children had not been previously diagnosed. Given the limited information in this population, our current findings of asthma risk and key contributing factors could affect health care policies that allow appropriate funding for programs dedicated to asthma care in this and other growing population.