Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 153
Filtrar
1.
Ear Hear ; 45(1): 81-93, 2024.
Artigo em Inglês | MEDLINE | ID: mdl-37415268

RESUMO

OBJECTIVES: The purpose of this study was to evaluate effects of masker type and hearing group on the relationship between school-age children's speech recognition and age, vocabulary, working memory, and selective attention. This study also explored effects of masker type and hearing group on the time course of maturation of masked speech recognition. DESIGN: Participants included 31 children with normal hearing (CNH) and 41 children with mild to severe bilateral sensorineural hearing loss (CHL), between 6.7 and 13 years of age. Children with hearing aids used their personal hearing aids throughout testing. Audiometric thresholds and standardized measures of vocabulary, working memory, and selective attention were obtained from each child, along with masked sentence recognition thresholds in a steady state, speech-spectrum noise (SSN) and in a two-talker speech masker (TTS). Aided audibility through children's hearing aids was calculated based on the Speech Intelligibility Index (SII) for all children wearing hearing aids. Linear mixed effects models were used to examine the contribution of group, age, vocabulary, working memory, and attention to individual differences in speech recognition thresholds in each masker. Additional models were constructed to examine the role of aided audibility on masked speech recognition in CHL. Finally, to explore the time course of maturation of masked speech perception, linear mixed effects models were used to examine interactions between age, masker type, and hearing group as predictors of masked speech recognition. RESULTS: Children's thresholds were higher in TTS than in SSN. There was no interaction of hearing group and masker type. CHL had higher thresholds than CNH in both maskers. In both hearing groups and masker types, children with better vocabularies had lower thresholds. An interaction of hearing group and attention was observed only in the TTS. Among CNH, attention predicted thresholds in TTS. Among CHL, vocabulary and aided audibility predicted thresholds in TTS. In both maskers, thresholds decreased as a function of age at a similar rate in CNH and CHL. CONCLUSIONS: The factors contributing to individual differences in speech recognition differed as a function of masker type. In TTS, the factors contributing to individual difference in speech recognition further differed as a function of hearing group. Whereas attention predicted variance for CNH in TTS, vocabulary and aided audibility predicted variance in CHL. CHL required a more favorable signal to noise ratio (SNR) to recognize speech in TTS than in SSN (mean = +1 dB in TTS, -3 dB in SSN). We posit that failures in auditory stream segregation limit the extent to which CHL can recognize speech in a speech masker. Larger sample sizes or longitudinal data are needed to characterize the time course of maturation of masked speech perception in CHL.


Assuntos
Surdez , Perda Auditiva Neurossensorial , Perda Auditiva , Percepção da Fala , Criança , Humanos , Mascaramento Perceptivo , Audição , Ruído , Inteligibilidade da Fala
2.
Cereb Cortex ; 33(9): 5228-5237, 2023 04 25.
Artigo em Inglês | MEDLINE | ID: mdl-36310092

RESUMO

Sensory gating is a process by which the brain filters out redundant information to preserve neural resources for behaviorally relevant stimuli. Although studies have shown alterations in auditory and visual processing in children who are hard-of-hearing (CHH) relative to children with normal hearing (CNH), it is unclear whether these alterations extend to the somatosensory domain, and how aberrations in sensory processing affect sensory gating. In this study, CHH and CNH were presented with a paired-pulse median nerve stimulation during magnetoencephalography. Stimulus-related gamma neural activity was imaged and virtual time series from peak somatosensory responses were extracted. We found significant effects of both stimulus and group, as well as a significant group-by-stimulus interaction. CHH showed a larger response to stimulation overall, as well as greater differences in gamma power from the first to the second stimulus. However, when looking at the ratio rather than the absolute difference in power, CHH showed comparable gating to CNH. In addition, smaller gating ratios were correlated with better classroom behavior and verbal ability in CHH, but not CNH. Taken together, these data underscore the importance of considering how CHH experience their multisensory environment when interpreting outcomes and designing interventions.


Assuntos
Perda Auditiva , Humanos , Criança , Cognição , Magnetoencefalografia/métodos , Encéfalo , Nervo Mediano , Filtro Sensorial , Córtex Somatossensorial/fisiologia
3.
Ear Hear ; 44(2): 338-357, 2023.
Artigo em Inglês | MEDLINE | ID: mdl-36253909

RESUMO

OBJECTIVE: The objective of this study was to characterize the dynamics of real-time lexical access, including lexical competition among phonologically similar words, and spreading semantic activation in school-age children with hearing aids (HAs) and children with cochlear implants (CIs). We hypothesized that developing spoken language via degraded auditory input would lead children with HAs or CIs to adapt their approach to spoken word recognition, especially by slowing down lexical access. DESIGN: Participants were children ages 9- to 12-years old with normal hearing (NH), HAs, or CIs. Participants completed a Visual World Paradigm task in which they heard a spoken word and selected the matching picture from four options. Competitor items were either phonologically similar, semantically similar, or unrelated to the target word. As the target word unfolded, children's fixations to the target word, cohort competitor, rhyme competitor, semantically related item, and unrelated item were recorded as indices of ongoing lexical access and spreading semantic activation. RESULTS: Children with HAs and children with CIs showed slower fixations to the target, reduced fixations to the cohort competitor, and increased fixations to the rhyme competitor, relative to children with NH. This wait-and-see profile was more pronounced in the children with CIs than the children with HAs. Children with HAs and children with CIs also showed delayed fixations to the semantically related item, although this delay was attributable to their delay in activating words in general, not to a distinct semantic source. CONCLUSIONS: Children with HAs and children with CIs showed qualitatively similar patterns of real-time spoken word recognition. Findings suggest that developing spoken language via degraded auditory input causes long-term cognitive adaptations to how listeners recognize spoken words, regardless of the type of hearing device used. Delayed lexical access directly led to delays in spreading semantic activation in children with HAs and CIs. This delay in semantic processing may impact these children's ability to understand connected speech in everyday life.


Assuntos
Implantes Cocleares , Auxiliares de Audição , Percepção da Fala , Humanos , Criança , Semântica , Tecnologia de Rastreamento Ocular , Percepção da Fala/fisiologia
4.
Ear Hear ; 44(4): 787-802, 2023.
Artigo em Inglês | MEDLINE | ID: mdl-36627755

RESUMO

OBJECTIVES: The purpose of this study was to determine if traditional audiologic measures (e.g., pure-tone average, speech recognition) and audibility-based measures predict risk for spoken language delay in children who are hard of hearing (CHH) who use hearing aids (HAs). Audibility-based measures included the Speech Intelligibility Index (SII), HA use, and auditory dosage, a measure of auditory access that weighs each child's unaided and aided audibility by the average hours of HA use per day. The authors also sought to estimate values of these measures at which CHH would be at greater risk for delayed outcomes compared with a group of children with typical hearing (CTH) matched for age and socioeconomic status, potentially signaling a need to make changes to a child's hearing technology or intervention plan. DESIGN: The authors compared spoken language outcomes of 182 CHH and 78 CTH and evaluated relationships between language and audiologic measures (e.g., aided SII) in CHH using generalized additive models. They used these models to identify values associated with falling below CTH (by > 1.5 SDs from the mean) on language assessments, putting CHH at risk for language delay. RESULTS: Risk for language delay was associated with aided speech recognition in noise performance (<59% phonemes correct, 95% confidence interval [55%, 62%]), aided Speech Intelligibility Index (SII < 0.61, 95% confidence internal [.53,.68]), and auditory dosage (dosage < 6.0, 95% confidence internal [5.3, 6.7]) in CHH. The level of speech recognition in quiet, unaided pure-tone average, and unaided SII that placed children at risk for language delay could not be determined due to imprecise estimates with broad confidence intervals. CONCLUSIONS: Results support using aided SII, aided speech recognition in noise measures, and auditory dosage as tools to facilitate clinical decision-making, such as deciding whether changes to a child's hearing technology are warranted. Values identified in this article can complement other metrics (e.g., unaided hearing thresholds, aided speech recognition testing, language assessment) when considering changes to intervention, such as adding language supports, making HA adjustments, or referring for cochlear implant candidacy evaluation.


Assuntos
Auxiliares de Audição , Perda Auditiva Neurossensorial , Perda Auditiva , Percepção da Fala , Criança , Humanos , Perda Auditiva/reabilitação , Desenvolvimento da Linguagem , Audição , Perda Auditiva Neurossensorial/reabilitação , Limiar Auditivo
5.
J Acoust Soc Am ; 154(2): 991-1002, 2023 08 01.
Artigo em Inglês | MEDLINE | ID: mdl-37581511

RESUMO

Individual differences in ear-canal acoustics introduce variability into hearing aid output that can affect speech audibility. Measuring ear-canal acoustics in young children can be challenging, and relying on normative real-ear-to-coupler difference (RECD) transforms can lead to large fitting errors. Acoustic immittance measures characterize the impedance of the ear and are more easily measured than RECD. Using 226 Hz tympanometry to predict the RECD is more accurate than using age-based average RECD values. The current study sought to determine whether wideband acoustic immittance measurements could improve predictions of wideband real-ear-to-coupler difference (wRECD). 150 children ages 2-10 years with intact tympanic membranes underwent wRECD and wideband acoustic immittance measures in each ear. Three models were constructed to predict each child's measured wRECD: the age-based average wRECD, 226 Hz admittance wRECD, and wideband absorbance wRECD. The average age-based wRECD model predicted the child's measured wRECD within 3 dB in 62% of cases, but both the 226 Hz admittance and wideband absorbance wRECD were within 3 dB in 90% of cases. Using individual 226 Hz or wideband absorbance to predict wRECD improved the accuracy and precision of transforms used for pediatric hearing aid fitting.


Assuntos
Testes de Impedância Acústica , Membrana Timpânica , Humanos , Criança , Pré-Escolar , Audição , Meato Acústico Externo , Acústica , Orelha Média
6.
Int J Audiol ; : 1-12, 2023 Dec 26.
Artigo em Inglês | MEDLINE | ID: mdl-38147879

RESUMO

OBJECTIVE: To determine if a stricter criterion for paediatric hearing aid fitting for proximity of fit-to-target of <3 dB root-mean-square (RMS) error produces better audibility and outcomes compared to the current <5 dB criterion, and to examine the relationship between aided audibility and RMS error by degree of hearing loss. DESIGN: We evaluated the influence of unaided hearing level on the relationship between RMS error and aided audibility. We assessed the effect of RMS error category (<3, 3-5, >5 dB) on aided audibility, speech recognition, expressive vocabulary, and morphosyntax. STUDY SAMPLE: The study included 2314 hearing aid verification measurements from 307 children with hearing aids. RESULTS: Children who met a <3 dB criterion had higher aided audibility than children who met no criterion (>5 dB error). Results showed no differences in speech recognition or vocabulary by error category, but children with <3 dB error demonstrated better morphosyntax than children with 3-5 and >5 dB RMS error. CONCLUSIONS: Fittings that are close to prescriptive targets provide a more positive outcome for children with hearing aids. Using probe microphone measures to adjust hearing aids to within 3 dB may benefit language abilities in children.

7.
J Trauma Dissociation ; 24(4): 489-505, 2023.
Artigo em Inglês | MEDLINE | ID: mdl-37183437

RESUMO

Adolescent relationship abuse (ARA) (i.e. physical, sexual, psychological, or economic abuse in the context of romantic relationships) is associated with adverse health outcomes, including anxiety, depression, suicidality, unintended pregnancy, and substance misuse. A related phenomenon, reproductive coercion involves interference with the reproductive decision making of a partner with the intention of promoting pregnancy or controlling outcomes of a pregnancy. Reproductive coercion is associated with unintended pregnancy, partner violence, and sexually transmitted infections. Little is known about the intersection between economic ARA, sexual exploitation, and reproductive coercion. This paper explores the intersections between reproductive coercion, transactional sex, and economic abuse victimization in adolescent dating relationships. In an online survey, 1,752 adolescents (ages 13-17) were asked about economic adolescent relationship abuse (educational, employment and financial interference), transactional sex, reproductive coercion, and contraceptive access within their relationships. We assessed associations with chi-square tests and logistic regression analysis. Youth who experienced economic ARA (70%, 1,232) reported financial dependence on their partner, contraceptive access, and reproductive coercion (74-83%; p-values<0.001) more often than their counterparts without economic ARA. Adolescents experiencing economic abuse were more likely to report transactional sex (aOR = 2.76, CI [2.12, 3.60], p < .001), depending on a partner to pay for contraception or birth control (aOR = 2.20, CI [1.71, 2.84], p < .001), and reproductive coercion (aOR = 3.20, CI [2.37, 4.32], p < .001). Youth-serving providers and agencies should be aware of intersections between economic ARA, transactional sex, financial dependence, and reproductive coercion, particularly for adolescents with health-related social needs.


Assuntos
Vítimas de Crime , Violência por Parceiro Íntimo , Gravidez , Feminino , Adolescente , Humanos , Estudos Transversais , Comportamento Sexual , Violência , Coerção , Violência por Parceiro Íntimo/psicologia
8.
Ear Hear ; 43(2): 347-360, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-34288630

RESUMO

OBJECTIVE: Children who are hard of hearing (CHH) experience delays in spoken language and executive function, but the mechanisms for these deficits remain unresolved. Differences in auditory experience and language skills have been examined as contributing factors to deficits in executive function, primarily with children who are deaf and children with cochlear implants. The theoretical model of cumulative auditory experience quantifies auditory dosage as how much speech is audible and how often children wear their hearing aids. CHH with higher auditory dosage have better language outcomes than peers with less auditory dosage. However, the effects of auditory experience on executive function have not been studied in CHH. The goal of this study was to examine the influences of auditory experience and language skills on the development of executive function in CHH. DESIGN: We collected measures of aided speech audibility, hearing aid use, executive function, and receptive vocabulary in 177 CHH and 86 children with typical hearing who were 5- to 10 years old and matched for socioeconomic status and nonverbal intelligence. Auditory dosage was calculated by combining each child's average hours of hearing aid use with their audibility for speech to create a variable that quantifies individual differences in auditory access. RESULTS: CHH had lower receptive vocabulary and deficits in executive function related to working memory and selective attention compared to peers with typical hearing. CHH with greater auditory dosage had higher receptive vocabulary than CHH with lower auditory dosage. Better receptive vocabulary was associated with better scores on executive function measures related to working memory and attention. Auditory dosage was also directly associated with measures of verbal working memory. CONCLUSIONS: CHH have deficits in language and some, but not all, areas of executive function related to working memory and attention. Auditory dosage was associated with language abilities and verbal working memory. Language was associated with individual differences in executive function skills related to attention and working memory. These results provide support for systems theories regarding the development of executive function in CHH. Interventions that improve auditory access and language may be effective for improving executive function related to working memory and attention in CHH.


Assuntos
Implantes Cocleares , Surdez , Perda Auditiva , Percepção da Fala , Criança , Pré-Escolar , Surdez/reabilitação , Função Executiva , Audição , Humanos , Idioma , Desenvolvimento da Linguagem , Memória de Curto Prazo
9.
Ear Hear ; 43(2): 408-419, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-34291759

RESUMO

OBJECTIVES: Children with hearing loss (CHL) may exhibit spoken language delays and may also experience deficits in other cognitive domains including working memory. Consistent hearing aid use (i.e., more than 10 hours per day) ameliorates these language delays; however, the impact of hearing aid intervention on the neural dynamics serving working memory remains unknown. The objective of this study was to examine the association between the amount of hearing aid use and neural oscillatory activity during verbal working memory processing in children with mild-to-severe hearing loss. DESIGN: Twenty-three CHL between 8 and 15 years-old performed a letter-based Sternberg working memory task during magnetoencephalography (MEG). Guardians also completed a questionnaire describing the participants' daily hearing aid use. Each participant's MEG data was coregistered to their structural MRI, epoched, and transformed into the time-frequency domain using complex demodulation. Significant oscillatory responses corresponding to working memory encoding and maintenance were independently imaged using beamforming. Finally, these whole-brain source images were correlated with the total number of hours of weekly hearing aid use, controlling for degree of hearing loss. RESULTS: During the encoding period, hearing aid use negatively correlated with alpha-beta oscillatory activity in the bilateral occipital cortices and right precentral gyrus. In the occipital cortices, this relationship suggested that with greater hearing aid use, there was a larger suppression of occipital activity (i.e., more negative relative to baseline). In the precentral gyrus, greater hearing aid use was related to less synchronous activity (i.e., less positive relative to baseline). During the maintenance period, hearing aid use significantly correlated with alpha activity in the right prefrontal cortex, such that with greater hearing aid use, there was less right prefrontal maintenance-related activity (i.e., less positive relative to baseline). CONCLUSIONS: This study is the first to investigate the impact of hearing aid use on the neural dynamics that underlie working memory function. These data show robust relationships between the amount of hearing aid use and phase-specific neural patterns during working memory encoding and maintenance after controlling for degree of hearing loss. Furthermore, our data demonstrate that wearing hearing aids for more than ~8.5 hours/day may serve to normalize these neural patterns. This study also demonstrates the potential for neuroimaging to help determine the locus of variability in outcomes in CHL.


Assuntos
Surdez , Auxiliares de Audição , Perda Auditiva , Transtornos do Desenvolvimento da Linguagem , Adolescente , Mapeamento Encefálico/métodos , Criança , Humanos , Magnetoencefalografia/métodos , Memória de Curto Prazo/fisiologia
10.
Proc Natl Acad Sci U S A ; 116(42): 21085-21093, 2019 10 15.
Artigo em Inglês | MEDLINE | ID: mdl-31570626

RESUMO

Understanding how phenotypes evolve requires disentangling the effects of mutation generating new variation from the effects of selection filtering it. Tests for selection frequently assume that mutation introduces phenotypic variation symmetrically around the population mean, yet few studies have tested this assumption by deeply sampling the distributions of mutational effects for particular traits. Here, we examine distributions of mutational effects for gene expression in the budding yeast Saccharomyces cerevisiae by measuring the effects of thousands of point mutations introduced randomly throughout the genome. We find that the distributions of mutational effects differ for the 10 genes surveyed and are inconsistent with normality. For example, all 10 distributions of mutational effects included more mutations with large effects than expected for normally distributed phenotypes. In addition, some genes also showed asymmetries in their distribution of mutational effects, with new mutations more likely to increase than decrease the gene's expression or vice versa. Neutral models of regulatory evolution that take these empirically determined distributions into account suggest that neutral processes may explain more expression variation within natural populations than currently appreciated.


Assuntos
Mutação Puntual/genética , Saccharomyces cerevisiae/genética , Evolução Molecular , Expressão Gênica/genética , Genoma Fúngico/genética , Fenótipo , Seleção Genética/genética
11.
Ann Behav Med ; 55(10): 938-948, 2021 10 04.
Artigo em Inglês | MEDLINE | ID: mdl-32914829

RESUMO

BACKGROUND: Conflicting research emphasizes depression, diabetes distress, or well-being in relation to diabetes self-care and risk for poor health outcomes. PURPOSE: The purpose of this study was to test whether a latent variable for general psychological distress derived from shared variance of depression symptoms, diabetes distress, and well-being predicts a latent variable of diabetes self-care and to examine evidence for unique effects once shared effects are adjusted for. METHODS: Adults with suboptimally controlled diabetes were recruited from the South Bronx, NY, for a telephonic diabetes self-management support trial. Baseline diabetes self-care, medication adherence, depression symptoms, diabetes distress, and well-being were measured by validated self-report. Structural equation modeling specified a latent variable for general psychological distress derived from shared variance of depression symptoms, diabetes distress, and well-being. Diabetes self-care was a latent variable indicated by diet, glucose self-monitoring, and medication adherence. RESULTS: Participants (N = 627, 65% female) were predominantly ethnic minority (70% Hispanic; 45% Black) and 77% reported household income <$20K/year. Mean (standard deviation) age = 56 (12) years; A1c = 9.1% (1.9%); body mass index = 32 (8) kg/m2. The latent variable for psychological distress was a robust predictor of poorer diabetes self-care (coefficient = -0.59 [confidence interval = -0.71, -0.46], p < .001) with good model fit. Unique paths from depression symptoms, diabetes distress, and well-being (all ps > .99) to self-care were not observed. CONCLUSIONS: In this population of disadvantaged adults with suboptimally controlled diabetes, general psychological distress was strongly associated with poorer diabetes self-care and fully accounted for the effects of depression, diabetes distress, and positive well-being. This suggests that general distress may underlie previously reported associations between these constructs and diabetes self-care.


Assuntos
Diabetes Mellitus Tipo 2 , Adulto , Depressão , Diabetes Mellitus Tipo 2/terapia , Minorias Étnicas e Raciais , Etnicidade , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Grupos Minoritários , Autocuidado , Estresse Psicológico
12.
Ear Hear ; 41(4): 775-789, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32032223

RESUMO

OBJECTIVES: There are very limited data regarding the spoken language and academic outcomes of children with mild to severe hearing loss (HL) during the elementary school years, and the findings of these studies are inconsistent. None of these studies have examined the possible role of aided hearing in these outcomes. This study used a large cohort of children to examine these outcomes and in particular to examine whether aided hearing moderates the effect of HL with regard to these outcomes. DESIGN: The spoken language, reading, writing, and calculation abilities were measured after second and fourth grades in children with mild to severe HL (children who are hard of hearing; CHH, n = 183) and a group of children with normal hearing (CNH, n = 91) after the completion of second and fourth grades. Also, among the CHH who wore hearing aids, aided better-ear speech intelligibility index values at the age of school entry were obtained. RESULTS: Oral language abilities of the CHH with mild and moderate HL were similar to the CNH at each grade. Children with moderately-severe HL (better-ear pure tone threshold >59 but <76 dB HL) had significantly poorer oral language and reading skills than the CNH at each grade. The children with mild and moderate HL did not differ from the CNH in oral language or reading. No differences were found between the CHH regardless of severity and CNH with regard to spelling, passage writing, or calculation. The degree to which hearing aids provided audible speech information played a moderating role in the oral language outcomes of CHH and this moderation of language mediated the relationship between the unaided hearing ability of the CHH and their academic outcomes. CONCLUSIONS: As a group, children with mild and moderate HL have good outcomes with regard to language and academic performance. Children with moderately-severe losses were less skilled in language and reading than the CNH and CHH children with mild and moderate losses. Audibility provided by hearing aids was found to moderate the effects of HL with respect to these outcomes. These findings emphasize the importance of including the effects of clinical interventions such as aided hearing when examining outcomes of CHH.


Assuntos
Auxiliares de Audição , Perda Auditiva , Criança , Audição , Testes Auditivos , Humanos , Desenvolvimento da Linguagem
13.
Child Dev ; 91(1): e179-e197, 2020 01.
Artigo em Inglês | MEDLINE | ID: mdl-30298910

RESUMO

This study contrasted the early literacy outcomes of children who are hard of hearing (CHH) with children with normal hearing (CNH). At age 5, prereading skills of oral language, phonological processing, and print knowledge were examined in CHH (N = 180) and CNH (N = 80). The CHH had poorer oral language and phonological processing abilities than the CNH but comparable knowledge of print. At age 8, measures of word reading, and reading comprehension yielded no differences between CHH (N = 108) and CNH (N = 62) except for reading comprehension for the moderately severe CHH. Reading achievement in CHH was found to exceed predictions based on prereading performance. This resilience was associated with gains in oral language during the early school years.


Assuntos
Sucesso Acadêmico , Crianças com Deficiência , Alfabetização , Pessoas com Deficiência Auditiva , Leitura , Criança , Pré-Escolar , Feminino , Humanos , Estudos Longitudinais , Masculino
14.
J Bacteriol ; 201(20)2019 10 15.
Artigo em Inglês | MEDLINE | ID: mdl-31331978

RESUMO

Streptococcus agalactiae, a leading cause of sepsis and meningitis in neonates, utilizes multiple virulence factors to survive and thrive within the human host during an infection. Unique among the pathogenic streptococci, S. agalactiae uses a bifunctional enzyme encoded by a single gene (gshAB) to synthesize glutathione (GSH), a major antioxidant in most aerobic organisms. Since S. agalactiae can also import GSH, similar to all other pathogenic streptococcal species, the contribution of GSH synthesis to the pathogenesis of S. agalactiae disease is not known. In the present study, gshAB deletion mutants were generated in strains representing three of the most prevalent clinical serotypes of S. agalactiae and were compared against isogenic wild-type and gshAB knock-in strains. When cultured in vitro in a chemically defined medium under nonstress conditions, each mutant and its corresponding wild type had comparable growth rates, generation times, and growth yields. However, gshAB deletion mutants were found to be more sensitive than wild-type or gshAB knock-in strains to killing and growth inhibition by several different reactive oxygen species. Furthermore, deletion of gshAB in S. agalactiae strain COH1 significantly attenuated virulence compared to the wild-type or gshAB knock-in strains in a mouse model of sepsis. Taken together, these data establish that GSH is a virulence factor important for resistance to oxidative stress and that de novo GSH synthesis plays a crucial role in S. agalactiae pathogenesis and further suggest that the inhibition of GSH synthesis may provide an opportunity for the development of novel therapies targeting S. agalactiae disease.IMPORTANCE Approximately 10 to 30% of women are naturally and asymptomatically colonized by Streptococcus agalactiae However, transmission of S. agalactiae from mother to newborn during vaginal birth is a leading cause of neonatal meningitis. Although colonized mothers who are at risk for transmission to the newborn are treated with antibiotics prior to delivery, S. agalactiae is becoming increasingly resistant to current antibiotic therapies, and new treatments are needed. This research reveals a critical stress resistance pathway, glutathione synthesis, that is utilized by S. agalactiae and contributes to its pathogenesis. Understanding the role of this unique bifunctional glutathione synthesis enzyme in S. agalactiae during sepsis may help elucidate why S. agalactiae produces such an abundance of glutathione compared to other bacteria.


Assuntos
Proteínas de Bactérias/genética , Sepse/microbiologia , Infecções Estreptocócicas/microbiologia , Streptococcus agalactiae/patogenicidade , Animais , Proteínas de Bactérias/metabolismo , Modelos Animais de Doenças , Deleção de Genes , Técnicas de Introdução de Genes , Glutationa/biossíntese , Humanos , Camundongos , Estresse Oxidativo , Streptococcus agalactiae/crescimento & desenvolvimento , Streptococcus agalactiae/metabolismo , Virulência
15.
Ear Hear ; 40(1): 213-217, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-29547477

RESUMO

The authors tested the hypothesis that children with cochlear implants (CIs) experience domain-general deficits in sequential learning. Twenty children with CIs and 40 children with normal hearing (NH) participated. Participants completed a serial reaction time task that measured implicit sequential learning. During random sequence phases, the CI group had significantly slower reaction times than the NH group. However, there were no significant differences in the rates of sequential learning between groups. Age at implantation was not significantly associated with learning rate in the CI group. Children with CIs demonstrated nonverbal sequential learning that is comparable to children with NH. Contrary to previous research, early auditory deprivation may not be associated with deficits in domain-general sequential learning, but may affect sequential processing. Further investigation is needed to understand the mechanisms underlying the overall delayed reaction times of children with CIs.


Assuntos
Surdez/reabilitação , Aprendizagem/fisiologia , Fatores Etários , Estudos de Casos e Controles , Criança , Implante Coclear , Implantes Cocleares , Surdez/fisiopatologia , Surdez/psicologia , Feminino , Humanos , Masculino , Tempo de Reação
16.
Int J Audiol ; 58(4): 200-207, 2019 04.
Artigo em Inglês | MEDLINE | ID: mdl-30614307

RESUMO

OBJECTIVES: Children who are hard of hearing (CHH) have restricted access to auditory-linguistic information. Remote-microphone (RM) systems reduce the negative consequences of limited auditory access. The purpose of this study was to characterise receipt and use of RM systems in young CHH in home and school settings. DESIGN: Through a combination of parent, teacher, and audiologist report, we identified children who received RM systems for home and/or school use by 4 years of age or younger. With cross-sectional surveys, parents estimated the amount of time the child used RM systems at home and school per day. STUDY SAMPLE: The participants included 217 CHH. RESULTS: Thirty-six percent of the children had personal RMs for home use and 50% had RM systems for school. Approximately, half of the parents reported that their children used RM systems for home use for 1-2 hours per use and RM systems for school use for 2-4 hours per day. CONCLUSIONS: Results indicated that the majority of the CHH in the current study did not receive RM systems for home use in early childhood, but half had access to RM technology in the educational setting. High-quality research studies are needed to determine ways in which RM systems benefit pre-school-age CHH.


Assuntos
Crianças com Deficiência/reabilitação , Auxiliares de Audição , Perda Auditiva Bilateral/reabilitação , Audição , Pessoas com Deficiência Auditiva/reabilitação , Percepção da Fala , Fatores Etários , Desenvolvimento Infantil , Pré-Escolar , Estudos Transversais , Crianças com Deficiência/educação , Crianças com Deficiência/psicologia , Intervenção Educacional Precoce , Intervenção Médica Precoce , Educação de Pessoas com Deficiência Auditiva , Desenho de Equipamento , Feminino , Acessibilidade aos Serviços de Saúde , Perda Auditiva Bilateral/diagnóstico , Perda Auditiva Bilateral/fisiopatologia , Perda Auditiva Bilateral/psicologia , Humanos , Lactente , Recém-Nascido , Masculino , Pessoas com Deficiência Auditiva/psicologia , Estados Unidos
17.
Ear Hear ; 39(5): 980-991, 2018.
Artigo em Inglês | MEDLINE | ID: mdl-29474219

RESUMO

OBJECTIVES: This study had two key objectives. First, to examine whether children who receive cochlear implants (CIs) before the age of 3 years and who are experienced implant users (mean length of CI use = 6 years; range = 4 to 9 years) show deficits on a word learning task relative to their hearing peers. Second, to examine whether variation in age at implantation within the first 3 years of life relates to later word learning abilities. DESIGN: Twenty-one 6- to 10-year-old children with CIs, 21 chronological age-matched (AM) hearing children, and 21 vocabulary-matched hearing children completed an auditory word learning task in which they were required to learn the names of eight rare animals. Comprehension and production probes tested their learning of these unfamiliar words. RESULTS: The children with CIs performed similarly to AM peers on the comprehension phase of the word learning task. Their production performance was significantly poorer than the AM group but was in line with that of their younger vocabulary-matched hearing peers. Differences between the CI and AM groups were accounted for by differences between the groups in terms of their existing vocabulary knowledge. Within the CI group, there was no evidence of an association between age at implantation and performance on the word learning task, but existing vocabulary size showed strong positive correlations with word learning performance, after adjustment for chronological age. CONCLUSIONS: When implanted by the age of 3 years, and with over 4 years CI experience, 6- to 10-year-old children are able to perform similarly to their AM hearing peers in terms of their comprehension of newly learned words. Producing accurate phonological forms of newly learned words may be a more challenging task for children with CIs, but their production performance is consistent with their vocabulary size. This cross-sectional study provides support for a relationship between existing vocabulary size and novel word learning skills in children with CIs; future longitudinal studies should test the hypothesis that this relationship is developmentally reciprocal.


Assuntos
Implante Coclear , Implantes Cocleares , Desenvolvimento da Linguagem , Vocabulário , Fatores Etários , Estudos de Casos e Controles , Criança , Pré-Escolar , Compreensão , Estudos Transversais , Surdez/cirurgia , Humanos , Valores de Referência , Aprendizagem Verbal
18.
Ear Hear ; 36 Suppl 1: 14S-23S, 2015.
Artigo em Inglês | MEDLINE | ID: mdl-26731154

RESUMO

OBJECTIVES: The primary objective of this article was to describe recruitment, data collection, and methods for a longitudinal, multicenter study involving children with bilateral mild to severe hearing loss. The goals of this research program were to characterize the developmental outcomes of children with mild to severe bilateral hearing loss during infancy and the preschool years. Furthermore, the researchers examined how these outcomes were associated with the child's hearing loss and how home background and clinical interventions mediated and moderated these outcomes. DESIGN: The participants in this study were children who are hard of hearing (CHH) and children with normal hearing (CNH) who provided comparison data. CHH were eligible for participation if (1) their chronological age was between 6 months and 7 years of age at the time of recruitment, (2) they had a better-ear pure-tone average of 25 to 75 dB HL, (3) they had not received a cochlear implant, (4) they were from homes where English was the primary language, and (5) they did not demonstrate significant cognitive or motor delays. Across the time span of recruitment, 430 parents of potential children with hearing loss made contact with the research group. This resulted in 317 CHH who qualified for enrollment. In addition, 117 CNH qualified for enrollment. An accelerated longitudinal design was used, in which multiple age cohorts were followed long enough to provide overlap. Specifically, children were recruited and enrolled continuously across an age span of 6.5 years and were followed for at least 3 years. This design allowed for tests of time (period) versus cohort age effects that could arise by changes in services and technology over time, yet still allowed for examination of important developmental relationships. RESULTS: The distribution of degree of hearing loss for the CHH showed that the majority of CHH had moderate or moderate-to-severe hearing losses, indicating that the sample undersampled children with mild HL. For mothers of both CHH and CNH, the distribution of maternal education level showed that few mothers lacked at least a high school education and a slight majority had completed a bachelor's degree, suggesting that this sample of research volunteers was more advantaged than the United States population. The test battery consisted of a variety of measures concerning participants' hearing and behavioral development. These data were gathered in sessions during which the child was examined by an audiologist and a speech-language examiner. In addition, questionnaires concerning the child's behavior and development were completed by the parents. CONCLUSION: The Outcomes of Children with Hearing Loss study was intended to examine the relationship between variation in hearing ability across children with normal and mild to severe hearing loss and variation in their outcomes across several domains of development. In addition, the research team sought to document important mediators and moderators that act between the hearing loss and the outcomes. Because the study design provided for the examination of outcomes throughout infancy and early childhood, it was necessary to employ a number of different measures of the same construct to accommodate changes in developmental performance across age. This resulted in a large matrix of measures across variable types and developmental levels, as described in this manuscript.


Assuntos
Perda Auditiva Bilateral/fisiopatologia , Desenvolvimento da Linguagem , Seleção de Pacientes , Projetos de Pesquisa , Percepção da Fala , Audiometria de Tons Puros , Estudos de Casos e Controles , Criança , Pré-Escolar , Cognição , Coleta de Dados , Feminino , Auxiliares de Audição , Perda Auditiva Bilateral/psicologia , Perda Auditiva Bilateral/reabilitação , Humanos , Lactente , Inteligência , Estudos Longitudinais , Masculino , Avaliação de Resultados em Cuidados de Saúde , Leitura , Índice de Gravidade de Doença , Percepção Social
19.
Ear Hear ; 36 Suppl 1: 60S-75S, 2015.
Artigo em Inglês | MEDLINE | ID: mdl-26731160

RESUMO

OBJECTIVES: Progress has been made in recent years in the provision of amplification and early intervention for children who are hard of hearing. However, children who use hearing aids (HAs) may have inconsistent access to their auditory environment due to limitations in speech audibility through their HAs or limited HA use. The effects of variability in children's auditory experience on parent-reported auditory skills questionnaires and on speech recognition in quiet and in noise were examined for a large group of children who were followed as part of the Outcomes of Children with Hearing Loss study. DESIGN: Parent ratings on auditory development questionnaires and children's speech recognition were assessed for 306 children who are hard of hearing. Children ranged in age from 12 months to 9 years. Three questionnaires involving parent ratings of auditory skill development and behavior were used, including the LittlEARS Auditory Questionnaire, Parents Evaluation of Oral/Aural Performance in Children rating scale, and an adaptation of the Speech, Spatial, and Qualities of Hearing scale. Speech recognition in quiet was assessed using the Open- and Closed-Set Test, Early Speech Perception test, Lexical Neighborhood Test, and Phonetically Balanced Kindergarten word lists. Speech recognition in noise was assessed using the Computer-Assisted Speech Perception Assessment. Children who are hard of hearing were compared with peers with normal hearing matched for age, maternal educational level, and nonverbal intelligence. The effects of aided audibility, HA use, and language ability on parent responses to auditory development questionnaires and on children's speech recognition were also examined. RESULTS: Children who are hard of hearing had poorer performance than peers with normal hearing on parent ratings of auditory skills and had poorer speech recognition. Significant individual variability among children who are hard of hearing was observed. Children with greater aided audibility through their HAs, more hours of HA use, and better language abilities generally had higher parent ratings of auditory skills and better speech-recognition abilities in quiet and in noise than peers with less audibility, more limited HA use, or poorer language abilities. In addition to the auditory and language factors that were predictive for speech recognition in quiet, phonological working memory was also a positive predictor for word recognition abilities in noise. CONCLUSIONS: Children who are hard of hearing continue to experience delays in auditory skill development and speech-recognition abilities compared with peers with normal hearing. However, significant improvements in these domains have occurred in comparison to similar data reported before the adoption of universal newborn hearing screening and early intervention programs for children who are hard of hearing. Increasing the audibility of speech has a direct positive effect on auditory skill development and speech-recognition abilities and also may enhance these skills by improving language abilities in children who are hard of hearing. Greater number of hours of HA use also had a significant positive impact on parent ratings of auditory skills and children's speech recognition.


Assuntos
Desenvolvimento Infantil , Auxiliares de Audição , Perda Auditiva Bilateral/fisiopatologia , Desenvolvimento da Linguagem , Pais , Percepção da Fala/fisiologia , Estudos de Casos e Controles , Criança , Pré-Escolar , Feminino , Perda Auditiva Bilateral/reabilitação , Humanos , Lactente , Estudos Longitudinais , Masculino , Memória de Curto Prazo , Índice de Gravidade de Doença , Inquéritos e Questionários
20.
Ear Hear ; 36 Suppl 1: 76S-91S, 2015.
Artigo em Inglês | MEDLINE | ID: mdl-26731161

RESUMO

OBJECTIVES: This study examined the language outcomes of children with mild to severe hearing loss during the preschool years. The longitudinal design was leveraged to test whether language growth trajectories were associated with degree of hearing loss and whether aided hearing influenced language growth in a systematic manner. The study also explored the influence of the timing of hearing aid fitting and extent of use on children's language growth. Finally, the study tested the hypothesis that morphosyntax may be at particular risk due to the demands it places on the processing of fine details in the linguistic input. DESIGN: The full cohort of children in this study comprised 290 children who were hard of hearing (CHH) and 112 children with normal hearing who participated in the Outcomes of Children with Hearing Loss (OCHL) study between the ages of 2 and 6 years. CHH had a mean better-ear pure-tone average of 47.66 dB HL (SD = 13.35). All children received a comprehensive battery of language measures at annual intervals, including standardized tests, parent-report measures, and spontaneous and elicited language samples. Principal components analysis supported the use of a single composite language score for each of the age levels (2, 3, 4, 5, and 6 years). Measures of unaided (better-ear pure-tone average, speech intelligibility index) and aided (residualized speech intelligibility index) hearing were collected, along with parent-report measures of daily hearing aid use time. Mixed modeling procedures were applied to examine the rate of change (227 CHH; 94 children with normal hearing) in language ability over time in relation to (1) degree of hearing loss, (2) aided hearing, (3) age of hearing aid fit and duration of use, and (4) daily hearing aid use. Principal components analysis was also employed to examine factor loadings from spontaneous language samples and to test their correspondence with standardized measures. Multiple regression analysis was used to test for differential effects of hearing loss on morphosyntax and lexical development. RESULTS: Children with mild to severe hearing loss, on average, showed depressed language levels compared with peers with normal hearing who were matched on age and socioeconomic status. The degree to which CHH fell behind increased with greater severity of hearing loss. The amount of improved audibility with hearing aids was associated with differential rates of language growth; better audibility was associated with faster rates of language growth in the preschool years. Children fit early with hearing aids had better early language achievement than children fit later. However, children who were fit after 18 months of age improved in their language abilities as a function of the duration of hearing aid use. These results suggest that the language learning system remains open to experience provided by improved access to linguistic input. Performance in the domain of morphosyntax was found to be more delayed in CHH than their semantic abilities. CONCLUSION: The data obtained in this study largely support the predictions, suggesting that mild to severe hearing loss places children at risk for delays in language development. Risks are moderated by the provision of early and consistent access to well-fit hearing aids that provide optimized audibility.


Assuntos
Auxiliares de Audição , Perda Auditiva Bilateral/fisiopatologia , Transtornos do Desenvolvimento da Linguagem/fisiopatologia , Desenvolvimento da Linguagem , Estudos de Casos e Controles , Criança , Pré-Escolar , Feminino , Perda Auditiva Bilateral/reabilitação , Humanos , Masculino , Análise de Regressão , Índice de Gravidade de Doença
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA