RESUMO
INTRODUCTION: Noise exposure during pregnancy may affect a child's auditory system, which may disturb fetal learning and language development. We examined the impact of occupational noise exposure during pregnancy on children's language acquisition at the age of one. METHODS: A cohort study was conducted among women working in the food industry, as kindergarten teachers, musicians, dental nurses, or pharmacists who had a child aged <1 year. The analyses covered 408 mother-child pairs. Language acquisition was measured using the Infant-Toddler Checklist. An occupational hygienist assessed noise exposure individually as no (N = 180), low (70-78 dB; N = 108) or moderate/high exposure (>79 dB; N = 120). RESULTS: Among the boys, the adjusted mean differences in language acquisition scores were -0.4 (95% CI -2.5, 1.8) for low, and -0.7 (95% CI -2.9, 1.4) for moderate/high exposure compared to no exposure. Among the girls the respective scores were +0.1 (95% CI -2.2, 2.5) and -0.1 (95% CI -2.3, 2.2). Among the children of kindergarten teachers, who were mainly exposed to human noise, low or moderate exposure was associated with lower language acquisition scores. The adjusted mean differences were -3.8 (95% CI -7.2, -0.4) for low and -4.9 (95% CI -8.6, -1.2) for moderate exposure. CONCLUSIONS: In general, we did not detect an association between maternal noise exposure and children's language acquisition among one-year-old children. However, the children of kindergarten teachers exposed to human noise had lower language acquisition scores than the children of the non-exposed participants. These suggestive findings merit further investigation by level and type of exposure.
Assuntos
Ruído Ocupacional , Exposição Ocupacional , Masculino , Gravidez , Lactente , Humanos , Feminino , Estudos de Coortes , Ruído Ocupacional/efeitos adversos , Desenvolvimento da Linguagem , Exposição Materna/efeitos adversosRESUMO
Speech production, both overt and covert, down-regulates the activation of auditory cortex. This is thought to be due to forward prediction of the sensory consequences of speech, contributing to a feedback control mechanism for speech production. Critically, however, these regulatory effects should be specific to speech content to enable accurate speech monitoring. To determine the extent to which such forward prediction is content-specific, we recorded the brain's neuromagnetic responses to heard multisyllabic pseudowords during covert rehearsal in working memory, contrasted with a control task. The cortical auditory processing of target syllables was significantly suppressed during rehearsal compared with control, but only when they matched the rehearsed items. This critical specificity to speech content enables accurate speech monitoring by forward prediction, as proposed by current models of speech production. The one-to-one phonological motor-to-auditory mappings also appear to serve the maintenance of information in phonological working memory. Further findings of right-hemispheric suppression in the case of whole-item matches and left-hemispheric enhancement for last-syllable mismatches suggest that speech production is monitored by 2 auditory-motor circuits operating on different timescales: Finer grain in the left versus coarser grain in the right hemisphere. Taken together, our findings provide hemisphere-specific evidence of the interface between inner and heard speech.
Assuntos
Córtex Auditivo/fisiologia , Mapeamento Encefálico , Inibição Psicológica , Vias Neurais/fisiologia , Percepção da Fala/fisiologia , Fala/fisiologia , Estimulação Acústica , Adulto , Análise de Variância , Feminino , Lateralidade Funcional , Humanos , Magnetoencefalografia , Masculino , Estimulação Luminosa , Medida da Produção da Fala , Adulto JovemRESUMO
It is suspected that the developmental delay in school-aged children diagnosed as infants suffering from plagiocephaly is caused by the modification of the skull form. To detect possible cognitive impairment in these children, we examined auditory ERPs to tones in infant patients. The infants with plagiocephaly exhibited smaller amplitudes of the P150 and the N250 responses to tones than healthy controls. Differences between the patients and control subjects indicate that already at this early age the presence of the plagiocephalic skull signals compromise of brain functioning. The present data suggest that most of the plagiocephalic infants have an elevated risk of auditory processing disorders. In the current study we demonstrated, for the first time, that the central sound processing, as reflected by ERPs, is affected in children with plagiocephaly.