Working Memory and Second‐Language Accent Acquisition

We explored the proposal that overt repetition of verbal information improves the acquisition of a native accent in a second language. Mandarin-speaking Chinese learners of English were recorded while repeating and reading out English sentences before and after one of three treatments: (1) Repeating native English sentences subvocally, "covert repetition,"(2) Repeating sentences out loud, "overt repetition," and(3) Unfilled time of comparable duration. The sentences were rated by English speakers for their nativeness, fluency, and intelligibility. Overt repetition improved accent rating for read-out sentences. Covert repetition did not. Neither condition improved accent rating for repeated sentences, suggesting that immediate repetition depends on temporary rather than long-term representations. Our results provide some support for the use of overt repetition in accent learning. From a theoretical perspective, an interpretation is proposed in terms of a separation between phonological and articulatory coding within the phonological loop component of working memory

Separability of tones and rhymes in Chinese speech perception : Evidence from perceptual migrations

This study used the perceptual-migration paradigm to explore whether Mandarin tones and syllable rhymes are processed separately during Mandarin speech perception. Following the logic of illusory conjunctions, we calculated the cross-ear migration of tones, rhymes, and their combination in Chinese and English listeners. For Chinese listeners, tones migrated more than rhymes. The opposite pattern was found for English listeners. The results lend empirical support to autosegmental theory, which claims separability and mobility between tonal and segmental representations. They also provide evidence that such representations and their involvement in perception are deeply shaped by a listener’s linguistic experience

Auditory verbal working memory as a predictor of speech perception in modulated maskers in normal-hearing listeners

Purpose: Background noise can interfere with our ability to understand speech. Working memory capacity (WMC) has been shown to contribute to the perception of speech in modulated noise maskers. WMC has been assessed with a variety of auditory and visual tests, often pertaining to different components of working memory. This study assessed the relationship between speech perception in modulated maskers and components of auditory verbal working memory (AVWM) over a range of signal-to-noise ratios. Method: Speech perception in noise and AVWM were measured in 30 listeners (age range 31-67 years) with normal hearing. AVWM was estimated using forward digit recall, backward digit recall, and non-word repetition. Results: After controlling for the effects of age and average pure-tone hearing threshold, speech perception in modulated maskers was related to individual differences in the phonological component of working memory (as assessed by non-word repetition) but only in the least favorable SNR. The executive component of working memory (as assessed by backward digit) was not predictive of speech perception in any conditions. Conclusions: AVWM is predictive of the ability to benefit from temporal dips in modulated maskers: Listeners with greater phonological WMC are better able to correctly identify sentences in modulated noise backgrounds

Saliency or template? ERP evidence for long-term representation of word stress

The present study investigated the event-related brain potential (ERP) correlates of word stress processing. Previous results showed that the violation of a legal stress pattern elicited two consecutive Mismatch Negativity (MMN) components synchronized to the changes on the first and second syllable. The aim of the present study was to test whether ERPs reflect only the detection of salient features present on the syllables, or they reflect the activation of long-term stress related representations. We examined ERPs elicited by pseudowords with no lexical representation in two conditions: the standard having a legal stress patterns, and the deviant an illegal one, and the standard having an illegal stress pattern, and the deviant a legal one. We found that the deviant having an illegal stress pattern elicited two consecutive MMN components, whereas the deviant having a legal stress pattern did not elicit MMN. Moreover, pseudowords with a legal stress pattern elicited the same ERP responses irrespective of their role in the oddball sequence, i.e., if they were standards or deviants. The results suggest that stress pattern changes are processed relying on long-term representation of word stress. To account for these results, we propose that the processing of stress cues is based on language-specific, pre-lexical stress templates

Cognitive load elevates discrimination thresholds of duration, intensity, and f0 for a synthesized vowel

Dual-tasking negatively impacts on speech perception by raising cognitive load (CL). Previous research has shown that CL increases reliance on lexical knowledge and decreases reliance on phonetic detail. Less is known about the effect of CL on the perception of acoustic dimensions below the phonetic level. This study tested the effect of CL on the ability to discriminate differences in duration, intensity, and fundamental frequency of a synthesized vowel. A psychophysical adaptive procedure was used to obtain just noticeable differences (JNDs) on each dimension under load and no load. Load was imposed by N-back tasks at two levels of difficulty (one-back, two-back) and under two types of load (images, nonwords). Compared to a control condition with no CL, all N-back conditions increased JNDs across the three dimensions. JNDs were also higher under two-back than one-back load. Nonword load was marginally more detrimental than image load for intensity and fundamental frequency discrimination. Overall, the decreased auditory acuity demonstrates that the effect of CL on the listening experience can be traced to distortions in the perception of core auditory dimensions

Avaliação das vias aéreas após correção transversal maxilar com MARPE e aparelhos convencionais

Introdução : A mordida cruzada posterior é uma característica dos pacientes com discrepâncias transversais maxilomandibulares. O subdesenvolvimento da maxila pode levar a dificuldades nas vias aéreas, razão pela qual muitas opções de tratamento estão disponíveis. A RME convencional é frequentemente utilizada como tratamento, no entanto uma técnica mais recente, a MARPE (Mini-screw-Assisted Rapid Palatal Expansion) tem sido bastante utilizada. Objetivos: Comparar as alterações das vias aéreas após a expansão rápida da maxila com duas técnicas: o método convencional (RME) e o MARPE, no tratamento da atresia transversal da maxila nos adolescentes e jovens adultos. Material e métodos: Formulou-se uma questão segundo a estratégia PICOS e com orientação do PRISMA. De seguida efetuou-se uma pesquisa bibliográfica nas bases de dados online Pubmed e Google Scholar entre 2015 e 2021, usando palavras-chave definidas. A pesquisa identificou um total de 254 artigos e, após uma análise rigorosa, foram selecionados 10. Resultados: Em particular, a constrição maxilar desempenha um papel na fisiopatologia dos problemas respiratórios. Vários estudos demonstraram que o volume da cavidade nasal aumenta com o uso do MARPE. O método convencional RME tem, tal como o MARPE, efeitos positivos no alargamento e aumento das vias aéreas, mas também possui efeitos negativos, tais como inclinação bucal e perda da altura alveolar sobre os dentes de ancoragem. Ambas as técnicas desempenham um papel favorável no tratamento da síndrome da apneia do sono. Conclusão: O MARPE é a técnica de eleição, porque quando se compara com o método convencional, é mais eficaz, atingindo uma ancoragem esquelética, minimizando os efeitos adversos e levando a um maior volume respiratório