Search

Previous research has shown the novelty of lexical-tone chimeras (artificially constructed speech sounds created by combining normal speech sounds of a given language) to native speakers of the language from which the chimera components were drawn. However, the source of such novelty remains unclear. Our goal in this study was to separate the effects of chimeric tonal novelty in Mandarin speech from the effects of auditory signal manipulations. We recruited 20 native speakers of Mandarin and constructed two sets of lexical-tone chimeras by interchanging the envelopes and fine structures of both a falling/yi4/and a rising/yi2/Mandarin tone through 1, 2, 3, 4, 6, 8, 16, 32, and 64 auditory filter banks. We conducted pitch-perception ability tasks via a two-alternative, forced-choice paradigm to produce behavioral (versus physiological) pitch perception data. We also obtained electroencephalographic measurements through the scalp-recorded frequency-following response (FFR). Analyses of variances and post hoc Greenhouse-Geisser procedures revealed that the differences observed in the participants' reaction times and FFR measurements were attributable primarily to chimeric novelty rather than signal manipulation effects. These findings can be useful in assessing neuroplasticity and developing speech-processing strategies. [ABSTRACT FROM AUTHOR]

Objective: Previous research has shown the usefulness of utilizing auditory chimeras in assessing a listener’s perception of the envelope and fine structure for an acoustic stimulus. However, research comparing and contrasting behavioral and electrophysiological responses to this stimulus type is scarce.Design: Two sets of chimeric stimuli were constructed by interchanging the envelopes and fine-structures of the rising/yi2/and falling/yi4/Mandarin pitch contours that were filtered through 1, 2, 4, 8, 16, 32, and 64 frequency banks. Behavioral pitch-perception tasks were administered through a two-alternative, forced-choice paradigm. Electrophysiological responses were measured through scalp-recorded frequency-following responses (FFRs) to the lexical-tone chimeras.Study sample: Twenty American and twenty Chinese adults were recruited.Results: A two-way analysis of variance showed significance (p < 0.05) within and across the filter bank and language background factors for the behavioral measurements, while the frequency-following response demonstrated a significance only across the filter banks.Conclusions: Perceptual importance of envelope cues increases starting from 16 filter banks, while the FFR accuracy and magnitude decreases with increasing number of filter banks. These results can be useful in assessing experience-dependent neuroplasticity and in designing speech processing strategies for cochlear-implant users who speak tonal or non-tonal languages around the globe. [ABSTRACT FROM AUTHOR]

Abstract Objective: Recent studies have shown that the frequency-following response (FFR) to voice pitch can be a useful method to evaluate the signal-processing mechanisms and neural plasticity in the human brainstem. The purpose of this study was to examine the quantitative properties of the FFR trends with an exponential curve-fitting model. Design: FFR trends obtained with increasing number of sweeps (up to 8000 sweeps) at three stimulus intensities (30, 45, and 60 dB nHL) were fit to an exponential model that consisted of estimates of background noise amplitude, asymptotic response amplitude, and a time constant. Five objective indices ( Frequency Error, Slope Error, Tracking Accuracy, Pitch Strength and RMS Ratio) were used to represent different perspectives of pitch processing in the human brainstem. Study Sample: Twenty-three native speakers (16 males; age == 24.7 ± 2.1 years) of Mandarin Chinese were recruited. Results: The results demonstrated that the exponential model provided a good fit ( r2 == 0.89 ± 0.10) to the FFR trends with increasing number of sweeps for the five objective indices. Conclusions: The exponential model, combined with the five objective indices, can be used for difficult-to-test patients and may prove to be useful as an assessment and diagnostic method in both clinical and basic research efforts. Sumario Objetivo: Estudios recientes han mostrado que la respuesta de seguimiento de frecuencia (FFR) al tono de la voz puede ser un método útil para evaluar los mecanismos de procesamiento de la señal y la plasticidad neural en el tallo cerebral humano. El propósito de este estudio fue examinar las propiedades cuantitativas de las tendencias del FFR con un modelo exponencial de curva de adaptación. Diseño: Las tendencias de la FFR obtenidas con un número creciente de barridos (hasta 8000 barridos), a tres intensidades diferentes (30, 45 y 60 dB nHL) fueron introducidas en un modelo exponencial que consistió en estimados de la amplitud del ruido de fondo, amplitud asintótica de respuesta y una constante de tiempo. Cinco índices objetivos (Error de frecuencia, error de pendiente, exactitud de seguimiento, fortaleza del tono y tasa RSM) fueron utilizados para representar diferentes perspectivas del procesamiento del tono en el tallo cerebral del humano. Muestra del estudio: Se reclutaron treinta y tres hablantes naturales (16 hombres; edades == 24,7 ± 2.1 años) del chino mandarín. Resultados: Los resultados demostraron que el modelo exponencial brindó una buena adaptación ( r2 == 0.89 ± 0.10) a la tendencias de la FFR con un número creciente de barridos para los cinco índices objetivos. Conclusiones: El modelo exponencial, combinado con los cinco índices objetivos, puede ser utilizado en pacientes difíciles de evaluar y demostrar su utilidad como un método de evaluación y diagnóstico, tanto en protocolos clínicos como de investigación. [ABSTRACT FROM AUTHOR]

Copyright of International Journal of Audiology is the property of Taylor & Francis Ltd and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)