RESUMEN
The goal of this study was to investigate Mandarin Chinese tone identification in quiet and multi-talker babble conditions for normal-hearing listeners. Tone identification was measured with speech stimuli and stimuli with low and/or high harmonics that were embedded in three Mandarin vowels with two fundamental frequencies. There were six types of stimuli: all harmonics (All), low harmonics (Low), high harmonics (High), and the first (H1), second (H2), and third (H3) harmonic. Results showed that, for quiet conditions, individual harmonics carried frequency contour information well enough for tone identification with high accuracy; however, in noisy conditions, tone identification with individual low harmonics (e.g., H1, H2, and H3) was significantly lower than that with the Low, High, and All harmonics. Moreover, tone identification with individual harmonics in noise was lower for a low F0 than for a high F0, and was also dependent on vowel category. Tone identification with individual low-frequency harmonics was accounted for by local signal-to-noise ratios, indicating that audibility of harmonics in noise may play a primary role in tone identification.
Asunto(s)
Ruido/efectos adversos , Enmascaramiento Perceptual , Fonética , Percepción de la Altura Tonal , Acústica del Lenguaje , Inteligibilidad del Habla , Percepción del Habla , Calidad de la Voz , Estimulación Acústica , Audiometría del Habla , Señales (Psicología) , Femenino , Humanos , Masculino , Psicoacústica , Detección de Señal Psicológica , Relación Señal-RuidoRESUMEN
PURPOSE: This study examined the effects of envelope dynamic-range mismatch on the intelligibility of Mandarin speech in noise by simulated bilateral electric hearing. METHOD: Noise-vocoded Mandarin speech, corrupted by speech-shaped noise at 5 and 0 dB signal-to-noise ratios, was presented unilaterally or bilaterally to 10 normal-hearing listeners for recognition. For unilateral conditions, the right ear was presented with the 8-channel noise-vocoded stimuli generated using a 15-dB envelope dynamic range (DR). To simulate the envelope DR mismatch between the 2 ears, the left ear was presented with the 8-channel noise-vocoded stimuli generated using a 5-, 10-, or 15-dB envelope DR, respectively. RESULTS: Significant binaural summation benefits for Mandarin speech recognition were observed only with matched envelope DR between the 2 ears. With reduced DR, the performance of tone identification was more consistent in the steady-state speech-shaped noise than that of sentence recognition. CONCLUSIONS: Consistent with previous findings, the present results suggest that Mandarin speech-perception performance of bilateral electric listening in noise is affected by the difference of envelope DR between the 2 implanted ears, and the binaural summation benefits are maximized when DR mismatch is minimized between the 2 implanted ears.
Asunto(s)
Implantación Coclear , Implantes Cocleares , Pruebas de Audición Dicótica , Fonética , Pruebas de Discriminación del Habla , Percepción del Habla , Estimulación Acústica/métodos , Adolescente , Adulto , Pueblo Asiatico , Femenino , Humanos , Masculino , Ruido , Reconocimiento en Psicología , Relación Señal-Ruido , Adulto JovenRESUMEN
This study investigated the contribution of low-frequency harmonics to identifying Mandarin tones in natural and vocoded speech in quiet and noisy conditions. Results showed that low-frequency harmonics of natural speech led to highly accurate tone identification; however, for vocoded speech, low-frequency harmonics yielded lower tone identification than stimuli with full harmonics, except for tone 4. Analysis of the correlation between tone accuracy and the amplitude-F0 correlation index suggested that "more" speech contents (i.e., more harmonics) did not necessarily yield better tone recognition for vocoded speech, especially when the amplitude contour of the signals did not co-vary with the F0 contour.
Asunto(s)
Lenguaje , Percepción de la Altura Tonal , Acústica del Lenguaje , Inteligibilidad del Habla , Percepción del Habla , Estimulación Acústica , Adulto , Análisis de Varianza , Audiometría de Tonos Puros , Audiometría del Habla , Umbral Auditivo , Femenino , Humanos , Masculino , Ruido/efectos adversos , Enmascaramiento Perceptual , Reconocimiento en Psicología , Detección de Señal Psicológica , Adulto JovenRESUMEN
This study assessed the effects of binaural spectral resolution mismatch on the intelligibility of Mandarin speech in noise using bilateral cochlear implant simulations. Noise-vocoded Mandarin speech, corrupted by speech-shaped noise at 0 and 5 dB signal-to-noise ratios, were presented unilaterally or bilaterally to normal-hearing listeners with mismatched spectral resolution between ears. Significant binaural benefits for Mandarin speech recognition were observed only with matched spectral resolution between ears. In addition, the performance of tone identification was more robust to noise than that of sentence recognition, suggesting factors other than tone identification might account more for the degraded sentence recognition in noise.