Perception of temporal fine-structure cues in speech with minimal envelope cues for listeners with mild-to-moderate hearing loss

Abstract

Abstract

The contribution of temporal fine-structure (TFS) cues to consonant identification was compared for seven young adults with normal hearing and five young adults with mild-to-moderate hearing loss and flat, high- or low-frequency gently sloping audiograms. Nonsense syllables were degraded using two schemes (PM: phase modulation; FM: frequency modulation) designed to remove temporal envelope (E) cues while preserving TFS cues in 16 0.35-octave-wide frequency bands spanning the range of 80 to 8020 Hz. For both schemes, hearing-impaired listeners performed significantly above chance level (PM: 36%; FM: 31%; chance level: 6.25%), but more poorly than normal-hearing listeners (PM: 80%; FM: 65%). Three hearing-impaired listeners showed normal or near-normal reception of nasality information. These results indicate that for mild to moderate levels of hearing loss, cochlear damage reduces but does not abolish the ability to use the TFS cues of speech. The deficits observed for both schemes in hearing-impaired listeners suggest involvement of factors other than only poor reconstruction of temporal envelope from temporal fine structure.

Sumario

Se comparó la contribución de claves temporales de estructura fina (TFS) para la identificación de consonantes en seis adultos jóvenes con audición normal y cinco adultos jóvenes con hipoacusia superficial a moderada con audiogramas planos, o con caídas suaves en graves o en agudos. Se degradaron sílabas sin sentido utilizando dos esquemas (PM: modulación de fase; FM: modulación de frecuencia) diseñados para remover las claves de envoltura temporal (E) mientras que se preservaron las caves TFS en 16 bandas con anchos de frecuencia de 0.35 de octava, espaciando el rango de 80 a 8020Hz. Para ambos esquemas, los oyentes con hipoacusia se desempeñaron significativamente por encima del nivel de azar (PM: 36%; FM: 31%; Nivel de azar : 6.5%) pero mucho menos que los normoyentes (PM: 80%; FM: 65%). Tres sujetos con hipoacusia mostraron una recepción normal o casi normal de la información de nasalidad. Estos resultados indican que para la hipoacusia superficial a moderada el daño coclear reduce pero no cancela la habilidad para usar las claves TFS del lenguaje. Los déficits observados para ambos esquemas en sujetos hipoacúsicos sugiere una participación de factores diferentes a la pobre reconstrucción de la envoltura temporal de la estructura fina.

Key Words:

• Hearing impairment
• speech
• temporal fine structure
• envelope

Acknowledgments

This research was supported by a MENRT grant to M. Ardoint, ANR-Presbycusis and RTRS ‘Fondation Voir & Entendre’ grants to C. Lorenzi, and GDR CNRS GRAEC #2967. The authors wish to thank two anonymous reviewers for their valuable comments that improved considerably the present manuscript.

Declaration of Interest: The authors report no conflicts of interest. The authors alone are responsible for the content and writing of the paper.