J Am Acad Audiol
DOI: 10.1055/s-0040-1709448
Research Article
Thieme Medical Publishers 333 Seventh Avenue, New York, NY 10001, USA.

Neural Coding of Syllable-Final Fricatives with and without Hearing Aid Amplification

Sharon E. Miller
1  Department of Audiology and Speech-Language Pathology, University of North Texas, Denton, Texas
,
Yang Zhang
2  Department of Speech-Language Hearing Science, University of Minnesota, Minneapolis, Minnesota
3  Center for Neurobehavioral Development, University of Minnesota, Minneapolis, Minnesota
4  Center for Applied and Translational Sensory Science, University of Minnesota, Minneapolis, Minnesota
› Author Affiliations
Funding Dr. Miller and Dr. Zhang received funds from the College of Liberal Arts, University of Minnesota.
Further Information

Publication History

15 April 2019

10 January 2020

Publication Date:
27 April 2020 (online)

Abstract

Background Cortical auditory event-related potentials are a potentially useful clinical tool to objectively assess speech outcomes with rehabilitative devices. Whether hearing aids reliably encode the spectrotemporal characteristics of fricative stimuli in different phonological contexts and whether these differences result in distinct neural responses with and without hearing aid amplification remain unclear.

Purpose To determine whether the neural coding of the voiceless fricatives /s/ and /ʃ/ in the syllable-final context reliably differed without hearing aid amplification and whether hearing aid amplification altered neural coding of the fricative contrast.

Research Design A repeated-measures, within subject design was used to compare the neural coding of a fricative contrast with and without hearing aid amplification.

Study Sample Ten adult listeners with normal hearing participated in the study.

Data Collection and Analysis Cortical auditory event-related potentials were elicited to an /ɑs/–/ɑʃ/ vowel-fricative contrast in unaided and aided listening conditions. Neural responses to the speech contrast were recorded at 64-electrode sites. Peak latencies and amplitudes of the cortical response waveforms to the fricatives were analyzed using repeated-measures analysis of variance.

Results The P2' component of the acoustic change complex significantly differed from the syllable-final fricative contrast with and without hearing aid amplification. Hearing aid amplification differentially altered the neural coding of the contrast across frontal, temporal, and parietal electrode regions.

Conclusions Hearing aid amplification altered the neural coding of syllable-final fricatives. However, the contrast remained acoustically distinct in the aided and unaided conditions, and cortical responses to the fricative significantly differed with and without the hearing aid.