Perception of Temporally Processed Speech by Listeners with Hearing Impairment
Year: 2007
Type: article
Abstract: In Brief Objectives: The purpose of this study was to assess a new signal-processing strategy, Spatiotemporal Pattern Correction (SPC), for a group of listeners with varying degrees of sensorineural hearing loss. SPC is based on a physiological model of the level-dependent temporal response properties of auditory nerve (AN) fibers in normal and impaired ears. SPC attempts to “correct” AN response patterns by introducing time-varying group delays that differ across frequency channels. Listeners' speech intelligibility and preference judgments were obtained at different strengths of SPC processing. Design: Fifteen listeners, 12 with bilateral sensorineural hearing loss and 3 with normal hearing, participated in this study. Listeners with hearing impairment were separated into 3 groups (mild, moderate, and moderate-to-severe), based on their pure-tone averages at 0.5, 1, 2, and 4 kHz. All preference judgments were made using sentences from the Hearing-In-Noise-Test (HINT). The sentences were processed at five SPC strengths (1.0, 1.1, 1.2, 1.3, and 1.4). At an SPC strength of 1.0, the speech was processed through the SPC signal processor, becoming bandlimited, but no dynamic group delays were added to the signal. On each trial, listeners were presented a single sentence at two different SPC strengths, 1.0 (uncorrected) and a randomly selected SPC strength. Listeners were instructed to identify which of the two sentences they preferred. Sixteen vowel-consonant syllables, a subset of the Nonsense Syllable Test (NST), were used to assess speech intelligibility at three SPC strengths (1.0, 1.1, and 1.2). Listeners were asked to push one of 16 buttons on a response box that corresponded to the vowel-consonant syllable they heard. The moderate-to-severe hearing loss group was also tested using the low-probability sentences of the Speech-Perception-In-Noise (SPIN) test. Results: Listeners with normal hearing and listeners with mild hearing loss preferred the quality of uncorrected sentences (SPC strength of 1.0) compared with SPC-processed sentences. As the strength of SPC increased, listeners' preference for uncorrected sentences also increased. Listeners with moderate and moderate-to-severe hearing loss had difficulty differentiating between uncorrected and lower strength SPC-processed sentences but strongly preferred the uncorrected sentences as compared with high strength SPC-processed sentences. Vowel-consonant intelligibility was not improved or degraded by SPC. Sentence recognition scores for listeners with moderate-to-severe hearing loss decreased with SPC processing. Conclusions: Although SPC-processed speech was not preferred by listeners with hearing loss, the listeners with a more moderate degree of impairment could not differentiate the unprocessed sentences from the SPC processed sentences. Speech intelligibility was not improved by SPC processing. Spatiotemporal Pattern Correction (SPC) is a new signal-processing strategy based on a physiological model of the level-dependent temporal response properties of auditory-nerve (AN) fibers in normal and impaired ears. SPC introduces time-varying group delays that differ across frequency channels in an attempt to “correct” AN population response patterns. Preference and intelligibility testing was conducted using SPC processed speech. Listeners with normal hearing and listeners with mild hearing loss did not prefer SPC processing; however, listeners with moderate hearing loss could not distinguish unprocessed and SPC processed speech. SPC processing did not improve speech intelligibility.
Source: Ear and Hearing
Authors: Lauren Calandruccio, Karen A. Doherty, Laurel H. Carney, Harshavardhana N. Kikkeri
Institution: Syracuse University
Language: English
Subfield: Cognitive Neuroscience
Field: Neuroscience
Domain: Life Sciences
Open Access status: green
OpenAlex ID: W2006280413