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Date of Graduation
Doctor of Audiology (AuD)
Department of Communication Sciences and Disorders
The primary purpose of this study is threefold: to use SRT measurements to examine the effect of various remote-frequency, narrowband maskers on adult’s perception of narrowband speech, to compare the performance between low and high band speech stimuli, and to evaluate the combination of these approaches by examining the correlation between the masking effect observed with speech and pure tone stimuli. Twelve subjects aged 22-34, with hearing thresholds no worse than 15 dB HL for frequencies 500-8000 Hz, participated in two listening tasks. In the speech perception task, coordinate response measure (CRM) sentences and their maskers were separately filtered into two ½-octave wide frequency bands with respective center frequencies of 500 Hz (low-band) and 2500 Hz (high-band). Three types of maskers were utilized: Gaussian noise, CRM sentences spoken by a talker different from the talker of the target sentences (speech-masked conditions), and time-reversed CRM sentences. Speech reception thresholds (SRTs) of either low- or high-band sentences were assessed in quiet and in the presence of a high- or low-band masker. Speech recognition scores (SRSs), or the percentages of keywords correctly identified, were measured in the same conditions. In the informational masking task, detection thresholds of a 1 kHz tone were measured in quiet and in the presence of a muli-tonal masker. SRTs in quiet were found to be significantly higher than in GNB and reverse speech maskers. SRTs were also found to be lower for high band target speech. In the SRS task, only the forward speech masker produced significantly worse recognition scores. Using pure tone stimuli, an average masking effect of approximately 18 dB was observed across participants. The pure tone masking effect was not found to correlate with the SRT masking effect, however, a trend of correlation appears to exist that may potentially reach significance with a larger sample size.
Arbogast, Taylor L., "Remote-Frequency Masking and Speech Perception in Adults" (2022). Dissertations, 2020-current. 83.