Seminars in Hearing Research (11/21/19) - Aditi Gargeshwari
Seminars in Hearing Research (11/21/19) - Aditi Gargeshwari
Author: | M. Heinz |
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Event Date: | November 21, 2019 |
Hosted By: | Hari Bharadwaj |
Time: | 1030-1120 |
Location: | LYLE 1150 |
Contact Name: | Bharadwaj, Hari M |
Contact Email: | hbharadw@purdue.edu |
Open To: | All |
Priority: | No |
School or Program: | Biomedical Engineering |
College Calendar: | Show |
Seminars in Hearing Research at Purdue (SHRP)
Title: Human frequency following response: Correlates of spatial release from masking
Speaker(s): Aditi Gargeshwari, Ph.D. Student (Krishnan lab), SLHS
Date: Nov 21, 2019
Time: 10:30 – 11:20 am
Location: LYLE 1150
Authors: Ananthanarayan Krishnan1, Bram Van Dunn2, Harvey Dillon2 & Aditi Gargeshwari1
1Department of Speech, Language and Hearing Sciences, Purdue University, USA
2National Acoustics Laboratory, Chatswood, NSW, Australia
Abstract:
Auditory stream segregation is the process by which a listener is able to differentiate the various auditory signals that arrive simultaneously at the ears and form meaningful representations of the incoming acoustic signals (Sussman et al, 1999). Auditory cues such as the perceived spatial location of sounds or the pitch of speakers’ voices help this process of segregating the total stream of sound (Bregman, 1990). Spatial release from masking (the improvement in the detection or reception threshold of a signal when spatially separated from competing sounds compared to when it is co-located with them) may account for this spatial auditory stream segregation. Here we examine whether the phase locked neural activity reflected in the brainstem frequency following response (FFR) exhibit spatial release from masking for a signal presented with either spatially co-located, or separated competing sounds. In this preliminary study, FFRs were obtained from normal-hearing young adults using a steady state vowel (/u/, d = 250 ms) as the target with its HRTF corresponding to 0 degree; and four-talker speech babble in each ear was used as the competing stimuli with HRTFs manipulated to produce either 0 degrees (spatially co-located with the target), or +/- 90 degrees (spatially separated from the target) azimuth. In Experiment 1, FFRs were obtained in quiet, with co-located speech babble (0 degrees), and with separated speech babble (+/- 90 degrees). Responses were obtained at +10 SNR for each of the masked conditions. In Experiment 2 responses were obtained for the binaural +/- 90 condition, and monaural (with stimuli to one ear turned off) presentation of the same stimuli to the left and right ear. Robust responses were observed for all conditions. Mean f0 magnitude reduction was significantly greater for BIN co-located condition compared to the spatially separated noise condition. Binaural, and summed monaural data were essentially similar when target was presented alone. Both, binaural and summed monaural responses for the separated conditions show magnitude reduction but the reduction was greater for the summed responses. No difference in magnitude between the BIN and MON sum for the quiet was seen, but f0 magnitude for bin +/- 90 condition was significantly greater than its monaural summed counterpart. These results suggest that binaural processing relevant to spatial release from masking (as opposed to a simple linear sum of monaural responses) may be reflected in the phase locked neural activity in the brainstem. The FFR in this spatial paradigm shows promise as an objective analytic tool to evaluate spatial processing in children with CAPD, and peripheral hearing loss.
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The working schedule for the year:
https://purdue.edu/TPAN/hearing/shrp_schedule
The titles and abstracts of the talks will be updated here:
https://purdue.edu/TPAN/hearing/shrp_abstracts