Date of Award

5-2019

Document Type

Dissertation

Degree Name

Doctor of Philosophy (PhD)

Program

Speech and Hearing Science

Track

Hearing Science

Research Advisor

Ashley W. Harkrider, Ph.D.

Committee

Aaron Buss, Patti Johnstone, Patrick Plyler, Tim Saltuklaroglu

Abstract

Growing evidence that speech perception tasks elicit sensorimotor activity, and that this activity varies due to context, sex, cognitive load, and cognitive ability. However, it is unknown as to whether the sex of the speaker and demands of the task differentially effect males and females during speech perception tasks. This study investigated whether speaker sex and task demands (i.e. passive listening or active discrimination) influence sensorimotor and auditory cortical activity in males and females differently. Raw EEG data were collected from 27 males and 29 females during passive listening to, and discrimination of /ba/ and /da/ syllable pairs spoken by a synthetic female or male speaker. Independent component analysis identified sensorimotor and auditory components characterized by alpha/beta and alpha peaks, respectively. Time- frequency decomposition revealed no significant differences between male and female groups in any testing conditions. Within the male group, stronger mu activity was found in active discrimination conditions compared to passive listening in only the left hemisphere, while females displayed stronger activity in both the left and right hemisphere. Auditory cluster activity revealed males utilizing stronger inhibition after stimulus offset in active discrimination conditions, while females showed stronger activation during stimulus presentation in the same conditions. Both males and females displayed stronger mu activation in response to male speakers compared to female speakers before, during, and after stimulus presentation. Given this, it appears that speaker sex does influence at least anterior dorsal stream activity in a similar fashion for both males and females, but task demands differentially alter anterior and posterior dorsal stream activity in each sex group. These findings may at least partially explain the high variability in findings across neuroimaging studies that feature males and females in the same population.

Declaration of Authorship

Declaration of Authorship is included in the supplemental files.

ORCID

0000-0002-1562-986X

DOI

10.21007/etd.cghs.2019.0478

2019-003-Thornton-DOA .pdf (301 kB)
Declaration of Authorship

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