Skip to Main Content
 

Global Search Box

 
 
 
 

Files

File List


5650.pdf (1.46 MB)

ETD Abstract Container

Abstract Header

Functional and Structural Abnormalities Underlying Left Ear vs. Right Ear Advantage in Dichotic Listening: an fMRI and DTI Study

Farah, Rola
http://rave.ohiolink.edu/etdc/view?acc_num=ucin1378194536

Abstract Details

, PhD, University of Cincinnati, Allied Health Sciences: Communication Sciences and Disorders.
Purpose: This study investigated the differences in brain functional activation patterns and in white matter microstructure integrity underlying atypical left ear advantage (LEA) for speech-related stimuli in dichotic listening. While a finding of atypical LEA for speech-related stimuli is often taken as an indication of mixed/reversed hemispheric language dominance and as a marker for auditory processing disorder (APD), validation studies using gold standard techniques failed to predict right hemispheric dominance from LEA. Furthermore, the interpretation made by clinical audiologists has never been tested using objective techniques of evoked potentials or imaging studies It is indeterminate whether a sensory processing deficit such as APD or other supramodal factors may underlie the finding of atypical LEA. Design: Functional magnetic resonance imaging (fMRI) and diffusion tensor imaging (DTI) data were acquired from a cohort of 12 children with auditory processing complaints, manifesting an atypical LEA and 12 typically developing children with right ear advantage (REA), aged 7 to 14 years. Significant clusters showing between-group activation differences (fMRI) and diffusivity measures (i.e., fractional anisotropy, mean diffusivity, radial and axial diffusivity) were computed. Results: fMRI results indicated that differences in brain activation patterns were due to attenuated deactivation of the default mode network (DMN) and increased activation in the dorsal anterior cingulate cortex (dACC) in the LEA compared to the REA group. DTI results indicated altered frontal white matter microstructure, reflected by decreased fractional anisotropy in frontal multifocal white matter regions, specifically in prefrontal cortex bilaterally and left anterior cingulate white matter. Furthermore, results revealed increased mean diffusivity in the left sublenticular part of the internal capsule in the LEA compared to the REA group. Conclusion: Collectively, our findings implicate both sensory deficit (increased MD in the sublenticular part of internal capsule) and supramodal factors (attenuated suppression of the default mode network and altered white matter microstructure in regions involved in attention and cognitive control) to underlie the differences in brain activation patterns and structural connectivity seen between the groups.
Robert Keith, Ph.D. (Committee Chair)
Vincent Schmithorst, Ph.D. (Committee Member)
Scott Holland, Ph.D. (Committee Member)
Fawen Zhang, Ph.D. (Committee Member)
124 p.
Audiology
Dichotic listening; auditory processing disorder; functional magnetic resonance imaging fMRI; Diffusion tensor Imaging DTI; Attentional model; Structural model

Recommended Citations

Citations

  • Farah, R. (n.d.). Functional and Structural Abnormalities Underlying Left Ear vs. Right Ear Advantage in Dichotic Listening: an fMRI and DTI Study [Doctoral dissertation, University of Cincinnati]. OhioLINK Electronic Theses and Dissertations Center. http://rave.ohiolink.edu/etdc/view?acc_num=ucin1378194536

    APA Style (7th edition)

  • Farah, Rola. Functional and Structural Abnormalities Underlying Left Ear vs. Right Ear Advantage in Dichotic Listening: an fMRI and DTI Study. University of Cincinnati, Doctoral dissertation. OhioLINK Electronic Theses and Dissertations Center, http://rave.ohiolink.edu/etdc/view?acc_num=ucin1378194536.

    MLA Style (8th edition)

  • Farah, Rola. "Functional and Structural Abnormalities Underlying Left Ear vs. Right Ear Advantage in Dichotic Listening: an fMRI and DTI Study." Doctoral dissertation, University of Cincinnati. Accessed APRIL 23, 2024. http://rave.ohiolink.edu/etdc/view?acc_num=ucin1378194536

    Chicago Manual of Style (17th edition)

ucin1378194536
483
© , all rights reserved.
This open access ETD is published by University of Cincinnati and OhioLINK.