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Hemispheric and Executive Influences on Low-Level Language Processing After Traumatic Brain Injury

Russell, Kathryn Courtney (2010) Hemispheric and Executive Influences on Low-Level Language Processing After Traumatic Brain Injury. Doctoral Dissertation, University of Pittsburgh. (Unpublished)

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Traumatic brain injury (TBI) has great impact, both to public health as well as to theindividuals who sustain one. Some of the most problematic deficits after TBI arise in cognitiveareas like executive functioning and language. Language deficits at the level of discourse arecommonly reported (e.g., Snow, et al., 1998), but evidence of lower-level language problems hasbeen more scarce. One possible explanation for that pattern of findings (e.g., McDonald, 1992) isthat underlying executive deficits are responsible for the discourse problems. A goal of the current studies is to see, then, what effect variations in executive demands have on lower-level language after TBI. A second goal is to begin to examine mechanisms for those processing differences. The most common neuropathology after TBI is diffuse axonal injury (DAI), which has been estimated to be present in a large percentage of cases, and commonly affects the corpus callosum (Pittella & Gusmão, 2004). Based on these facts, it was hypothesized that altered interhemispheric communication might be involved in the cognition problems faced by peoplewith TBI. To examine the effects of hemispheric communication and executive demands onlanguage processing after TBI, two behavioral experiments using split visual hemifieldpresentation and one functional connectivity analysis of resting-state fMRI data were conducted. The task in the first experiment was semantic priming with lexical decision. As compared to controls, participants with TBI showed a stronger right visual field (RVF) advantage and selective impairments suggestive that language was primarily affected when executive demands were higher. The second experiment confirmed these results with a verb generation task collecting vocal latencies (from Chiarello, et al., 2006). Finally, the functional connectivity analysis compared connectivity values between right and left hemisphere areas thought to be involved in language and executive functioning. This analysis, while preliminary, provided some evidence suggesting that persons with TBI may have higher functional connectivity at rest than matched controls, especially for right hemisphere connections and links to anterior cingulate cortex. Together these findings begin to reveal a complex picture where hemispheric and executive factors have important bearing upon language processing in people with TBI.


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Item Type: University of Pittsburgh ETD
Status: Unpublished
CreatorsEmailPitt UsernameORCID
Russell, Kathryn Courtneykcr9@pitt.eduKCR9
ETD Committee:
TitleMemberEmail AddressPitt UsernameORCID
Committee CoChairRicker, Joseph
Committee CoChairFiez, Julie
Committee Member Perfetti, Charles
Committee MemberWheeler, Mark
Date: 28 January 2010
Date Type: Completion
Defense Date: 28 August 2009
Approval Date: 28 January 2010
Submission Date: 10 November 2009
Access Restriction: No restriction; Release the ETD for access worldwide immediately.
Institution: University of Pittsburgh
Schools and Programs: Dietrich School of Arts and Sciences > Psychology
Degree: PhD - Doctor of Philosophy
Thesis Type: Doctoral Dissertation
Refereed: Yes
Uncontrolled Keywords: closed head injury; cognition; corpus callosum; fcMRI; traumatic axonal injury
Other ID:, etd-11102009-141438
Date Deposited: 10 Nov 2011 20:04
Last Modified: 15 Nov 2016 13:51


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