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Title Recovery-related brain alterations after mild traumatic brain injury: a longitudinal, multimodal imaging approach
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University/Publisher University of Zurich
Abstract Mild traumatic brain injury (mTBI) is one of the most challenging neurological injuries and represents a public health issue worldwide. Although mTBI can cause various, sometimes persistent, symptoms, structural lesions cannot be detected with standard clinical magnetic resonance imaging (MRI) scans. To date, the long-term evolution of mTBI remains poorly defined, and no objective markers of recovery exist. The main objective of this thesis was to investigate early post-injury functional and structural brain alterations in mTBI patients compared with well-matched healthy controls, to monitor these neural alterations when patients transit from the acute to the chronic stage (≤ 7 days and 1-year post-injury, respectively) and to associate neural alterations with alterations in symptom severity and cognitive performance. Study I explored connectivity alterations by means of resting-state functional and diffusion tensor MRI. In the acute phase, reduced functional connectivity was found in a network that overlaps the nodes of the default mode network. Moreover, a network of enhanced structural connectivity was identified that included central hubs such as the anterior and posterior cingulate cortex. These altered networks demonstrated strong inverse relations and anatomical similarity. Both networks recovered partially over the course of a year, and these recoveries were accompanied by cognitive improvements. Study II evaluated morphological reorganization with the use of 3D T1-weighted MRI. The results showed an increase in cortical thickness that was spatially focused on prefrontal clusters and was not yet normalized in the chronic phase. Slight cortical thickening was associated with cognitive recovery in the good-outcome subgroup, while strong thickening was linked to cognitive decline in the poor-outcome subgroup, potentially indicating neuroinflammation. Taken together, the results show that mTBI-induced neuroplasticity differs in time course between brain regions, with highly interconnected hubs being the slowest to recover. Residual neural alterations at 1-year post-injury emphasize the importance of monitoring the consequences of mTBI over a sufficiently long period. These findings have important clinical implications for prevention, intervention, and prognosis of mTBI. Zusammenfassung Die leichte traumatische Hirnverletzung (LTHV) ist eine der herausforderndsten neurologischen Verletzungen und stellt weltweit ein öffentliches Gesundheitsproblem dar. Obwohl die Diagnose LTHV zu verschiedenen, manchmal langanhaltenden klinischen Symptomen führen kann, können mit konventionellen bildgebenden Verfahren keine strukturellen Hirnverletzungen nachgewiesen werden. Der langfristige Verlauf einer LTHV bleibt bis heute unzureichend geklärt; objektive neurobiologische Erholungsmarker existieren kaum. Das Hauptziel der vorliegenden Doktorarbeit war die Untersuchung von posttraumatischen funktionellen und strukturellen Hirnveränderungen bei Patienten mit LTHV in der Frühphase im Vergleich zu den entsprechenden gesunden…
Subjects/Keywords Clinic for Neurology; Institute of Psychology; UZH Dissertations; 150 Psychology
Language en
Rights info:eu-repo/semantics/openAccess
Country of Publication ch
Format application/pdf
Record ID oai:www.zora.uzh.ch:165194
Other Identifiers info:doi/10.5167/uzh-165194
Repository zurich
Date Retrieved
Date Indexed 2020-06-30

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