Quantity and Quality: The Importance of Structural Integrity in Metacognitive Functioning Following Moderate and Severe Traumatic Brain Injury

Open Access
Author:
Chiou, Kathy Shiang
Graduate Program:
Psychology
Degree:
Doctor of Philosophy
Document Type:
Dissertation
Date of Defense:
June 10, 2013
Committee Members:
  • Frank Gerard Hillary, Dissertation Advisor
  • Frank Gerard Hillary, Committee Chair
  • Peter Andrew Arnett, Committee Member
  • Nancy Anne Coulter Dennis, Committee Member
  • Elana Farace, Committee Member
Keywords:
  • traumatic brain injury (TBI)
  • metacognition
  • voxel based morphometry (VBM)
  • diffusion tensor imaging (DTI)
Abstract:
Moderate to severe traumatic brain injury (TBI) often results in residual deficits in cognitive, emotional, and physical functioning. Metacognition, the in-the-moment self-awareness of cognitive performance, has been found to be affected after such injuries. Although deficits in metacognition have been documented, the organization of this domain in the brain is unclear; specifically, the contribution of structural brain tissue integrity to metacognitive functioning has yet to be examined. In the current study, Voxel Based Morphometry (VBM) methods were used to explore two potential contributors to metacognitive functioning after injury: 1) the amount of total brain tissue volume present, and 2) the location of injury. Characteristics of white matter integrity were also examined using Diffusion Tensor Imaging (DTI) methods. A relationship between metacognitive performance and global brain tissue volume was found when performance differences were present between the two sample groups (participants with TBI and non-injured peers). Particular measures of global white matter integrity were also found to be related to metacognitive functioning. Together, findings suggest that global brain tissue volume, rather than specific location of injury, is better associated with metacognitive awareness. Furthermore, there may be a “threshold effect” at which point metacognition and brain tissue volume are not linearly related.