Cognitive impairment after a traumatic brain injury (TBI) is common, often adversely affecting quality of life for those 1.7 million Americans who experience a TBI each year. Researchers at the Center for BrainHealth have identified complex brain connectivity patterns in individuals with chronic phases of traumatic brain injury that may explain long-term higher order cognitive function deficits.
A study recently published in the Journal of International Neuropsychological Society found that individuals who are at least six months post-injury exhibit between-network, long-range and inter-hemispheric connectivity disruptions. Specifically, scientists observed TBI-related connectivity disruptions in the default mode and dorsal attention networks and the default mode and frontoparietal control networks. Interactions among the networks are key to achieving daily life goals.
“Cooperation between the default mode network, dorsal attention and the frontoparietal control networks is key to controlling internal trains of thought and achieving tasks in changing environments,” said Dr. Kihwan Han, study lead author and postdoctoral research associate at the Center for BrainHealth. “Interactions among these networks are intricately intertwined and critical to daily life tasks such as planning, learning and problem solving. This work suggests that cognitive deficits may be a result of reduced efficiency in brain-network communications.”
For the study, researchers analyzed MRI scans of 40 TBI people with those of 17 healthy people matched for gender, age and years of education. Participants were ages 19 to 45. While all individuals in the TBI group were at least six months post-injury at the time of the study, the average length of time since injury was eight years with no history of any significant, clinically diagnosed neurological or psychiatric disorders before their TBI.
“Much research has focused on separating out individual brain networks,” said Dr. Daniel C. Krawczyk, principal investigator, associate professor of cognitive neuroscience and cognitive psychology in the School of Behavioral and Brain Sciences and Debbie and Jim Francis Chair. “This is the first study of its kind to show the intercorrelations among different networks and disruptions among them in individuals with TBI.”
“If key brain networks cannot interact in a normal way, the brain becomes inefficient,” Krawczyk said. “Our future research will examine how networks can be improved or enhanced, even after a traumatic brain injury, with cognitive intervention.”
This work has been supported by grants from the Department of Defense and a grant from the Meadows Foundation.
