Abnormal Default-Mode Network Connectivity Seen in Mild TBI
(HealthDay News) – Patients with mild traumatic brain injury (mTBI) exhibit abnormal default-mode network (DMN) connectivity, according to a study published in the December issue of Radiology.
Yongxia Zhou, PhD, from the New York University School of Medicine in New York City, and colleagues characterized the DMN using independent component analysis based on resting state functional magnetic resonance imaging from 23 patients with mTBI who had posttraumatic symptoms shortly after injury (less than two months) and 18 age-matched healthy control subjects. Components of the DMN were compared between the groups and correlated with neurocognitive test results.
The researchers observed significantly reduced connectivity in the posterior cingulate cortex and parietal regions and increased frontal connectivity around the medial prefrontal cortex in patients with mTBI compared to healthy controls. There was a significant correlation between these fronto-posterior opposing changes within the DMN. There was a positive correlation between the reduced posterior connectivity and neurocognitive dysfunction (cognitive flexibility). There was also a negative correlation with the increased frontal connectivity and posttraumatic symptoms (depression, anxiety, fatigue, and postconcussion syndrome).
"Given the important role of the DMN in brain cognitive function, our results of significant changes of DMN functional connectivity in patients with mTBI may provide insights into the underlying mechanisms of the reduced performance in neurocognitive testing," the authors write. "Longitudinal studies are warranted to further evaluate whether the DMN can serve as a biomarker to monitor disease progression and recovery in mTBI."