A new study may have made a breakthrough in explaining why soldiers who have experienced a traumatic brain injury (TBI) also face a high chance of developing depression.
With the use of several brain imaging techniques, a team of researchers from the National Intrepid Center of Excellence were able to find a disruption in the brain’s cognitive-emotional pathways that could serve as a foundation for depression symptoms following TBI.
The team is presenting their findings today at the annual meeting of the Radiological Society of North America (RSNA).
“We can link these connectivity changes in the brain to poor top-down emotional processing and greater maladaptive rumination, or worrying, in symptomatic depressed soldiers after mTBI,” said Ping-Hong Yeh, Ph.D., scientist and physicist at the National Intrepid Center of Excellence, Walter Reed National Military Medical Center in Bethesda, Md.
Data from the Defense and Veterans Brain Injury Center suggests over 350,000 service members around the world have been diagnosed with TBI since 2000. Many of these service members have also been diagnosed with psychiatric disorders like major depressive disorder and anxiety.
“With the increased survival of soldiers due to improvements in body armor and advanced medical care, there has been an increase in the number of soldiers surviving major trauma. Consequently, a large number of soldiers are returning from war with mTBI,” Dr. Yeh said. “Mood disorders are very common in military-related mTBI patients. This is an ongoing problem facing a large number of warriors in current areas of conflict, and it is likely to be a persistent problem for the foreseeable future.”
For this study, the team utilized two separate MRI techniques to evaluate 130 active service members diagnosed with mild traumatic brain injury, as well as a control group of 52 men without a history of TBI. Specifically, the team used diffusion-weighted imagine (DWI) to measure how water moves through tissue in the brain and resting-state functional MRI (fMRI) to assess brain behavior in a resting state.
The participants also completed depression assessments using the Beck Depression Inventory (BDI). A score of over 20 on the BDI assessment are considered to have moderate to severe depression symptoms.
Of the 130 service members with mTBI, 75 scored high enough to be categorized as having moderate to severe depression symptoms. After comparing the results with the MRI scans, the researchers noticed these service members also had changes in the gray matter cognitive-emotional networks of the brain.
“We found consistencies in the locations of disrupted neurocircuitry as revealed by DWI and resting-state fMRI that are unique to the clinical symptoms of mTBI patients,” Dr. Yeh said. “We have related the brain structural and functional changes in cognitive-emotional networks to depressive symptoms in mTBI patients.”
While the early findings have to be confirmed in larger populations and explored further, Dr. Yeh believes the results could potentially lead to more effective treatment strategies in the future.
“Though the results of this study were not applied directly to patient care, the neuroimaging changes we found might be incorporated into treatment plans for personalized medicine in the future,” he said.