In Postconcussion Syndrome Patients, MRI Reveals Brain Disruption

Magnetic resonance imaging (MRI) scans are showing changes in the brains of individuals with postconcussion syndrome (PCS), according to new research. Researchers hope these new findings lead to improved detection and treatment for the disorder.

PCS affects approximately 20%–30% of people who suffer mild traumatic brain injury (MTBI) — classified by the World Health Organization (Geneva, Switzerland) as a traumatic event causing brief loss of consciousness and/or transient memory dysfunction or disorientation. Symptoms of PCS include poor concentration, headache, and problems with memory.

The study’s findings were published online November 25, 2012, in the journal Radiology. Traditional neuroimaging modalities cannot differentiate which MTBI patients will develop PCS. “Conventional imaging with CT [computed tomography] or MRI is pretty much normal in MTBI patients, even though some go on to develop symptoms, including severe cognitive problems,” said Yulin Ge, MD, associate professor, department of radiology at the New York University (NYU) School of Medicine (New York, NY, USA). “We want to try to better understand why and how these symptoms arise.”

Dr. Ge’s study used MRI to visualize at the brain during its resting state (when it is not engaged in a specific task), such as when the mind daydreams or meanders. The resting state is believed to involve connections among a number of regions, with the default mode network (DMN) playing an especially significant function. “Baseline DMN is very important for information processing and maintenance,” Dr. Ge noted.

Alterations in DMN have been found in several psychiatric disorders, including autism, Alzheimer’s disease, and schizophrenia, but not much is known about DMN connectivity changes in MTBI. Dr. Ge and colleagues employed resting-state functional MRI in this study to compare 23 MTBI patients who had post-traumatic symptoms within two months of the injury and 18 age-matched healthy controls. Resting state MRI identifies distinctive changes in baseline oxygen-level fluctuations associated with brain functional networks between patients with MTBI and control patients.

The MRI results showed that communication and information integration in the brain were disrupted among key DMN structures after mild head injury, and that the brain tapped into different neural resources to compensate for the impaired function. “We found decreased functional connectivity in the posterior network of the brain and increased connectivity in the anterior component, probably due to functional compensation in patients with PCS,” Dr. Ge said. “The reduced posterior connectivity correlated positively with neurocognitive dysfunction.”

Dr. Ge and the other investigators hope to recruit more MTBI patients for further studies with an eye toward developing a biomarker to monitor disease progression and recovery as well as treatment effects. “We want to do studies to look at the changes in the network over time and correlate these functional changes with structural changes in the brain,” he concluded. “This could give us hints on treatments to bring back cognitive function.”

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New York University School of Medicine