Neurologic Basis of Depression Following Sports Concussion Identified by fMRI

The study has important clinical implications for the treatment of individuals who have suffered a cerebral concussion.

Depression is one of a number of persisting symptoms experienced by athletes following sports concussion. The prevalence of depression in the general population is approximately 5%, while the prevalence of depression in head trauma patients can reach an astonishing 40%.

"Until now, very little was known about the neurological basis of the depression frequently reported by athletes following concussion,” stated Dr. Alain Ptito, neuropsychologist and researcher from the Montreal Neurological Institute of McGill University (Canada), and lead investigator for the study. Traditional testing techniques for concussion yielded normal results with no obvious cognitive or neurologic deficits. Persistent complaints have been perceived as subjective and ill defined without neurologic foundation. Injury to the brain following concussion occurs at a microscopic level and is therefore difficult to measure in a patient.

Utilizing enhanced brain imaging technology, researchers were able to gain new insights into the damage caused by concussion. "Using functional MRI [fMRI], a computerized imaging technique that measures blood oxygen levels, we were able to detect areas of the brain with abnormal neural activity,” explained Dr. Ptito. He and colleagues assessed 56 male athletes, 40 with concussion and 16 healthy controls. Using a depression index, 16 of the concussed individuals had no symptoms of depression, 16 expressed mild depression, and eight had moderate symptoms of depressions. Concussed athletes with depression showed reduced brain activity in regions known to be implicated in depression, specifically, the dorsolateral prefrontal cortex and striatum, and attenuated deactivation in medial frontal and temporal regions. The researchers discovered that concussed subjects with depression presented with the same pattern of brain activation as that seen for patients with major depression.

Other research has shown a link between a history of brain injury and probability of developing major depression later in life. Therefore, understanding the pathology of depression in concussed individuals has important implications for early intervention and successful outcomes.

The study was published in the January 2008 issue of the journal Archives of General Psychiatry.


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Montreal Neurological Institute of McGill University