Every year, 1.5 million Americans sustain traumatic brain injuries (TBI), which occur when sudden traumas damage the brain. TBI commonly occurs when the head suddenly and violently hits an object, as in a car accident or during a football tackle. Over 75% of TBI cases are considered mild traumatic brain injuries (MTBI), which include concussions. This name is deceiving, however, since almost half of these MTBI cases actually results in major neurologic and psychological problems.
After a concussion, patients may experience a brief loss of consciousness, but their other symptoms (headache, fatigue, dizziness, memory loss, attention deficit, depression, and anxiety) may last for months or even years. In moderate and severe cases of TBI, the brain actually undergoes atrophy, as brain cells die. However, not much is known about the brain’s atrophy following mild traumatic brain injuries. In an effort to understand the extent of brain damage following a concussion, researchers from the New York University School of Medicine examined the brains of 28 patients with MTBI. They hypothesized that, since neurological and psychological symptoms persist long after a concussion, MTBI probably causes permanent damage and brain atrophy.
In their study, the researchers used three-dimensional magnetic resonance imaging (resonancia magnética) to measure the amount of gray matter and white matter in the brains of MTBI patients. Gray matter is composed of neurons, while white matter is mostly made up of glial cells and myelinated axons. Usually, there is no evidence of structural brain abnormalities immediately after a concussion, but the researchers found that there was measurable brain atrophy one year after a concussion.
Specifically, there was significant atrophy in the white matter of the anterior cingulate y cingulate gyrus isthmus brain regions. The anterior cingulate is important for many complex neuronal systems, including mood, attention, working memory, and executive function, all of which are frequently abnormal after a concussion. The cingulate gyrus isthmus helps regulate anxiety, as dysfunction of the cingulum has been implicated in several psychological disorders, including schizophrenia. The structural damage seen in patients with MTBI correlates with behavioral symptoms they report. Taken together, these findings confirm what has been long been suspected: patients who are symptomatic long after a concussion actually have permanent brain damage.
Last week, the American Academy of Neurology released new guidelines for evaluating and managing athletes with concussions. They recommended that any athlete suspected of experiencing a concussion should be immediately relieved from play and should return only when all acute symptoms disappear. Absolute rest following a concussion helps the brain heal, so instead of toughing it out, take it easy. After all, you only get one brain!
Escrito por Kate Fehlhaber.
Zhou Y., Kierans A., Kenul D., Ge Y., Rath J., Reaume J., Grossman R.I. & Lui Y.W. Mild Traumatic Brain Injury: Longitudinal Regional Brain Volume Changes, Radiology, DOI: 10.1148/radiol.13122542
Giza C.C., Kutcher J.S., Ashwal S., Barth J., Getchius T.S.D., Gioia G.A., Gronseth G.S., Guskiewicz K., Mandel S., Manley G. & McKeag D.B. Summary of evidence-based guideline update: Evaluation and management of concussion in sports: Report of the Guideline Development Subcommittee of the American Academy of Neurology, Neurology, DOI: 10.1212/WNL.0b013e31828d57dd