A single concussion may cause lasting structural damage to
the brain, according to a new study published online in the journal Radiology.
"This is the first study that shows brain areas undergo
measureable volume loss after concussion," said Yvonne W. Lui, M.D.,
Neuroradiology section chief and assistant professor of radiology at NYU
Langone School of Medicine. "In some patients, there are structural
changes to the brain after a single concussive episode."
Many people affected
According to the Centers for Disease Control and Prevention,
each year in the US, 1.7 million people sustain traumatic brain injuries,
resulting from sudden trauma to the brain. Mild traumatic brain injury (MTBI),
or concussion, accounts for at least 75% of all traumatic brain injuries.
Following a concussion, some patients experience a brief
loss of consciousness. Other symptoms include headache, dizziness, memory loss,
attention deficit, depression and anxiety. Some of these conditions may persist
for months or even years.
Studies show that 10 to 20% of MTBI patients continue to
experience neurological and psychological symptoms more than one year following
trauma. Brain atrophy has long been known to occur after moderate and severe
head trauma, but less is known about the lasting effects of a single
Dr Lui and colleagues set out to investigate changes in
global and regional brain volume in patients one year after MTBI. Twenty-eight
MTBI patients (with 19 followed at one year) with post-traumatic symptoms after
injury and 22 matched controls (with 12 followed at one year) were enrolled in
the study. The researchers used three-dimensional magnetic resonance imaging
(MRI) to determine regional gray matter and white matter volumes and correlated
these findings with other clinical and cognitive measurements.
What the researchers
The researchers found that at one year after concussion,
there was measurable global and regional brain atrophy in the MTBI patients.
These findings show that brain atrophy is not exclusive to more severe brain
injuries but can occur after a single concussion.
"This study confirms what we have long suspected,"
Dr. Lui said. "After MTBI, there is true structural injury to the brain,
even though we don't see much on routine clinical imaging. This means that
patients who are symptomatic in the long-term after a concussion may have a
biologic underpinning of their symptoms."
Certain brain regions showed a significant decrease in
regional volume in patients with MTBI over the first year after injury,
compared to controls. These volume changes correlated with cognitive changes in
memory, attention and anxiety.
"Two of the brain regions affected were the anterior
cingulate and the precuneal region," Dr. Lui said. "The anterior
cingulate has been implicated in mood disorders including depression, and the
precuneal region has a lot of different connections to areas of the brain
responsible for executive function or higher order thinking."
According to Dr. Lui, researchers are still investigating
the long-term effects of concussion, and she advises caution in generalizing
the results of this study to any particular individual.
"It is important for patients who have had a concussion
to be evaluated by a physician," she said. "If patients continue to
have symptoms after concussion, they should follow-up with their physician
before engaging in high-risk activities such as contact sports."