NFL players and league officials are not the only ones who should be concerned about brain injury. Brain scans reveal that even one concussion can lead to a permanent decrease in brain volume. These brain changes could be the physical underpinning of the headaches, dizziness, memory loss, depression, and anxiety that many concussion sufferers experience for months, or even years, after their injury.

The new research is the first to show a measurable loss in brain volume after concussions and, in some cases, after a single concussion.

These losses of brain volume in the concussion patients correlated with declines in memory and attention and increased anxiety.

Brain atrophy has been known to be a consequence of more severe head trauma, but not from concussions, which are also called mild traumatic brain injury (MTBI). Doctors have suspected that it might occur after concussions, but it hasn't shown up in routine clinical imaging.

Researchers at NYU Langone School of Medicine used 3-D magnetic resonance imaging (MRI) to measure the volumes of brain tissue, both gray and white matter, and correlated these measurements with other measurements of changes in memory attention and anxiety.

Nineteen concussion patients with post-traumatic symptoms were compared with 12 matched controls one year after the concussion. There was measurable total and local brain atrophy in the concussion patients.

One year afterwards, certain areas of the brain showed a significant decrease in volume in the concussion patients compared to the controls. The anterior cingulate region, which has been implicated in mood disorders, including depression, was affected, as was the precuneal region, an area which has many connections with parts of the brain responsible for executive function — organization, memory, the ability to pay attention and planning.

These losses of brain volume in the concussion patients correlated with declines in memory and attention and increased anxiety. From 10-20% of concussion sufferers experience neurological and psychological symptoms more than one year after the initial injury.

The results don't mean that everyone who has a concussion will suffer ill effects from it for a year or longer. But they do show that such long-term effects are possible, even from a single concussion. Anyone who has had a concussion needs to be evaluated by a doctor and should take their time before resuming normal activity. Those who continue to have symptoms after a concussion should avoid high-risk activities, like contact sports, until cleared for them by their doctor.

The study appears in the journal, Radiology.