An Overview of Concussion

How Concussions Cause Headaches
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A concussion is an injury to the brain that affects thinking and other aspects of cognitive function. It can be caused by a blow to the head, a literal head-on collision (for example, two football players bumping helmets during a tackle or a head-first fall), or violent shaking of the head or the body.

This type of injury is a common form of traumatic brain injury (TBI). According to the American Society of Neuroradiology, about 75 percent of TBIs are concussions.

Concussion also is regarded as a mild TBI, but to anyone who bangs their head on something hard, or who sees their child take a blow to the head on a sports field, the term may seem anything but mild. This may partly be due to headline-making long-term problems caused by concussions and other head injuries in athletes that have prompted growing concern about the safety of contact sports.

If there's a possibility you (or a loved one) has suffered a concussion, it can be helpful to understand what this brain injury is, how it's diagnosed and treated, and the potential complications it can cause.

Symptoms of a Concussion

There is no one-size-fits-all list of concussion symptoms. Researchers aren't completely sure how a concussion works, but it definitely affects the brain's ability to function correctly, at least in the short term. This can lead to behavior changes that often are very subtle and ambiguous.

One useful way to think about concussion symptoms is to categorize them as symptoms and sensations the injured person feels and can describe—such as headache, nausea, dizziness (vertigo), and ringing in the ears—and those that can be observed by someone else.

Examples of observable symptoms of concussion include fumbling or stumbling; slurred speech; unequally-sized pupils; loss of consciousness; memory loss; and any behavior that is unusual for that person.

A baby or small child with a concussion may cry inconsolably or refuse to eat or nurse.

One concussion rarely results in long-term consequences. Multiple concussions, however, can cause serious and lasting effects, especially if a repeat concussion occurs before full recovery from a previous concussion. Long-term effects of repeated concussions or unusually severe concussions include permanent cognitive (thinking) problems and mood problems, especially depression.

Diagnosing a Concussion

When the brain gets knocked around inside the skull, it can undergo damage. A severe TBI will cause damage that can be seen on some type of brain scan, such as a magnetic resonance imaging (MRI).

However, the degree and type of damage typically associated with a concussion aren't visible with imaging. To diagnose a concussion, doctors typically rely on questionnaires, symptom checklists, and other more subjective techniques.

How Concussions Are Treated

The most important aspect of treating a concussion is rest. This means giving the brain an extended time-out. When an athlete suffers a concussion, it's vital that he stay off the field or the court until he's fully healed: Multiple concussions greatly increase the risk of long-term problems.

Resting the brain also means taking a break from most mental activities—reading, writing, watching television, doing homework.

If a concussion causes a headache, it's usually fine to treat the pain with a non-steroidal anti-inflammatory medication such as Tylenol (acetaminophen) or Advil (ibuprofen). 

A Word From VeryWell

The idea of having a concussion can be scary, but it's important to know that most people recover completely from these mild brain injuries. The key is to follow doctors' orders to avoid any activities that could lead to a second concussion—which means athletes in particular must be willing to stay out of the game until they're fully healed.

It's also vital to give the brain ample time to heal by taking a mental time-out, often for weeks or even months. That may seem easier said than done; it's hard to be away from school or work for an extended period, or to avoid reading, watching TV, or even listening to music. But these steps will allow the minute damage to your brain to heal itself completely.


American Society of Neuroradiology. "Traumatic Brain Injury (TBI) and Concussion."

Kraus MF, et al. "White Matter Integrity and Cognition in Chronic Traumatic Brain Injury: A Diffusion Tensor Imaging Study."Brain. 2007 Oct;130(Pt 10):2508-19. DOI:​ 10.1093/brain/awm216.