Not that long ago, an athlete who got a bad blow to the head might have been treated with some time out and a bag of ice. But today, everyone is aware that a concussion is a serious matter: It’s an injury to the brain that can temporarily disrupt normal brain function and while concussions are considered to be mild brain injuries from which most people make a full recovery, they still need to be taken seriously.

Every day, thousands of people across the United States suffer concussions from car accidents and falls and while playing sports. The Centers for Disease Control and Prevention (CDC) estimates that there are up to 3.8 million sports- and recreation-related concussions each year in the U.S. Another recent study estimated that between 1.1 and 1.9 million kids aged 18 or under get a concussion during recreational and sports activities every year in the U.S.

A concussion is a type of traumatic brain injury (TBI) that results in temporary impairment of mental function. Concussions are sometimes referred to as mild traumatic brain injuries (mTBI) to distinguish them from more serious types of brain injuries. 

Concussions occur when a sudden movement causes the brain to bounce against or around the skull. This can damage brain cells and bring about chemical changes in the brain that alter how the brain works in the short-term. People with concussions, for instance, often experience short-lived confusion, memory loss, and disorientation, among other symptoms.

In many cases, concussions are caused by a direct blow to the head, either from an object that strikes the head or the head hitting an object. They can also result from injuries that don’t involve a blow to the head, for instance, from whiplash injuries that involve acceleration and deceleration of the head. Exposure to explosions or blasts can also cause a concussion, as can the penetration of a foreign object in the brain.

Symptoms of a concussion may begin immediately or within minutes or hours of an injury, while others may not develop for days. They may include:

• Confusion
• Difficulty concentrating and paying attention
• Loss of memory, especially of events that occurred just before or after the injury
• Slow to respond to questions
• Seeing stars or flashing lights
• Disorientation
• Drowsiness
• Headache
• Nausea and vomiting
• Dizziness or balance problems
• Blurred or double vision
• Sensitivity to light or noise
• Ringing ears
• Difficulty sleeping
• Irritability
• Mood swings
• Depression
• Loss of consciousness

Concussion symptoms usually get better on their own within a week to 10 days. But around 10% to 15% of people develop what’s known as post-concussion syndrome (PCS), a condition in which symptoms persist for weeks, months, or even years. The symptoms of PCS are similar to those of concussion and in most cases, resolve within three months.

To diagnose a concussion, your doctor will collect your medical history, perform a physical exam, and conduct a neurological assessment.

Your doctor will ask about your symptoms and whether they have worsened or changed since they began. During the physical exam, your doctor will take a close look at your eyes, head, and neck to check for signs of concussion, skull fracture, neck injury, or a more severe traumatic brain injury.

A neurological assessment—evaluation of mental function—is an important part of diagnosing concussions. As part of the assessment, you may be asked to say the current date and time, memorize and recall a short list of words, and state the months in reverse order. Your doctor will observe your gait to assess your balance and check your reflexes, coordination, and strength.

Depending on your symptoms, your doctor may also order one or more imaging tests such as a head X-ray, computed tomography (CT) scan, or magnetic resonance imaging (MRI) scan. These tests are not used to diagnose concussion, but rather to rule out more serious brain injuries.

People who are diagnosed with a concussion are usually sent home from the hospital. An adult will need to supervise the injured person for the first 24 hours to keep an eye on symptoms and possible complications such as seizures, vomiting, worsening headache, or difficulty waking up.

Concussion symptoms usually resolve on their own over the course of a week to 10 days, but this can sometimes take longer. The main treatment for concussion is rest, both physical and mental, usually for one to two days following the injury. This means limiting physical activity that could aggravate a concussion, as well as mental activity, such as schoolwork or office work. After this initial period of rest, patients are usually advised to gradually return to physical and mental activities starting a day or two after the injury.

While medications cannot cure a concussion or speed up recovery, they can help control symptoms. Acetaminophen may be taken to relieve headache, and other medications may be used to treat depression, nausea, sleep problems, or other symptoms. Psychotherapy, also known as talk therapy, may also be an option for people suffering from depression or anxiety.

Decisions regarding the timing of a return to school, work, or play should be made in consultation with a doctor. The time it takes to return to these activities can vary greatly depending on the severity of the concussion and the course of each patient’s recovery. In general, though, patients should gradually return to these activities.

Schools may need to make special accommodations for students who have had concussions. For instance, until they are fully recovered, students may need assignment extensions, extended time for taking tests, supplemental tutoring, and shortened school days.

Workers may also need special accommodations to ease their return to work. Similar to students, workers may benefit from extended project deadlines and a reduced workload and work schedule.

Athletes who’ve had a concussion, whether children or adults, should only return to play when they are granted approval to do so by a doctor. In all cases, before making a return to sports, they should be symptom-free and their cognitive and neurologic function should be at pre-injury baseline levels.

To return to play, athletes typically follow a sport-specific protocol in which over the course of several days or longer, they progressively increase their exercise and training intensity. For contact sports, the protocol usually involves four steps: The athlete starts with light aerobic activity then progresses to sport-specific exercises, non-contact drills, and finally, to contact drills. If the athlete experiences symptoms at any of these steps, they should repeat the previous step until they can complete it without symptoms.  

Anyone who has suffered a concussion should make sure they are fully recovered before returning to activities that put them at risk for another concussion. Getting another head injury while still recovering from a concussion can result in a condition called second-impact syndrome. This second injury can cause rapid and life-threatening brain swelling.

Concussions can lead to other complications as well. For instance, evidence suggests that repeated concussions are linked to the development of a progressive neurodegenerative disease called chronic traumatic encephalopathy (CTE) that can cause cognitive impairment as well as behavioral and mood changes.

The majority of people make a complete recovery from a concussion. Children may need more time to fully recover than adults. After a graduated return to physical and mental activities, they are able to successfully return to school and work. Most athletes are able to safely return to sports after completing a return-to-sports protocol designed to ensure they are fully recovered from concussion before they step back onto the field.

A minority of people, however, develop long-lasting symptoms that may persist for weeks, months, or years after the initial injury. Fortunately, in the majority of such cases, symptoms get better within a few months.