A concussion is a traumatic brain injury (TBI) that is caused by a blow to the head or body that can lead to a range of symptoms, including persistent headaches, dizziness, and problems with memory or thinking.
Symptoms of concussions and other mild TBIs usually resolve on their own within one to six weeks. However, for some people, symptoms last longer and can result in further complications.
Here are some of the more common complications of a concussion:
Headaches and dizziness are common symptoms of a concussion, but in most cases, they will go away in a couple days to a few weeks with adequate rest. However, in certain people who have suffered a head injury, these symptoms persist and can lead to post-concussion syndrome.
In addition to headaches and dizziness, symptoms of post-concussion syndrome can include fatigue, irritability, anxiety, blurred vision, tinnitus (ringing in the ears), insomnia, loss of concentration and memory, and sensitivity to noise and light.
Researchers have yet to determine why some people with a concussion develop post-concussion syndrome and others do not.
If symptoms of a concussion persist past the time your healthcare provider said they should go away, speak to your doctor. (1)
Post-traumatic vertigo is the dizziness that follows a head or neck injury like a concussion. There are several types of post-traumatic vertigo one can get following this type of injury.
The first is called benign paroxysmal positional vertigo (BPPV). This is a pattern of dizziness that is brought on only when the head is placed in certain positions or when there’s a change in position. Getting out of bed or rolling over in bed are common movements that will bring on dizziness.
After a head injury, scarring of the drainage pathways of the brain may cause fluid to build up and lead to post-traumatic Ménière’s disease, sometimes called hydrops. In this case, episodes of dizziness are accompanied by noises in the ear or hearing changes. The onset of symptoms can be immediate or take as long as one year after the initial trauma.
Following a concussion or other head injury, people may also get vertigo when they strain or blow their nose, when they get headaches or migraines, or when there is a change in their psychological state, such as with depression or anxiety.
Doctors can diagnose post-traumatic vertigo through an exam and a number of tests that evaluate dizziness, balance, and hearing.
Post-traumatic vertigo is typically treated with a combination of medication, changes in lifestyle, and sometimes physical therapy. Occasionally, doctors may recommend surgery. (2)
Second Impact Syndrome
Second impact syndrome is rare but occurs when a second concussion occurs before the first one has completely healed. This can lead to rapid and severe brain swelling, which can turn fatal.
Second impact syndrome can occur from even a very mild trauma that occurs within days or even weeks after the initial concussion.
The condition is most common in young athletes, especially those who participate in sports like football, hockey, boxing, or soccer. In this population, concussions can sometimes go undetected, putting players at risk for second impact syndrome.
It’s vital that athletes and coaches are aware of the signs of concussion to ensure that athletes get adequate time for their brains to heal.
People with a concussion need to rest in order to properly heal and should avoid any activity that is physically or mentally demanding immediately after a diagnosis. They should not return to play until they have been given the all clear by their doctor, and when regular activity is resumed, it should be done so gradually. (3)
Predisposition to Degenerative Brain Diseases
Over the past few decades, research has linked moderate to severe brain trauma with an increased risk of Alzheimer’s disease and other types of dementia.
One study published in 2000 found that young adults who experience a moderate head injury have more than double the risk of developing Alzheimer’s and other forms of dementia later in life. A more severe head injury — defined as being admitted to the hospital and remaining unconscious or having amnesia for 24 hours or more — quadrupled the risk. (4)
Another study, published in 2018 in PLOS Medicine, found in older adults aged 50 and above, the risk of dementia was increased by four to six times the first year after traumatic brain injury. After the first year, the risk decreased rapidly but was still there more than 30 years after the initial trauma. (5)
However, other studies show mixed results and more research is needed to better understand the link, according to the Alzheimer’s Association.
Emerging research indicates that people who have experienced repeated traumatic brain injuries or multiple blows to the head without loss of consciousness are at an increased risk of developing a brain disease called chronic traumatic encephalopathy, or CTE. Professional athletes, including former NFL players, and combat veterans appear to be at a higher risk for CTE. (6)
In 2015, researchers from the Department of Veterans Affairs and Boston University reported that 87 of the 91 deceased former NFL players they studied tested positive for CTE. More research is under way to better understand the relationship between head trauma and CTE, how to identify it early, and potential treatments. (7)
Editorial Sources and Fact-Checking
- Severe Head Injury. NHS Choices. December 1, 2016.
- Post-Traumatic Vertigo. American Hearing Research Foundation. October 2012.
- Second Impact Syndrome. BrainandSpinalCord.org.
- Head Injury Doubles the Risk of Alzheimer’s Disease. U.S. National Library of Medicine National Institutes of Health. November 4, 2000.
- Traumatic Brain Injury and the Risk of Dementia Diagnosis: A Nationwide Cohort Study. PLOS Medicine. January 30, 2018.
- Alzheimer’s & Dementia. Traumatic Brain Injury. Alzheimer’s Association.
- New: 87 Deceased NFL Players Test Positive for Brain Disease. Frontline. September 18, 2015.