Head injuries can affect any part of the head, the skull, the brain, or other soft tissues such as blood vessels, skin and cartilage. They can result in any degree of damage from superficial abrasions and cuts, to tearing of blood vessels, injury to the brain, bleeding in the brain, and skull fractures. Head injuries may result from even the most minimal or innocuous events to the most severe traumas. Injuries to the brain can even result when there is no direct trauma to the head, such as in a whiplash type injury where there are rapid acceleration and deceleration events.
The skull is made of bone, and is relatively resistant to injury. Larger forces generally need to be experienced to result in fracture. Cartilage is also somewhat resistant to injury, and in fact, can absorb some of the excess forces experienced in a trauma. On the other hand, skin, blood vessels and brain can be injured by relatively small forces.
The brain is the most sensitive of all of these, because injury can be caused in two ways. The brain can sustain injury when tissue (neurons) are cut, torn, stretched or deprived of oxygen, and these occur often when bones are fractured and blood vessels in the brain are disrupted. The other way that brain can be damaged, though, is by mere disruption of the chemical and electrical balance that is required for efficient functioning. When this type of injury occurs, it cannot generally be seen on x-rays, CAT scans, or MRIs, and often can only be measured by assessing how the brain is functioning.
Concussion, by definition, is a closed head injury that results in disturbance in brain function. That is, there is no fracture or bleeding into the brain. When there is bleeding in the brain, or fractures, the injury is classified differently. A mild concussion can involve brief dysfunction of the brain with no loss of consciousness. A more severe concussion results in more sustained dysfunction and/or loss of consciousness.
A concussion can result in only a momentary dazed feeling, but can include many more symptoms that may be present for anywhere from minutes to days, weeks, and longer. When a concussion is sustained, it sets off a cascade of events in the brain which result in impaired neuronal function, and sometimes even permanent loss of neurons. Repeated concussions increase the risk of having permanent loss of brain function. Sustaining a second concussion before the brain has had a chance to heal from the first increases the risk of having permanent loss of brain function.
Symptoms of Concussions
Disorientation, confusion, amnesia, headache, head pressure, blurred vision, sluggishness, foggy sensation, dizziness, sensitivity to light or noise, nausea, loss of balance or impaired coordination, irritability, excessive emotionality, sleep disturbance (excessive sleep or insomnia), mood disturbance, memory impairment, difficulty concentrating.
This is a longer term condition in which many of the symptoms of concussion may be present. The most common symptom is post-traumatic headaches, and this condition is often marked by ongoing difficulties with dizziness, memory and concentration difficulties, mood changes, and sleep disturbances.
Treatment for Concussion
The only treatment for brain injury is rest. This includes both physical rest and sometimes cognitive rest. If symptoms are persisting, and the athlete develops post-concussive syndrome, medications can help alleviate some of the symptoms such as headaches and mood changes, but the underlying brain injury really just needs time to heal.
Risks for prolonged recovery from concussion: younger age, female gender, prior concussions, pre-existing depression or anxiety, pre-existing migraine disorder, attention deficit disorder, hyperactivity, and learning disabilities.
ImPACT is a computerized test to assess neurocognitive functioning. When persons who have sustained a concussion have ongoing symptoms, it is relatively easier to say they are still suffering from the brain dysfunction associated with a concussion. But what if you feel fine? It actually doesn’t mean your brain is back to normal. Neurocognitive testing can identify impairments in brain function that are so subtle, that people often don’t recognize them. This is an important tool in assessing the effects of concussion. As the brain heals from the concussion, testing scores can normalize, letting the interpreter know that the concussed individual is back to normal or “baseline.”
Long Term Consequences
The long term consequences of a single mild concussion are usually nil. A single isolated mild concussion will often resolve within 1-4 weeks. When a person sustains multiple concussions, there are more likely to be long term consequences. There has been a lot of attention lately given to this topic, largely due to the discovery of a number of football players who during their life suffered from multiple concussions, and went on to develop chronic headaches, depression, substance abuse issues, and dementia. These are the symptoms of “chronic traumatic encephalopathy” and the donated brains of some of these players showed specific types of damage responsible for this condition. The only known way to prevent this condition is to prevent concussions. Not all people who sustain multiple concussions develop this condition, but we do not know of any way to identify who may be at specific risk for this condition. All people are at risk, though, of have some of the long term consequences if multiple concussions are sustained.
There are several ways in which we can prevent concussions and the consequences of repeated concussions. These include avoiding contact sports and risky activities, changing the amount and type of contact in certain sports, wearing proper protective gear, and allowing for enough time to heal after a concussion to avoid the damaging effects of sustaining a second concussion on top of the first.