Even after a minor head injury, brain function can be temporarily impaired and this is sometimes referred to as concussion. This can lead to difficulties such as headaches, dizziness, fatigue, depression, irritability and memory problems.
While most people are symptom-free within two weeks, some can experience problems for months or even years after a minor head injury.
The more severe the brain injury, the more pronounced the long-term effects are likely to be. Survivors of more severe brain injury are likely to have complex long-term problems affecting their personality, their relationships and their ability to lead an independent life.
Even with good rehabilitation, support and help in the community, survivors and their families are likely to face uncertain and challenging futures.
Browse this section to find out more about the effects of brain injury. You can also download our Effects of brain injury and how to help (PDF) booklet in the related resources section.
Traumatic brain injury (TBI) is an injury to the brain caused by an external force. Common causes include falls, car accidents, assault or being struck by objects such as might occur during sport. TBI is classified according to its severity: mild, moderate or severe. From a medical perspective this judgment is based on what’s known as the Glasgow Coma Scale (GCS), which assesses motor, verbal and eye-opening responses. The scale runs from 3 to 15, where 3 is assigned to someone who is dead or comatose and 15 is normal. Someone with a mild TBI generally has a GCS of 13–15.
In the absence of clinical assessment, TBI is considered moderate-to-severe if there is a loss of consciousness that is longer than 30 minutes and amnesia – memory loss – lasts for more than 24 hours. It’s mild if those conditions are not met. Concussion is classified as a mild TBI (mTBI).
Signs and symptoms of traumatic brain injury (TBI)
Common symptoms of mild TBI are headaches, dizziness and fatigue, sleep disturbances, memory or concentration problems, and blurred vision. But a person may not display all of these at all times.
For severe TBI, symptoms can include slurred speech, profound confusion, seizures, persistant headaches, or loss of consciousness.
Prominent TBIs
The tragic outcomes of a spate of one-punch attacks – so-called ‘coward punches’ – in recent years has drawn considerable attention and resulted in harsher sentencing laws for perpetrators. Many researchers in the TBI field argue the tough laws are justified because even when a single punch isn’t lethal, or doesn’t have any apparent immediate effects, the head trauma can lead to irreversible consequences years or decades later.
Recent highly publicised cases of severe TBI have included Formula One driver Jules Bianchi, who died as the result of head injuries received when the car he was driving crashed during the 2015 Japanese Grand Prix. Retired Formula One driver Michael Schumacher continues to receive intensive treatment for severe head injuries that he suffered during a skiing accident in France, in 2013. In both of these cases, a severe TBI resulted in an immediate and prolonged loss of consciousness.
However, a loss of consciousness isn’t always necessary for the consequences of TBI to be catastrophic. In 2009, British actress Natasha Richardson knocked her head while skiing. Thinking she was fine, she declined medical care on multiple occasions before later experiencing headaches that prompted her to go to hospital. Richardson subsequently died due to an epidural haematoma, a build-up of blood between the skull and the membrane that surrounds the brain. Haematomas are considered secondary injuries, meaning that the damage done to the brain doesn’t coincide directly with the blow to the head.
Image by Levent Efe
What research is being done? NINDS supports TBI research through grants to major medical institutions across the country and conducts TBI research in its intramural laboratories and Clinical Center at NIH in Bethesda, Maryland. The Center for Neuroscience and Regenerative Medicine (CNRM) is a TBI research collaboration between intramural NIH and the Uniformed Services University for the Health Sciences (USUHS). NINDS-funded research involves studies in the laboratory and in clinical settings to better understand TBI and the biological mechanisms underlying damage to the brain. This research will allow scientists to develop strategies and interventions to limit the primary and secondary brain damage that occurs within days of a head trauma, and to devise therapies to treat brain injury and improve long-term recovery of function.
Combining the efforts of the many physicians and scientists who work to develop better treatments for TBI requires everyone to collect the same types of information from people including details about injuries and treatment results. The NINDS Common Data Elements (CDEs) project brings the research community together to develop data collection standards. The Project recently released a set of Sports-Related Concussion CDEs for use in clinical research. These CDEs are avaialable at: //commondataelements.ninds.nih.gov/SRC.aspx#tab=Data_Standards.
More information about Traumatic Brain Injury (TBI) Research is available at: Focus on Traumatic Brain Injury
More information about CNRM clinical studies is available at: //www.cnrmstudies.org/
Focus on Traumatic Brain Injury
Information from the National Library of Medicine’s MedlinePlus
Traumatic Brain Injury
Traumatic brain injury (TBI), a form of acquired brain injury, occurs when a sudden trauma causes damage to the brain. TBI can result when the head suddenly and violently hits an object, or when an object pierces the skull and enters brain tissue. Symptoms of a TBI can be mild, moderate, or severe, depending on the extent of the damage to the brain. A person with a mild TBI may remain conscious or may experience a loss of consciousness for a few seconds or minutes. Other symptoms of mild TBI include headache, confusion, lightheadedness, dizziness, blurred vision or tired eyes, ringing in the ears, bad taste in the mouth, fatigue or lethargy, a change in sleep patterns, behavioral or mood changes, and trouble with memory, concentration, attention, or thinking. A person with a moderate or severe TBI may show these same symptoms, but may also have a headache that gets worse or does not go away, repeated vomiting or nausea, convulsions or seizures, an inability to awaken from sleep, dilation of one or both pupils of the eyes, slurred speech, weakness or numbness in the extremities, loss of coordination, and increased confusion, restlessness, or agitation.
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Anyone with signs of moderate or severe TBI should receive medical attention as soon as possible. Because little can be done to reverse the initial brain damage caused by trauma, medical personnel try to stabilize an individual with TBI and focus on preventing further injury. Primary concerns include insuring proper oxygen supply to the brain and the rest of the body, maintaining adequate blood flow, and controlling blood pressure. Imaging tests help in determining the diagnosis and prognosis of a TBI patient. A blood test to evaluate mild traumatic brain injury in adults was approved by the U.S. Food and Drug Administration in February 2018. People with mild to moderate injuries may receive skull and neck X-rays to check for bone fractures or spinal instability. For moderate to severe cases, the imaging test is a computed tomography (CT) scan. Moderately to severely injured patients receive rehabilitation that involves individually tailored treatment programs in the areas of physical therapy, occupational therapy, speech/language therapy, physiatry (physical medicine), psychology/psychiatry, and social support.
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Approximately half of severely head-injured patients will need surgery to remove or repair hematomas (ruptured blood vessels) or contusions (bruised brain tissue). Disabilities resulting from a TBI depend upon the severity of the injury, the location of the injury, and the age and general health of the individual. Some common disabilities include problems with cognition (thinking, memory, and reasoning), sensory processing (sight, hearing, touch, taste, and smell), communication (expression and understanding), and behavior or mental health (depression, anxiety, personality changes, aggression, acting out, and social inappropriateness). More serious head injuries may result in stupor, an unresponsive state, but one in which an individual can be aroused briefly by a strong stimulus, such as sharp pain; coma, a state in which an individual is totally unconscious, unresponsive, unaware, and unarousable; vegetative state, in which an individual is unconscious and unaware of his or her surroundings, but continues to have a sleep-wake cycle and periods of alertness; and a persistent vegetative state (PVS), in which an individual stays in a vegetative state for more than a month.
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Last reviewed on July 25, 2022