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Definition & Consequences of Brain Injury


Traumatic brain injury: An insult to the brain caused by an external physical force, affecting either a specific part of the brain (focal) or more than one area (diffuse).

Atraumatic, or acquired, brain injury: A brain injury that has occurred after birth as the result of internal causes, such as stroke, aneurysm, meningitis, generally affecting more than one area of the brain.

Consequences of Brain Injury

Any brain injury can temporarily or permanently change the way a person thinks, acts, feels, and moves his or her body. In addition, it can affect involuntary bodily functions such as temperature and blood pressure regulation. In many instances, however, a person’s physical appearance does not change.

Many people experience a difficult adjustment period following brain injury because they seem different to themselves, but others treat them as if they were the same. They may have subtle problems with concentration, processing speed, memory, planning and organization, and in addition, may experience depression and anxiety but not relate any of these difficulties to their brain injury. A person’s failure to recognize her or his deficits may be neurologically induced, called anosognosia: Some people cognitively are incapable of understanding their functional limitations and others either do not remember, or idealize, their pre-injury capabilities.

Neuropsychological impairments caused by brain injury generally affect (1) intellect, or information processing; (2) emotionality, which involves feelings and motivations; and (3) control, or how behavior is expressed. A person who has a brain injury may experience some consequences that are apparent to other people, while other consequences may be invisible. The following lists are not exhaustive, and a person generally will experience a number of consequences concurrently. It is important to understand that while many of the consequences affecting how a person thinks, acts, and feels might appear to be something the person can change—because his or her behavior may seem intentional—they actually might be outside her or his control.

The most common problems experienced by people who have brain injuries are:

  • Physical
    • Headaches
    • Fatigue, both physical and mental, which can cause headaches and affect memory and cognition
  • Cognitive
    • Altered attention/concentration
    • Impaired memory, especially short-term, and difficulties with both storage and retrieval of information, making it difficult for a person to learn new information.
    • Altered verbal reasoning capacity, affecting the ability to identify the main idea, distinguish between relevant and irrelevant detail, compare and contrast, and draw analogies.
    • Altered critical thinking/logic skills, affecting abstract thinking, problem-solving, decision-making, judgment, and processing speed.
    • Communication difficulties such as anomia—the inability to find the right word—that often is worse in reading and writing situations (as compared to speaking and understanding), asphasia—difficulty expressing thoughts, and difficulty with pragmatics—understanding the meaning of words, or discerning humor or anger from a person’s tone of voice.
    • Overload, both auditory and visual, which can affect memory and cause fatigue, headaches and frustration.
  • Psychosocial, involving altered emotional and behavioral responses that can be misinterpreted in school, work, and social situations. Such responses might include egocentrism, “flat” affect (lack of emotional response), rapid mood shifts, heightened and/or inappropriate emotional responses, decreased frustration tolerance, impulsivity/disinhibition, lack of initiative, depression and anxiety.

Some invisible consequences that can affect the person’s functional ability may include:

  • Dizziness and balance disorders that can result in additional injury
  • Diminished or absent sense of smell, our most powerful sense
  • Hearing abnormalities, including hearing loss and ringing in the ears (tinnitus)
  • Visual disturbances such as double vision or visual field cuts where the person can not see to one side
  • Diminished or absent sensation
  • Seizure disorders


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