Q&A on Traumatic Brain Injury

1. What is traumatic brain injury (TBI)?

When a head in motion suddenly strikes a stationary object, the brain will violently slam against the bony interior of the skull resulting in a “traumatic brain injury.” Striking a windshield or the ground at even a modest rate of speed, or an object striking the head (such as a flying or falling object), can cause contusion (cerebral bruising) resulting in injury to neuronal cells. Blast exposure can also cause brain injury presumably by causing a pulse of powerful brain movement within the cranium.

Damage to brain cells disrupts interneural communication and interferes with cognitive processes such as thinking, learning, remembering, perceiving, self-awareness, and impulse control. Traumatic injury also frequently interferes with the brain’s ability to coordinate body movements and regulate emotions.

Consequences of injury can range from relatively mild to catastrophically severe depending on multiple factors including the degree of force, past head traumas, neurological or other physiological complications, injury location in the brain, and timeliness of emergency medical treatment. Each individual who sustains traumatic brain injury responds differently. In addition to the individual dynamics of direct injury to the brain, accompanying bodily injuries, psychological reactions, idiosyncratic physiological and molecular reactions, weak social supports and other factors potentially contribute to brain injury consequences.

2. What is the difference between “closed head injury” and “traumatic brain injury”?

A closed head injury (CHI) implies force trauma to the head that does not result in penetration or breaking of the skull. A bullet or a skull fracture would produce an “open head injury.” Usually, closed head injury implies traumatic brain injury, but this may not necessarily always be the case. Whether or not, and to what extent, the brain is injured depends on the power of the physical force to the head. If the trauma is great enough, physical force radiates from the skull into the brain, through the cortex (gray matter) and possibly deep into the subcortex (white matter). Injury may also occur to delicate blood vessels and other tissues within and covering the brain. Brain swelling may add complications. Even if closed head injury does not cause brain injury, it may cause “soft tissue” injury to muscles, tendons, and other non-brain tissues. Symptoms of soft tissue injury may mimic mild brain injury, producing headaches, fatigue, mental confusion, irritability, cognitive problems, or emotional reactions.

 3. What is specific about the term “mild traumatic brain injury”?

Severity of brain injury is classified based on length of alteration in consciousness (alertness), depth of unconsciousness, extent of posttraumatic (retrograde) amnesia (memory loss), and functional changes in behavioral regulation, cognition, and/or emotions. Change in consciousness and amnesia are directly caused by damage to nerve cells. Injured neurons may or may not recover, depending on the extent and severity of injury. “Mild traumatic brain injury” is the term used when loss of consciousness is about 30 minutes or less and posttraumatic amnesia lasts for about 24 hours or less. Measurement of the initial effect of trauma is usually accomplished using the Glasgow Coma Scale. The diagnosis of MTBI may be made whenever consciousness is altered at all (such as being “dazed,” even briefly), amnesia of any length, or neurological abnormalities occur (such as temporarily altered vision, or a seizure). “Mild” used in the context of brain injury is merely a relative term; it does not mean inconsequential, or not serious.

Cognitive changes may occur following MTBI, and may show delayed onset, with resolution usually occurring over a few weeks. Some individuals may have permanent changes in cognitive, behavioral, emotional, or physical capacities. Assessment of the individual’s functional history, neuropsychological test performance, and emotional and psychological reactions is necessary for teasing out the effects of brain injury sustained at any level of severity.

4. What are typical  functional consequences of traumatic brain injury?

Thinking and psychomotor skills become slow, selective memory becomes unreliable, attention and concentration may become haphazard, and social behaviors (such as being disinhibited or child-like) may change following TBI of any severity. Due to damage in anterior brain regions, individuals often express varying degrees of anosognosia (unawareness of the consequences of injury), making treatment and readjustment challenging.

Damaged neurons mar the processing of electrochemical messages within brain networks. Generally, the greater the damage, the more widespread and severe the symptoms. The brain simply cannot process electrochemical information as efficiently as it used to. Thinking takes more time because it is subject to errors caused by unfamiliar neural detours around damaged neurons. Judgment and decision-making may be faulty because the complex interrelated brain connections are not available to the person now in the way they were before the injury. Thinking, thus, becomes rigid and inflexible.

Individuals sometimes sense incomplete mental processing and lose confidence in thinking. Complex or unfamiliar tasks may become frustrating and discouraging, as thinking no longer yields insights or flexibility in solving problems. Irritability prevails, as the individual attempts to cope with a brain that seems always to function in a mental fog.

A host of complicating cognitive, emotional, and social reactions can evolve. To an extent, some of these problems can be permanent. Symptoms usually respond to brain injury rehabilitation—methods for helping the individual learn effective self-awareness and coping strategies to deal with the cognitive and behavioral challenges and to minimize frustration and negative emotional responses. Traumatic brain injury also increases risk factors for developing psychiatric disorder or dementia. Psychotic symptoms must be addressed as soon as they appear to prevent potentially irreversible worsening.

5. Can brain injury occur without sustaining a direct blow to the head?

Yes. Whiplash injury, violent shaking of the head, or blasts can cause brain injury. Sudden movement of the brain inside the cranium potentially causes damage to neurons and other brain structures and may cause blood vessels to tear. Sudden acceleration-deceleration of the head in an automobile collision, even with airbag deployment where the head is protected from striking a solid object, can cause brain injury because the brain may still slam against the inside of the skull, displacing, tearing, and bruising nerve cells and other tissues. This causes loss of communication within neural networks, and loss of integrity in how the brain has been managing its familiar cognitive and behavioral ways of doing things.

6. Are MRI or CT scans essential for diagnosing brain injury?

MRI scanning is essential in discovering extent and location of damage, especially (but not exclusively) in cases of moderate to severe injury. However, brain imaging scans often are not sensitive enough to reveal microscopic injury to neurons or small areas of molecular/physiological damage within brain tissue. Traumatic brain injury, especially if mild, involves scattered injury to neurons and supportive tissue, stretched (and damaged) axon membranes (diffuse axonal injury), chemical injury due to neurotransmitter toxicity, and cellular dysfunction due to changes in ionic balance. Even if diffuse axonal injury causes subtle change in brain tissue, the injury may be so scattered throughout the brain that there is insufficient focal concentration of injury to yield detection by these imaging procedures. Thus, a normal MRI does not rule out brain injury. Sometimes, a metabolic imaging technique, such as PET (positron emission tomography), can detect changes due to brain injury causing neurons to function poorly, thus interfering with cognitive skills. Diffusion tensor imaging (a type of MRI) examines integrity of white matter pathways that can increase sensitivity to detecting damage. A CT scan is usually employed in emergency assessment of head trauma to check for life threatening bleeding or swelling in the head and brain.

7. What are the differences among “post concussion syndrome,” “contusion,” “posttraumatic stress disorder,” and “brain damage”?

“Post concussion syndrome” refers to a set of often-reported symptoms that occur, and often linger for weeks, months, or years following traumatic brain injury, mild or otherwise. Post concussion symptoms are not very specific and may be due to brain injury, soft tissue injury, or psychological reaction to injury. The syndrome typically includes headache, dizziness, concentration difficulty, memory problems, irritability, mental dullness, fatigue and weakness, light or sound hypersensitivity, sleep difficulty, depression, and loss of self-confidence.
 
“Post-traumatic stress disorder” refers, specifically, to an emotional (anxiety-based) disorder caused by a psychologically intense fear-producing event. PTSD does not always (but may) accompany post concussion syndrome, especially if the person remembers some horrifying aspect of an injury event. The term “trauma” in this case refers to emotional, not physical, impact.
 
“Brain damage” is a general term referring to any injury to brain tissue from any cause—trauma, stroke, tumor, infection.
 
“Contusion” refers to bruising. Presence of a contusion— injury to blood vessels—often accompanies traumatic brain injury.
 
 8. How does the neuropsychological examination aid in diagnosis and understanding of TBI?

Brain injury causes structural brain changes and, consequentially, functional behavioral changes. Assessing functional changes in memory, thinking, coordination, language, emotions, personality, and social behaviors provides insight and understanding about underlying structural damage, and the practical consequences of traumatic brain injury. Specific patterns of results on objective neuropsychological tests reveal trauma-induced functional changes. By combining data from a thorough interview and history with results from neuropsychological tests, the neuropsychologist creates a functional profile that can be compared to the kinds of profiles usually produced by persons with various kinds of brain injury, and by profiles produced by non-injured persons (as in personality, psychological, emotional, or developmental disorders). Neuropsychological examination is extremely useful in differential diagnosis of symptoms and revealing causes of those symptoms.

9. Who performs the neuropsychological examination?

Psychologists who specialize in neuropsychology (the study of brain and behavior relationships) are qualified to administer and interpret neuropsychological tests, and to interpret the meaning of test results vis-à-vis personal, social, and medical history. Neurologists and neurosurgeons often administer a variety of brief mental status procedures but these are neither standardized nor sensitive enough to detect diverse or subtle dysfunctions revealed by objective neuropsychological tests. Neurologists, neurosurgeons, and neuropsychiatrists are medical doctors who rely on physical procedures and trained observation for diagnosis, and medical/surgical techniques for treatment. Neuropsychologists are clinical psychologists who, through the use of standardized behavioral assessments, and their specialized training and background knowledge in brain-behavior relationships, seek to understand the complex interactions of psychological, biological, social, and developmental components that produce dysfunctional behavior. Comprehensive understanding is essential for diagnostic formulation and treatment planning.

10. Can a neuropsychological examination differentiate acquired from pre-existing problems?

Relying on an extensive history, chronology of symptom development, knowledge of developmental neuropsychology, and analysis of patterns of results from an array of neuropsychological tests, differential diagnosis of cause of current cognitive and emotional problems can usually be achieved. Comprehensive, differential diagnosis is the hallmark of a thorough neuropsychological examination. The neuropsychologist sorts out the pre-existing developmental (biological/genetic and social), emotional, and cognitive factors from the changes directly produced by brain injury.

11. Why does brain injury in different persons produce different outcomes?

Just as no two people are alike in behavior and personality, no two brains are exactly alike structurally. Brain injury manifests itself depending on a host of factors such as native intellectual capacity, developmental experience, physical health, age, emotional and personality resources, social supports, attitudes toward illness and health, concurrent (non-brain) injuries, quality of immediate medical attention following an injury, psychological adjustment or maladjustment, and dozens of other factors. Also, just as the kinds and amount of physical injury (broken bones, soft tissue contusions, or lacerations) vary among individuals involved in accidents, so do the amount and kind of head rotation, impact speed, and other physical factors that determine the specific nature and consequences of injury.

12. What effect does pain have on the experience of brain injury?

Pain often accompanies traumatic brain injury due to head and neck soft tissue injury, cervical strain, spinal injuries, and other acquired somatic and medical problems. Chronic pain and suffering (and medications one might take for this) certainly diminishes one’s concentration, stamina, and emotional well-being. Thus, the potential for pain to influence the consequences of brain injury is always a concern. Research has demonstrated the robustness of neuropsychological tests and documented their ability to differentiate brain dysfunction from non-brain injury conditions. A comprehensive examination must consider pain and discomfort factors as well as cognitive, behavioral, and emotional factors in the overall clinical presentation and the potential for recovery.

13. How important are health, educational, and medical records to the neuropsychologist conducting a neuropsychological examination?

Medical records are essential for a thorough examination. Records provide the background for understanding the individual before the injury, the quality and outcome of medical and other interventions following an injury, pre-existing health issues, and other background that helps in the interpretation of neuropsychological test results. Educational, employment, and service records can help establish level of pre-injury mental functioning. Collateral interviews with parents or spouses can provide additional history and insight the patient is unable to provide.

14. Does the neuropsychological examination provide an accurate prognosis?

Neuropsychological functioning, as well as one’s medical condition, forms the basis for predicting recovery following a brain injury. Extent of an injury (structurally and functionally), rate of recovery so far, complicating factors such as pain and other injuries, emotional and psychological reactions, support (or lack thereof) from family and employers, attitudes in the injured person about health and recovery, potential secondary gains from injury, personality strengths, and other factors contribute to the foundation for predicting outcome from brain injury. The comprehensive neuropsychological examination evaluates these factors to help determine the injured person’s potential to achieve functional improvement and to return to some level of work.  The examination helps identify treatment options tailored to the individual’s needs. Improvement and adjustment to brain injury can take weeks to years, depending on severity and other factors.

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