Mild Traumatic Brain Injury (mTBI) Assessment

An uncomplicated mild traumatic brain injury (mTBI) is traumatic brain injury in which there is a brief loss of consciousness, brief posttraumatic amnesia, or an alteration of mental status (e.g., feeling dazed) without evidence of neurological damage. Physical, cognitive, and psychological symptoms are common in the days and weeks immediately following the injury, but these resolve naturally within a few months in the vast majority of patients. A relatively small number of patients show continued symptoms, which can be due to a range of other issues besides the mTBI. Psychological evaluation of these patients should include an assessment of cognitive and emotional functioning, as well as effort or motivation. Because these patients are commonly seen in forensic evaluations, where malingering is more likely, specific cognitive tests of effort should be administered. Symptom exaggeration or suboptimal performance can also be assessed on measures of emotional functioning.

Nature, Symptoms, and Outcomes From mTBI

Mild traumatic brain injury is a trauma to the brain that results in a brief loss of consciousness; a loss of memory for events immediately before or after the event, but not greater than 24 hours; or an alteration in mental status (e.g., feeling dazed, disoriented, or confused). When evaluated immediately postinjury, mTBIs are characterized by a high Glasgow Coma Scale score (between 13 and 15), which is a measure of the ability to follow eye-opening, motor-response, and verbal-response commands. When these injury characteristics are present, and there is no evidence of neurological damage, such as hemorrhage or contusion on neuroimaging (e.g., CT or MRI scan) of the brain, the mTBI is considered to be uncomplicated. A mild complicated TBI has not only a similarly short loss of consciousness and posttraumatic amnesia but also evidence of brain damage on neuroimaging (e.g., skull fracture), thus making it a more severe injury. Uncomplicated mTBIs can be contrasted with moderate or severe TBIs in which loss of consciousness and posttraumatic amnesia are significantly longer, typically measured in days or weeks, and are often accompanied by neuroimaging evidence of brain damage.

Common causes of mTBIs include the head being struck by an object, the head striking an object, or the brain undergoing an acceleration/deceleration movement, or whiplash, without direct external trauma to the head. The latter injury is common in motor vehicle accidents. The term mTBI is synonymous with concussion, with the latter term often used to describe the injury in athletics. These can be graded on their level of severity and are most common in contact sports such as football and hockey. Of the different levels of brain injury severity, mTBIs are by far the most common, accounting for more than 75% of all TBIs.

Common symptoms in the initial days and weeks post-mTBI can include a range of physical, cognitive, and psychological changes. Common physical symptoms include headache, nausea, vomiting, dizziness, blurred vision, and sleep disturbance; common cognitive deficits include attention and memory deficits. Psychologically, symptoms such as anxiety, irritability, or depression may be present. Depending on severity, these symptoms can interfere with an individual’s ability to function effectively. These acute symptoms are due to temporary dysfunction of the brain, such as metabolic changes, diminished cerebral blood flow, and impaired neurotransmission secondary to the injury. Although most neurons recover, a small number of neurons may degenerate and die. Nevertheless, the brain tends to recover quite quickly and naturally in an uncomplicated mTBI and there is typically significant improvement in symptoms within the first few days postinjury. Moreover, research has demonstrated that the vast majority of individuals are essentially symptom free and return to baseline levels of functioning within a few days to weeks, and sometimes a few months, after their injury. Recovery in athletes tends to be even more rapid, as these individuals are often highly motivated to recover and return to play. Nevertheless, a small number of individuals, fewer than approximately 5%, have prolonged and, at times, disabling symptoms postinjury that present a more complex clinical picture. Historically, various terms have been used to describe these patients, but today they are typically diagnosed with postconcussion syndrome. Not surprisingly, these individuals tend to seek continued psychological and medical treatment and may seek legal redress for their injury.

There is controversy about individuals with poor outcomes after uncomplicated mTBI and the cause of their persisting symptoms. While some have argued that these symptoms may be due to undetected and persisting brain abnormalities, most clinicians and researchers argue that other factors besides mTBI must be considered. For instance, many of these patients are in litigation and thus have external incentives to complain of persisting symptoms, even years after injury. Research has also demonstrated that those individuals who have had previous psychological or neurological problems or other life stressors tend to recover more poorly. Older age does not appear to be a risk factor for poor outcome after a single mTBI, although this is controversial, and the impact of repeated mTBIs and age (i.e., NFL players or boxers) may increase the chances of developing dementia in later life. Clearly, ongoing psychological or substance abuse postinjury, medical or pain complications from other injuries sustained in the accident (e.g., orthopedic), or additional mTBIs (more likely in an athlete) can prolong and complicate recovery. It should be noted that recovery is slower after more severe TBIs, including complicated mTBIs, and some individuals may suffer persisting symptoms that impair social and occupational functioning. What is expected, however, is that the vast majority of individuals who suffer mTBI will completely recover and have no persistent difficulties attributable to the injury.

Psychological Evaluation of mTBI

For an individual who has sustained an mTBI, the purpose of a psychological evaluation varies. Some evaluations may be within days or a few weeks after an accident, in the context of seeking assistance with management of cognitive and behavioral symptoms, whereas others may be years later in the context of a personal injury lawsuit seeking recompense for the injury. In these latter cases, it is unlikely that any observed deficits would be due to the direct effects of the mTBI, and other causes for these should be explored. In athletics, a series of brief evaluations, with cognitive testing typically done via computerized assessment, may be performed to assist in return-to-play decisions.

The clinical evaluation of the individual who has suffered an mTBI typically includes the following: review of available psychological and/or medical records, clinical interview with the patient, neuropsychological or cognitive testing, and psychological testing. Each of these is briefly described below. When reviewing medical records, psychologists seek to obtain as much information as possible about the nature and extent of the injury, such as how the individual behaved immediately after injury, whether there is any documented loss of consciousness, and whether there is any posttraumatic amnesia. In addition, it is useful to know if the individual suffered other injuries in the accident, such as orthopedic injuries, which might affect outcome. If possible, medical records predating the injury can be obtained to determine if the individual had preexisting medical or psychological problems, such as learning disabilities or perhaps a seizure disorder that might affect recovery. The clinical interview with the patient should focus on the nature and extent of the injury, as well as the symptoms, including cognitive, behavioral, and psychological, that the patient is currently experiencing. How such symptoms are interfering with the patient’s daily life is important. In addition to such injury information, the clinical interview should address the following: medical and psychiatric history, prescribed medications, neurological history such as previous TBIs or learning disabilities, substance abuse, current stressors in addition to the injury, occupation and social functioning, and litigation status. In such an interview, it is important to attempt to rule out alternative causes for the symptoms the person is experiencing. For instance, complaints for difficulty concentrating post-mTBI may not be due to the injury per se but to a preexisting anxiety disorder.

Because of the symptoms described above, evaluation of the mTBI patient typically includes both neuropsychological and psychological testing. Neuropsychological testing should include use of well-normed and psychometrically sound tests with established reliability and validity. A battery of tests should evaluate, at minimum, intelligence (e.g., Wechsler Adult Intelligence Test-III), learning and memory (e.g., California Verbal Learning Test-II), attention (e.g., Conners’ Continuous Performance Test), visuospatial processing (e.g., Judgment of Line Orientation), and executive functioning (e.g., Wisconsin Card Sorting Test). Other cognitive domains may need to be assessed, including academic (e.g., Wide Range Achievement Test) and sensory-motor functioning (e.g., Finger Tapping Test), depending on the nature of the referral and patient complaints.

In addition to evaluating specific areas of cognitive functioning, it is important to evaluate the patient’s effort or motivation, which may be suspect, particularly in a forensic setting where there may be motive for performing poorly (e.g., getting a larger monetary settlement in a personal injury case or evading responsibility in a criminal trial). If this is not done, impaired cognitive performances may erroneously be attributed to the mTBI and not to a patient’s poor effort. When patients exert poor effort consciously for external reward, this is termed malingering. Psychologists have recently developed multiple cognitive tests to detect malingering or poor effort that are efficient and accurate. For instance, one commonly used test requires patients to learn multiple word pairs (which appears difficult) and then to recognize each of the words on separate trials when a distractor word is presented. Because the word pairs are so obvious (e.g., grass-green), this test is actually quiet easy, and individuals with serious neurological disorder or mental retardation perform well on it. A poor performance in an individual with mTBI is suspicious for poor effort, and performance on other cognitive testing is thus of questionable validity. In addition to other tests designed to detect poor effort only, it can be detected on cognitive tests for which built-in validity detectors have been developed. Poor effort or malingering is also suspect when a patient does not cooperate with testing, performs inconsistently across similar tests (e.g., verbal memory), endorses symptoms inconsistent with the alleged injury, and presents during the interview in a manner inconsistent with testing (e.g., demonstrates good recall when queried about recent personal events, but poor performance on memory testing).

In addition to cognitive testing, psychological testing is also recommended in mTBI to evaluate the nature and severity of psychological involvement. Commonly used tests include the Minnesota Multiphasic Personality Inventory-2 and the Personality Assessment Inventory. These lengthy self-report tests evaluate a range of clinical complaints, such as mood, personality, and behavioral disturbance, as well as patient response variables. These latter variables evaluate whether a patient responded honestly and consistently to the items or whether he overreported symptoms (i.e., presented himself negatively) or underreported symptoms (i.e., presented himself positively). Within the forensic evaluation, overreporting symptoms are much more common in mTBI, as patients seek to emphasize experienced symptoms. It is thus important that whatever measure of personality is used, it includes a measure of patient response style. Unfortunately, the existing measures of postconcussive symptoms, which might be ideal for evaluation of an mTBI patient, typically do not include such measures.

References:

  1. Binder, L. M., Rohling, M. R., & Larrabee, G. J. (1997). A review of mild head trauma. Part 1: Meta-analytic review of neuropsychological studies. Journal of Clinical and ExperimentalNeuropsychology, 19, 421-131.
  2. Iverson, G. L. (2005). Outcome from mild traumatic brain injury. Current Opinion in Psychiatry, 18, 301-317.
  3. Putnam, S. H., Millis, S. R., & Adams, K. M. (1996). Mild traumatic brain injury: Beyond cognitive assessment. In I. Grant & K. M. Adams (Eds.), Neuropsychological assessment of neuropsychiatric disorders (pp. 529-551). New York: Oxford University Press.
  4. Ruff, R. M., & Richardson, A. M. (1999). Mild traumatic brain injury. In J. J. Sweet (Ed.), Forensic neuropsychology: Fundamentals and practice (pp. 313-338). Lisse, The Netherlands: Swets & Zeitlinger.

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