Traumatic Brain Injuries (TBI) affect close to 2,000,000 people in the US each year. Currently, 3.2 million Americans are living with disabilities related to a TBI.
TBI is a trauma-induced structural and functional injury to the brain, including closed and open head injuries. Concussion is a generic term often but not necessarily implying a mild and transient closed head injury. In reality, concussions can lead to long term and even lifelong disabilities. A broad definition of concussion/mild TBI (mTBI) from the American Congress of Rehabilitation Medicine (ACRM) is as follows: “Concussion/mild TBI (mTBI) is a physiological disruption of brain function as a result of a traumatic event as manifested by at least one of the following: alteration of mental state, loss of consciousness, loss of memory or focal neurological deficit that may or may not be transient, but where the severity of the injury does not exceed the following: posttraumatic amnesia for greater than 24 hours, after the first 30 minutes Glasgow Coma Scale score is 13–15, and loss of consciousness is less than 30 minutes.” The presence or absence of skull fracture does not define the severity of brain injury. The ACRM does not require loss of consciousness as a criteria. Subjects with concussion/mTBI who did not lose consciousness are among those most likely to be missed. Loss of consciousness may be present in concussions but many individuals may simply feel dazed, dizzy or have altered mental status and not realize that they have suffered an injury to the brain.
Contrary to what may be believed, the most common problems after a head injury are not neurological but neuropsychiatric. Serious brain injuries resulting from vehicle accidents, falls, assaults and penetrating projectiles may result in obvious neurological deficits and seizures. In less severe cases which constitute the overwhelming majority of head injuries, there are subtle behavior and mood changes. Subjects themselves may not associate the head injury with subsequent symptoms, failing to reporaft their changed condition to medical personnel. Confusion, intellectual changes, mood lability, anger outbursts, depression or even loss of touch with reality may occur directly after the trauma or many years later. About half of hospitalized TBI survivors in the United States in 2003 experienced related long-term disability.
Subtle manifestations of brain injury include problems with concentration, memory, language use, abstraction, calculation, planning and processing information. Problems with arousal and loss of mental flexibility can result in inattention, distractibility, and difficulty in switching and dividing attention. Purposeful and decisive action taking which requires reflection, motivation, ongoing error correction and impulse control may change impulsive and perseverative behavior.
Such defects may be missed with cursory cognitive testing. Careful, focused, in depth examinations and specific tests that mimic real life decision-making situations are required to uncover executive function deficits. Executive functions include setting goals, assessing strengths and weaknesses, planning and directing activity, initiating and inhibiting behavior, monitoring current activity, and evaluating results.
While cognitive impairment is among the most common consequence of traumatic brain injury (TBI) at all levels of severity, neurobehavioral sequelae consisting of neuropsychiatric and somatic symptoms may be more striking and disabling.
Mood disturbances are common after a traumatic brain injury. Subjects often recognize and feel sad and frustrated by deficits in intellectual and motor abilities. Apathy due to brain injury may include decreased motivation in the pursuit of pleasurable activities. Subjects may come across as schizoid or depressed. There is an eight fold increase in severe depression and significant increase in suicides. Mania is also associated with TBI.
Acute symptoms of mTBI such as headaches and dizziness resolve within 8-10 days in 80-90 percent of cases. The majority of individuals with mTBI/PCS recover from cognitive, somatic, and behavioral symptoms within 3-12 months. A subset of individuals goes on to develop chronic problems of mood, cognition or behavior described as persistent post concussive syndromes (PPCS). Studies indicate that seriously injured trauma victims with mTBI, are at greater risk of developing Posttraumatic Stress Disorder (PTSD) and chronic pain syndromes. These complicating conditions are likely to worsen prognosis and increase disability.
The evaluation of a subject with concerns of TBI/PCS requires an in depth investigation of neurological, psychiatric and medical illness both before and after the injury. Psychiatric disorders (including Axis I and II) are common. Individuals with pre-existing conditions will have more problems with TBI and poorer recoveries. The impact of prior TBIs and non-injury related dementing processes also need to be considered in the assessment of TBI. When subjects develop progressive cognitive decline following TBI, the clinical assessment should focus on identification of other causes for that decline, including dementias such as Alzheimer’s disease or psychiatric conditions such as major depression.
Neuropsychological testing is useful but may not correlate with everyday functioning and outcome. To date, imaging studies have been of marginal help in the evaluation and treatment of mTBI/PCS. Moreover, imaging data may be misused in court, both in civil and criminal matters, to support a claim of brain injury.
Though TBIs may go unrecognized, malingering has to be considered in all forensic evaluations. Litigants may be coached by their attorneys or obtain information from the internet on how to feign mTBI. Conversely, athletes and soldiers with actual mild head injuries may hide or downplay cognitive defects and try to come across as “normal” so they can continue to play or stay on in their units.
In summary, a neuropsychiatric exam that integrates neurological, neuropsychological, imaging and sociobehavioral data is the most comprehensive and appropriate way of conducting med-legal exams on subjects with mild TBI.