Behavioral or personality changes (e.g., becoming more impulsive or aggressive; showing uncharacteristic social inappropriateness), mood change and moodiness (e.g., such as uncharacteristic depression, anxiety, intense anger or frustration), and cognitive problems (such as memory impairments (difficulty remembering things); difficulty paying attention or in sustaining concentration, difficulty making decisions, difficulty getting organized and following through with tasks, difficulty finding the correct words to express thoughts, and a feeling of being routinely overloaded by too much information) may also be observed.
About half of the people with mild TBIs recover quickly. Others show persistent symptoms that linger for six months or longer. 10% of individuals with mild TBI go on to experience chronic and disabling impairment that interferes with their ability to handle daily work and life tasks. The extent and permanency of damage associated with mild TBI, and how such damage may compound across repeated mild TBIs is not entirely clear at present and remains the focus of active study. This issue is of particular concern to soldiers and their families, as troops out in the field may be exposed to repeated IED blasts (and sustain cumulative brain damage) over the course of days or weeks.
Moderate/severe traumatic brain injury is associated with loss of consciousness for more than 30 minutes immediately after the time of injury, and with memory loss that lasts longer than 24 hours duration. People with a moderate or severe TBI tend to show more intense expressions of the symptoms displayed by a person with a mild TBI. In other words, they show more severe and profoundly disabling behavioral, personality, emotional and cognitive changes and symptoms. In addition, people with moderate or severe TBIs often show additional symptoms that are not characteristic of a mild TBI, including headaches that do not go away; repeated vomiting or nausea; seizures (convulsions), an inability to awaken from sleep; dilation of one or both pupils; slurred speech; weakness or numbness in the arms or legs; impaired muscle coordination; and increased confusion, restlessness, or agitation. The most serious head injuries result in stupor (i.e., a state of being mostly unresponsive, but briefly arousable with strong stimulation), coma (i.e., being unconscious and unresponsive, but continuing to have a sleep-wake cycle and periods of alertness), or a persistent vegetative state (i.e., being in an irreversible state of coma that lacks both awareness and wakefulness).
Traumatic Brain Injuries (particularly mild ones) are often hard to diagnose. Doctors may use imaging studies (e.g., non-surgical, non-invasive procedures that produce pictures of the brain such as MRI, CT and X-ray) to try and pinpoint the location and extent of brain damage that has occurred. For instance, skull and neck X-rays are often used to check for bone breaks or damage. CT (computerized tomography) scans or MRIs (magnetic resonance imaging scans (click here to view an in-depth discussion of imaging techniques) may be used to determine which internal brain tissues and structures have sustained damage. Unfortunately, current imaging techniques, though very powerful, lack the resolution and magnification precision necessary to show damage that has occurred at the level of individual neurons (e.g., tears in individual neurons or damage to axonal connections between neurons). Therefore, imaging scans may suggest that there is minimal or no damage, when in fact, significant damage at the neuronal level has actually occurred. Alternatively, imaging scans may show that some brain damage has occurred, but not prove helpful in accurately quantifying the degree or severity of this damage.
When imaging scans prove unable to clarify the level or location of damage that is likely present, physicians may order neuropsychological tests to assist with diagnosis. Neuropsychological tests measure brain-behavior relationships based on what people can or cannot do (e.g., how they are functioning) rather than constructing an actual image of how their body or brains have been damaged. Such tests are administered by specially trained psychologists (or their psychometrist assistants) and typically examine how well a person is functioning in terms of their cognition or thinking abilities (e.g., how well they can focus and switch their attention, remember things, solve problems, think abstractly, intuit rules and make appropriate social judgments). An individual's test results are compared against large collections of similar test results for normal and brain-damaged populations, and are corrected for age, education and gender. Brain damage is suggested when someone's pattern of scores is more similar to brain-damaged populations than to normal populations. Neuropsychological testing is capable of documenting very fine-grained and specific deficits in cognitive functioning which are known to be associated with very specific kinds of brain damage, some of which are not visible on a brain scan. Besides being used for diagnostic purposes, information gathered via neuropsychological testing can also be utilized to help develop a treatment plan that capitalizes on the injured person's preserved abilities and cognitive strengths.