Many people with TBI have problems with basic cognitive skills: learning, remembering, thinking. It’s more than a mere loss of "intelligence." TBI victims may find it hard to pay attention or concentrate, and they might have trouble learning new material. A TBI can also cause the victim to think more slowly, or to get easily confused. Sometimes these skills are described as “executive functions” because they require a higher level of thinking, such as planning, understanding abstract ideas and conceptualization. People with TBI may become impulsive, or develop unusual habits. Things that were once easy — like talking and listening — may become difficult or impossible.

Because the brain regulates our emotional and psychological lives, a TBI can alter a victim’s sense of mental wellness. The TBI might cause a personality change, or introduce mental problems. A person with TBI may have mood swings, depression, irritability, aggression, or disinhibition. 

To assess the extent of the victim’s deficit, a neuropsychological evaluation may be recommended. The person conducting the evaluation interviews the victims and then administers a series of tests. The majority of the tests are pencil and paper standardized tests, meaning that they are given in the same manner to all patients and scored in a similar manner time after time. The tests must be administered by a neuropsychologist or a trained, skilled test administrator. 

The test giver will rarely, however, give a test that was specifically designed for someone who suffered a TBI.  For that reason, the cognitive test scores – alone– seldom paint the full picture of the TBI victim’s deficits

When dealing with a TBI victim, the test administrator should personally observe and evaluate the victim’s behavior during the test.  The test administrator’s observations may corroborate the reports of close friends and family members that the victim’s behavior has changed as a result of the injury.  In fact, interviews of friends and family are critical sources information concerning the loss the TBI victim has suffered.  

Regardless, cognitive testing is not designed to evaluate all behavioral changes that may result from a TBI.   Cognitive test results cannot be relied on as a sole measure of the TBI victim’s loss.