Do Cognitive Tests Accurately Measure the Loss Resulting from a Traumatic Brain Injuries?

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.
 

Diffuse Brain Injury -- a Misnomer?

When a head is twisted violently, such as in a car crash, microscopic brain structures, called axons, can tear.  The damage to the brain is a called a "diffuse axonal injury," or DAI.  When the axons tear, chemicals that were contained in those structures can leak into the brain tissue.  The torn axons and chemicals in the brain tissue disrupt the brain’s regular processes.  

The injury has been named "diffuse" because it was believed the damage occurred throughout the brain, and not in any one particular location.  We now know that that isn't quite right.  For example, in severe cases, the axonal injury appears on an MRI.  When it does, it usually appears as one small foggy area.  (Seen in the center of the graphic as an opaque area.)   In fact, as it turns out, the damage caused by a "diffuse axonal injury" is usually centered in a specific part of the brain called the corpus callosum -- the bundle of fibers that connect the two-halves of the brain. 

Victims suffering from DAI often have cognitive problems such as:

  • lack of concentration
  • poor long-term memory
  • difficulty dealing with more than one thing at a time,
  • lack of attentiveness
  • trouble keeping track of appointments, and
  • disorganization.

A victim can suffer a diffuse axonal injury even if there wasn't any impact to the head. Because there is no tell-tale external bruising or bleeding, and because the DAI doesn't always appear on an MRI, health care providers sometimes fail to diagnose the injury initially.  To represent an accident victim effectively, the personal injury attorney must be alert to symptoms which may suggest that the client should seek further medical evaluation.