Defending claims of postconcussion syndrome.

• Author: Price, David R.

Defending claims of mild head injury, put forward even in the absence of positive physical findings from computer axial tomography (CT scan) or magnetic resonance imaging (MRI), is becoming more difficult and complex for claims officials and defense counsel. There has been a rise in claims of head injury that allege significant impairment but where the only positive support of the injury is neuropsychological test findings of cognitive impairment. The claimants' experts in these cases then render the opinion that these findings are causally related to a previous trauma to the brain. Since there has been no skull fracture or penetration of the brain, these injuries are referred to as "closed head injuries."

Closed head injuries occur with great frequency, their estimated incidence ranging from 430 to 1,830 per 100,000. Most occur in motor vehicle accidents, which account for 50 to 70 percent of reported cases. Other causes include domestic injuries or falls, sports accidents and work-related injuries.

There has been a large increase in the number of personal injury lawsuits in which plaintiffs allege significant brain damage when the only supporting evidence is neuropsychological test data. These data are produced by neuropsychologists or clinical psychologists who base their opinions on a claimant's subjective report in the absence of any documentation of genuine physical injury, supplemented by neuropsychological testing.

Posttraumatic concussion

Although controversial, the concept of posttraumatic concussion - gross derangement of cerebral function without obvious structural damage to the brain - is familiar to lay persons and physicians alike. Its symptoms were first described by Berengario da Carpi in the 16th century.(1)

There have been many attempts to define and quantify both concussion and postconcussion syndromes. These range from Bakay and Glashauer's definition of a concussion as "characterized as a brief loss of consciousness followed by prompt recovery without any localizing neurological signs"(2) to Roberts's "a brief and reversible coma occurring at the time of trauma...which would almost always be accompanied by some degree of posttraumatic retrograde amnesia."(3) Roberts goes on to define postconcussion syndrome as "an injury caused by trauma to the head accompanied by a transient loss of consciousness and/or significant degree of mental confusion which has an initial Glascow Coma Scale (GCS) of 13 to 15."

There also have been many attempts to define the severity of a mild head injury based on a number of factors. These include Teasdale and Gennett's (1974) use of the Glascow Coma Scale, which considers three components of wakefulness independent of each other. The Composite Glascow Coma Scale score has gained wide acceptance as an indicator of the over-all severity of head injury. A widespread interpretation of the GCS is to consider scores of 13 to 15 as minor, 9 to 12 as moderate, and 3 to 8 as severe.

Other attempts to define the severity of a mild head injury have included the development of diagnostic criteria for concussion, based on the length of time of a loss of consciousness, and in the International Classification of Diseases, Ninth Revision, Clinical Modifications (ICD-9-CM, 1979). According to ICD-9-CM, a diagnosis of concussion may be defined as:

8.50: "with no loss of consciousness which includes concussion with mental confusion or disorientation without loss of consciousness"

850. 1: "with a brief loss of consciousness which would include loss of consciousness for an hour"

850.2: "with moderate loss of consciousness from one to twenty-four hours"

850.3: "with a prolonged loss of consciousness and return pre-existing consciousness level," which would be a "loss of consciousness for more than twenty-four hours with complete recovery"

Historically, as in ICD-9-CM, there have been attempts to equate the severity of head injury with the depth and loss of consciousness, as was done in the GCS and other diagnostic criteria. There is controversy in the field over whether one must have a loss of consciousness, or even experience disorientation, to have a postconcussion syndrome. This professional controversy has contributed to the rise of litigation in claims of closed head injury, resulting most often from minor motor vehicle accidents.

Levin et al.(4) followed...