Of approximately 425,000 brain injuries from all causes of trauma estimated to have occurred in the United States in 1984, about 329,000 experienced good recovery with minimal or no deficit. Fatalities accounted for 71,000 (about 70% dead on arrival, 30% after admission to a hospital), leaving 25,000 experiencing long-term neurologic sequelae ranging from coma to memory deficits. Since as many as 10% of those classified as good recovery exhibit psychological or cognitive deficits which may affect employment or quality of life, the total incidence of individuals suffering serious functional loss due to brain injury may be as high as 58,000 annually. Brain injuries contribute significantly to fatalities and disabilities resulting from crash injury. In 1984, car, truck and bus occupants sustained 29.8% of all brain injuries, suggesting a total of 21,000 fatal brain injuries to occupants, or almost 60% of all 1984 fatalities reported for vehicle occupants.

While only 12,500 acute spinal cord injuries were estimated to occur in the United States for 1984, fewer than 1% of those injuries were projected to experience good recovery. Since about 4,700 were dead on arrival and another 1,300 died after admission to a hospital, an estimated 6,500 cases of neurologic impairment resulted. Approximately 37% of all spinal cord injuries are to car, truck or bus occupants.

Our analysis of these historical data shows that although the incidence of brain injury from all causes is thirty-four times that of spinal cord injury, many of the brain injuries carry little or no long-term consequence. Since good recovery occurs in fewer than 1% of those with spinal cord injury, the incidence of permanent disability from spinal cord injury equals 25% of the incidence of total disability after brain injury. Even if all potential mild disability cases are included for brain injury, the incidence of spinal cord disability is approximately 11% that resulting from brain injury. These data suggest that spinal cord injuries contribute proportionately more to long-term disability than implied by hospital admission data alone relative to brain injury. These data should be carefully considered in setting priorities for occupant protection and crash injury prevention.