A comparison of recent studies on the extent of the head and spinal cord injury problem in the United States.

Several recent studies that provide estimates on the occurrence of new cases and the frequency of existing cases of injury to the head or spinal cord in the United States are compared. These studies include the National Head and Spinal Cord Injury Survey, the Health Interview Survey, the Hospital Discharge Survey, and separate investigations of spinal cord injury in Northern California and Connecticut. The comparison made of methodological approaches between the studies will enable the reader to better understand the estimates and why they differ.