Traumatic Brain Injury in the United States:
A Report to Congress
Appendix: Methods Used to Produce Estimates for This Report
CDC Case Definition for Traumatic Brain Injury
CDC issued the following case definition for traumatic brain injury in its 1995 publication, Guidelines for Surveillance of Central Nervous System Injury.
For the purposes of public health surveillance, jurisdictions may elect to ascertain cases of traumatic brain injury from clinical records or from existing uniform data systems. Case definitions are presented for both types of ascertainment.
Clinical Case Definition. For surveillance systems using data from clinical records, a case of traumatic brain injury (craniocerebral trauma) is defined either:
as an occurrence of injury to the head that is documented in a medical record, with one or more of the following conditions attributed to head injury:*
- observed or self-reported decreased level of consciousness,?
- amnesia,?
- skull fracture,
- objective neurological or neuropsychological abnormality,? or
- diagnosed intracranial lesion;||
or as an occurrence of death resulting from trauma, with head injury listed on the death certificate, autopsy report, or medical examiner's report in the sequence of conditions that resulted in death.
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*Injuries to the head may arise from blunt or penetrating trauma or from acceleration-deceleration forces.
?Decreased level of consciousness refers to partial or complete loss of consciousness. This includes states described as obtundation, stupor, or coma.
?Amnesia may include loss of memory for events immediately preceding the injury (retrograde amnesia), for the injury event itself, and for events subsequent to the injury (posttraumatic amnesia).
?Neurological abnormalities are determined from neurological examination. Examples include abnormalities of motor function, sensory function, or reflexes; abnormalities of speech (aphasia or dysphasia); or seizures acutely following head trauma. Neuropsychological abnormalities are determined from mental status and neuropsychological examinations. Examples include disorders of mental status (such as disorientation, agitation, or confusion) and other changes in cognition, behavior, or personality.
||Examples of diagnosed intracranial lesions include traumatic intracranial hematomas or hemorrhage (epidural, subdural, subarachnoid, or intracerebral), cerebral contusions or lacerations, or penetrating cerebral injuries (e.g., gunshot wounds). The diagnosis of such intracranial lesions is usually confirmed with a computed tomography (CT) or magnetic resonance imaging (MRI) brain scan or by other neurodiagnostic procedures.
The clinical definition of traumatic brain injury excludes the following:
lacerations or contusions of the face, eye, ear, or scalp, without other criteria listed above
fractures of facial bones, without other criteria listed above
birth trauma
primary anoxic, inflammatory, infectious, toxic, or metabolic encephalopathies which are not complications of head trauma
neoplasms
brain infarction (ischemic stroke) and intracranial hemorrhage (hemorrhagic stroke) without associated trauma
Data Systems Case Definition. For surveillance systems receiving case reports from coded death certificates or hospital discharge data, the following International Classification of Diseases, Ninth Revision (ICD-9)2 or International Classification of Diseases, Ninth Revision, Clinical Modification (ICD-9-CM)3 diagnostic codes? are included in the definition of traumatic brain injury:
800.0-801.9 Fracture of the vault or base of the skull
803.0-804.9 Other and unqualified and multiple fractures of the skull
850.0-854.1 Intracranial injury, including concussion, contusion, laceration, and hemorrhage.
Additional cases of traumatic brain injury may be ascertained from death certificates coded as follows:
873.0-873.9 Other open wound of head.**
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?Note: ICD-9 codes are used for coding death certificates. ICD-9-CM codes are used for morbidity data. The codes are comparable except that ICD-9-CM codes include a fifth digit not found in ICD-9 codes.
**Note: This code range should not be applied to intracranial injuries. However, reviews of multiple cause mortality data from death certificates indicate that a substantial number of cases of intracranial injury, especially gunshot wounds, are mistakenly given these codes.3 Suspected cases of head trauma which have been so coded may be confirmed by review of medical records or death certificates.
Surveillance Methods Used by States
State health departments in Arizona, Colorado, Minnesota, Missouri, Oklahoma, New York, and South Carolina reviewed hospital discharge data collected from January 1 to December 31, 1994, using CDC guidelines to identify cases of TBI. The review identified all cases of TBI among patients in acute care hospitals who had been discharged with primary or secondary diagnoses consistent with the CDC case definition (i.e., ICD-9-CM code ranges 800.0-801.9, 803.0-804.9, and 850.0-854.1). In addition, the review identified TBI-related deaths and collected information from all death certificates or medical examiner reports that listed TBI or head injury among the conditions associated with death. Records were linked to eliminate duplicate cases reported from more than one source. Surveillance in New York excluded residents of New York City. Surveillance was statewide in all other States. In most States, supplementary information on severity and external cause of injury was obtained from abstracts of medical records or health-care provider report forms for all cases (Missouri and Oklahoma) or from representative samples of cases (Arizona [31 percent sample], Colorado [47 percent sample], and South Carolina [45 percent sample]). The TBI incidence rate for all seven States combined was calculated by using the sum of the number of cases for each State and the sum of the population of each State estimated at the midpoint of 1994 (35.3 million total).
Appendix References
1. Thurman DJ, Sniezek JE, Johnson D, et al. Guidelines for Surveillance of Central Nervous System Injury. Atlanta: Centers for Disease Control and Prevention, 1995.
2. International Classification of Diseases, 9th Revision (ICD-9). Geneva, Switzerland: World Health Organization, 1977.
3. International Classification of Diseases, 9th Revision, Clinical Modification, 3rd ed. (ICD-9-CM). Washington DC: U.S. Department of Health and Human Services, 1989.
4. Sosin DM, Nelson DE, Sacks JJ. Head injury deaths: the enormity of firearms. JAMA 1992;268:791.
Contact Information
National Center for Injury Prevention and Control
Mailstop K65
4770 Buford Highway NE
Atlanta, GA 30341-3724
Phone: 770.488.1506
Fax: 770.488.1667
Email: OHCINFO@cdc.gov
Executive Summary
Introduction
CDC's Traumatic Brain Injury Surveillance Program, 1989-1998
Current Data on Traumatic Brain Injury Mortality and Morbidity
CDC Estimates of Traumatic Brain Injury-Related Disability
Public Health Goals
References
Appendix: Methods Used to Produce Estimates for This Report
