Report to Congress on 

Mild Traumatic Brain Injury 

in the United States: 

Steps to Prevent a Serious 

Public Health Problem 

September 2003

The Report to Congress on Mild Traumatic Brain Injury in the United States: Steps to 

Prevent a Serious Public Health Problem is a publication of the National Center for 

Injury Prevention and Control, part of the Centers for Disease Control and Prevention. 

Centers for Disease Control and Prevention 

Julie Louise Gerberding, M.D., M.P.H. 

Director 

National Center for Injury Prevention and Control 

Sue Binder, M.D. 

Director 

Suggested Citation: National Center for Injury Prevention and Control. Report to 

Congress on Mild Traumatic Brain Injury in the United States: Steps to Prevent a Serious 

Public Health Problem. Atlanta, GA: Centers for Disease Control and Prevention; 2003. 
Dear Colleague: 

Traumatic brain injury is frequently referred to as the silent epidemic because the 

problems that result from it (e.g., impaired memory) often are not visible. Mild 

traumatic brain injury (MTBI) accounts for at least 75 percent of all traumatic 

brain injuries in the United States. However, it is clear that the consequences of 

MTBI are often not mild. 

In response to these concerns, Congress passed the Children’s Health Act of 2000 

(Public Law 106-310), which required the Centers for Disease Control and 

Prevention (CDC) to submit a report to Congress on appropriate methodological 

strategies to obtain data on the incidence and prevalence of MTBI. To that end, 

CDC formed the Mild Traumatic Brain Injury Work Group, composed of brain 

injury experts, to determine appropriate and feasible methods for assessing the 

incidence and prevalence of MTBI in the United States. 

This report, Mild Traumatic Brain Injury (MTBI) in the United States: Steps 

to Prevent a Serious Public Health Problem, presents the significant findings 

and recommendations of the members of the MTBI Work Group, which are the 

product of numerous discussions and a thorough review of the scientific literature. It describes the public health significance of MTBI and makes recommendations on how to better measure the magnitude of the problem of MTBI in this 

country. Incorporating the recommendations of this report into public health 

policy and public health practice will help the nation to better understand the 

full impact and the long-term consequences of MTBI. 

Julie Louise Gerberding, M.D., M.P.H. 

Director 

Centers for Disease Control and Prevention 

Department of Health and Human Services 

Contents


I. Preface 

II. Executive Summary
 1 

III. Body of the Report 

Introduction
 7 

Formation and Objectives of the CDC
 13 

Mild Traumatic Brain Injury Work Group


Findings and Recommendations of the
 15 

CDC Mild Traumatic Brain Injury Work Group


Conclusion
 26 

References
 27 

Appendices 

A.	 CDC Mild Traumatic Brain Injury
 31 

Work Group


B.	 Criteria Used to Evaluate Proposed,
 35 

Ongoing Surveillance Systems to


Identify Persons with Mild Traumatic


Brain Injury in the United States


C. 	Descriptions of Recommended
 37 

Mild Traumatic Brain Injury


Databases


Preface 

In recent decades, public health and health care communities have become increasingly 

aware that the consequences of mild traumatic brain injury (MTBI) may not, in fact, be 

mild. Epidemiologic research has identified MTBI as a public health problem of large 

magnitude, while clinical research has provided evidence that these injuries can cause 

serious, lasting problems. 

In response to public health concerns, Congress passed the Children’s Health Act of 

2000, which required the Centers for Disease Control and Prevention (CDC) to determine 

how best to measure the rate at which new cases of MTBI occur (i.e., incidence) and the 

proportion of the U.S. population at any given time that is experiencing the effects of a 

MTBI (i.e., prevalence) and to report the findings to Congress. To that end, CDC formed 

the Mild Traumatic Brain Injury Work Group, composed of experts in the field of brain 

injury, to determine appropriate and feasible methods for assessing the incidence and 

prevalence of MTBI in the United States. 

This report presents the significant findings and recommendations of the members of 

the CDC MTBI Work Group, which are the product of numerous discussions and a 

thorough review of the scientific literature. It describes the public health significance 

of MTBI and recommends how to better measure the magnitude of the problem of 

MTBI in this country. 

Executive Summary 

Background 

According to existing data, more than 1.5 million people experience a traumatic brain 

injury (TBI) each year in the United States. Of them, as many as 75 percent sustain a 

mild traumatic brain injury—or MTBI. These injuries may cause long-term or permanent 

impairments and disabilities. Many people with MTBI have difficulty returning to routine, daily activities and may be unable to return to work for many weeks or months. In 

addition to the human toll of these injuries, MTBI costs the nation nearly $17 billion 

each year. 

These data, however, likely underestimate the problem of MTBI in this country—for 

several reasons. First, no standard definitions exist for MTBI and MTBI-related impairments and disabilities. The existing Centers for Disease Control and Prevention (CDC) 

definition for TBI surveillance is designed to identify cases of TBI that result in hospitalization, which tend to be more severe. MTBI is most often treated in emergency departments or in non-hospital medical settings, or it is not treated at all. Few states conduct 

emergency department-based surveillance, and current efforts do not capture data about 

persons with MTBI who receive no medical treatment. Additionally, neither hospital- nor 

emergency department-based data can provide estimates of the long-term consequences 

of MTBI. 

In response to concerns about this public health problem, Congress passed the Children’s 

Health Act of 2000, which required CDC to determine how best to measure the incidence 

(i.e., rate at which new cases of MTBI occur) and the prevalence (i.e., proportion of the 

U.S. population at any given time that is experiencing the effects) of MTBI and to report 

the findings to Congress. To that end, CDC formed the Mild Traumatic Brain Injury 

Work Group to determine appropriate and feasible methods for assessing the incidence 

and prevalence of MTBI in the United States. 

The Mild Traumatic Brain Injury Work Group 

The Mild Traumatic Brain Injury Work Group brought together 17 external experts from 

fields including epidemiology, neurology, neurosurgery, neuropsychology, statistics, and 

an organization representing the brain injury community. The work group was divided 

into two subgroups. The Definitions Subgroup developed a conceptual definition of 

MTBI based on clinical signs, symptoms, and neuroimaging; and an operational definition to be used in identifying cases of MTBI in administrative databases, medical 

records, and survey and interview results. The Methods Subgroup evaluated surveillance 

databases and identified those that would best capture the types of data needed to determine the full magnitude of MTBI and related impairments and disabilities. 
2 

Recommended Definitions for 

Mild Traumatic Brain Injury 

Incident Cases of MTBI 

The conceptual definition of MTBI is an injury to the head as a result of blunt trauma or 

acceleration or deceleration forces that result in one or more of the following conditions: 

● Any period of observed or self-reported: 

◆ Transient confusion, disorientation, or impaired consciousness;


◆ Dysfunction of memory around the time of injury;


◆ Loss of consciousness lasting less than 30 minutes.


● Observed signs of neurological or neuropsychological dysfunction, such as: 

◆ Seizures acutely following injury to the head; 

◆	 Among infants and very young children: irritability, lethargy, 

or vomiting following head injury; 

◆	 Symptoms among older children and adults such as headache, 

dizziness, irritability, fatigue or poor concentration, when 

identified soon after injury, can be used to support the diagnosis 

of mild TBI, but cannot be used to make the diagnosis in the 

absence of loss of consciousness or altered consciousness. 

Research may provide additional guidance in this area. 

Based on this conceptual definition, separate operational definitions of MTBI are 

recommended for cases identified from interviews and surveys, administrative health 

care data sets, and patient medical records. These operational definitions are described 

in detail in the Definitions Subgroup Findings and Recommendations section 

(pages 15–21). 

Prevalent Cases of MTBI-Related Impairments, Functional Limitations, 

Disabilities, and Persistent Symptoms 

The conceptual definition of a prevalent case of MTBI is any degree of neurological or 

neuropsychological impairment, functional limitation, disability, or persistent symptom 

attributable to an MTBI. 

The operational definition of a prevalent case of MTBI-related impairment, functional 

limitation, disability, or persistent symptoms is any case in which current symptoms are 
 3 

reported consequent to MTBI or made worse in severity or frequency by the MTBI, 

or in which current limitations in functional status are reported consequent to MTBI. 

Symptoms and limitations are described on pages 19-21. 

Recommended Methods for


Mild Traumatic Brain Injury Surveillance


To obtain data on the incidence and prevalence of MTBI, established methods such as 

hospital emergency department- and hospital-based data collection and analysis should 

be the first priority. The other methods provided in this report can serve as additional 

sources of good information as resources and capacity will allow. 

Priority Recommendations to Obtain Data on the 

Incidence and Prevalence of MTBI 

●	 Increase the number of states conducting emergency department- and 

hospital-based TBI surveillance, and apply the recommended operational 

definitions of MTBI to improve detection of cases in these and national 

systems. 

●	 Explore using large, national hospital discharge databases that have not 

been used previously for injury surveillance. 

Additional Recommendations – Detection and Surveillance of 

New Cases of Medically-Treated MTBI 

●	 Routinely analyze data from CDC health and medical care surveys to 

estimate incidence and external causes of MTBIs treated in hospital 

outpatient settings and those treated outside hospitals and hospital 

emergency departments. 

●	 Analyze data from a collegiate sports surveillance system to assess 

the incidence of MTBI among participants in selected college sports. 

Detection and Surveillance of New Cases (Incidence) of 

MTBI Not Receiving Medical Care 

●	 Explore adding MTBI-related questions to large, existing, state-based 

surveys. 
4 

● Determine the feasibility of using existing, national health surveys 

to identify people with MTBI who do not receive medical care. 

Identifying and Assessing Prevalent Cases of 

MTBI-Related Impairment, Functional Limitation, 

Disability, and Persistent Symptoms 

●	 Explore adding MTBI-related questions to existing surveys and surveillance systems to determine the prevalence of individuals with 

MTBI-related functional and cognitive impairments or disabilities. 

●	 Explore determining the occurrence of MTBI-related disabilities and 

impairments among children by adding MTBI-related questions to large, 

longitudinal studies. 

●	 Collaborate with the Defense and Veterans Head Injury Program to use 

their databases to determine the occurrence of MTBI-related disabilities. 

●	 Use existing TBI surveillance systems and registries to develop prospective follow-up studies to determine what percentage of persons 

with MTBI become disabled or experience persistent symptoms, and 

to improve linkage of brain-injury persons with appropriate services. 

Establishing the Natural History of 

MTBI-Related Impairments and Disabilities 

●	 Collaborate with the Defense and Veterans Brain Injury Program to 

use their databases to determine the natural history of MTBIs 

experienced by military personnel and to identify pre-existing,acute, 

and chronic factors that predict the likelihood of disabilities, impairments, and persistent symptoms. 

●	 Explore adding questions to longitudinal studies to track the evolution 

of impairments, functional limitations, disabilities, and persistent 

symptoms associated with MTBI. 

●	 Support the development of state-based TBI registries with the ability 

to track acute MTBI cases longitudinally. 

●	 Develop methods to determine how pre-injury and post-injury conditions 

affect MTBI outcomes. 

●	 Research how symptoms and their resolution relate to the presence of 

biological markers. 
5 

Documenting the Prevalence of 

Individuals with MTBI-Related Disabilities 

in Special Populations 

The Methods Subgroup determined that information about special populations 

(e.g., persons in mental health institutions and educational settings) is not of sufficient 

quantity or quality to recommend MTBI surveillance methods at this time. They recommended that stakeholders coordinate activities to promote research and standardize data 

collection instruments and methods. 

Conclusion 

Evidence indicates that MTBI is a public health problem, the magnitude and impact of 

which are underestimated by current surveillance systems. Much research is needed to 

determine the full magnitude of MTBI, to identify preventable and modifiable risk 

factors, and to develop and test strategies to reduce MTBIs and to improve outcomes 

for those who sustain these injuries. Such research will inform the development of more 

effective primary prevention strategies and policies to address the service and rehabilitation needs of persons with MTBI. The recommendations in this report can help shape 

that research. 

7 

Introduction 

Mild Traumatic Brain Injury: 

Signs, Symptoms, and Diagnosis 

Historically, clinicians and investigators have classified traumatic brain injury as mild, 

moderate, and severe by using the scores of the Glasgow Coma Scale, a widely-used 

scoring system to assess coma and impaired consciousness (Teasdale and Jennett 1974; 

Rimel, Giordani, Barth, et al. 1981, 1982). Patients with scores of 8 or less are classified 

as “severe”; scores of 9 to 12 are “moderate”; and scores of 13 to 15 are “mild.” 

Mild traumatic brain injury or MTBI—also called concussion, minor head injury, minor 

brain injury, minor head trauma, or minor TBI (Rimel, Giordani, Barth, et al. 1981; 

Tellier, Della Malva, Cwinn, et al. 1999; Rutherford 1989)—is one of the most common 

neurologic disorders (Kurtzke and Jurland 1993). It occurs when an impact or forceful 

motion of the head results in a brief alteration of mental status, such as confusion or 

disorientation, loss of memory for events immediately before or after the injury, or brief 

loss of consciousness. In contrast, more severe traumatic brain injuries are associated 

with extended periods of unconsciousness (more than 30 minutes), prolonged posttraumatic amnesia (more than 24 hours), or penetrating skull injury. Although the 

distinction between MTBI and more severe TBI seems straightforward, establishing 

definitive, measurable criteria to identify and quantify the occurrence of MTBI has 

proven challenging because clinicians and investigators have been using different 

diagnostic criteria and methodologies to study this condition (Ruff and Jurica 1999; 

American Congress of Rehabilitation Medicine 1993). 

A variety of radiological and laboratory techniques have been used to diagnose TBI, 

including X-rays of the skull, computed tomography of the brain, MRI (magnetic resonance imaging), and SPECT (single photon emission computed tomography) (De Kruijk, 

Twijnstra and Leffers 2001; Bigler and Snyder 1995). To monitor the severity of brain 

damage, several biological markers, such as Serum S-100, that indicate damage to brain 

cells are under investigation (De Kruijk, Twijnstra and Leffers 2001; Ingebrigtsen, 

Romner, Marup-Jensen, et al. 2000). Although these imaging and laboratory techniques 

help to rule out more serious TBIs, some patients with MTBI do not present abnormalities, or the markers are not sensitive enough to accurately diagnose the condition 

(De Kruijk, Twijnstra and Leffers 2001; Ingebrigtsen, Romner, Marup-Jensen, et al. 

2000). Thus, additional research is needed about using these and other more advanced 

techniques to accurately diagnose MTBI. 
8 

Consequences of Mild Traumatic Brain Injury 

People with MTBI and their health care providers may fail to recognize the potential 

severity of a brief period of unconsciousness or memory loss caused by a blow to the 

head (Alexander 1995; Swift and Wilson 2001). Many individuals with MTBI do not 

receive medical care at the time of the injury and may later present to their primary care 

physician days, weeks, or even months after the injury with complaints of persistent 

symptoms (Alexander 1995; Kushner 1998). 

A person with MTBI may manifest brief symptoms or experience persistent and disabling problems (Kushner 1998). The clinical consequences of such an injury can, for 

example, affect one’s ability to return to work and complete routine, daily activities. In 

one study, employed persons who were hospitalized for MTBI lost an average of nearly 

four weeks of work after injury (Binder, Rohling and Larrabee 1997). Other researchers 

reported unemployment rates among previously employed MTBI victims of 34 percent 

at 3 months and 9 percent at 12 months after injury (Rimel, Giordani, Barth, et al. 1981; 

Guthkelch 1980). Also, people with MTBI may return to work despite incomplete 

recovery (Russell 1971). 

Despite widespread agreement that MTBI may be associated with substantial neuropsychological problems, there is disagreement about how often and for how long such 

problems persist. Some researchers suggest that pre-injury factors such as age, alcohol 

abuse, educational level, and neuropsychiatric history, and post-injury factors such as 

stress, litigation, and compensation claims may affect the recovery of persons with 

MTBI and contribute to their disabilities (Kibby and Long 1996). However, findings 

in the literature are inconsistent, possibly resulting from study design limitations 

(Bernstein 1999) such as the lack of a control group and the absence of a standard 

definition for MTBI (Culotta, Sementilli, Gerold and Watts 1996; Dikmen and 

Levin 1993). 

Knowledge about the natural clinical history of MTBI is incomplete. Impaired attention, 

concentration, information processing speed, and memory are the most common, persistent complaints following MTBI; others include headaches, dizziness, nausea, fatigue, 

and emotional problems such as impulsiveness and mood swings (Barth, Macciocchi, 

Giordani, et al. 1983; Bohnen, Twijnstra and Jolles 1992; Alves, Macciocchi and Barth 

1993; Macciocchi, Barth and Littlefield 1998). However, these symptoms are not specific to MTBI and commonly occur in the general population (Barsky and Borus 1999; 

Wessely, Nimnuan and Sharpe 1999; Iverson and McCracken 1997). Moreover, considerable variability exists in the frequency with which persons with MTBI report post-injury 

complaints (Steadman and Graham 1970; Rutherford, Merrett and McDonald 1978; 
9 

Alves, Macciocchi and Barth 1993; Bohnen, Twijnstra and Jolles 1992; Deb, Lyons 

and Koutzoukis 1998). The lack of certainty about out-comes suggests a need for 

follow-up studies to assess the prevalence of symptoms and disabilities in representative 

populations. 

The Burden of All Traumatic Brain Injury 

in the United States 

TBI, including all levels of severity, is a major cause of death and life-long disability 

in the United States. Each year, an estimated 1.5 million Americans sustain a TBI 

(Sosin, Sniezek and Thurman 1996); 50,000 die from these injuries; and 80,000 to 

90,000 experience onset of long-term disability (CDC 1999). An estimated 5.3 million 

Americans live with a permanent TBI-related disability today (CDC 1999). 

Magnitude of Mild Traumatic Brain Injury 

in the United States 

Of the 1.5 million people who survived a TBI, 392,000 (25 percent) were hospitalized; 

543,000 (35 percent) were treated in emergency departments (EDs) and released; 

221,000 (14 percent) were treated in clinics and physicians’ offices; and 381,000 

(25 percent) did not receive medical care (Sosin, Sniezek and Thurman 1996). Of those 

who were hospitalized, 146,000 stayed in the hospital for only one night. These data 

suggest that as many as 75 percent of traumatic brain injured persons sustain mild traumatic brain injury (MTBI). Using hospital and ED data, the TBI Surveillance Program of 

the South Carolina Department of Health (SC DOH) identified 56,780 new cases of TBI 

in the state from 1996 to 2000. Of them, 86 percent (49,099) were mild injuries; of these, 

85 percent were identified through ED surveillance (Table 1, page 10). Both national 

surveillance systems and the SC DOH data underestimate the occurrence of TBI because 

they do not include injured people who received medical care in other facilities, such as 

outpatient clinics, or those who received no medical care for their injuries. 

The incidence of MTBI in EDs appears to have increased—almost doubling from 

216 per 100,000 in 1991 (Sosin, Sniezek and Thurman 1996) to 392 per 100,000 in 

1995–1996 (Guerrero, Thurman and Sniezek 2000). In contrast, MTBI hospitalizations 

appear to have declined from 130 per 100,000 to 51 per 100,000 between 1980 and 1994 

(Thurman and Guerrero 1999). These findings may reflect changes in hospital practices 

that shift the care of persons with less severe forms of TBI from hospital inpatient care 

to ED and outpatient treatment. Such changes indicate a growing need to document and 

study MTBIs treated in EDs and outpatient settings. 
10 

Table 1. Frequency and Distribution (Percent) of Traumatic Brain Injury 

in South Carolina by Severity and Level of Care, 1996–2000 

Level of Care

Injury Severity EDs Only Hospitalization Total 

Mild TBI 41,734

(85 percent)

 7,365 

 (15 percent) 

49,099 

(100 percent) 

Moderate and

Severe TBI

 — 7,681 

 (100 percent)

7,681 

 (100 percent) 

TOTAL 41,734

(74 percent)

 15,046 

 (26 percent) 

56,780 

(100 percent) 

Source: Selassie A. 1996–2000 South Carolina Department of 

Health Traumatic Brain Injury Surveillance Program. 

Unplublished Data. 

Mild Traumatic Brain Injury: Special Considerations 

We need to further explore issues related to MTBI among children and among sports 

participants. Very few population-based studies have examined MTBI among children 

(Kraus, Fife and Conroy 1987). However, existing data indicate that the rates of hospital 

admissions and ED visits for head injuries are several times higher among children than 

the general adult population (Jennett 1996), with the highest rates among children under 

age five (Beattie 1997) and among children in lower socioeconomic groups (Adelson and 

Kochanek 1998). Further research is needed to assess the magnitude of MTBI among this 

population and to guide prevention efforts. 

Sports-related injuries accounted for 20 percent (306,000) of the 1.5 million TBIs in 

the United States in 1991 (Sosin, Sniezek and Thurman 1996). Of persons with sportsrelated TBI, 12 percent (35,000) were hospitalized; 55 percent (168,000) received outpatient care only; and 34 percent (103,000) received no medical care (Sosin, Sniezek 

and Thurman 1996; Thurman, Branche and Sniezek 1998). These data suggest that 

most sports-related traumatic brain injuries fall into the mild or moderate category. 

While it is important to the health of children to be physically active, we must further 

investigate the relationship that sports may pose on the injuries one incurs, especially 

if the injury occurs at a young age. 
11 

Economic Burden of Mild Traumatic Brain Injury 

Max and colleagues (1991) analyzed U.S. incidence and cost data for all TBIs that 

resulted in hospitalization or death in 1985. MTBI accounted for $16.5 billion or 

44 percent of the estimated total lifetime cost ($37.8 billion) of TBIs that year. CDC 

updated these estimates using incidence data from 1995 and adjusting for inflation to 

yield an estimated total cost of $56 billion, $16.7 billion of which was for MTBI 

(Thurman 2001). For several reasons, this figure underestimates the economic burden 

MTBI poses on the United States. First, it does not include injuries treated in EDs; this 

omission is significant, given the decreasing trend to hospitalize persons with TBI. 

Additionally, it excludes injured persons treated in other, non-hospital medical care 

settings, such as private physicians’ offices; the costs of lost productivity and lost 

quality of life; and indirect costs borne by family members and friends who care for 

persons with MTBI. Because our knowledge about the current cost to society from TBI 

and MTBI is limited (Thurman 2001), these additional costs need to be quantified and 

need to be studied to address the impact of the changes in health care practices that 

shifted the care of less severe forms of TBI from inpatient care to ED and outpatient 

treatment and follow-up (Thurman and Guerrero 1999). 

Limitations in Defining the Problem of

Mild Traumatic Brain Injury in the United States

MTBI has been studied in great detail from a clinical perspective, by looking at its signs, 

symptoms, and management, mainly among hospitalized patients. Few studies have 

described the magnitude and impact of MTBI from a population perspective that includes 

persons who are not hospitalized (Kraus, McArthur and Silberman 1994). 

Complicating efforts to establish true measures of this problem are a lack of an accepted, 

standard definition for MTBI; a limited understanding of the consequences of MTBI; 

and inadequate methods of collecting data about MTBI and its outcomes (Kraus, 

McArthur and Silberman 1994). 

Lack of a Standard Definition 

Definitions of MTBI used by clinicians and investigators vary significantly (Culotta, 

Sementilli, Gerold and Watts 1996; Dikmen and Levin 1993). The current CDC case 

definition used for TBI surveillance activities is designed to identify cases of TBI that 

are treated in hospitals—cases that tend to be more severe. To address this limitation, 

CDC recognizes a need for standard surveillance case definitions to assist in identifying 

new MTBI cases and cases with impairments, functional limitations, disabilities, or 

persistent symptoms. 
12 

Limited Understanding of Consequences of MTBI 

Many health care providers fail to recognize the potential impact of MTBI (Alexander 

1995; Kushner 1998; Swift and Wilson 2001). Greater awareness of the problems experienced by persons with MTBI is needed to improve recognition of the condition, to reduce 

the extent of MTBI-related disability, and to ensure that injured persons get the services 

they need to allow them to resume their societal roles. 

Limitations in Surveillance 

Currently, most TBI surveillance relies on hospitalization data; only a few states conduct 

ED-based surveillance.1 With hospitalization rates for cases of MTBI declining and more 

patients with these injuries receiving care in EDs or non-hospital settings, traditional 

inpatient, hospital-based surveillance identifies only a small percentage of persons with 

MTBI. Moreover, current surveillance does not capture data about persons who receive 

no medical care (Thurman and Guerrero 1999). 

Neither hospital discharge nor ED data can estimate the number of individuals living 

with the consequences of MTBI or determine the full spectrum of long-term symptoms 

and disabilities associated with this type of injury. Some studies have attempted to 

assess prognosis and sequelae of MTBI. However, because these studies were conducted 

in small, selected clinical samples using different methodologies, their findings cannot 

be generalized to the U.S. population (Dikmen and Levin 1993; Bohnen, Twijnstra and 

Jolles 1992). 

Accurate estimates of the prevalence of MTBI-related impairments, functional limitations, disabilities, and persistent symptoms require follow-up assessments among 

representative samples of the brain-injured population after recovery from the acute 

phase of injury: for example, three months, six months, and one year or longer after 

injury. However, population-based studies of MTBI prevalence may have substantial 

limitations. For example, attrition (number of persons lost to follow-up during a study) 

is likely to increase as the follow-up interval increases. Also, detailed or face-to-face 

examinations to assess neurological impairments common after MTBI may be impractical for large, population-based samples; the amount and quality of disability-related 

information gathered might be limited by necessary cost-saving methods such as telephone interviewing. Research is needed to address these issues that make it difficult to 

estimate the prevalence of disabilities resulting from MTBI. 

1CDC funds 12 states to conduct hospital dischargebased TBI surveillance and 2 states to conduct 

ED-based TBI surveillance. 
13 

Formation and Objectives

of the CDC

Mild Traumatic Brain Injury Work Group

To address the challenges outlined previously and to meet the objectives set by Congress 

in the Children’s Health Act of 2000, CDC formed the Mild Traumatic Brain Injury 

(MTBI) Work Group, composed of 17 external experts from diverse fields, including 

epidemiology, neurology, neurosurgery, neuropsychology, statistics, and an organization 

representing the brain injury community. The Work Group’s objectives were as follows: 

● Recommend standard MTBI surveillance case definitions to help detect: 

◆	 Persons receiving medical care for MTBI in hospitals, EDs, or other 

health care settings; 

◆ Persons experiencing MTBIs who do not receive immediate medical care; 

◆	 Persons who experience MTBI-related impairments, functional limitations, 

disabilities, or persistent symptoms. 

●	 Recommend the best ways to measure the incidence ofacute cases of MTBI 

among persons who: 

◆ Receive inpatient hospital care; 

◆ Receive treatment in EDs or other outpatient settings; 

◆ Do not receive immediate medical care. 

●	 Recommend the best ways to assess the prevalence of persons experiencing 

long-term impairments, functional limitations, disabilities, or persistent 

symptoms resulting from MTBI. 

●	 Recommend approaches to better establish the natural clinical history of 

MTBI-related impairments, functional limitations, disabilities, and persistent 

symptoms. 

●	 Recommend approaches to identify prevalence of MTBI-related impairments, 

functional limitations, disabilities, and persistent symptoms among special 

populations, including persons in school, special education classes, mental 

health institutions, and prisons. 
14 

To achieve these objectives, the Work Group was divided into the MTBI Surveillance 

Case Definition Subgroup (the Definitions Subgroup) and the MTBI Surveillance 

Methods and Database Subgroup (the Methods Subgroup). As a foundation for the 

subgroups’ activities, CDC conducted a systematic literature review that found more 

than 400 articles relevant to MTBI to be reviewed by subgroup members. 

Definitions Subgroup 

The Definitions Subgroup reviewed key literature from 1980 to 2001 to summarize 

clinical case definitions and diagnostic criteria for MTBI as a foundation for developing 

a conceptual definition of MTBI and for formulating operational definitions for important 

surveillance measures, such as incidence of medically-treated and non-treated cases and 

prevalence of disabilities. 

Methods Subgroup 

The Methods Subgroup reviewed key literature and data to identify potential surveillance 

databases and surveys to gather data about MTBI and its consequences. Subgroup members interviewed experts on databases and surveillance and evaluated systems using 

standard public health surveillance criteria (Teutsch 2000; CDC 2001); a summary of 

the evaluation criteria is found in Appendix B. They considered validity and reliability 

of data in making final recommendations. They also reviewed information about special 

populations, such as persons in school, special education classes, mental health institutions, and prisons. 
15 

Findings and Recommendations

of the CDC

Mild Traumatic Brain Injury Work Group

The subgroups met twice per month by teleconference from June 2001 to November 2001 

to share information and to develop a plan for producing the Report to Congress. In late 

November 2001, the MTBI Work Group met with CDC staff in Atlanta to review findings and to formulate recommendations. 

Definitions Subgroup Findings and Recommendations 

The Definitions Subgroup found wide variation in the clinical case definitions and 

criteria used to identify MTBIs. As a foundation for developing operational definitions 

for MTBI, the subgroup developed conceptual definitions. 

A conceptual case definition provides criteria to identify a case of MTBI for surveillance purposes based on selected clinical signs, symptoms, and neuroimaging. This 

definition is necessary as a reference standard for the evaluation of operational or 

working definitions of MTBI used by surveillance systems. 

An operational case definition provides quantifiable criteria to consistently identify 

cases of MTBI for surveillance purposes when reviewing coded health care administrative databases, abstracting information from medical records, or analyzing data from 

surveys and personal interviews. Operational definitions should be designed to approximate the conceptual definition as closely as possible. 

The Definitions Subgroup used the Traumatic Brain Injury (TBI) definition found in 

CDC’s Guidelines for Surveillance of Central Nervous System Injury (Thurman, Sniezek, 

Johnson, Greenspan and Smith 1995) as the foundation for its definitions. However, that 

definition does not categorize injuries by severity and is not well suited for surveillance 

of less severe injuries that may not be treated in hospital settings. 

The recommended definitions for MTBI were developed with the following premises 

in mind: 

●	 TBI severity refers to the degree of brain trauma as it is assessed during 

the acute phase of injury. TBI severity assessment focuses on acute signs 

and symptoms indicating brain pathophysiology. 
16 

●	 TBI severity should be distinguished from TBI outcome (Dikmen and 

Levin 1993). Assessment of TBI outcome focuses on subacute or chronic 

signs and symptoms related to impairment and disability. TBI outcome is 

most relevant to measures of TBI prevalence. 

●	 Major criteria for distinguishing levels of TBI severity are based primarily 

on the immediate effects of TBI on consciousness or cognition. In addition, 

focal signs and intracranial pathology (demonstrable on neuroimaging 

studies such as computed tomography) are considered. 

●	 An incident case should meet either conceptual or operational definition 

criteria within the surveillance period. 

●	 Some criteria for distinguishing grades of severity await further clinical 

study and more conclusive evidence. 

Recommended Conceptual Definition of 

Incident Cases of MTBI 

A case of MTBI is an occurrence of injury to the head resulting from blunt trauma or 

acceleration or deceleration forces with one or more of the following conditions attributable to the head injury during the surveillance period: 

●	 Any period of observed or self-reported transient confusion, disorientation, 

or impaired consciousness; 

●	 Any period of observed or self-reported dysfunction of memory (amnesia) 

around the time of injury; 

●	 Observed signs of other neurological or neuropsychological dysfunction, 

such as— 

◆ Seizures acutely following head injury; 

◆	 Among infants and very young children: irritability, lethargy, or 

vomiting following head injury; 

◆	 Symptoms among older children and adults such as headache, dizziness, 

irritability, fatigue, or poor concentration, when identified soon after injury, 

can be used to support the diagnosis of mild TBI, but cannot be used to 

make the diagnosis in the absence of loss of consciousness or altered consciousness. Further research may provide additional guidance in this area. 

●	 Any period of observed or self-reported loss of consciousness lasting 

30 minutes or less. 
17 

More severe brain injuries were excluded from the definition of MTBI and include one 

or more of the following conditions attributable to the injury: 

● Loss of consciousness lasting longer than 30 minutes; 

● Post-traumatic amnesia lasting longer than 24 hours; 

● Penetrating craniocerebral injury. 

A wide range of severity and the possibility of further gradation exists within this definition. The Definitions Subgroup identified additional criteria that may further distinguish 

degrees of severity within the spectrum of mild TBI. Under this recommended definition, 

TBI cases with intracranial lesions demonstrated by neuroimaging studies (e.g., computed tomography) or with focal neurological deficits (e.g., hemiplegia) may still be 

considered mild if the criteria described previously are met. Some evidence, although 

inconsistent, indicates that such cases may have poorer outcomes (Williams, Levin and 

Eisenberg 1990; Dikmen and Temkin, unpublished data, 2001). To the extent allowed 

by data sources, TBI surveillance systems and epidemiological studies should obtain 

information about the presence of intracranial lesions, focal findings, and duration of 

unconsciousness in reported cases. Mild TBI cases with such abnormalities should be 

distinguished from cases without them in analyses of MTBI outcome. The value of such 

findings to predict outcome may be better defined by future research. 

Recommended Operational Definitions of 

Incident Cases of MTBI 

Three operational definitions are recommended for case ascertainment based on 

interviews and surveys; health care administrative data sets, such as hospital billing 

data; and clinical records, such as hospital medical record reviews or trauma registry 

data. 

Interview/survey definition 

A case of MTBI is recognized when a person surveyed or interviewed (or his or her 

proxy respondent) affirms the occurrence, within the period under surveillance, of a 

nonfatal injury to the head that is accompanied by: 

● Criteria consistent with the recommended conceptual case definition (above); 

● Loss of consciousness or altered consciousness; 

● Loss of memory for events immediately before, during, or after the injury. 
18 

Surveys and interviews should ask whether health care professionals evaluated such 

injuries and, if so, what level of care was received. Where possible, analyses of data 

should distinguish between injuries receiving no medical care, non-hospital-based care, 

hospital ED care, inpatient hospital care of 24 hours or less, and inpatient hospital care 

of more than 24 hours. Occurrences of brain injury with inpatient hospital care of more 

than 24 hours may be classified as more severe (i.e., they do not meet the criteria for 

MTBI). 

Administrative data definition for surveillance or research (ICD-9-CM) 

A case of MTBI is recognized among persons treated in health care facilities who are 

assigned the following ICD-9-CM diagnostic codes (International Classification of 

Diseases 1989): 

ICD-9-CM First Four Digits = 

800.0, 800.5, 801.0, 801.5, 

803.0, 803.5, 804.0, 804.5, 

850.0, 850.1, 850.5 or 850.9 

854.0 

959.0* 

ICD-9-CM Fifth Digit = 

0, 1, 2, 6, 9, or Missing 

1, 2, 6, 9, or Missing 

1 

*The current inclusion of code 959.01 (i.e., head injury, unspecified) 

in this definition is provisional. Although a recent clarification in the 

definition of this code is intended to exclude concussions, there is 

evidence that nosologists have been using it to code TBIs. Accordingly, 

this code may be removed from the recommended definition of mild 

TBI when there is evidence that in common practice nosologists no 

longer assign this code for TBI. 

The codes in this table represent one possible approach for identifying MTBI using 

ICD-9-CM codes obtained from administrative records. Research is needed to determine 

the reliability and validity of these codes for defining MTBI. The full range of ICD-9-

CM codes consistent with TBI of any severity is published in the CDC Guidelines for 

Surveillance of Central Nervous System Injury (Thurman, Sniezek, Johnson, Greenspan 

and Smith 1995). 
19 

Clinical records data definition 

A case of MTBI is recognized when medical records document any one of the following: 

● Criteria consistent with the recommended conceptual case definition (page 16); 

●	 Glasgow Coma Scale (GCS) score between 13 and 15 assigned at the time 

of first medical evaluation at a health care facility (Teasdale and Jennett 

1974; 1976);2 

●	 Abbreviated Injury Severity (AIS) Scale score of 2 for the head region 

(Association for the Advancement of Automotive Medicine 1998). 

Injuries accompanied by indicators of neurological deterioration during the course of 

acute care, such as cases in which subsequent GCS scores fall below 13 are excluded. 

Recommended Conceptual Definition of Prevalent Cases 

of MTBI-Related Impairments, Functional Limitations, 

Disabilities, and Persistent Symptoms 

A prevalent case of MTBI-related impairment, functional limitation, disability, or 

persistent symptoms is recognized among persons with a history of MTBI who are 

experiencing any degree of neurological or neuropsychological problem attributable 

to the MTBI. 

Recommended Operational Definitions of Prevalent Cases 

of MTBI-Related Impairments, Functional Limitations, 

Disabilities, and Persistent Symptoms 

Measuring the prevalence of MTBI-related impairments, functional limitations, disabilities, and persistent symptoms requires follow-up assessments after recovery from 

the acute phase of injury: for example, at three months, six months, and one year or 

longer after injury. Follow-up studies of representative samples of persons who 

2 The Glasgow Coma Scale is widely used in clinical practice to distinguish degrees of 

TBI severity. The routine recording of GCS scores by clinicians and the collection of 

GCS data by surveillance systems are strongly recommended. 

Among children under 36 months, a pediatric coma scale can be used. Some scales are 

intended to approximate the GCS, with a score of 13 to 15 indicating a mild injury. See 

Hahn YS, Chyung C, Barthel MJ, et al. Head injuries in children under 36 months of 

age: demography and outcome. Child’s Nervous System 1988;4:34–40. See also 

Simpson DA, Cockington RA, Hanieh A, et al. Head injuries in infants and young 

children: The value of the pediatric coma scale. Review of the literature and report on 

a study. Child’s Nervous System 1991;7:183–90. 
20 

experience MTBI are needed to generate accurate estimates of prevalence. To date, most 

follow-up studies have focused on persons who have been hospitalized for TBI and 

whose injuries were more severe. Follow-up studies should include persons with less 

severe injuries and those who were not hospitalized for their TBI; the prevalence of 

TBI-related disability is assumed to be lower in this population. 

No widely accepted, standard assessment tool currently exists to identify prevalent cases 

of MTBI-related impairment, functional limitation, disability, and persistent symptoms 

in population-based surveys. CDC proposes the following limited criteria for constructing an operational definition for such surveys, when respondents are persons with a 

history of MTBI or reliable proxy respondents: 

●	 Current symptoms reported consequent to MTBI not present before injury or


those made worse in severity or frequency by the MTBI:


◆ Problems with memory


◆ Problems with concentration


◆ Problems with emotional control


◆ Headaches


◆ Fatigue


◆ Irritability


◆ Dizziness


◆ Blurred vision


◆ Seizures


● Current limitations in functional status reported consequent to MTBI: 

◆	 Basic activities of daily living (e.g., personal care, 

ambulation, travel) 

◆ Major activities (e.g., work, school, homemaking) 

◆ Leisure and recreation 

◆ Social integration 

◆ Financial independence 

Most of these symptoms and limitations are associated with many other conditions in 

addition to MTBI. This lack of specificity for MTBI places some limitations on the 

validity of studies of the prevalence of MTBI-related impairments, functional limitations, 

disabilities, and persistent symptoms. However, these limitations may be minimized by 
21 

appropriate selection of comparison groups and cautious interpretation of findings, and 

by assessing pre- and post-injury symptom occurrence. If pre-existing symptoms cannot 

be “attributable” to the MTBI, these data should also be documented for further study 

and interpretation. 

Methods Subgroup Findings and Recommendations 

The Methods Subgroup reviewed a wide range of databases and surveys to identify 

those that would be most appropriate for measuring the incidence of MTBI; to determine 

the prevalence of MTBI-related impairments and disabilities; to determine underlying 

causes of MTBIs; and to identify population groups at risk regardless of age. Most of 

these databases and surveys were set up largely to provide information about other 

medical issues, but together, and with additional questions added, they can provide a 

more complete picture of MTBI. To obtain data on the incidence and prevalence of 

MTBI, established methods such as hospital emergency department- and hospital-based 

data collection and analysis should be the first priority. As resources and capacity will 

allow, the other methods provided in this report can serve as additional sources of good 

information. A summary of the subgroup’s review and findings follows. 

Detection and Surveillance of New Cases (Incidence) 

of Medically-Treated MTBI 

In making recommendations for measuring the incidence of medically-treated MTBIs, 

the Methods Subgroup was primarily concerned with including data sources that are 

accessible, valid, and reliable. The recommendations focused largely on enhancing 

capabilities to conduct TBI surveillance in emergency departments (EDs), because 

many more MTBIs are diagnosed and treated in EDs than in hospital inpatient settings 

and because such ED data systems already exist in some states and at the national level. 

However, the subgroup also recognized the need to improve surveillance of hospitalized 

cases of MTBI. Specific recommendations include: 

Priority Recommendations to Obtain Data on the 

Incidence and Prevalence of MTBI 

●	 Increase the number of states conducting ED-based TBI surveillance using 

the South Carolina Department of Health (SC DOH) TBI Surveillance 

Program as a model. 
22 

●	 Routinely analyze data from CDC’s National Hospital Ambulatory Medical 

Care Survey (NHAMCS) and National Ambulatory Medical Care Survey 

(NAMCS) to estimate incidence of, study external causes related to, and 

identify trends in MTBIs treated in, outpatient settings. 

●	 Increase the number of states conducting MTBI surveillance using hospital 

discharge data. 

●	 Consider using large, national hospital discharge databases, such as the Nationwide Inpatient Sample database [conducted by the Agency for Health Care 

Research and Quality (AHRQ)/Healthcare Cost and Utilization Project (HCUP)] 

that have not been used previously for injury surveillance. 

●	 Explore using data from the National Electronic Injury Surveillance System 

(NEISS) to assess the incidence and external causes of MTBI in the United 

States among persons treated in EDs. 

Additional Recommendations 

●	 Routinely analyze data collected by CDC’s National Health Interview 

Survey (NHIS) to estimate the incidence of MTBI among persons who 

receive medical care outside of hospitals and hospital EDs. 

●	 Analyze data from the National Collegiate Athletic Association Injury 

Surveillance System (NCAAISS) to assess the incidence of MTBI among 

participants in selected college sports. 

●	 Apply the recommended operational definition of MTBI to enhance the 

capability of current CDC-funded state TBI Surveillance Systems and 

other national and state hospital discharge databases to detect and monitor 

MTBI incidence. 

●	 Routinely analyze data from the National Hospital Discharge Survey 

(NHDS) to assess hospitalization patterns due to MTBI. 

●	 Collaborate with the Defense and Veterans Head Injury Program to use 

use their database and the Defense and Medical Surveillance System 

databases to determine the occurrence of MTBI in these systems. 
23 

Detection and Surveillance of New Cases (Incidence) 

of MTBI Not Receiving Medical Care 

Measuring the incidence of MTBIs that are not treated medically is difficult because the 

injuries are not documented in any routinely-collected health information system. To the 

extent possible, the Methods Subgroup considered ways to add modules to existing 

surveys or studies. Specific recommendations include the following: 

●	 Explore adding MTBI-related questions to large, existing state-based 

surveys, such as those conducted through CDC’s Behavioral Risk Factor 

Surveillance System (BRFSS) and Youth Risk Behavior Surveillance 

System (YRBSS). 

●	 Explore adding a module to CDC’s National Health Interview Survey 

(NHIS) to study the incidence, external causes, and the consequences 

of MTBI among persons in the community, including those who did 

not receive medical care. 

●	 For a sample of individuals self-reporting the receipt of medical care as a 

result of MTBI (identified via NHIS-DS and BRFSS), special follow-up 

studies with health care providers will be considered to determine the 

accuracy of self-reporting. 

Identifying and Assessing Prevalent Cases of 

MTBI-Related Impairment, Functional Limitation, 

Disability, and Persistent Symptoms 

Identifying individuals disabled by the effects of a MTBI presents a challenge not only 

because they are not routinely documented in current health information systems, but 

also because many of the impairments, functional limitations, disabilities, and persistent 

symptoms experienced by persons with MTBI, may result from other conditions. Most 

existing health information systems and surveys are inadequate for this type of surveillance. Thus, documenting who and how many people are disabled by MTBI-related 

problems will be more costly than the surveillance and study of acute, medically-treated 

cases. With these considerations in mind, the Methods Subgroup recommended the 

following: 

●	 Explore adding MTBI-related questions to existing surveys, such as the 

National Health Interview Survey–Disability Supplement (NHIS-DS), to 

determine the prevalence of individuals with MTBI-related functional and 

cognitive impairments or disabilities. 
24 

●	 Determine the feasibility of adding MTBI disability questions to state-based 

surveillance systems or surveys, such as BRFSS. 

●	 For a sample of individuals self-reporting the receipt of medical care as a 

result of MTBI (identified via NHIS-DS and BRFSS), special follow-up 

studies with health care providers should be considered to determine the 

accuracy of self-reporting. 

●	 Consider determining the occurrence of MTBI-related disabilities and 

impairments among children by adding questions to large, longitudinal 

studies such as the 30-year follow-up National Children’s Study 

(http://nationalchildrensstudy.gov). 

●	 Collaborate with the Defense and Veterans Head Injury Program to use 

their database and the Defense and Medical Surveillance System databases to determine the occurrence of MTBI-related disabilities. 

●	 Use existing TBI surveillance systems and registries to develop prospective 

follow-up studies to determine what percentage of persons with MTBI 

become disabled or experience persistent symptoms, to identify which cases 

receive appropriate services, and to link brain-injured persons with appropriate 

rehabilitation support and other services. 

Establishing the Natural History of 

MTBI-Related Disabilities and Impairments 

Health care providers need a better understanding of the progression of acute injury into 

long-term disability to identify brain-injured persons at greatest risk for lasting problems 

and to determine when to intervene to ensure the best possible outcomes. This knowledge 

will be gained through studying patients with MTBI over time. To this end, the Methods 

Subgroup focused on using existing or proposed databases and studies capable of tracking MTBI cases from occurrence to two or more years after injury. Specific recommendations include the following: 

●	 Collaborate with the Defense and Veterans Head Injury Program to use their 

database to determine the natural history of MTBIs experienced by military 

personnel and to identify pre-existing, acute, and chronic factors that predict 

the likelihood of disabilities, impairments, and persistent symptoms. 

●	 Explore adding MTBI-related questions to longitudinal studies, such as the 

National Children’s Study to track the evolution of symptoms and disabilities 

associated with MTBI. 
25 

●	 Support the development of state-based TBI registries with the ability to 

track acute MTBI cases longitudinally. 

●	 Develop methods to determine the effects of pre-injury conditions, such 

as learning disabilities and psychiatric problems, and post-injury conditions 

and circumstances, such as depression, substance abuse, and compensation. 

The relationship of symptoms and their resolution to the presence of biological markers 

that may be developed in the future, is an important research question that also needs to 

be addressed. 

Documenting the Prevalence of Individuals with 

MTBI-Related Disabilities in Special Populations 

Documenting the prevalence of individuals impaired by MTBIs in special populations— 

such as those in school programs, mental health institutions, and prisons—is difficult for 

several reasons. First, there is a lack of standardized definitions for special populations. 

Second, no health data systems exist for these populations specifically. Finally, in many 

cases, no data of any kind exist about MTBI among these groups. For these reasons, the 

Methods Subgroup determined that information about special populations is not of 

sufficient quantity or quality to make recommendations at this time. Given the current 

knowledge in these areas, stakeholders should coordinate activities to promote research 

and to standardize data collection instruments and methods. 
26 

Conclusion 

Evidence indicates that MTBI is a public health problem, the magnitude and impact 

of which are underestimated by current surveillance systems. Much research is needed 

to determine the full magnitude of MTBI, to identify preventable and modifiable risk 

factors, and to develop and test strategies to reduce MTBIs and to improve outcomes 

for those who sustain these injuries. Such research will inform the development of more 

effective primary prevention strategies and policies to address the service and rehabilitation needs of persons with MTBI. The recommendations in this report can help 

shape that research. 

Already, the definitions of MTBI recommended in this report have received support 

from the public health community. The World Health Organization’s Task Force on 

Mild Traumatic Brain Injury reviewed the definitions, and, at the time this report 

was prepared, recommended that these definitions be used worldwide for surveillance 

purposes. This recommendation is an important first step in establishing acceptance of 

uniform definitions of MTBI. 
27 

References 

Adelson PD, Kochanek PM. Head injury in children. J Child Neurol 1998;13:2–15. 

Alexander MP. Mild traumatic brain injury: pathophysiology, natural history, and 

clinical management. Neurology 1995;45:1253–60. 

Alves W, Macciocchi SN, Barth JT. Postconcussive symptoms after uncomplicated 

mild head injury. J Head Trauma Rehabil 1993;8(3)48–59. 

American Congress of Rehabilitation Medicine. Definition of mild traumatic brain 

injury. J Head Trauma Rehabil 1993;8:86–8. 

Association for the Advancement of Automotive Medicine. The Abbreviated Injury 

Scale, 1990 Revision. Barrington (IL): (UpDate); 1998. 

Barsky AJ, Borus JF. Functional somatic syndromes. Ann Intern Med 1999;130:910–21. 

Barth JT, Macciocchi SN, Giordani B, Rimel R, Jane JA, Boll TJ. Neuropsychological 

sequelae of minor head injury. Neurosurgery 1983;13:529–33. 

Beattie TF. Minor head injury. Arch Dis Child 1997;77:82–5. 

Bernstein DM. Recovery from mild head injury. Brain Inj 1999;13:151–72. 

Bigler ED, Snyder JL. Neuropsychological outcome and quantitative neuroimaging 

in mild head injury. Arch Clin Neuropsychol 1995;10:159–74. 

Binder LM, Rohling ML, Larrabee GJ. A review of mild head trauma. Part I: 

Meta-analytic review of neuropsychological studies. J Clin Exp Neuropsychol 

1997;3:421–31. 

Bohnen N, Twijnstra A, Jolles J. Post-traumatic and emotional symptoms in different 

subgroups of patients with mild head injury. Brain Inj 1992;6:481–7. 

CDC. Traumatic brain injury in the United States: A Report to Congress. Atlanta (GA): 

Centers for Disease Control and Prevention, National Center for Injury Prevention and 

Control; 1999. 

CDC. Updated guidelines for evaluating public health surveillance systems. Recommendations from the guidelines working group. MMWR 2001;50(RR13):1–35. 
28 

Culotta VP, Sementilli ME, Gerold K, Watts CC. Clinicopathological heterogeneity in 

the classification of mild head injury. Neurosurgery 1996;38:245–50. 

Deb S, Lyons I, Koutzoukis C. Neuropsychiatric sequelae one year after a minor head 

injury. J Neurol Neurosurg Psychiatry 1998;65:899–902. 

De Kruijk JR, Twijnstra A, Leffers P. Diagnostic criteria and differential diagnosis of 

mild traumatic brain injury. Brain Inj 2001;15:99–106. 

Dikmen SS, Levin HS. Methodological issues in the study of mild head injury. 

J Head Trauma Rehabil 1993;8(3):30–7. 

Guerrero JL, Thurman DJ, Sniezek JE. Emergency department visits associated with 

traumatic brain injury: United States, 1995–1996. Brain Inj 2000;14:181–6. 

Guthkelch AN. Posttraumatic amnesia, postconcussional symptoms and accident 

neurosis. Eur Neurol 1980;19:91–102. 

Hahn YS, Chyung C, Barthel MJ, Bailes J, Flannery AM, McLone DG. Head injuries 

in children under 36 months of age: demography and outcome. Child’s Nerv Syst 1988; 

4:34–40. 

Ingebrigtsen T, Romner B, Marup-Jensen S, Dons M, Lundqvist C, Bellner J, et al. The 

clinical value of serum S-100 protein measurements in minor head injury: a Scandinavian 

multicentre study. Brain Inj 2000;14(12):1047–55. 

International Classification of Diseases, Ninth Revision, Clinical Modification, 3rd ed. 

(ICD-9-CM). Washington (DC): Department of Health and Human Services; 1989. 

Iverson GL, McCracken LM. ‘Postconcussive’ symptoms in persons with chronic pain. 

Brain Inj 1997;11:783–90. 

Jennett B. Epidemiology of head injury. J Neurol Neurosurg Psychiatry 1996;60:362–9. 

Kibby MY, Long CJ. Minor head injury: attempts at clarifying the confusion. 

Brain Inj 1996;10(3):159–86. Review. 

Kraus JF, Fife D, Conroy C. Pediatric brain injuries: the nature, clinical course, and 

early outcomes in a defined United States’ population. Pediatrics 1987;79:501–7. 

Kraus JF, McArthur DL, Silberman TA. Epidemiology of Mild Brain Injury. 

Semin Neurol 1994;14:1–7. 
29 

Kurtzke JF, Jurland LT. The Epidemiology of neurologic disease. In: Joynt RJ, editor. 

Clin Neurol, Rev. Philadelphia: JB Lippincott; 1993. 

Kushner D. Mild traumatic brain injury: toward understanding manifestations and 

treatment. Arch Intern Medicine 1998;158(15):1617–24. 

Macciocchi SN, Barth JT, Littlefield LM. Outcome after mild head injury. 

Clin Sports Med 1998;17(1):27–36. 

Max W, MacKenzie EJ, Rice DP. Head injuries: costs and consequences. 

J Head Trauma Rehabil 1991;6(2):76–91. 

Rimel RW, Giordani B, Barth JT, Boll TJ, Jane JA. Disability caused by minor head 

injury. Neurosurgery 1981;9:221–8. 

Rimel RW, Giordani B, Barth JT, Jane JA. Moderate head injury: completing the clinical 

spectrum of brain trauma. Neurosurgery 1982;11:344–51. 

Ruff R, Jurica P. In search of a unified definition for mild traumatic brain injury. 

Brain Inj 1999;3(12):943–52. 

Russell WR. The traumatic amnesias. London: Oxford University Press; 1971. 

Rutherford WH. Postconcussion symptoms: relationship to acute neurological indices, 

individual differences, and circumstances of injury. In: Levin HS, Eisenberg HM, 

Benton AL, editors. Mild Head Injury. New York: Oxford University Press; 1989. 

p. 217–28. 

Rutherford WH, Merrett JD, McDonald JR. Symptoms at one year following concussion 

from minor head injuries. Injury 1978;10:225–30. 

Simpson DA, Cockington RA, Hanieh A, Raftos J, Reilly PL. Head injuries in infants 

and young children: the value of the pediatric coma scale. Review of the literature and 

report on a study. Child’s Nerv Syst 1991;7:183–90. 

Sosin DM, Sniezek JE, Thurman DJ. Incidence of mild and moderate brain injury in 

the United States, 1991. Brain Inj 1996;10:47–54. 

Steadman JH, Graham JG. Head injuries: an analysis and follow-up study. 

Proc R Soc Med 1970;63:23–8. 
30 

Swift TL, Wilson SL. Misconceptions about brain injury among the general public and 

non-expert health professionals: an exploratory study. Brain Inj 2001;15:149–65. 

Teasdale G, Jennett B. Assessment of coma and impaired consciousness: a practical 

scale. Lancet 1974;2:81–4. 

Teasdale G, Jennett B. Assessment and prognosis of coma after head injury. 

Acta Neurochir (Wien) 1976;34:45–55. 

Tellier A, Della Malva LC, Cwinn A, Grahovac S, Morrish W, Brennan-Barnes M. 

Mild head injury: a misnomer. Brain Inj 1999;13:463–75. 

Teutsch SM. Considerations in planning a surveillance system. In: Teutsch SM, 

Churchill RE, editors. Principles and Practice of Public Health Surveillance. 2nd edition. 

New York: Oxford University Press; 2000. p. 17–29. 

Thurman DJ, Branche CM, Sniezek JE. The epidemiology of sports-related traumatic 

brain injuries in the United States: recent developments. J Head Trauma Rehabil 1998; 

13(2):1–8. 

Thurman D, Guerrero J. Trends in hospitalization associated with traumatic brain injury. 

JAMA 1999;282:954–7. 

Thurman DJ, Sniezek JE, Johnson D, Greenspan A, Smith SM. Guidelines for 

Surveillance of Central Nervous System Injury. Atlanta (GA): Centers for Disease 

Control and Prevention; 1995. 

Thurman DJ. The epidemiology and economics of head trauma. In: Miller L, Hayes R, 

editors. Head Trauma: Basic, Preclinical, and Clinical Directions. New York: John Wiley 

and Sons; 2001. 

Wessely S, Nimnuan C, Sharpe M. Functional somatic syndromes: one or many? 

Lancet 1999;354:936–9. 

Williams DH, Levin HS, Eisenberg HM. Mild health injury classification. 

Neurosurgery 1990;217(3):442–8. 
31 

Appendix A:

CDC Mild Traumatic Brain Injury

Work Group

Senior Editor 

Victor G. Coronado, M.D., M.P.H. 

Medical Epidemiologist


Division of Injury and Disability Outcomes and Programs


National Center for Injury Prevention and Control


Centers for Disease Control and Prevention


Atlanta, Georgia


Editor 

Bruce Jones, M.D., M.P.H. 

Acting Team Leader


Disability and Rehabilitation Team


Division of Injury and Disability Outcomes and Programs


National Center for Injury Prevention and Control


Centers for Disease Control and Prevention


Atlanta, Georgia


Executive Secretary 

Victor G. Coronado, M.D., M.P.H. 

Medical Epidemiologist


Division of Injury and Disability Outcomes and Programs


National Center for Injury Prevention and Control


Centers for Disease Control and Prevention


Atlanta, Georgia

32 

Definitions Subgroup 

Jeffrey J. Bazarian, M.D. 

Assistant Professor


University of Rochester Medical Center


Department of Emergency Medicine


Rochester, New York


Kathleen R. Bell, M.D. 

Associate Professor


Department of Rehabilitation Medicine


University of Washington Medical Center


Seattle, Washington


Jörgen Borg, M.D. 

Associate Professor, Neurology, Karolinska Institutet 

Head, Department of Rehabilitation Medicine 

Stockholm, Sweden 

Sureyya Dikmen, Ph.D. 

Professor, Department of Rehabilitation Medicine


Neurological Surgery and Psychiatry and Behavioral Sciences


University of Washington


Seattle, Washington


Jess F. Kraus, Ph.D., M.P.H. 

Director, Southern California Injury Prevention Research Center


UCLA School of Public Health


Los Angeles, California


Charles J. Long, Ph.D. 

Chair, Director, MS Graduate Psychology Program


Psychology Department


The University of Memphis


Memphis, Tennessee


David Thurman, M.D. 

Medical Epidemiologist


National Center for Chronic Disease Prevention and Health Promotion


Centers for Disease Control and Prevention


Atlanta, Georgia

33 

Methods Subgroup 

Robert C. Cantu, M.D. 

Medical Director


National Center for Catastrophic Sports Injury Research


University of North Carolina


Chief, Neurosurgery Service


Emerson Hospital


Concord, Massachusetts


J. David Cassidy, Ph.D. 

Associate Professor, Epidemiology and Medicine


Alberta Centre for Injury Control and Research


Department of Public Health Sciences


Faculty, Medicine and Dentistry


University of Alberta


Edmonton, Alberta, Canada


John D. Corrigan, Ph.D. 

Professor, Department of Physical Medicine and Rehabilitation


The Ohio State University


Columbus, Ohio


Virginia M. Lesser, Dr.P.H., M.S. 

Assistant Professor, Statistics 

Director, Survey Research Center 

Oregon State University 

Corvallis, Oregon 

Gregory O’Shanick, M.D. 

Co-Chair, U.S. Mild Traumatic Brain Injury (MTBI)


Guideline Development Work Group


National Medical Director, Brain Injury Association of America


Medical Director, Center for Neuro-Rehabilitation Services


Midlothian, Virginia

34 

Peter Patrick, Ph.D. 

Associate Professor, Clinical Pediatrics


School of Medicine, University of Virginia


Director, Pediatric Psychology/Neuropsychology


Children’s Medical Center


Kluge Children’s Rehabilitation Center


Charlottesville, Virginia


Karen Schwab, Ph.D. 

Assistant Director for Statistics


Defense and Veterans Head Injury Program


Department of Neurology


Walter Reed Army Medical Center


Gaithersburg, Maryland


Anbesaw W. Selassie, Dr.P.H. 

Chair, Department of Biometry and Epidemiology


Medical University of South Carolina


Charleston, South Carolina


Nancy Temkin, Ph.D. 

Associate Professor, Neurological Surgery and Biostatistics


Department of Neurological Surgery


University of Washington


Seattle, Washington


Barbara Weissman, M.D. 

Associate Professor Pediatrics (Neurology)


Emory University School of Medicine


Medical Director, Rehabilitation Services


Children’s Healthcare of Atlanta at Egleston


Medical Director, Day RehabilitationProgram


Children’s Healthcare of Atlanta


Atlanta, Georgia

35 

Appendix B:

Criteria Used to Evaluate Proposed,

Ongoing Surveillance Systems to

Identify Persons with

Mild Traumatic Brain Injury in the United States

The following criteria are summarized from CDC guidelines for evaluating public health

surveillance systems (CDC 2001).


Simplicity. Structure and ease of operating the surveillance system. Is the operational


case definition easy to apply? Are cases easily ascertained? How much time and how

many resources are or will be required to maintain the system?

Flexibility. System’s ability to adapt as information needs or operating conditions

change, given limited availability of personnel and/or funds.

Data Quality. Completeness and accuracy of the data collected. What is the

proportion of unknown and missing responses?

Acceptability. Willingness of the survey population to participate in the

surveillance system. What are the participation rates? What are the interview

completion rates and refusal rates?

Sensitivity. System’s ability to detect true cases of MTBI. What is the proportion

of cases detected? How well can the system track changes and trends over time?

Predictive Value Positive. Proportion of reported cases that actually experienced

the health event or have the health condition under surveillance.

Representativeness. Accuracy of a system to describe the occurrence of a health event

or condition under surveillance over time and its distribution in the population


by place and person.

Timeliness. Speed between steps in public health surveillance from the occurrence

of the event to feedback to clinicians, investigators, legislators, and the public.

Stability. System’s ability to collect, manage, and report data properly without failure.

37 

Appendix C:

Descriptions of Recommended

Mild Traumatic Brain Injury Databases

South Carolina Department of Health (SC DOH) 

TBI Surveillance System 

Characteristics: Statewide surveillance system conducted by the SC DOH with CDC 

funds since 1995 to characterize the epidemiology of TBI in this state. Targets all state 

residents, regardless of age, who receive health care in hospitals and in self-standing or 

hospital-based EDs. Data are abstracted from coded hospital discharge and ED administrative databases. Medical records are reviewed for a sample. Data are unduplicated 

(thus, it is a true patient-level). Coded mortality data is also collected. It requires 

$300,000 to $370,000 a year ($150,000 to $200,000 for ED data and $150,000 to 

$170,000 for hospital and vital statistics data). 

Strengths: Population-based. State representative. Targets all ages. Timely. Economical. 

Includes ED-based data. Reports true, unduplicated cases. Uses International Classification of Diseases, Ninth Revision, Clinical Modification (ICD-9-CM) rubrics to code 

medical diagnoses. 

Limitations: If implemented in other states, a law requiring all self-standing and hospitalbased EDs to report in standard format may be necessary. 

Recommendations: Use as model to be implemented in selected states. Allows the yearly 

study of incidence, trends, demographics, external causes, and selected risk factors in the 

population. Potential use for follow-up studies to improve understanding of the natural 

history of MTBI. 

National Electronic Injury Surveillance System (NEISS) 

Characteristics: Nationally-representative, probability sample surveillance system of all 

U.S. hospitals with EDs conducted by the U.S. Consumer Product Safety Commission 

since 1972 and expanded through collaboration with CDC in July 2000. Targets all 

persons regardless of age who receive health care in 100 representative hospital-based 

EDs. NEISS collects data for over 500,000 cases per year, visiting selected EDs. Trained 

NEISS staff abstract data daily from eligible records. Subsequent telephone or on-site 

follow-back interviews yield clues about the causes of injury. Only first-time-visit data 

are reported. Routine analysis of NEISS data costs $100,000 to $150,000 per year. 
38 

Strengths: Nationally representative. Large population under study may allow better 

estimates. Targets all ages. Timely. Economical. Has a follow-back system. Identifies 

unduplicated cases. Provides patient-level data. 

Limitations: Coding accuracy varies by variable from 27 percent (for adverse effects) 

to 92 percent (for transportation-related cases). Has its own special coding system 

different from that of the International Classification of Diseases, Ninth Revision, 

Clinical Modification (ICD-9-CM). 

Recommendations: Analyze routinely to study incidence, external causes, occupation 

and type of industry, and risk factors. Potential uses for follow-up or follow-back studies 

to assess the natural history of MTBI. 

National Hospital Ambulatory Medical Care Survey (NHAMCS) – 

Emergency Department and Outpatient Department Modules 

Characteristics: Nationally-representative, four-stage probability sample survey of visits 

to hospital EDs and outpatient departments (ODs) of non-federal, short-stay general 

hospitals in the United States. Conducted by CDC’s National Center for Health Statistics 

since 1992. Targets all persons regardless of age who receive health care in hospitalbased EDs and ODs. Hospital staff collects health care information for all visits to EDs 

and ODs during a randomly assigned four week reporting period. Sample data are 

weighted to produce annual, nationally-representative estimates. Routine analysis of 

NHAMCS data costs $100,000 to $150,000 per year. Adding more variables to obtain 

two more diagnostic codes costs $100,000 per year. 

Strengths: Nationally representative. Targets all ages. Timely. Economical. Uses 

International Classification of Diseases, Ninth Revision, Clinical Modification 

(ICD-9-CM) rubrics to code medical diagnoses. 

Limitations: Only three diagnostic codes are collected; thus, MTBI cases may be 

missed (estimated missing cases range from 25 to 30 percent). Production of more 

precise estimates requires aggregating data from at least two survey years. 

Recommendations: Analyze routinely (at intervals of at least two years) to study incidence, trends, demographics, external causes of injury, service use, hospital characteristics, expected source of payment, chief complaint and diagnosis, medications, type of 

provider, and disposition of MTBI-related visits to EDs and ODs. Additional funds will 

be necessary to collect at least five diagnostic codes; this will allow detection of 90 to 

95 percent of all MTBIs. 
39 

National Ambulatory Medical Care Survey (NAMCS) 

Characteristics: Nationally-representative, multistage probability sample survey of visits 

to the offices of non-federally employed physicians (excluding those in anesthesiology, 

radiology, and pathology), including visits to non-hospital-based clinics and health 

maintenance organizations. Conducted by CDC’s National Center for Health Statistics 

since 1973. Targets all persons regardless of age who receive health care from selected 

office-based physicians. Health data for a systematic random sample of office visits 

occurring during a randomly assigned one-week reporting period are abstracted by 

sampled physicians (1,088 in 1999). Routine analysis of the NAMCS costs $100,000 to 

$150,000 yearly. 

Strengths: Nationally representative. Targets persons of all ages. Economical. Uses 

International Classification of Diseases, Ninth Revision, Clinical Modification 

(ICD-9-CM) rubrics to code medical diagnoses. 

Limitations: Only three diagnostic codes are collected; thus, MTBI cases may be missed. 

Excludes specialties of radiology, anesthesiology, and pathology. Precise estimates 

require aggregating data from at least two consecutive years. 

Recommendations: Analyze routinely (at intervals of at least two years) to study incidence, trends, demographics, reasons for visits, place of injury, use of preventive services 

(including violence and injury prevention), medications, and disposition of MTBI-related 

visits. 

National Health Interview Survey (NHIS) 

Characteristics: Population-based, nationally-representative, face-to-face area probability sample survey conducted by CDC’s National Center for Health Statistics since 

1957. Used to assess public health issues among the civilian, non-institutionalized 

U.S. population. Respondents are household residents ages 18 years and older. Data is 

obtained for all members of the family residing in the household; respondents are the 

proxies for younger persons living in the household. Topical data (e.g., disability) are 

collected. In 1997, data from 40,000 households were collected; 103,5000 persons 

responded to the interview. The Injury Section of the Core NHIS Instrument identifies 

injuries requiring medical attention occurring in the three months preceding the interview 

among respondents or family members residing in the household at the time of the 

interview. Causes and consequences of each injury episode are also collected. Routine 

analysis of the NHIS data costs $100,000 to $150,000 per year. 
40 

Strengths: Population based. Nationally representative. Targets all ages. Economical. 

Potential use for follow-up; costs for this aspect were not estimated at this time. Uses 

International Classification of Diseases, Ninth Revision, Clinical Modification 

(ICD-9-CM) rubrics to code medical diagnoses. 

Limitations: Current care-of-injury eligibility criteria exclude people who did not receive 

health care or advice. Current time-of-injury eligibility criteria (i.e., injuries requiring 

medical attention occurring in the three months preceding the interview) limit study of 

the natural history and sample size. Any proposed follow-up study requires funding and 

up to two to three years for implementation. 

Recommendations: Analyze routinely to study incidence, trends, and demographics. 

Data from the Disability Supplement can also be analyzed routinely. Findings can also 

be compared with methods of contemporaneous surveillance of health events and can 

serve as a validation system. Propose modifying current care-of-injury eligibility criteria 

to allow for identification and interview of persons who had a MTBI but did not receive 

medical care or advice. Extend current time-of-injury eligibility criteria to generate a 

larger sample. Follow-up studies can be proposed and implemented, provided that 

questions regarding natural history and associated disability are included in the 

instrument. 

National Collegiate Athletic Association Injury 

Surveillance System (NCAAISS) 

Characteristics: Population-based, nationally-representative sports-related injury 

surveillance system that has collected data from a representative sample of colleges 

that are members of the National Collegiate Athletic Association (NCAA) since 1982 

(450 of 977 in 2000). Final selection of participant colleges is random and includes at 

least 10 percent of each NCAA division. Data are used to reduce injury through changes 

in rules, protective equipment, and coaching techniques. Targets college students practicing spring football; wrestling; baseball; ice and field hockey; women’s volleyball and 

softball; and men’s and women’s soccer, basketball, gymnastics, and Lacrosse. Data on 

at least one sport are collected in a standardized questionnaire by certified and student 

athletic trainers from the first official day of pre-season practice to the final tournament 

contest. 

Strengths: Population based. NCAA representative. Conducted at no cost to CDC. 

Can produce regional and state-level estimates. Potential use for follow-up studies. 

Limitations: Excludes all non-NCAA colleges. Does not include some contact sports 

(e.g., karate). Data are not validated. 
41 

Recommendations: Analyze routinely to assess the incidence of MTBI in selected college 

sports. Follow-up/follow-back studies can be added; these enhancements will allow 

clinicians and investigators to characterize natural history, adverse outcomes, and 

associated disability. 

CDC Traumatic Brain Injury Surveillance System 

Characteristics: Statewide, representative surveillance system conducted in selected 

states receiving CDC funding since 1996. This system is the only ongoing, populationbased TBI surveillance system in the United States. It has two aspects: core surveillance, 

which relies on International Classification of Diseases, Version 9, Clinical Modification 

codes found in hospital discharge and vital statistics data; and extended surveillance, 

which relies on abstraction of relevant health information via medical record review. 

Targets hospitalized persons regardless of age. During the funding cycle that ended in 

2000, 15 states received funds to conduct the core aspect; 14 of these also conducted 

the expanded aspect. In the cycle that began in late 2000, only 12 states were funded 

to conduct core TBI surveillance; of these, six were funded to conduct expanded 

surveillance. This system requires $140,000 to $180,000 per state per year ($80,000 to 

$100,000 to conduct the core aspect and $60,000 to $80,000 to conduct the expanded 

surveillance aspect). 

Strengths: Representative at the state level. Economical. Targets persons of all ages. 

Uses International Classification of Diseases, Ninth Revision, Clinical Modification 

(ICD-9-CM) rubrics to code medical diagnoses. Potential use for follow-up studies. 

Limitations: Not timely. Current TBI definition is not suitable for detecting cases of 

MTBI. Does not include ED data. 

Recommendations: Analyze routinely to assess incidence, external causes, and risk 

factors of MTBI among persons who are hospitalized. Apply the recommended 

definitions for MTBI to enhance the system’s ability to detect and monitor MTBI 

in the United States. Increase the number of states conducting TBI surveillance. 

National Hospital Discharge Survey (NHDS) 

Characteristics: Nationally-representative, three-stage stratified sample survey of inpatient records acquired from a representative probability sample of about 500 non-federal, 

short-stay hospitals (average length of stay of 30 days or shorter) having six or more beds 

in the United States. Conducted by CDC’s National Center for Health Statistics (NCHS) 
42 

since 1965. The NHDS is designed to provide information about characteristics of inpatients (regardless of age) hospitalized and discharged from the hospitals in the survey. 

Medical and administrative data—including date of birth, sex, race, ethnicity, marital 

status, ZIP codes, dates of admission and discharge, discharge status, expected source of 

payment, procedures, diagnoses, size of hospital, and hospital ownership—for approximately 300,000 hospital discharges are obtained from two sources. The first source uses 

data that is manually-abstracted and transcribed by hospital and U.S. Bureau of the 

Census staff from a manually-selected sample of hospital discharge records. Completed 

forms are coded, computerized, and edited by NCHS. The second source uses a systematic sample of electronic hospital discharge files containing medical record data selected 

from electronic files purchased from public and private organizations authorized by the 

states. Approximately 10 percent of the abstracts are independently recoded with an 

overall error of 0.6 percent for medical coding and 0.3 percent for administrative coding. 

Approximately 40 percent of respondent hospitals provided data through the automated 

system. Sample data are weighted to produce annual, nationally-representative estimates. 

Routine analysis of NHDS data costs $100,000 to $150,000 per year. 

Strengths: Nationally representative. Targets all ages. Excellent quality. Timely. 

Economical. Uses International Classification of Diseases, Ninth Revision, Clinical 

Modification (ICD-9-CM) rubrics to code medical diagnoses. 

Limitations: Does not include ED data. Cannot distinguish first admissions from readmissions in some states; thus, allowing for discharge rates, not injury rates. Measures 

discharges and not individual patients (potential duplicates). 

Recommendations: Analyze routinely to study incidence, trends, demographics, external 

causes of injury, service use, hospital characteristics, expected source of payment, chief 

complaint and diagnosis, medications, type of provider, and disposition of MTBI-related 

hospitalizations in non-federal, short-stay hospitals in the United States. 

Nationwide Inpatient Sample (NIS) 

Characteristics: Nationally-representative, multi-state health data system based on all 

hospital discharges from a stratified probability sample of non-federal, short-stay 

hospitals (994 in 28 participant states in 2000). Sponsored by the Agency for Healthcare Research and Quality since 1988. Designed to approximate a 20 percent sample 

of all non-federal, short-term, general and other specialty hospitals in the United States. 

The NIS 2000 is a sample of hospitals that comprise about 80 percent of all hospital 

discharges in the United States. States voluntarily report allowable electronic, coded 

discharge data from all persons hospitalized regardless of age. Analysis of NIS data 

costs $100,000 to $150,000 annually. 
43 

Strengths: Representative at the participant state and national levels. Economical. Targets 

persons of all ages. Contains data on discharge disposition, procedures, service use, 

length of hospitalization, source of payment, and costs among hospitalized persons with 

MTBI at the national level. Contains 7 million records (in contrast, the National Hospital 

Discharge Survey (NHDS) contains 300,000). Uses International Classification of 

Diseases, Ninth Revision, Clinical Modification (ICD-9-CM) rubrics to code medical 

diagnoses. 

Limitations: Does not include ED data. Reporting is not uniform: small hospitals are 

underrepresented in some states; hospitals in some states report only a subset of their 

discharges. Cannot distinguish first admissions from readmissions in some states; thus, 

allowing for discharge rates, not injury rates. Measures discharges and not individual 

patients (potential duplicates). 

Recommendations: Analyze routinely to study the incidence of MTBI-related 

hospitalization and discharge in non-federal, short-stay hospitals in the United States. 

Behavioral Risk Factor Surveillance System (BRFSS) and the 

South Carolina Department of Health Interagency Office of 

Disability and Health Disability Surveillance (SC DOH IODH-DS) 

Characteristics: CDC-sponsored, population-based, random digit dialing telephone 

surveillance system that collects topical data about varying health issues, including 

disability, among persons in the community. Includes persons who did not seek medical 

care. SC DOH IODH-DS has used BRFSS since the early 1990s, including a question 

about the likely cause of any disability in the “Quality of Life and Care Giving” module. 

BRFSS targets primarily people ages 18 years and older; however, some states collect 

infor-mation about children from parents or legal guardians. Costs vary with the number 

of questions added to the data collection instrument. Adding questions and administering 

them to the target population costs $35,000 to $50,000 per question. Routine data analysis costs $50,000 to $70,000 per year. 

Strengths: Population based. Representative at the state level; nationally representative 

if questions are administered by all participating states. Relatively economical. Allows 

identification of cases of persons with MTBI who did not receive health care. Potential 

use for follow-up studies among both adults and children. 

Limitations: Nationally representative only if questions are administered by all states. 

Question about the likely cause of any disability in the “Quality of Life and Care Giving” 

module has low completion rates; thus, it needs to be re-written and tested. Does not 

cover population of persons in households without phones. 
44 

Recommendations: Injury-related questions or module can be added to the data collection 

instrument and used to study MTBI incidence in the community, especially among those 

who did not receive health care (requires pre-testing of proposed questions before administering them in states). Follow-up studies can also be proposed. 

National Children’s Study (NCS) 

Characteristics: Planned, population-based, nationally-representative, longitudinal 

cohort study of 100,000 children (from birth to adulthood) to measure exposure of risks 

for asthma, unintentional injuries, cancer, and developmental disorders; to assess outcomes of such health and safety problems; and to identify factors for improving 

children’s health and well being. Children will be recruited, measured, and followed-up 

in geographically-distributed centers using sampling techniques. Special populations 

will be oversampled. The National Institute of Child Health and Human Development 

(part of the National Institutes of Health), the Environmental Protection Agency (EPA), 

and CDC are leading a consortium of federal and non-federal partners. It includes 

children, their families, and their environment, physical, chemical, biological, and 

psychosocial influences. Biomarkers and exposure measurements will be collected 

and evaluated. Methodological development and pilot studies began in FY 2001 and 

will run through FY 2003; the study should begin in 2004 and is expected to end 

by 2035. 

Strengths: Population based. Nationally representative. Targets children and their 

families. Hypothesis driven. Longitudinal design allows for determining causality and 

natural history. Biomarkers will be used. Special populations will be oversampled. Study 

design allows pilot tests to recommend standard tests or measures. CDC will incur no 

costs. 

Limitations: Not a tested system. Excludes intentional injuries. Preliminary finding and 

results will not be available until 2010. 

Recommendations: CDC should ensure the inclusion of a follow-up component to study 

the incidence and the natural history of MTBI among children in the United States. A 

pilot study could develop an injury severity scale to measure the long-term cognitive 

outcomes for MTBI, especially the cumulative effects of repetitive injuries (e.g., multiple 

minor concussions). In addition, a scale could distinguish between acute and chronic 

injuries; however, this distinction does not relate to outcome. 
45 

Defense and Veterans Head Injury Program (DVHIP) 

Characteristics: Military and VA beneficiary TBI registry, based on patient information 

from seven lead sites and 20 network sites in the DVHIP. Conducted by the Department 

of Defense (DoD) and the Department of Veterans Affairs (VA) sites of the DVHIP since 

1992. Data collected include those from standardized evaluation batteries, randomized 

trials, and data from the Defense National Databases. Components considered to study 

MTBI are primarily found among military patients included in the TBI registry and the 

DoD and VA national discharge databases for incidence studies, a helmet study in a 

paratrooper population, and a proposed follow-up study for prevalence and outcomes. 

Targets primarily adults who are hospitalized or receive health care in emergency departments and out-patient departments in the military and VA systems. Hospital discharge, 

ED, and outpatient data are used to identify cases of TBI (including MTBI). Routine 

analysis of the DVHIP registry data will cost $100,000 to $150,000 per year. 

Strengths: Military- and VA-based. Military- and VA-representative. Timely. Economical. 

Contains baseline data (i.e., prior to injury), such as drug use and prior medical history. 

Includes ED data. Reports unduplicated cases; thus, allowing for study of MTBI incidence. Military cases generally healthy pre-injury. Excellent potential to follow-up adults 

with MTBI to characterize outcomes and the natural history of this condition; no costs 

for this option have been determined at this time. Includes wartime injuries. Uses International Classification of Diseases, Ninth Revision, Clinical Modification (ICD-9-CM) 

rubrics to code medical diagnoses. 

Limitations: Does not represent the entire U.S. population. In general, younger adult 

males are over-represented in this database, consistent with TBI in the general population. Population in the VA system is older than the U.S. population as a whole. 

Recommendations: Collaborative routine analysis with DVHIP to assess incidence, risk 

factors, external causes, service needs and use, and long-term consequences of MTBI 

and its associated disabilities in the military system. Excellent option for implementing 

follow-up and tracking systems for persons with MTBI (through personal interviews and 

medical record reviews). Because military hospitals serve enlisted personnel and their 

families, children constitute a small proportion of the population in these databases. Any 

proposed, large follow-up study would target mainly adults; findings for non-wartime 

injuries can be extrapolated to the general population. Special follow-up studies that 

target children can be proposed. Follow-up studies will allow for the characterization 

of the natural history of MTBI among adults. No costs have been determined for the 

use of these resources at this point. 
N O T E S
N O T E S