Gulf War and Health, Volume 7: Long-Term Consequences of Traumatic Brain Injury THE NATIONAL ACADEMIES PRESS Committee on Gulf War and Health: Brain Injury in Veterans and Long-Term Health Outcomes Board on Population Health and Public Health Practice THE NATIONAL ACADEMIES PRESS 500 Fifth Street, N.W. Washington, DC 20001 NOTICE: The project that is the subject of this report was approved by the Governing Board of the National Research Council, whose members are drawn from the councils of the National Academy of Sciences, the National Academy of Engineering, and the Institute of Medicine. The members of the committee responsible for the report were chosen for their special competences and with regard for appropriate balance. This study was supported by Contract V101(93) P-2136, Task Order 8 between the National Academy of Sciences and Department of Veterans Affairs. Any opinions, findings, conclusions, or recommendations expressed in this publication are those of the authors and do not necessarily reflect the view of the organizations or agencies that provided support for this project. International Standard Book Number-13: 978-0-309-12408-9 International Standard Book Number-10: 0-309-12408-5 Additional copies of this report are available from the National Academies Press, 500 Fifth Street, N.W., Lockbox 285, Washington, DC 20055; (800) 624-6242 or (202) 334-3313 (in the Washington metropolitan area); Internet, http://www.nap.edu. For more information about the Institute of Medicine, visit the IOM home page at www.iom.edu. Copyright 2009 by the National Academy of Sciences. All rights reserved. Printed in the United States of America The serpent has been a symbol of long life, healing, and knowledge among almost all cultures and religions since the beginning of recorded history. The serpent adopted as a logotype by the Institute of Medicine is a relief carving from ancient Greece, now held by the Staatliche Museen in Berlin. Suggested citation: IOM (Institute of Medicine). 2009. Gulf War and Health, Volume 7: Long-term Consequences of Traumatic Brain Injury. Washington, DC: The National Academies Press. The National Academy of Sciences is a private, nonprofit, self-perpetuating society of distinguished scholars engaged in scientific and engineering research, dedicated to the furtherance of science and technology and to their use for the general welfare. Upon the authority of the charter granted to it by the Congress in 1863, the Academy has a mandate that requires it to advise the federal government on scientific and technical matters. Dr. Ralph J. Cicerone is president of the National Academy of Sciences. 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The Institute acts under the responsibility given to the National Academy of Sciences by its congressional charter to be an adviser to the federal government and, upon its own initiative, to identify issues of medical care, research, and education. Dr. Harvey V. Fineberg is president of the Institute of Medicine. The National Research Council was organized by the National Academy of Sciences in 1916 to associate the broad community of science and technology with the Academy’s purposes of furthering knowledge and advising the federal government. Functioning in accordance with general policies determined by the Academy, the Council has become the principal operating agency of both the National Academy of Sciences and the National Academy of Engineering in providing services to the government, the public, and the scientific and engineering communities. The Council is administered jointly by both Academies and the Institute of Medicine. Dr. Ralph J. Cicerone and Dr. Charles M. Vest are chair and vice chair, respectively, of the National Research Council. www.national-academies.org . iv COMMITTEE ON GULF WAR AND HEALTH: BRAIN INJURY IN VETERANS AND LONG-TERM HEALTH OUTCOMES GEORGE W. RUTHERFORD, MD (Chair) Salvatore Pablo Lucia Professor and Vice Chair, Department of Epidemiology and Biostatistics; Director, Prevention and Public Health Group, Global Health Sciences, University of California, San Francisco School of Medicine JEFFREY J. BAZARIAN, MD, MPH, Associate Professor, Departments of Emergency Medicine and Neurology, University of Rochester School of Medicine and Dentistry IBOLJA CERNAK, PhD, MD, Medical Director, Johns Hopkins University, Applied Physics Laboratory JOHN D. CORRIGAN, PhD, Professor, Department of Physical Medicine and Rehabilitation, Ohio State University SUREYYA S. DIKMEN, PhD, Professor, Department of Rehabilitation Medicine and Adjunct Professor of Neurological Surgery and Psychiatry and Behavioral Sciences, University of Washington M. SEAN GRADY, MD, Chairman, Department of Neurosurgery, University of Pennsylvania School of Medicine DALE C. HESDORFFER, PhD, MPH, Associate Professor of Clinical Epidemiology, Gertrude H. Sergievsky Center, Columbia University JESS F. KRAUS, PhD, MPH, Director, Southern California Injury Prevention Research Center, Professor of Epidemiology, University of California, Los Angeles, School of Public Health HARVEY S. LEVIN, PhD, Professor, Director of Research, Cognitive Neuroscience Laboratory, Department of Physical Medicine and Rehabilitation, Baylor College of Medicine LINDA NOBLE, PhD, Professor, Department of Neurological Surgery and Department of Physical Therapy and Rehabilitation Science, University of California, San Francisco SAMUEL J. POTOLICCHIO, MD, Professor, Department of Neurology, George Washington University Medical Center SCOTT L. RAUCH, MD, Chair, Partners Psychiatry and Mental Health; President and Psychiatrist in Chief, McLean Hospital; Professor of Psychiatry, Harvard Medical School WILLIAM STIERS, PhD, ABPP, Assistant Professor, Department of Physical Medicine and Rehabilitation, Johns Hopkins University CAROL A. TAMMINGA, MD, Professor, Department of Psychiatry, University of Texas Southwestern Medical Center at Dallas NANCY TEMKIN, PhD, Professor, Departments of Neurological Surgery and Biostatistics, University of Washington MARC G. WEISSKOPF, PhD, ScD, Mark and Catherine Winkler Assistant Professor, Departments of Environmental Health and Epidemiology, Harvard School of Public Health v STAFF CAROLYN FULCO, Senior Program Officer ABIGAIL MITCHELL, Senior Program Officer ROBERTA WEDGE, Senior Program Officer NAOKO ISHIBE, Program Officer JENNIFER SAUNDERS, Senior Program Associate DEEPALI PATEL, Senior Program Associate (until October 2007) RENEE WLODARCZYK, Senior Program Associate JOE GOODMAN, Senior Program Assistant NORMAN GROSSBLATT, Senior Editor CHRISTIE BELL, Financial Officer HOPE HARE, Administrative Assistant ROSE MARIE MARTINEZ, Director, Board on Population Health and Public Health Practice CONSULTANTS MIRIAM DAVIS, Independent Medical Writer, Silver Spring, MD JOAN MACHAMER, Independent Consultant, University of Washington, Seattle, WA vi REVIEWERS This report has been reviewed in draft form by persons chosen for their diverse perspectives and technical expertise, in accordance with procedures approved by the National Research Council’s Report Review Committee. The purpose of this independent review is to provide candid and critical comments that will assist the institution in making its published report as sound as possible and to ensure that the report meets institutional standards of objectivity, evidence, and responsiveness to the study charge. The review comments and draft manuscript remain confidential to protect the integrity of the deliberative process. We thank the following for their review of this report: Dan G. Blazer, Duke University Medical Center Linda Cowan, Department of Biostatistics and Epidemiology, University of Oklahoma Health Sciences Center Ramon Diaz-Arrastia, Department of Neurology, University of Texas Southwestern Medical School Sandro Galea, Center for Social Epidemiology and Population Health, University of Michigan Tessa Hart, Moss Rehabilitation Research Institute, Albert Einstein Healthcare Network Janice L. Krupnick, Department of Psychiatry, Trauma and Loss Program, Georgetown University Medical Center James L. Levenson, Department of Psychiatry, Virginia Commonwealth School of Medicine Kathryn Saatman, Spinal Cord and Brain Injury Research Center, University of Kentucky Chandler Medical Center Murray B. Stein, Department of Psychiatry, University of California, San Diego Although the reviewers listed above have provided many constructive comments and suggestions, they were not asked to endorse the conclusions or recommendations, nor did they see the final draft of the report before its release. The review of this report was overseen by Dr. Johanna T. Dwyer, Tufts University School of Medicine and Friedman School of Nutrition Science and Policy, Frances Stern Nutrition Center, Tufts-New England Medical Center and Dr. Robert S. Lawrence, Center for a Livable Future, Johns Hopkins Bloomberg School of Public Health. Appointed by the National Research Council and the Institute of Medicine, they were responsible for making certain that an independent examination of the report was carried out in accordance with institutional procedures and that all review comments were carefully considered. Responsibility for the final content of the report rests entirely with the author committee and the institution. vii viii CONTENTS PREFACE.................................................................................................................................... xiii SUMMARY.....................................................................................................................................1 1 INTRODUCTION ....................................................................................................................13 Background ...............................................................................................................................13 Traumatic Brain Injury..............................................................................................................14 Operation Enduring Freedom and Operation Iraqi Freedom ....................................................15 Charge to the Committee ..........................................................................................................15 Scope of the Report...................................................................................................................15 Organization of the Report........................................................................................................16 References .................................................................................................................................17 2 BIOLOGY OF TRAUMATIC BRAIN INJURY .....................................................................19 Pathobiology of Traumatic Brain Injury ...................................................................................19 Traditional Classifications of Traumatic Brain Injury..............................................................25 Classification According to Extent of Pathology......................................................................25 Classification According to Biomechanics of Injury ................................................................27 Therapeutics and Traumatic Brain Injury .................................................................................28 Summary of Pathobiology of Traumatic Brain Injury ..............................................................29 Traumatic Brain Injuries Relevant to the Military....................................................................30 Basic Mechanisms of Explosive Injuries ..................................................................................31 Severity Scoring of Blast Injuries and Traumatic Brain Injury ................................................41 References .................................................................................................................................46 3 EPIDEMIOLOGY OF ADULT TRAUMATIC BRAIN INJURY ..........................................59 Incidence of Traumatic Brain Injury.........................................................................................61 Brain Injury Severity.................................................................................................................63 Risk Factors for Traumatic Brain Injury...................................................................................64 Recurrent Traumatic Brain Injury.............................................................................................67 Traumatic Brain Injury and Short-Term Outcomes ..................................................................68 Summary ...................................................................................................................................69 References .................................................................................................................................96 4 CONSIDERATIONS IN IDENTIFYING AND EVALUATING THE LITERATURE .......103 Identification of the Literature ................................................................................................103 Types of Evidence...................................................................................................................104 Inclusion Criteria.....................................................................................................................110 Considerations in Assessing the Strength of Evidence ...........................................................112 Limitations of Studies .............................................................................................................113 References ...............................................................................................................................115 ix