TEEMU LUOTO Clinical Assessment of Acute Mild Traumatic Brain Injury ACADEMIC DISSERTATION To be presented, with the permission of the Board of the School of Medicine of the University of Tampere, for public discussion in the Jarmo Visakorpi Auditorium of the Arvo Building, Lääkärinkatu 1, Tampere, on June 13th, 2014, at 12 o’clock. UNIVERSITY OF TAMPERE TEEMU LUOTO Clinical Assessment of Acute Mild Traumatic Brain Injury Acta Universitatis Tamperensis 1940 Tampere University Press Tampere 2014 ACADEMIC DISSERTATION University of Tampere, School of Medicine Tampere University Hospital Turku University Central Hospital Finland Harvard Medical School USA University of British Columbia Canada Reviewed by Supervised by Docent Martin Lehecka Professor Juha Öhman University of Helsinki University of Tampere Finland Finland Docent Ville Leinonen Docent Olli Tenovuo University of Eastern Finland University of Turku Finland Finland The originality of this thesis has been checked using the Turnitin OriginalityCheck service in accordance with the quality management system of the University of Tampere. Copyright ©2014 Tampere University Press and the author Cover design by Mikko Reinikka Page design by Maaret Kihlakaski Distributor: [email protected] http://granum.uta.fi Acta Universitatis Tamperensis 1940 Acta Electronica Universitatis Tamperensis 1424 ISBN 978-951-44-9465-9 (print) ISBN 978-951-44-9466-6 (pdf) ISSN-L 1455-1616 ISSN 1456-954X ISSN 1455-1616 http://tampub.uta.fi Suomen Yliopistopaino Oy – Juvenes Print Tampere 2014 441 729 Painotuote To Tiina Author’s contact information Teemu Luoto Department of Neurosciences and Rehabilitation Tampere University Hospital Teiskontie 35 P.O. Box 2000 FI-33521 Tampere, Finland Teemu.Luoto@pshp.fi +358 40 7039696 http://www.researchgate.net/profile/Teemu_Luoto Contents 1 LIST OF ORIGINAL PUBLICATIONS ................................................... 9 2 ABBREVIATIONS ..................................................................................... 11 3 ABSTRACT ................................................................................................ 13 4 TIIVISTELMÄ (ABSTRACT IN FINNISH) ............................................. 15 5 INTRODUCTION .................................................................................... 17 6 REVIEW OF THE LITERATURE ............................................................ 19 6.1 Definitions ........................................................................................... 19 6.2 Diagnostic Criteria for Mild Traumatic Brain Injury ............................. 19 6.2.1 Glasgow Coma Scale .................................................................... 21 6.2.2 Loss of Consciousness .................................................................. 22 6.2.3 Post-traumatic Amnesia ................................................................ 22 6.2.4 Confusion or Disorientation ........................................................ 23 6.2.5 Focal Neurological Deficits........................................................... 23 6.2.6 Traumatic Intracranial Lesions ...................................................... 23 6.3 Epidemiology ....................................................................................... 24 6.4 Pathophysiology ................................................................................... 25 6.5 Acute Clinical Assessment ..................................................................... 27 6.5.1 Medical History ........................................................................... 29 6.5.2 Injury-related Information ........................................................... 30 6.5.3 Neurologic Examination .............................................................. 31 6.5.3.1 Cognitive Evaluation ................................................................. 35 6.5.4 Additional Physical Examination .................................................. 37 6.5.5 Neuroimaging .............................................................................. 37 Clinical Assessment of Acute Mild Traumatic Brain Injury – 5 6.5.5.1 Computed Tomography ................................................... 38 6.5.5.2 Magnetic Resonance Imaging .......................................... 40 6.5.6 Blood-based Biomarkers of Brain Injury ....................................... 40 6.6 Outcome of Mild Traumatic Brain Injury ............................................ 41 7 AIMS OF THE STUDY ............................................................................. 45 8 MATERIALS .............................................................................................. 46 8.1 Study Frame and Ethical Aspects .......................................................... 46 8.2 Patients with Mild Traumatic Brain Injury ............................................ 48 8.3 Controls ............................................................................................... 48 8.4 Study Process ........................................................................................ 50 9 METHODS ............................................................................................... 51 9.1 Acute Clinical Assessment ..................................................................... 51 9.3 Neuroimaging....................................................................................... 53 9.4 Follow-up Visits .................................................................................... 53 9.5 Statistical Analysis ................................................................................. 55 10 SUMMARY OF THE RESULTS .............................................................. 56 10.1 Sample Characteristics ..................................................................... 56 10.1.1 Screened Patients with Head Injury ............................................ 56 10.1.2 Ground-level Falls....................................................................... 57 10.1.3 Enrolled Patients with Mild Traumatic Brain Injury ................... 59 10.2 Recognition of Mild Traumatic Brain Injury ..................................... 64 10.3 Acute Assessment of the Effects of MTBI with the SCAT2 ................. 65 10.4 The MACE and the MACE-SCAT2 Comparison ............................... 69 10.5 Retrograde Amnesia and Other Clinical Correlates of Mild .............. 72 Traumatic Brain Injury ....................................................................... 72 10.6 Background and Clinical Correlates in Relation to Neuroimaging Findings ...................................................................... 73 10.7 Outcome Assessment .......................................................................... 75 11 DISCUSSION .......................................................................................... 79 11.1 Study Population ................................................................................ 79 11.2 Clinical Assessment ............................................................................ 81 11.3 Using the SCAT2 in the Emergency Department ............................... 84 11.4 SCAT2-MACE Head-to-Head Comparison ....................................... 88 11.5 Functional Outcome: Return to Work and Persistent Symptoms ........ 88 11.6 Study Strengths and Limitations ......................................................... 90 6 – Teemu Luoto 11.7 Future Prospectives ............................................................................. 92 12 CONCLUSIONS ..................................................................................... 93 13 ACKNOWLEDGEMENTS ..................................................................... 94 REFERENCES .............................................................................................. 96 APPENDICES ............................................................................................. 115 ORIGINAL PUBLICATIONS I–IV ........................................................... 127 Clinical Assessment of Acute Mild Traumatic Brain Injury – 7 1 LIST OF ORIGINAL PUBLICATIONS This thesis is based on the following four original publications, which are referred to in Roman numerals I–IV. The original publications have been reprinted with the permission of the copyright holders. I Luoto TM, Kataja A, Brander A, Tenovuo O, Öhman J, Iverson GL. Who Gets Recruited in Mild Traumatic Brain Injury Research? J Neurotrauma. 2013;30(1):11-6. II Pöyry T, Luoto TM, Kataja A, Brander A, Tenovuo O, Iverson GL, Öhman J. Acute Assessment of Brain Injuries in Ground-Level Falls. J Head Trauma Rehabil. 2013;28(2):89-97. III Luoto TM, Silverberg ND, Kataja A, Brander A, Tenovuo O, Öhman J. Sport Concussion Assessment Tool 2 in a Civilian Trauma Sample with Mild Trau- matic Brain Injury. J Neurotrauma. 2014;31(8):728-38 IV Luoto TM, Iverson GL, Losoi H, Wäljas M, Tenovuo O, Kataja A, Brander A, Öhman J. Clinical Correlates of Retrograde Amnesia in Mild Traumatic Brain Injury. Brain Inj. (submitted) Clinical Assessment of Acute Mild Traumatic Brain Injury – 9