Vestibular Consequences of Blast-related Mild Traumatic Brain Injury

描述(由申请人提供)： 项目概述：本项目的目标是确定轻度创伤性脑损伤(MTBI)和冲击波暴露对前庭系统和中枢神经系统的影响。头晕和平衡障碍是与mTBI或头部损伤相关的常见症状。许多研究已经提供了重要的证据表明，mTBI或头部损伤可以导致前庭系统的损害；然而，大多数研究将前庭评估局限于水平半规管功能的评估。最近，人们发展了评估耳石功能的方法，有证据表明，头部损伤对耳石器官的影响可能比半规管的程度更大。MTBI被称为从持久自由行动/伊拉克自由行动(OEF/OIF)返回的退伍军人的标志性疾病，其原因往往与简易爆炸装置、迫击炮或火箭榴弹的爆炸暴露有关。一些研究人员推测，冲击波暴露后的头晕和平衡障碍与颅脑损伤造成的中枢神经系统损伤有关，而不是与冲击伤的压力波有关。因此，大多数研究都集中在颅脑损伤(或头部损伤)对前庭的影响上，而关于冲击波暴露对前庭功能或平衡的影响的数据有限。最近，磁共振成像技术已经发展起来，可以测试与头部损伤或冲击波暴露相关的头晕或失衡症状通常是由于中央前庭或中枢神经系统受累的假设。本项目的具体目标是确定mTBI和冲击波暴露对(1)外周前庭系统功能(特别是水平半规管功能和耳石器官功能)、(2)中央前庭/中枢神经系统功能、(3)姿势稳定性和(4)与头晕相关的生活质量的影响。四个受试组将包括抱怨头晕/不平衡的退伍军人，(1)爆炸暴露史，(2)mTBI，(3)爆炸暴露和mTBI，以及(4)对照组。每个受试者将接受水平半规管功能测试(卡路里和转椅)，耳石功能测试(前庭诱发肌源性电位，主观视觉垂直)，中央前庭功能/中枢神经系统功能(眼运动测试，扩散张量和敏感度加权成像)，步态和平衡测试，以及头晕残疾调查。 公共卫生相关性： 项目叙述拟议工作与退伍军人事务部患者护理任务的相关性：改善前庭功能的临床评估对于患有冲击性脑损伤(TBI)的退伍军人来说是一个重要的医疗保健问题。TBI被描述为参与伊拉克和阿富汗战斗的美国军事人员的标志性疾病。持久自由行动(OEF)和伊拉克自由行动(OIF)中的TBI比率被认为比以往任何一次战争都要高得多(狱长，2006年)。截至2007年6月，国防部(DoD)报告称，有3000多名OEF/OIF士兵因爆炸伤、坠落或车祸而遭受脑外伤。随着退伍军人事务部改进mTBI的筛查方法，被确认为脑外伤的OEF/OIF退伍军人的数量预计将增加。在兰德公司(2008)最近的一项研究中，约19%(约320,000)的服役人员报告称，他们在部署在伊拉克或阿富汗时经历了可能的创伤性脑损伤。山上之家VA医疗系统目前包括约4000名OEF/OIF退伍军人，到目前为止，已有约60人接受了脑损伤治疗。听力学服务通常是许多OEF/OIF退伍军人进入VA系统的切入点，因为由于有噪音和/或冲击波暴露的历史，听力损害在补偿和养老金检查中进行评估。头晕是mTBI患者的常见主诉，症状可持续六个月或更长时间(例如，Scherer等人，2007年)。该项目将为退伍军人管理局提供重要信息，以改善临床评估，并最终为与脑外伤和冲击伤相关的头晕和失衡的退伍军人提供康复。

DESCRIPTION (provided by applicant): Project Summary: The goal of this project is to determine the effects of mild traumatic brain injury (mTBI) and blast exposure on the vestibular system and CNS. Dizziness and balance disorders are common symptoms associated with mTBI or head injury. Numerous studies have provided significant evidence that mTBI or head injury can cause damage to the vestibular system; however, most have limited the vestibular evaluation to assessment of horizontal semicircular canal function. Recently, methods have been developed to assess otolith function, and there is some evidence that head injury may affect the otolith organs to a greater degree than the semicircular canals. mTBI has been called the signature condition of veterans returning from Operation Enduring Freedom/Operation Iraqi Freedom (OEF/OIF), and the cause is often related to blast exposure from improvised explosive devices, mortars or rocket-propelled grenades. Some investigators have presumed that dizziness and balance disorders following blast exposure are related to CNS damage caused by the TBI rather than the pressure wave from the blast injury. Thus, most research has focused on the vestibular consequences of TBI (or head injury), and there is limited data on the effects of blast exposure on vestibular function or balance. Recently, magnetic resonance imaging techniques have been developed that may allow for testing the assumption that the symptoms of dizziness or imbalance related to head injury or blast exposure are often due to central vestibular or CNS involvement. Specific aims of this project are to determine the effect of mTBI and blast exposure on (1) peripheral vestibular system function (specifically, horizontal semicircular canal function, and otolith organ function), (2) central vestibular/CNS function, (3) postural stability, and (4) dizziness-related quality of life. Four subject groups will include veterans complaining of dizziness/imbalance with (1) a history of blast exposure, (2) with mTBI, (3) with blast exposure and mTBI, and (4) a control group. Each subject will undergo tests of horizontal semicircular canal function (caloric and rotary chair), tests of otolith function (vestibular evoked myogenic potentials, subjective visual vertical), central vestibular function/CNS function (ocular motor tests, diffusion tensor and susceptibility weighting imaging), gait and balance testing, and the Dizziness Handicap Inventory. PUBLIC HEALTH RELEVANCE: Project Narrative Relevance of the Proposed Work to the VA Patient Care Mission: Improving the clinical assessment of vestibular function is an important healthcare issue for veterans suffering from blast-related traumatic brain injury (TBI). TBI has been described as the signature condition among United States military personnel involved in combat in Iraq and Afghanistan. The rate of TBI in Operation Enduring Freedom (OEF) and Operation Iraqi Freedom (OIF) is thought to be significantly higher than any previous war (Warden, 2006). As of June 2007, the Department of Defense (DoD) reported over 3,000 OEF/OIF soldiers suffering from TBI caused by blast injuries, falls, or vehicular accidents. The number of OEF/OIF veterans identified with TBI is expected to increase as the VA/DoD improves methods of screening for mTBI. In a recent study by the RAND Corporation (2008), ~19% (~320,000) of service members reported that they experienced a possible TBI while deployed in Iraq or Afghanistan. The Mountain Home VA Healthcare System currently includes ~4000 OEF/OIF veterans and, to date, ~60 have received treatment for TBI. The Audiology service is often the point of entry to the VA system for many OEF/OIF veterans as hearing damage is assessed in compensation and pension examinations due to a history of noise and/or blast exposure. Dizziness is a common complaint in patients with mTBI, and the symptoms can last six months or longer (e.g., Scherer et al., 2007). This project will provide the VA with important information to improve clinical assessment and, ultimately, rehabilitation of veterans with dizziness and imbalance associated with TBI and blast injuries.