Mild TBI related to deployment in the Middle East is rampant among our soldiers. The RAND Corporation has estimated that 320,000 of our soldiers may have experienced at least mild TBI. Even in mild TBI, which accounts for 80% of all TBI cases, causes damage to the brain that results in significant behavioral and cognitive changes. Veterans often report changes in personality, including irritability and aggression, loss of memory and loss of effectiveness. These problems are often permanent. The diagnosis of mild TBI is very challenging because there are no grossly evident neurological findings, like paralysis. The diagnosis of mild TBI is also complicated because this disorder frequently occurs together with the symptoms of post-traumatic stress disorder (PTSD), which include anxiety and depression, which are present in 44 and 27%, respectively, in soldiers with mild TBI. PTSD and depression can independently degrade cognitive and behavioral performance, and they can both exacerbate both the subjective complaints and objective cognitive deficits in mild to moderate TBI. Consequently, these psychological factors can be difficult to separate from the consequences of physical injury to the brain itself. This tangle of factors substantially increases the risk of diagnostic imprecision, particularly when purely subjective reports is used to assess the state of psychological health. Failure to establish the correct profile of disabilities leaves affected soldiers without a full explanation for their disabilities and hinders appropriate delivery of medical care. This proposal seeks to develop a new and portable eye movement test that has the potential to provide an objective method to diagnose TBI. There is substantial evidence that this type of eye movement test will prove especially valuable in the diagnosis of the milder cases of TBI which could otherwise go unrecognized. This battery of eye movement tests will be given to control subjects and veterans who have been diagnosed with TBI by the Neuro-Cognitive scientists at the Boston VA. The clinical study that is proposed in this grant seeks to determine the degree to which this new test predicts the presence of TBI and the severity of exposure to blasts. Given the opportunity to develop this new test instrument, our long-range goal is to use this new and portable eye movement test as a screening tool that would be administered 'pre-deployment' at the same time as other basic medical examinations are being given. The same test would then be given 'post-deployment' for those soldiers who were exposed to a blast. Certain differences in the pre- vs. post-deployment test might provide an objective parameter to corroborate a clinical diagnosis of blast- induced TBI.
Importance of the Research to the VA Research Portfolio and Patient-care Mission Mild traumatic brain injury (TBI) related to deployment in the Middle East is rampant among our soldiers -- 18% of all of our troops in Iraq have mild TBI and the RAND Corporation has estimated that 320,000 of our soldiers may have experienced at least mild TBI. Even in mild TBI, which accounts for 80% of all TBI cases, there is evidence of diffuse axonal injury which is believed to be the cause of the behavioral and cognitive abnormalities that very frequently develop in the veterans. These changes can be severe and are typically permanent. The diagnosis of mild TBI is very challenging because there are no grossly evident neurological findings (like paralysis) and because of the frequent co-existence of post-traumatic stress disorder (PTSD) and depression, which are present in 44% and 27%, respectively, in soldiers with mild TBI. PTSD and depression can independently degrade cognitive and behavioral performance, and they exacerbate both the subjective complaints and objective cognitive deficits in mild to moderate TBI. Consequently, these psychological factors can be difficult to separate from the consequences of physical injury to the brain itself. This tangle of factors substantially increases the risk of diagnostic imprecision, particularly when purely subjective reports or tests are used to assess the state of psychological health. Failure to establish the correct profile of disabilities leaves affected soldiers without a full explanation for their disabilities and hinders the appropriate delivery of medical care. This proposal is motivated by the desire to improve the diagnostic sensitivity of TBI, especially mild TBI. Our research strategy proposes development of a non-invasive and portable visual test to objectively diagnose cases of mild TBI by recording eye movements. There is solid evidence that certain eye movement functions are preferentially damaged in TBI, and we hypothesize that certain signature eye movement profiles will have a high degree of concordance with the clinical diagnosis of TBI. Our proposal calls for the development of this new eye movement test by using advanced monitors and customized software. The monitor that we propose to use is lightweight and can therefore be used as a testing platform outside of a traditional laboratory setting. Given the opportunity to develop this new test instrument, our long-range goal is to use this new and portable eye movement test as a screening tool that would be administered pre-deployment at the same time as other basic medical examinations are being given. The same test would then be given post-deployment for those soldiers who were exposed to a blast. Certain differences in the pre- vs. post-deployment test might provide an objective parameter to corroborate a clinical diagnosis of blast-induced TBI. We also hypothesize that certain eye movement characteristics might correlate with the presence of anxiety (i.e. poor visual fixation control) or depression (i.e. slowed response times on certain tests). The test will be designed so that it can be given by a technician who would follow simple instructions that would be embedded into the testing methods. The portability of the device and the ease of administration of the test would enable widespread use of the test should our research demonstrate value of the test in the diagnosis of TBI. This proposal is part of the research effort of the Center for Innovative Visual Rehabilitation (CIVR) in Boston. The CIVR exists as one of several centers of advanced engineering and biological technologies (RR&D Centers of Excellence) within the VA family. Collectively, these VA-based researchers are committed to the development of novel solutions to improve quality-of-life for our veterans. Our Center is devoted to the use of these methods to provide improved visual rehabilitation opportunities for veterans.
