Recent advances in medical science, as well as growing public awareness of the potentially disabling effects of concussions in athletes and in combat veterans, have highlighted the growing need for effective methods for diagnosing and quantifying the effects of acute mild TBI (mTBI). Brain imaging techniques can be useful in identifying large scale changes in global functional connectivity and temporal incoherence (fMRI, MEG, EEG), white matter integrity (DTI), and some neurotransmitter concentration changes (MRS), but the current standard of care for evaluating concussion using imagery is a CT or MRI of the brain, both of which are useful in identifying gross morphological changes but cannot rule out mTBI. Additionally, these imaging methodologies, even when successful in detecting mTBI, are costly, relatively slow and impractical to make available to a wide spectrum of users. Clinical neurological examinations are relatively insensitive to subtle changes which may be associated with mTBI. Neuropsychological testing may be effective in characterizing changes in neurocognitive functioning following mTBI but is vulnerable to potential biases arising from suboptimal effort and individual differences in baseline performance. Similarly, self-report of post-concussive symptoms is subject to potential under- or over-reporting, and lacks specificity, as many symptoms of post-concussion syndrome are prevalent in individuals with no history of TBI. To address this problem, we developed a novel approach to sensory testing, and to enable this approach we designed and fabricated a new device, which is a low cost portable computer peripheral that enables high resolution tactile sensory testing. Design and validation of the methods was based on non-human primate neurophysiological studies, and because of the high degree of correlation between the evoked cortical activity in those studies, and the metrics obtained from subsequent human sensory perceptual studies, the measures are referred to as cortical metrics. The system designed to deliver these tests does not require significant training to administer, and individual tests or protocols can be delivered rapidly (1-3 minutes per test). A number of these tests non-invasively deliver tactile illusions to the skin, which in healthy CNS conditions, causes subjects to perform worse on sensory assessment tasks. Subjects or patients with some type of neurological insult typically perform better than healthy controls on these illusory tasks, and utilizing a battery of protocols and a combinatorial mathematical approach, our pilot data demonstrates a 99% confidence level for differentiating concussed vs. non-concussed individuals. This application proposes to establish solid proof-of-concept that the methodology can be used as a reliable indicator of CNS health status for differentiating concussed vs. non-concussed individuals and to further optimize the method. The overall long term goal of the work is to develop standardized measures of CNS health that can be utilized to compliment the assessments currently used for concussion/TBI in both clinical and sports training center environments.
TO PUBLIC HEALTH The overall goal of the proposed work is to investigate the utility of novel sensory-based methodologies that are currently being used in both basic and clinical research. Recently, utilizing state-of-the-art technology, we built a multi-site tactile stimulator that allows for investigation of central nervos system (CNS) health and advanced methods in sensory perceptual metrics. These metrics have been demonstrated to be sensitive to changes in centrally mediated mechanisms;and systemic alterations of cortical health (via neurodegenerational, neurodevelopmental, pharmacological or trauma induced changes) robustly change the measures. It is anticipated that clinicians will be able to utilize these measures to improve diagnostic performance and enable assessment of efficacy of treatment. The study itself will serve to validate the utility of a number of these measures in concussion and eventually provide health workers with a means to detect when an individual is concussed and to track the recovery of an individual from concussion. The information from this study could aid in understanding centrally mediated mechanisms that undergo significant alterations with concussion/TBI.