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Abstract—Mild traumatic brain injury (mTBI), or concussion, is one of the most common forms of injury sustained throughout Operations Iraqi Freedom and Enduring Freedom. Diagnosis is difficult for many of the symptoms are very common and may not manifest themselves immediately after the injury. Many studies on blast-related mTBI have been published from research regarding the current war in Iraq and Afghanistan. Continuous work is underway to more accurately determine its causes and symptoms, as mTBI is considered difficult to diagnose. Using the Oak Ridge National Laboratory (ORNL) developed data mining software Piranha, an integrative literature analysis was conducted to assist and facilitate possible research on the processes of mTBI. Data were collected from academic databases as well as Piranha’s internet search function. The Piranha categories feature was employed to visualize the areas of overlapping research regarding manifestations of mTBI relating to the biological processes and behavioral changes. Piranha was also used to review current research on mTBI, including animal testing on mice and swine. The integrated results from these data mining analyses revealed areas that could be studied further, as well as a clearer indication of the specific processes of mTBI. This research provides a fresh perspective on one of the war’s most common and yet least understood injuries.

I. INTRODUCTION HE focus of this paper is to explain the process of applying data mining methods to literature regarding mild traumatic brain injury (mTBI). Mild traumatic

brain injury, or concussion, is one of the most common forms of injury sustained throughout Operations Iraqi Freedom and Enduring Freedom. Although immediate symptoms may appear mild, patients with mTBI can have lifelong, debilitating complications. Diagnosis is difficult for many of the symptoms are very common and may not manifest themselves immediately after the injury. Although no standard treatment for patients with mTBI exists, doctors

Manuscript received May 15, 2010. The work was performed at the Oak Ridge National Laboratory, which is managed by UT-Battelle, LLC under Contract No. De-AC05-00OR22725. This work has been authored by a contractor of the U.S. Government, accordingly, the U.S. Government retains a non-exclusive, royalty-free license to publish or reproduce the published form of this contribution, or allow others to do so, for U.S Government purposes. The Research Alliance in Math and Science (RAMS) student program is sponsored by the U.S. Department of Energy. J.S. Gauld is an undergraduate from Queen's University in Kingston, Ontario participating in the RAMS program at Oak Ridge National Laboratory. Email: 8jg@queensu.ca. B.G. Beckerman is the Acting Director of the Biomedical Science and Engineering Center and the Program Manager for Biomedical Engineering and Biomedical Informatics in the Modeling and Simulation Group, Computational Sciences and Engineering Division at Oak Ridge National Laboratory. Email: beckermanbg@ornl.gov.

are able to treat their individual symptoms, such as migraines and anxiety. mTBI due to blast injury is the focus of this project. There is a large amount of published literature concerning concussions related to sports injuries and car accidents, but the mechanisms of injury are suspected to be vastly different for blast-related mTBI. Many studies on blast-related mTBI have been published from research regarding the current war in Iraq and Afghanistan. Continuous work is underway to more accurately determine its causes and symptoms, as mTBI is considered difficult to diagnose.

Using the Oak Ridge National Laboratory (ORNL) developed data mining software Piranha, an integrative literature analysis was conducted to assist and facilitate possible research on the processes of mTBI. Piranha is used for large scale text analysis. The program organizes and clusters uploaded documents based on commonly used words and phrases.

A few key features of Piranha were utilized throughout the data mining process. The folder view of Piranha allows top words and phrases in each article to be displayed (See Fig.1). This provides an overview of the articles as a group, as well as the focus of the individual articles. The cluster view of Piranha is the primary visual analysis for the literature. Articles are grouped together based on similar words and phrases. The stop words list allows for the removal of insignificant words and phrases in the literature search, and provides a customization of the data mining to a particular focus. The category feature, as seen in Fig. 2, functions to divide literature automatically by top words and phrases, for comparison and organization in the cluster view. Piranha’s many features allowed for an in-depth analysis of current mTBI literature.

II. METHODS Piranha’s Yahoo search function was initially utilized to

retrieve abstracts and articles related to blast mTBI on the internet. The articles were then clustered in Piranha, and basic knowledge of mTBI’s key characteristics were found.

71 articles were then gathered from resources such as PubMed and Google Scholar, and integrated separately into Piranha. Categories were initially created to divide articles based on their relation to biological processes and physical manifestations. After overlaps in the research were observed using the cluster view, new categories were produced. These categories were divided into a focus on primary, secondary, and tertiary effects of mild traumatic brain injury.

Applying Data Mining Methods to Blast-Related Mild Traumatic Brain Injury

Jillian S. Gauld, Barbara G. Beckerman

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Fig. 1. View of the folder feature of Piranha. Top words and phrases are displayed as well as categorized.

Fig. 2. View of Piranha’s categories feature. Key words entered into categories of primary, secondary and tertiary injuries.

III. RESULTS The visual analysis of collected literature provided the

most useful information. The cluster analyses show the significant articles from this research, as well as trends in current studies. The initial categorization was between articles regarding biological markers, and physical manifestations, as seen in Fig. 3. With the cluster view in Piranha, relevant articles were found that integrate the two approaches of research (See Fig. 4). The most significant articles were indicated by their categorization as biological markers, while included in a cluster of primarily physical manifestations, or vice versa. Using these articles, categories were created based on key words regarding primary, secondary, and tertiary effects of mTBI (See Fig. 5).

The stages of injury were key for dividing literature and analyzing the processes of mTBI. The primary injury was defined as the immediate physical damage resulting from a blast. Axonal shearing is a known form of primary injury. Another primary injury, reduced blood flow to the thalamus, was found as a trend in new research [2]. The thalamus is

thought to control sleep and motor functions, but the exact role is unknown. Damage to the thalamus may account for the tertiary effects after blast injury.

Because the mTBI is caused by a physical impact, it was thought that imaging tests might be useful in detecting the primary injury of mTBIs. Unfortunately, tests such as MRIs and CT scans are often inconclusive in detecting brain damage after blast injury. Unless scanned immediately after a blast injury, any signs of brain damage are mostly overlooked. Often patients that are diagnosed with mTBI do not have any indication of damage to the brain [3].

Fig.3. Cluster analysis of mTBI literature with categories relating to biological markers and physical manifestations.

Fig. 4. A node from the cluster in Fig. 3. Mainly biological markers, the articles relating to physical manifestations (in yellow) indicate an overlap in research.

Fig.5. Cluster analysis of primary, secondary, and tertiary effects of mTBI. Secondary effects involve the inflammatory responses of

the brain after injury. A few biomarkers were repeated in literature that may be significant in future mTBI research. Microglial cells, astrocytic activation, caspsase upregulation, and GFAP (glial fibrillary acidic protein) are all possible biomarkers of mTBI. Recently, though, GFAP was found as an accurate marker of brain injury, but when detected it was fatal [1]. This would not indicate a mTBI. The other biomarkers are possible indicators of a mTBI, but future research is necessary. These biomarkers may be detected up to two weeks after injury, though, so a more permanent biomarker may be more useful in mTBI detection.

Tertiary effects involve the physical manifestations of mTBI, such as sleep problems, depression, and memory loss [5]. These symptoms may be detected from months to a year after injury. The build-up of APP (amyloid precursor protein) in the white matter may contribute to the transient tertiary effects of mTBI. The build of APP is not permanent, and can occur at any time. Similarly, symptoms of mTBI such as sleep problems and depression aren’t always permanent, and may manifest themselves at any time after the injury [4].

There was evidence of co-morbidities relating to blast mTBI. Some research indicated that mood changes were not always a result of brain injury, but damage to other organs. In rat testing, the reason for their loss of appetite and reduced activity may have been related to the blast injury of the intestines [6].

IV. CONCLUSION Mild traumatic brain injury is a condition characterized by

depression, sleep disorders, amnesia, and headaches. The

specific mechanisms of mTBI are still unknown, but may be related to reduced blood flow to the thalamus, and the inflammatory responses of the brain. Although imaging studies are often inconclusive, testing for specific biomarkers such as microglial cells, astrocytes, and caspases, may yield significant results. More permanent biomarkers may be more useful in detecting mTBI. With a two-week window for detecting inflammatory responses, and mTBI not manifesting itself for sometimes months, research into permanent biological markers may contribute to a more clear diagnosis of mTBI.

There is also continuous work being done to distinguish mTBI symptoms from those of post-traumatic stress disorder (PTSD). Because both are war-related, and can cause mental and mood disorders, distinguishing the symptoms is not always possible. A patient may experience a blast injury, but also witness a traumatic event that causes completely unrelated PTSD symptoms. The difference between these two conditions is that in mTBI, molecular changes occur within the brain as a result of injury, while PTSD patients have no physical brain injury. A more in-depth and specific testing process for mTBI will allow the distinction between the two.

Mild traumatic brain injury continues to be a prevalent and debilitating injury among veterans. Research to understand the specific processes of blast injury will help to develop a clearer diagnosis, and more effective treatment for patients with mild traumatic brain injury.

ACKNOWLEDGMENTS Thank you to April McMillan and Robert Patton for contributions to research.

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