Auditory and Visual Stimuli System for Fast Eye Movement Analysis Team #3: Brian Lewis Anthony Vessicchio Steven Kapinos Client Contact: Dr. John D. Enderle Biomedical Engineering Book Series Editor for Morgan & Claypool Publishers Professor of Biomedical Engineering University of Connecticut Bronwell Building, Room 209 260 Glenbrook Road Storrs, Connecticut 06269-2247 Phone: (860) 486 5521 Fax: (860) 486-2500 Email: jenderle@bme.uconn.edu Web: http://engr.uconn.edu/~jenderle
2 Executive Summary The auditory and visual stimuli system for tracking fast eye movement is being designed to allow our client, Dr. John Enderle, to expand on his research and to achieve his goal of creating a system that is able to diagnose mild traumatic brain injury. Our design will consist of a combination of visual and auditory stimuli. Our device will use an EOG signal in order to accurately record eye movements in response to the two types of stimuli. The device will consist of several sources of visual and auditory stimuli at various locations on the device in order to examine the patient as thoroughly as possible. Our device will be designed so that each source of visual stimuli will have a corresponding speaker at the same location. Our system will also be designed so that the stimuli appear to be activated randomly to the patient in order to get the most accurate test possible. Our system will also use a LabView program in order to input the EOG signals and display them in a way that will allow for the determination of whether or not a person has suffered a mild traumatic brain injury. Previous senior design teams have already built a preliminary device for our project and not many additional expensive parts are needed which will help keep our budget under 1,000 USD. 1 Introduction 1.1 Background Our client, Dr. John Enderle, is a researcher and professor at the University of Connecticut. Over the past thirty years, he has spent his time researching rapid eye movements and their corresponding neuronal activities. His research has led to the belief that there is a way to determine whether or not a person has suffered a mild traumatic brain injury based on their results from a visual/auditory combination eye movement test. His final goal is to build a device that is able to produce a combination of auditory and visual stimuli at several different locations in order to test as many different eye movements as possible. The device will use an EOG signal in order to track the eye movements and to get the most accurate readings possible. By recording the rapid eye movements of the patients in response to the visual and auditory stimuli, the device will be able to determine an accurate diagnosis. In the United States alone, around one million people suffer at least one concussion every year. In today s society, many people are at risk for concussions including people who partake in popular contact sports such as football and hockey, as well as active members of the military. If ignored or treated improperly, concussions can lead to very serious long term traumatic brain injuries and even death. Dr. John Enderle, along with previous senior design teams, has come up with a preliminary design for the auditory and visual stimuli system for tracking fast eye movements and has asked that we modify the design in order to implement an accurate way to record the response to the auditory and visual stimuli at several different locations. 1.2 Purpose of the Project The auditory and visual stimuli system for fast eye movements will be used in order to help our client further pursue his goal of diagnosing patients with mild traumatic brain injury. The design for this system is necessary in order to achieve a way to safely, efficiently, and accurately diagnose a patient with mild brain trauma. The auditory and visual stimuli system
3 will be able to test patients of all heights and weights and will be durable so that it will be able to run several tests. As previously mentioned, the device will be made so that the auditory and visual stimuli sources are activated in a randomized fashion so that the subject does not know the location of the stimuli prior to testing. This will assure that the recorded response of the subject s eye movements are an accurate portrayal of the subject s ability to react to the stimuli. Our client will be able to use the results from the auditory/visual stimuli tests done using our device and ultimately use them to accurately diagnose patients with potential mild traumatic brain injury. Once the device is properly modified to include clear auditory stimuli at each visual stimuli location, it will be able to accurately track the subject s ability to respond to the different types of stimuli and ultimately determine an accurate diagnosis using the data from their eye movements. 1.3 Previous Work Done by Others As previously discussed, in today s society may people are at a high risk for concussions. There is a great need in the military and in contact sports such as football and hockey for an accurate and efficient way to test for concussions. Currently, there are several concussion tests available on the market. However, most of them involve a series of long cognitive tests that require in depth baseline tests. There is a great need for a test that is more efficient while still accurate. The most commonly used computerized concussion test today is the ImPACT test. The ImPACT test is able to measure patient symptoms and help assist a doctor in making return-to-play decisions. However, the ImPACT test takes around 20 minutes to complete and is not supposed to be used as a stand-alone tool. Our client hopes that our design will be more efficient and that it will be able to be used as a stand-alone tool to diagnose mild traumatic brain injury. 1.3.1 Products Dr. Laura J. Balcer of the Departments of Neurology, Ophthalmology, and Epidemiology at the University of Pennsylvania School of Medicine determined in 2010 that the King- Devick test is and accurate and reliable method for diagnosing athletes with head trauma. She is currently trying to implement the test into being used on the sidelines of contact sports for concussion testing. However, Dr. Balcer s method does not involve the neurological response of the patient s to auditory stimuli which our client feels is important in proper concussion testing. Dr. Enderle plans to be the first researcher to study eye movements in response to auditory and visual stimuli for the purpose of diagnosing concussions. 1.3.2 Patent Search Results United States patent number 12/979,419 is held by David W. Hagedorn and James W.G. Thompon and is similar to the device we are building in that it uses an electrode system in order to analyze the brain s response to auditory and visual stimuli. However, the device in this patent does not involve mechanical structure like our black board containing the visual and auditory stimuli sites. Our device is very unique in that Dr. John Enderle is the first researcher to study the possible diagnosis of mild traumatic brain injury using the data from rapid eye movements in response to auditory and visual stimuli. Due to this, this patent and
4 other products on the market are not similar enough to jeopardize the originality of our design. 2 Product Description 2.1 Objective The device that will be designed will be an auditory and visual stimuli system for fast eye movement analysis. It will be designed to include several LED lights which will serve as visual stimuli sources. Each LED light will have its own individual speaker at the same location. The device will use an EOG signal as the input and will be able to record the rapid eye movements of the subject in order to determine whether or not they have suffered mild traumatic brain injury. The EOG signal will be used to obtain an accurate response from each subject during testing. During the test, the patient will be asked to focus on the location of the visual and auditory stimuli and their eye movements will be recorded. The stimuli sources will be activated in a randomized manner to assure that the subject does not know the location of the stimuli prior to testing. The device will be able input the signal from the EOG signal in response to the two types of stimuli and using LabView, the system will be able to display the recordings in a readable format that will be able to be used for diagnosis. The device itself will consist of a curved black board with several LED lights used as the visual stimuli at several locations. The goal is to implement small speakers behind each LED light in order to have auditory and visual stimuli at each LED location. This will allow for our client to test each subject and see compare data such as Auditory-Visual vs. Visual, Auditory-Visual vs. Auditory, and Auditory vs. Visual in order to determine the differences between each test method and to determine which is most effective. As the test is run on the device, all eye movements will be collected through the previously mentioned EOG signal. The input signal from the EOG signal will output through a LabView program which will be able to display the movements in a manner that can be analyzed by our client and/or future researchers. The data collected from our device will be used by our client for further research in determining the relationship between rapid eye movement response to stimuli and mild traumatic brain injury. This will help with the ultimate goal of our client which is to be able to successfully build a device that is able to diagnose mild traumatic brain injury using data from fast eye movements. 2.2 Methods The project will include a curved black board that includes several LED lights used as visual stimuli. The LED lights will be organized in a manner in which they are spread out so that our client is able to test eye movements at as many angles as possible. The LED lights will be organized in a series of rows and columns so that they are equally spread out from each other. There will be an individual speaker implemented at the same location of each LED light to make it so that our device is able to produce visual and auditory stimuli at several different locations. The two sources of stimuli will be able to activate simultaneously from the same location in order to test patient s responses to each type of stimulus. The
5 device will also be able to generate sounds with different acoustic features such as intensity and frequency. This feature will allow for the testing of patient responses to different types of sounds which will in turn make the test more effective in diagnosing mild traumatic brain injury. An EOG electrode system will generate the input signal for our device and because an EOG is used, our device will be able to test patients of all heights and weights. No major adjustments will need to be made from test to test. An EOG electrode system is relatively easy to set up from patient to patient and the general placement of EOG electrodes is almost the same for each patient making it as easy as possible for someone to use our device. Figure 1: EOG Electrode Placement One major goal of the device is to assure that the sound generated at each visual stimuli location is clear and precisely at the same location of the visual stimuli. The sound will be generated using the Longcat H3D plugin software on the host of Adobe Audition. The device requires several speakers to be wired into the device in order to produce the previously mentioned auditory stimuli. Due to the large number of speakers that will need to be implemented into the device, the speakers will need to be relatively small to allow them all to fit on the device and they also need to be relatively inexpensive in in order to help us stay under our budget. Each LED and speaker will need to work in conjunction with each other in order to produce simultaneous auditory and visual stimuli.
6 Figure 2: Small and Inexpensive Speaker The device will also require a software component in order to record and display the data from the testing. The software component that will be used is LabView. LabView is compatible with EOG signaling and will be used to input the eye movements recorded from the EOG signal and display them in a manner that allows for the analysis of the testing. The LabView program will display the eye movement response of each patient and allow for us to further analyze and compare the data. The LabView program will allow for us to compare data sets such as: Auditory-Visual vs. Visual, Auditory-Visual vs. Auditory, and Auditory vs. Visual. The ability to analyze and compare the multiple data sets previously mentioned will allow for our client to further his research in the ability to diagnose mild traumatic brain injuries with the use of rapid eye movement testing. The mechanical aspect of our design is relatively simple. As previously mentioned, our device will involve a curved black board. The board is black to allow the patient to focus on the visual stimuli as much as possible. The red LED lights that will be used significantly contrast the black board and allow for the visual stimuli to stand out as much as possible to the patient. The curvature of the board allows the device to be able to test all eye movements including peripheral visual control. This is vital because in order to accurately test a patient for a concussion, it is ideal to examine as many eye movements as possible. 3 Budget Previous work has been done in building the auditory and visual stimuli system for fast eye movement analysis so a lot of the costs have already been paid for. The black board has already been built and assembled so that it is mountable. The LED lights have also been previously supplied. The LabView software has already been purchased by the University of Connecticut so that is another part of the project that has no cost to our team. Although it is necessary to stay under our budget of 1,000 USD, we do not want to jeopardize the functionality, performance, or durability of our device. As previously mentioned, we want to use small and inexpensive speakers to the large number required, however it is still necessary to ensure that the speakers are of good quality. The majority of the parts that we will purchase will be made online to save money on taxes and will also be purchased from U.S. distributors in order to save money on shipping costs. Our client has specifically requested that we purchase an H3D Binaural Spatializer from the company
7 Longcat. Although this product is not made by an American distributor, it is still not very expensive and we have found that it will only cost around 110 USD. Along with the speakers that need to be purchased, the H3D Binaural Spatializer will cost us the bulk of our budget. We have found several different small speakers that can be purchased for 1-3 USD each and once we determine the quality of speaker needed for the device, we will know exactly how much the speakers will cost. Multiple EOG electrodes will be purchased in order to complete several tests using the device. The wiring and circuit estimation of costs was approximated using a rough estimate of the wiring and circuit parts we will need. An estimate of our budgeting can be seen below: Part Estimated Cost H3D Binaural Spatializer $110 Small Speakers $2x77=$144 EOG Electrodes $2x20=$80 Wiring/Circuit Parts $50 Total $384 Table 1: Estimation of Costs It was estimated that this project will cost around $384 which leaves enough room for miscellaneous costs and small parts that we may need to order over the course of designing the project. 4 Conclusion The system we are building will allow for our client, Dr. John Enderle, to further his research in diagnosing mild traumatic brain injuries using data from rapid eye movements. Our device will be capable of producing visual and auditory stimuli at several different locations while being able to test eye movements at several different angles. Our device will use standard EOG electrode placement to record rapid eye movements which makes our device a universal fit for all patients. Many of the components of our device have already been purchased by previous senior design teams and the remaining components are off the shelf products which will allow for us to stay under our budget. Although there are several types of concussion tests already on the market, many of the tests presently available involve running lengthy tests and rely on cognitive questionnaires. Dr. John Enderle is the first researcher to attempt to use fast eye movements as the determining factor for concussion diagnosis which will allow for more efficient and precise concussion diagnosis. Using data from fast eye movement testing will also allow for a quantitative diagnosis of concussions which will make future diagnoses more accurate. Over one million people a year are affected by concussions in the United States alone and there is a great need for a more efficient and accurate way to test for concussions. Once the device is complete, Dr. Enderle will be able to present the device to organizations in need of such a device such as the military and contact
sport leagues of all levels. This great need makes for a very significant market for the device and if successful, can be a product that is used worldwide by millions of people. 8