Portable Electroencephalogram Biofeedback Device Final Report Update December 16 th 2005 P P BME 200 Team Members Ashley Anderson III Christopher Wegener Ryan Thome Shikha Michele Lorenz Client Daniel Muller Advisor John Webster Table of Contents 1 Abstract 2 Problem Statement 3 Introduction 4 Literature Search 5 Design Constraints 6 Proposed and Final Designs 6 1 Electrodes Design Matrix Modified Final Design Electrolyte Solution 6 2 Amplifier 6 3 Feedback Method 6 4 Current Prototype 7 Design Testing 8 Future Work 8 1 Signal Acquisition 8 2 Signal Conversion to Feedback 8 3 Aesthetics 9 References 10 Product Design Specifications 1 Abstract Biofeedback is a therapy currently being researched to treat many psychological and physiological disorders It is not known how attempting to control autonomic functions of the brain may help resolve abnormalities but results overwhelmingly point towards biofeedback s legitimacy EEG biofeedback involves the monitoring and altering of brain activity and has been shown to effectively treat such problems as epilepsy mood disorders addictions and attention deficit hyperactivity disorder The majority of EEG biofeedback devices are designed for use in clinical situations by experience personnel To apply this technology to a personal setting an inexpensive and user friendly device is required that can process brain signals and provide logical interpretations of the recorded activity Several electrode types and feedback mechanisms as well as a design for high gain amplifiers have been researched and analyzed The current early prototype design and anticipated future work are also discussed 2 Problem Statement The goal of our project is to design and build an inexpensive portable electroencephalogram EEG brain wave monitor that teaches meditation practitioners to achieve optimal meditation by the recognition and promotion of EEG alpha and theta waves 3 Introduction Pharmacological therapies have been the standard way of treating most types of disorders and syndromes However alternative therapies are currently being prescribed by physicians as a new approach to healing and include such treatments as acupuncture chiropractics and biofeedback These treatments mechanisms are not very well understood but results demonstrate promising progress in patient rehabilitation One of the most promising of these newly developed alternatives biofeedback allows the user to view their own autonomic physiological changes Physiological variation like pulse blood pressure respiratory rate and brain activity can be monitored and eventually controlled through conscious practice of recognition and propagation of healthy ranges of such bodily functions Our client Dan Muller M D Ph D frequently prescribes meditation as a means of mental health management In order for inexperienced patients to learn how to meditate a device is needed to tell the user exactly what type of activity their brain is currently undergoing When meditation occurs a specific frequency of waves is observed in the brain Typical active brain waves are called beta waves Figure 1 Raw EEG Data and vary between 15 40 Hz Relaxation and drowsiness are noted as alpha waves in the 8 15 Hz range Meditation occurs in the theta waveform at 4 7 Hz In order to monitor neuro biofeedback electroencephalographs EEGs are used to measure surface voltages on the scalp caused by neuron action potentials in the brain These cellular action potentials directly relate to the qualitative and quantitative aspects of brain activity reflecting the mental state within discrete frequency ranges When the user can quantitatively observe the state that their brain is in they can begin to coach themselves into lower frequencies of brain activity without the aid of a biofeedback device This allows the user to achieve a theta waveform meditation much faster and with greater ease in the future With frequent use EEG biofeedback has been shown to improve a variety of ailments such as addictions mood disorders epilepsy and attentiondeficit hyperactive disorder Raymond 2005 4 Literature Search A patent search revealed several methods 6 855 112 5 450 855 5 280 793 for regulating neural responses via monitoring them on a display for the purposes of biofeedback Commercially available products are very expensive and are not typically EEG specific For instance the Stens NeXus 10 serves as an electroencephalogram EEG electrocardiogram ECG electromyogram EMG and slow cortical potentials SCP This device while providing professional grade quality will also run the buyer 4395 C2 and ProComp also manufacture high quality EEG biofeedback devices starting at about 2000 5 Design Constraints The portable EEG brain wave monitor will take an incoming signal from a series of electrodes amplify the signal to measurable and interpretable levels filter out specific frequencies and present the occurrence of those distinctive brain waves in a manner applicable for biofeedback The device should also be small and portable have the ability to be used daily have a relatively simple interface and be comfortable as it will be used while meditating In order to conserve costs internal and external parts need to be as simple and minimal as allowed All aspects of the device need to be in compliance with AAMI and FDA standards and regulations for related devices 6 Proposed Designs The EEG biofeedback device is actually an accumulation of three different areas of designs electrodes for signal acquisition an amplifier to create signal amplification and processing and a biofeedback method for signal feedback Described here are the individual designs for each 6 1 Electrodes The previous years electrode design consisted of an elastic headband with two electrodes made of coiled wire folded over a felt surface and covered by another layer of felt Another option that they mentioned was the use of an array of conducting probes which protrude through the hair to make direct contact with the scalp As per their report they could not get a good signal from these electrodes Hence in fall of 2005 we decided to develop a new design for the electrodes The electrodes should be highly conductive easy to use and inexpensive at the same time In the process of brain storming developed three main electrode styles including plate disc electrodes pin electrodes and sponge coaxial electrodes The plate electrode consisted of a flat disc plate http www electrodestore com generally around 6 10 mm in
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