Biofeedback and Stress Management

Design and build an inexpensive and portable electroencephalogram for use during meditation. The device must provide adequate, non-disturbing feedback informing the the practitioner of their current meditation state. The ultimate goal is to help the user reach an optimal state of meditation. Problem Statement

Motivation Difficult to asses when meditative states have been reached for novice practitionersDifficult to asses when meditative states have been reached for novice practitioners Helps aid advanced users to achieve optimal meditation statesHelps aid advanced users to achieve optimal meditation states Research has shown that feedback increases user’s awareness of mental stateResearch has shown that feedback increases user’s awareness of mental state

Brain activity shifts from right to left frontal cortex – lowers stress levels Brain activity shifts from right to left frontal cortex – lowers stress levels Decreases the negative effects of stress, mild depression and anxiety Decreases the negative effects of stress, mild depression and anxiety Less activity in the amygdala, where the brain processes fear and aggression Less activity in the amygdala, where the brain processes fear and aggressionBackground Benefits of Meditation Kabat-Zinn, et.al

Beta State Beta State – 13 – 40 Hz – Alertness, Concentration, Cognition Alpha State Alpha State – 8 – 13 Hz – Relaxation, Visualization, CreativityBackground Meditation States

Theta State Theta State – 4 – 7 Hz – Meditation, Intuition, Memory Delta State Delta State – 8 – 13 Hz – Detached awareness, Healing, Sleep Background Meditation States

Previous Work Circuit Design Electrodes Amplifier and switch  -filter  -filter Rectifier and Averager Feedback Meditation Practitioner Analog circuit block diagram

Previous Work Electrodes Slim suction cupSlim suction cup Silver wire for signal transductionSilver wire for signal transduction Stitched felt layersStitched felt layers Adequate for this semester’s prototypeAdequate for this semester’s prototype

Previous Work Electrode Placement Ground(1)—anterior cranial (frontal lobe)Ground(1)—anterior cranial (frontal lobe) Signal Reference(2)—posterior inferior cranial (occipital lobe)Signal Reference(2)—posterior inferior cranial (occipital lobe) Interference from muscle and hair movements reduced with this arrangementInterference from muscle and hair movements reduced with this arrangement

Previous Work Feedback Inadequate Feedback Auditory feedback distracting to the userAuditory feedback distracting to the user Difficult to distinguish between tonesDifficult to distinguish between tones Uses voltage controlled oscillator (VCO)Uses voltage controlled oscillator (VCO) Provides audio feedback based on a variable frequency square waveProvides audio feedback based on a variable frequency square wave

Design Focus for Fall 2003 and Spring 2004 The creation of a computer based model designed to test the feasibility of auditory and or visual feedback options without the time consuming task of developing and manipulating an analog circuit. Solution: Labview

Advantages of Labview Acquisition and Recording of Data Acquisition and Recording of Data Allows historical analysis of a complete meditation session Allows historical analysis of a complete meditation session Can determine percentage of time spent in desired frequency states Can determine percentage of time spent in desired frequency states Gives a complete computerized model of the ideal prototype we would like to develop Gives a complete computerized model of the ideal prototype we would like to develop

Computer Model Block Diagram Electrodes Low pass filter (f c = 50 Hz) Amplifier (15000 gain) Meditation Practitioner Labjack Data Acquisition Visual feedback Power Spectrum vs. time Power Spectrum (  awake) Filters ( , awake) Audio feedback - analog - analog - digital - digital

Graphical User Interface Power SpectrumsPower Spectrums InputInput Awake, Alpha, Theta Filtered SignalAwake, Alpha, Theta Filtered Signal “LED” Visual Indicators“LED” Visual Indicators Awake, Alpha, ThetaAwake, Alpha, Theta Maximum of power spectrum vs. timeMaximum of power spectrum vs. time

Future Work: Spring 2004 Electrode Placement Electrode Placement Electrode gel conductivity Electrode gel conductivity Continue work on Labview Model Continue work on Labview Model Implement Computer based model into portable microprocessor Implement Computer based model into portable microprocessor Test Model on meditation subjects Test Model on meditation subjects