EMG Biofeedback Device BME 200/300 Fall 2003 Department of Biomedical Engineering University of Wisconsin-Madison

Introduction Team Members : Team Members : Tom Chia Jason Ethington Tim Rand Kim Treml Brent Geiger

Introduction Client: Client: Arleigh Birchler MDiv, BSN Advisor: Advisor: Professor John Webster

Presentation Overview Problem statement/description Problem statement/description Background Background Client requirements Client requirements Subgroup Presentations Subgroup Presentations - Proposed designs -Final design solution -Potential Problems

Problem Statement The goal of the project is to design an EMG biofeedback device to allow a patient with Lissencephaly to exhibit some physical control over their life The goal of the project is to design an EMG biofeedback device to allow a patient with Lissencephaly to exhibit some physical control over their life Measure, amplify, and process EMG signal to provide physical and cognitive stimulation Measure, amplify, and process EMG signal to provide physical and cognitive stimulation

Lissencephaly Malformation of the Brain Malformation of the Brain Causes Vary Causes Vary Symptoms Symptoms Severe Mental Retardation Severe Mental Retardation Poor Control of Movement Poor Control of Movement Frequent Seizers Frequent Seizers Pneumonia Pneumonia Background

Background Description of Child Description of Child  Occasional C-posturing  Responsive to tactile stimuli (touch/vibration/heat)  Very limited muscle control  Fully developed limbic system - Full range of emotions -Ability for operant and/or classical conditioning  Confined to chair

Background The Chair   Padded guards stabilize the child’s chest.   Shoulders above the guards, arms on either side

Client Requirements Feedback triggered by EMG signal Feedback triggered by EMG signal Vibration triggered by only voluntary muscle contractions Vibration triggered by only voluntary muscle contractions Timer to control duration of vibration Timer to control duration of vibration Vibrating pad comfortable for continuous use Vibrating pad comfortable for continuous use Processor to record activity of device Processor to record activity of device

Proposed Design Solutions Subgroup Presentations Subgroup Presentations

EMG Biofeedback Device Proposed Design Solution Brent Geiger Jason Ethington

Basic Circuitry Analog vs. Digital Analog vs. Digital Simple Inexpensive Easy to build and test Ideal for simple activation and deactivation of massage pad Programmable Memory/data storage Allows for logic/learning operations Ideal for more complex circuit operations Advantages:

Basic Circuitry Analog vs. Digital Analog vs. Digital No memory Perform only one function No logic/learning applications Complex Require programming experience and expertise to design and build Disadvantages:

Basic Circuitry Simple analog circuit design chosen Simple analog circuit design chosen - Time Constraints -Limited experience with digital circuitry Digital Circuit basis for future work Digital Circuit basis for future work

Analog Circuit Design Function Function - Detect Voluntary EMG Signal - Activate massage pad for set time period - Terminate massage after period expires

Analog Circuit Design

EMG Amplifier – Common biosignal amplifier EMG Amplifier – Common biosignal amplifier Rectifier – Passes only positive signal component Rectifier – Passes only positive signal component Low Pass Filter – Outputs steady DC signal Low Pass Filter – Outputs steady DC signal Comparator – Compares signal with prescribed reference voltage Comparator – Compares signal with prescribed reference voltage Timer – Terminates massage after set time period Timer – Terminates massage after set time period Triac – Activates massage pad Triac – Activates massage pad

Design Variables Placement of Electrodes Placement of Electrodes - Detect only Voluntary Movement - Detect only Voluntary Movement - Large Muscle - Large Muscle - Easy to apply - Easy to apply Options Options - Thigh muscle - Thigh muscle - Bicep - Bicep - Calf - Calf

Design Variables Massage Pad Massage Pad - Fit in child’s chair - Fit in child’s chair - Cause no discomfort/irritation - Cause no discomfort/irritation - Easy to maintain - Easy to maintain Options Options - Purchase commercial pad - Purchase commercial pad - Design and construct own pad - Design and construct own pad

Final Design Analog Circuit Analog Circuit Electrodes on Thigh Electrodes on Thigh Build our own Pad Build our own Pad Vibrating Pad Analog Circuitry Electrodes

Potential Problems Pending agreement of child’s mother to allow testing Pending agreement of child’s mother to allow testing Irregular EMG signal Irregular EMG signal

Future Work Design Circuit Schematic Design Circuit Schematic Select and order circuit components Select and order circuit components Build and test circuit on breadboard Build and test circuit on breadboard Buy massage pad and modify Buy massage pad and modify After circuit test order and build design on circuit board After circuit test order and build design on circuit board