EMG Biofeedback EMG Biofeedback DeviceDevice

BME 200/300BME 200/300Fall 2003 Fall 2003

Department of Biomedical Department of Biomedical Engineering Engineering

University of Wisconsin-University of Wisconsin-MadisonMadison

IntroductionIntroduction

Team MembersTeam Members::

Tom ChiaTom ChiaJason EthingtonJason Ethington

Tim Rand Tim Rand Kim TremlKim Treml

Brent GeigerBrent Geiger

IntroductionIntroduction Client:Client:

Arleigh BirchlerArleigh BirchlerMDiv, BSNMDiv, BSN

Advisor:Advisor:Professor John WebsterProfessor John Webster

Presentation OverviewPresentation Overview Problem statement/descriptionProblem statement/description BackgroundBackground Client requirementsClient requirements Subgroup PresentationsSubgroup Presentations

--Proposed designsProposed designs-Final design solution-Final design solution-Potential Problems-Potential Problems

Problem StatementProblem Statement The goal of the project is to design The goal of the project is to design

an EMG biofeedback device to allow an EMG biofeedback device to allow a patient with Lissencephaly to a patient with Lissencephaly to exhibit some physical control over exhibit some physical control over their life their life

Measure, amplify, and process EMG Measure, amplify, and process EMG signal to provide physical and signal to provide physical and cognitive stimulationcognitive stimulation

LissencephalyLissencephalyMalformation of the BrainMalformation of the BrainCauses VaryCauses VarySymptoms Symptoms Severe Mental RetardationSevere Mental Retardation Poor Control of MovementPoor Control of Movement Frequent SeizersFrequent Seizers PneumoniaPneumonia

Background

BackgroundBackground Description of ChildDescription of Child

Occasional C-posturingResponsive to tactile stimuli (touch/vibration/heat)Very limited muscle controlFully developed limbic system

-Full range of emotions-Ability for operant and/or classical conditioning

Confined to chair

BackgroundBackground

The ChairThe Chair Padded guards

stabilize the child’s chest.

Shoulders above the guards, arms on either side

Client RequirementsClient Requirements

Feedback triggered by EMG signalFeedback triggered by EMG signalVibration triggered by only voluntary Vibration triggered by only voluntary muscle contractionsmuscle contractionsTimer to control duration of vibrationTimer to control duration of vibrationVibrating pad comfortable for Vibrating pad comfortable for continuous usecontinuous useProcessor to record activity of deviceProcessor to record activity of device

Proposed Design Proposed Design SolutionsSolutions Subgroup PresentationsSubgroup Presentations

EMG Biofeedback EMG Biofeedback DeviceDevice

Proposed Design Solution Proposed Design Solution

Brent Geiger Brent Geiger Jason EthingtonJason Ethington

Basic CircuitryBasic Circuitry

Analog Analog vs. vs. DigitalDigital

•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: Advantages:

Basic CircuitryBasic Circuitry

Analog Analog vs. vs. DigitalDigital

•No memory •Perform only one function•No logic/learning applications

•Complex•Require programming experience and expertise to design and build

Disadvantages: Disadvantages:

BasicBasic Circuitry Circuitry Simple analog circuit design Simple analog circuit design

chosenchosen--Time ConstraintsTime Constraints-Limited experience with digital -Limited experience with digital

circuitrycircuitry

Digital Circuit basis for future workDigital Circuit basis for future work

Analog Circuit DesignAnalog Circuit Design FunctionFunction

- Detect Voluntary EMG Signal- Detect Voluntary EMG Signal- Activate massage pad for set time - Activate massage pad for set time

periodperiod- Terminate massage after period - Terminate massage after period

expiresexpires

Analog Circuit DesignAnalog Circuit Design

EMG AmplifierInput

Electrodes Rectifier

Passive Low PassFilterComparator

ProgrammableMicrocontroller

Timer

Triac Massage Pad

Analog Circuit DesignAnalog Circuit Design

EMG Amplifier – Common biosignal amplifierEMG Amplifier – Common biosignal amplifier Rectifier – Passes only positive signal componentRectifier – Passes only positive signal component Low Pass Filter – Outputs steady DC signalLow Pass Filter – Outputs steady DC signal Comparator – Compares signal with prescribed Comparator – Compares signal with prescribed

reference voltagereference voltage Timer – Terminates massage after set time Timer – Terminates massage after set time

period period Triac – Activates massage padTriac – Activates massage pad

Design VariablesDesign Variables Placement of ElectrodesPlacement of Electrodes - Detect only Voluntary Movement- Detect only Voluntary Movement - Large Muscle- Large Muscle - Easy to apply- Easy to apply

OptionsOptions - Thigh muscle - Thigh muscle - Bicep- Bicep - Calf- Calf

Design VariablesDesign Variables Massage PadMassage 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

OptionsOptions - Purchase commercial pad- Purchase commercial pad - Design and construct own pad- Design and construct own pad

Final DesignFinal Design Analog CircuitAnalog Circuit Electrodes on ThighElectrodes on Thigh Build our own PadBuild our own Pad

Vibrating PadAnalog Circuitry

Electrodes

Potential ProblemsPotential Problems Pending agreement of child’s Pending agreement of child’s

mother to allow testingmother to allow testing Irregular EMG signalIrregular EMG signal

Future WorkFuture Work Design Circuit Schematic Design Circuit Schematic Select and order circuit componentsSelect and order circuit components Build and test circuit on breadboardBuild and test circuit on breadboard Buy massage pad and modifyBuy massage pad and modify After circuit test order and build After circuit test order and build

design on circuit boarddesign on circuit board