Download Motion Analysis

Motion Analysis in Rehabilitation
WHAT IS IT?
 Use of a variety of techniques to analyze and measure human movement and the
underlying forces involved in the movement
WHY DO IT?
 Overall - To provide valid & reliable measurements of ______________________
_________________________________________while the person is moving.
o Patient Management - To compare patient’s movement to typical/normal
movement & identify impairments; to determine underlying causes of
pathological movement, which will guide interventions; to measure change
during/after intervention
o To ________________________________
o For ______________________________
HOW DO WE DO IT?
Simple observational analysis
 Easily done any setting; Low cost
 _____________________ help to organize your observations for Gait Analysis
 BUT…
o Can’t see subtleties/details of movement
o Objectivity is a problem: Interrater reliability only with highly _______________
o No information about underlying causes; requires other tests/measures
Instrument-based Video Motion Analysis
Basic recorded video
 Available & affordable in most settings
 Best with >1 camera; Need digital video camera(s) and computer
 Using still/pause & frame-by-frame playback; can measure some directly from video
Video-based / software enhanced motion analysis systems (2-D)
 Typically 1 – 2 cameras (2-D in two planes – not real 3D); digital video is recorded first.
 Reference points are
identified on “key” still frames and then software
determines angles and distances and produces overlays.
 Other data typically NOT collected simultaneously
 Commercially available systems (Dartfish, Medical Motion)
 Cost is in the hardware – basic camera 30fps, high speed cameras 60-100+ fps
 There’s an app for that! – Simi Move and Dartfish Express on your iPad or iPhone
Active Sensor (LED) based systems (2-D/3-D)
 1 – 2 high speed digital cameras
 Predetermined landmarks (joint centers) are marked with colored LEDs.
 The software determines the segments and joint angles in real-time as the subject
performs the task. Gives a continuous recording of ROM and displacement.
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Key events are marked manually, e.g. gait events, and reports can be generated to
compare against norms.
Commercially available systems (Simi Aktysis)
High-End Automated Motion Analysis
Traditional Infrared (IR) systems
 Typically 6-8 high speed cameras, digital data directly to computer
 Reflective markers placed on the ______________________
 Stringent requirements for setup (usually in lab)
 Other data can be collected simultaneously and synchronized
 Commercially available IR systems (Vicon, Motion Analysis, Optitrack)
Markerless Systems
 Typically 8+ cameras (IR or color high speed), digital data directly to computer
 No markers but contrasting clothing/background is necessary
 Other data can be collected simultaneously and synchronized
 Commercially available systems (DARI and SimiShape 3D)
WHAT CAN WE MEASURE USING HIGH-END AUTOMATED SYSTEMS?
What you get:
 3-Dimensional joint angles and translations, (6
)
 Direction, Velocity, and Acceleration of motion (each joint and whole body)
 Peaks of motion data (minimum, maximum)
 Anything related to time/timing and distance
What you don’t get:
 Forces involved with the movement; i.e. What’s causing the motion?
o What are the __________________ (internal and external) at each joint?
o What ____________________ are contracting (EMG)?
Non-video based Sensors/Systems for Motion Analysis
Force Data via Force Platforms
 Detects __________________________________________ (GRFs)
 GRFs are equal and opposite to those in the body. Given anthropometric
measurements and 3-D motion data, software can be used to determine joint reaction
forces and torques at each joint, and muscle control needed around each joint.
 Can also determine ___________________________________ (COP)
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Kinesiological EMG Data
 Indirect indicator of muscle function
 Can determine timing, relative intensity, and fatigue.
 Electrode types = ______________________________
 Electrode placement important, to avoid cross talk from other muscles
 Signal must be amplified, and filtered (to get rid of noise, movement artifact, etc.)
 Raw EMG is typically then rectified (all signals “flipped” to positive)
 Signals are usually “normalized” for comparison across trial, subjects (e.g., % MVC)
Electrogoniometers
 Worn on subject, can be cumbersome; Most reliable for _______________________
 Single axis or Twin-axis. Total cost >$1,000
 Continuous measurement of joint angles.
 Processing can provide angular velocity.
 Not typically stand-alone but are integrated into other systems.
Electromagnetic and Inertial Measurement Units
 Example: Myomotion by Noraxon and the Polhemus Patriot
 The small units placed on any segment of the body precisely tracks the 3D angular
orientation of that body section.
 Sensors on two contiguous body segments allows the intervening joint ROM to be
determined.
 This data is incorporated into models of the “major joints” to create an animation. (real
time for Myomotion)
 Can also be synchronized with single camera digital video
Instrumented Walkways
 Examples: GAITRite and Protokinetics
 Pressure sensor arrays embedded in portable walkways.
 Objective spatial, temporal and pressure data for automated gait analysis
 Sync with video
Pressure Insoles
 Examples: F-scan, Pedar
 Pressure sensor embedded in flexible insoles that go inside shoes.
 Capture real world in-shoe pressure data for foot function & gait analysis
 Data fed to a data collection unit (wireless, logging, tethered options to PC for
processing/display)
 Sync with video
Motion Monitors - Accelerometers/Gyroscopes +
 Examples: Fitbit and Actigraph
 Wearable sensors that track _
, i.e. steps taken, calories burned,
active minutes and sleep.
 Data is stored in the unit and then downloaded.
 Software (simple apps or complex algorithms) helps make sense of the data.
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