electromyography
Download
Skip this Video
Download Presentation
Electromyography

Loading in 2 Seconds...

play fullscreen
1 / 14

Electromyography - PowerPoint PPT Presentation


  • 288 Views
  • Uploaded on

Electromyography. ENGR 518 – Experimental Techniques Katlin Landers. outline. Overview of Electromyography Significance Theory How Electromyography Systems work Converting MUP to Electrical Signal Acquiring Signal Post-processing Methods Common Factors Affecting EMG Summary

loader
I am the owner, or an agent authorized to act on behalf of the owner, of the copyrighted work described.
capcha
Download Presentation

PowerPoint Slideshow about ' Electromyography' - kin


An Image/Link below is provided (as is) to download presentation

Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author.While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server.


- - - - - - - - - - - - - - - - - - - - - - - - - - E N D - - - - - - - - - - - - - - - - - - - - - - - - - -
Presentation Transcript
electromyography

Electromyography

ENGR 518 – Experimental Techniques

Katlin Landers

outline
outline
  • Overview of Electromyography
  • Significance
  • Theory
  • How Electromyography Systems work
    • Converting MUP to Electrical Signal
    • Acquiring Signal
    • Post-processing Methods
  • Common Factors Affecting EMG
  • Summary
  • References
overview of electromyography
Overview of Electromyography
  • Electromyography
    • Used to evaluate and record skeletal muscle activation
    • Electrical potential is detected
  • Used in Biomechanics
    • Research
    • Medical Evaluation
    • Therapy

http://www.amputation.research.va.gov/images/emg_testing.png

significance
Significance
  • Research
    • Analyze muscle patterns
      • During static and dynamic movements
    • Optimize athlete performance
  • Medical Evaluation
    • Detect neuromuscular abnormalities
      • Involuntary muscle twitching
      • Muscular dystrophy
  • Therapy
    • Evaluate muscle recovery post-injury or surgery
    • Help control movement of devices

H. Hendricks, M. IJzerman, J de, Kroon, and G. Zilvold, “Functional electrical stimulation by means of the ‘Ness HandmasterOrthosis’ in chronic stroke patients: an exploratory study,” Clinical Rehabilitation, vol.15, pp.217-220, 2001.

theory
Theory
  • Resting Membrane Potential
    • -70 to -90 mV
  • Nerve Action Potential (NAP)
    • Releases chemical transmitter
    • Depolarizes muscle fibers
  • Muscle Action Potential (MAP)
    • Electrical potential of muscle

fiber

  • Motor Unit Potential (MUP)
    • Superimposed MAP from

multiple fibers

converting mup to electrical signal
Converting mup to Electrical Signal

http://sine.ni.com/images/products/us/040716_usb6008_m.jpg;http://smpp.northwestern.edu/bmec66/weightlifting/images/emg_electrode.jpg;http://noraxon.com/products/instruments.php3; http://www.officeclipart.com/office_clipart_images/laptop_computer_0515-0909-2120-0444_SMU.jpg

acquiring signal
Acquiring signal
  • Surface Electrodes
    • Commonly used
  • Intramuscular Electrodes
    • Used for access to deep muscles
    • Needle and fine- wire electrodes

http://www.noraxon.com/img/electrodes/dual-electrodes.jpg

http://www.rehab.research.va.gov/jour/02/39/6/Knutsonf01.jpg

post processing methods
Post-processing methods
  • Evaluate offset
  • Rectify Data
    • Take the absolute value of the acquired data
  • Low Pass Filter Data
  • Normalize Data
    • With maximum EMG contraction
  • Result is a percent of Maximum contraction
common factors affecting emg
Common factors affecting emg
  • Electrical Noise
    • Decreased Impedance
      • Use of gel, shave hair, abrade skin
    • Grounding
    • Motion Artifact
  • Electrode Placement
    • Incorrect muscle
    • Incorrect placement on desired muscle
      • Correct: Belly of muscle
      • Incorrect: muscle-tendon connection
summary
Summary
  • Electromyography has a variety of uses
  • EMG is a process which converts action potentials into electrical signals
  • Systems used to record signals
    • Surface vs intramuscular
    • Wireless vs wired
  • Negative aspects
    • Mechanical adjustments
    • Post-processing
references
References
  • Human Factors BME 533
  • “Occupational Biomechanics (4thEd.)” Don B. Chaffin, Gunnar B. J. Andersson, Bernard J. Martin Wiley Interscience, 2006
  • http://www.noraxon.com/
  • http://psychology.uchicago.edu/people/faculty/cacioppo/jtcreprints/fc86.pdf
ad