Transcript Myoelectric Prostheses - Electrical, Computer & Biomedical

Myoelectric Prostheses
By: Courtney Medeiros
BME 281
10/26/11
What are Myoelectric
Prostheses?
• Uses electromyography
signals/ electric potentials from
voluntarily contracted muscles
within a person’s residual limb
to control movements of the
prosthesis.
• Electromyography (EMG):
process of detecting electric
potentials and translating them
into motions.
• Movements include:
• Elbow flexion/extension
• Wrist supination/pronation
• Opening/closing of fingers
History of Myoelectric
Prostheses
•
The typical alternative to myoelectric prostheses are hook
prostheses (which began in the middle ages with pirates), bodypowered prostheses, and cosmetic prostheses
•
1920’s: Ferdinand Sauerburch & Aurel Stodola in Zürich,
Switzerland: created a hand prosthesis controlled and powered
by muscles of residual limb
•
WWII (1945): America & the rest of the world started
mobilizing for research and development
• 1949: Alderson: external power source to develop first electrically
powered arm
• 1958: Russians: first myoelectric arm
• 1980’s-Present: Many developments and advancements
Who is Eligible?
• Used for congenital limb deficiencies and
amputations from cancer, trauma, or surgery.
• Must have EMG voltage of at least 15μV, the scar
must be able to hold the weight of the arm, and must
pass motor/control test
How it Works
More Device Information
• Weight:
• Can weigh as little as ¼ the weight of an average
human arm
• For children it can be made to weigh as little as a ½
pound
• Has a rechargeable battery
• Proprioceptive feedback
Maintenance
• Can get first myoelectric prosthesis
between 16 to 24 months of age
• When used on a child, the sockets need
to be replaced every year due to growth
• Typically come with one-year warranty
• Motor and drive last about two to three
years
• With heavy use, the entire prosthesis
may need to be replaced after only five
years
Advantages & Disadvantages
• Advantages
• Greater range of
movement
• Less bulky compared
to a body powered
prosthesis
• Disadvantages
• Expensive!
• Not suitable to people
involved with heavy
work loads
• Don’t last that long
Future
• Smoother motions
• Cheaper
• Eventually make lower limb myoelectric protheses
• Make them more durable to last longer and make them
available to people who have heavy work loads
Questions?
Sources
• Meier, R.H. (2004). Functional restoration of adults and children
with upper extremity amputation. New York, NY: Demos Medical
Publishing Inc.
• http://www.aetna.com/cpb/medical/data/300_399/0399.htm
l
• http://www.ballert-op.com/myoelectric_control.asp
• http://www.ncbi.nlm.nih.gov/pubmed/10989484
• http://medtraining.northwestern.edu/repoc/research/projects
/upperlimb/uplimb_imes.html
• http://www.scribd.com/doc/18651364/Myoelectric-Arm
• De Luca, C.J. (1979, June). Physiology and mathematics of
myoelectric signals. IEEE Transactions on Biomedical Engineering,
26(6), 313-325.