Myoelectric Upper Limb Prostheses
Ledbrook Clinic now provides electronic upper limb prosthetic devices. Myoelectric-controlled prosthetics offer a combination of both function and a natural-looking appearance. They are designed to replicate the human anatomy in both form and movement. Ledbrook Clinic offers Ottobock upper limb devices which contain electronic components that enable the closest possible alternative to an anatomical hand or arm.
Ottobock provides Myoelectric technology, which gives our upper limb patients the ability to:
- Elbows that flex and extend with muscle signals so you can reach for a beverage and bring it to your lips
- Wrists that bend and rotate, allowing you to position objects for convenient viewing and handling
- Hands that can lug a suitcase or hold an egg without cracking it
- Thumbs that can change orientation to multiple hand positions
What is a Myoelectric prosthesis?
“Myoelectric” is the term for electric properties of muscles within the human body. A myoelectric-controlled prosthesis is an externally powered artificial limb that you control with the electrical signals generated naturally by your own muscles. Essentially, these prosthetic devices are able to replicate the movement of the original limb, almost like a robotic arm or limb.
With myoelectric hand, wrist and elbow movement are all available. With amputations above the elbow, a hybrid prosthesis may combine myoelectric-controlled components with body-powered components to control shoulder and/or elbow function. A skin-like glove covers the prosthesis for a natural appearance.
How do electric prosthetic limbs work?
A myoelectric prosthesis uses the existing muscles in your residual limb to control its functions. One or more sensors fabricated into the prosthetic socket receive electrical signals when you intentionally engage specific muscles in your residual limb. Sensors relay information to a controller, which translates the data into commands for the electric motors and moves your joints. If muscle signals cannot be used to control the prosthesis, you may be able to use switches with a rocker or pull-push or touch pad.
Myoelectric hands may feature:
- A variety of sizes for children as young as 18 months and adults
- A cosmetic glove in a variety of skin colours or a transparent glove to show the hi-tech inner workings
- A hand for amputation at or below the wrist
- Ability to carry heavy loads (up to a set limit)
- Aluminium construction for lighter weight
- A manually adjustable thumb
- A positionable thumb, driven by a separate motor, which allows for multiple grip patterns
- A neutral position for a natural look and action while walking or at rest
- Powerful grip force and grip speed
- Grip force and grip speed proportional to the strength of the myoelectric signal
- A virtual switch that requires a slightly stronger myoelectric signal to open the hand after applying maximum gripping force
- A sensor in the thumb that detects friction caused by objects slipping and automatically tightens the grip to prevent dropping
- A slip-clutch to quickly release the hand’s grip in an emergency
- Passive functions to resist weight bearing and other loads
- Multiple grip options, such as pinching with the thumb and index finger, power grip for handles, open palm for holding a platter, opposition power grip for grasping a cylindrical object with a big diameter, three-point grip with the thumb, index finger and middle finger, and holding flat objects between two fingers
- A handshake function that automatically sets the grip force
- A choice of multiple programs to tailor the speed and build-up of grip force to individual abilities and requirements
- Separate fingers
- Individually powered fingers with movable joints
- Ability to extend the index finger to point or press a button
- Fingers that spread when the hand opens and come together when the hand closes—so you can hold credit cards or bills between your finger
Is a Myoelectric prosthesis right for you?
A myoelectric-controlled prosthesis may be a good choice if you:
- Had an amputation above the fingers
- Have the ability to control the prosthesis using your own muscle nerves in or near your residual limb
- Want the best combination of function and natural appearance
- Want a solution that will give your greater function for everyday tasks
- Currently have a body-powered prosthesis and:
- Want more grip force
- Want greater range of motion and a larger ‘functional envelope’ (area of use)
- Find your harness uncomfortable or restrictive
- Experience symptoms of overuse or nerve entrapment syndrome in your intact arm
- Want a more natural-looking prosthesis
- Want relief from back pain related to unbalanced posture