Myoelectric orthosis for the upper limb

Interview with Paul Gudonis, CEO of Myomo.

The MyoPro has been used to assist individuals with paralysis due to a variety of neurological injuries and disorders, and the VA has approved it for US veterans with upper limb impairment.

Conn Hastings, Medgadget January 13, 2017

Myomo, a medical robotics firm based in Cambridge, MA, has developed the MyoPro Motion-G, a powered rigid brace designed to support an arm that is weak or deformed by neurologic impairments such as stroke or brachial plexus injuries.

The MyoPro can help patients make functional movements in their home and community, when they might otherwise be left to function with only one arm. Earlier inceptions of the device have been covered previously on Medgadget. However, Myomo has since launched a new generation of features on the device, which functions by responding to EMG (electromyography) signals initiated in the user’s muscles. The device then aids in supporting and moving the arm and hand in the desired direction. This means that the movement is self-initiated and the robotic brace serves to supplement and enhance the movement of the user.

Medgadget had the opportunity to ask Paul Gudonis, CEO of Myomo, some questions about the MyoPro.

Conn Hastings, Medgadget: In simple terms, how does the device work?
Paul Gudonis, Myomo: The MyoPro uses non-invasive sensors which rest on the skin and detect the body’s electromyographic (EMG) signals, which are emitted when you try to initiate movement of the arm or hand. We use advanced signal processing to determine what the user is trying to do, such as bend the arm and open the hand to grasp an object, and the robotic components assist the arm with this desired action. It’s like power steering for the arm.
Medgadget: What types of users can benefit from this device?
Paul Gudonis: Individuals with partial paralysis or arm weakness due to stroke, spinal cord injury, traumatic brain injury, peripheral nerve damage, and progressive conditions such as ALS or MS may be good candidates for the MyoPro.
Medgadget: The arm and hand can move in a variety of complex ways. Can the MyoPro assist in a variety of movements? What about grasping motions using the fingers?
Paul Gudonis: Our latest product, the MyoPro Motion G, uses multiple sensors and motors to enable elbow flexion and extension as well as opening and closing of the hand so that users can cook, feed themselves, perform household tasks, and even return to work. In the future, we plan to use even smaller motors and sensors to enable individual finger movements.
Medgadget: Can the device modulate the strength of the response based on the strength of the input myoelectric signal, or is a simple on/off sufficient for this application?
Paul Gudonis: The MyoPro responds proportionally to the user’s intention, so it can move quickly or slowly depending on the user. In addition, we’ve sought to enable very natural functions so that users can hold and carry a household object like a cookie sheet or cut their food with a knife and fork.
Medgadget: Do users require a lot of training or practice?
Paul Gudonis: We require new users to have training from a Myomo-certified Occupational Therapist (OT) so that they can become proficient in using the device. We conduct training programs for these OTs so that they can work with new MyoPro users.
Medgadget: Is the MyoPro custom-made for each user or can it be purchased off the shelf?
Paul Gudonis: The device is a custom-fabricated orthosis (brace) that is provided by a Certified Prosthetist or Orthotist (CPO). For an effective fit, the CPO takes a mold and precise measurements of the user’s arm and ships it to our central fabrication facility, which then returns a MyoPro with the exact dimensions of the user’s arm and hand. The CPO then adjusts it during the fitting and calibrates the software to properly amplify the user’s EMG signals.

Source Medgadget

The MyoPro Motion-Gis the first powered orthosis to enable both elbow flexion/extension and grasping function. The Motion-G is the latest innovation in the company’s MyoPro line, which enables people to initiate and control movement of a partially paralyzed arm using their own muscle signals, supporting a return to function. Published on YouTube Oct 27, 2015

Also see
User Evaluation of a Dynamic Arm Orthosis for People With Neuromuscular Disorders, Gunn M, Shank T, Eppes M, Hossain J, Rahman T. IEEE Trans Neural Syst Rehabil Eng. 2015 Oct 26. [Epub ahead of print]

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