Authorities approve prosthesis controlled by muscle signals

A prosthetic arm that performs multiple, simultaneous powered movements controlled by electrical signals from electromyogram (EMG) electrodes has been approved by the US Food and Drug Administration (FDA).

According to the FDA, EMG electrodes in DEKA Integrated Solutions’ DEKA Arm System detect electrical activity caused by the contraction of muscles close to where the prosthesis is attached. The electrodes send the electrical signals to a computer processor in the prosthesis that translates them to a specific movement or movements.

The EMG electrodes in DEKA Arm System convert electrical signals into up to 10 powered movements, and it is said to be the same shape and weight as an adult arm. In addition to the EMG electrodes, the DEKA Arm System contains a combination of mechanisms including switches, movement sensors, and force sensors that cause the prosthesis to move.

In a statement, Christy Foreman, director of the Office of Device Evaluation at the FDA’s Center for Devices and Radiological Health said: ‘This innovative prosthesis provides a new option for people with certain kinds of arm amputations.

‘The DEKA Arm System may allow some people to perform more complex tasks than they can with current prostheses in a way that more closely resembles the natural motion of the arm.’

The FDA said it reviewed clinical information relating to the device, including a 4-site US Department of Veterans Affairs study in which 36 DEKA Arm System study participants provided data on how the arm performed in common household and self-care tasks.

The study found that approximately 90 per cent of study participants were able to perform activities with the DEKA Arm System that they were not able to perform with their current prosthesis, such as using keys and locks, preparing food, feeding, using zips, and brushing and combing hair.

The DEKA Arm System can be configured for people with limb loss occurring at the shoulder joint, mid-upper arm, or mid-lower arm but cannot be configured for limb loss at the elbow or wrist joint.

Data reviewed by the FDA also included testing of software and electrical and battery systems, mitigations to prevent or stop unintended movements of the arm and hand mechanisms, durability testing (such as ability to withstand exposure to common environmental factors such as dust and light rain), and impact testing.

The DEKA Arm System is manufactured by DEKA Integrated Solutions in Manchester, New Hampshire.