Magnetomyography shows potential in prosthetics and wearables

A new way to monitor and measure the signals created when nerve cells transmit information to skeletal muscles is being investigated by researchers from Glasgow University.

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The EU-funded MAGNABLE project could enable future generations of prosthetic limbs to respond directly to instructions from users’ muscles.

According to the University, it could also enable improved control of digital spaces, removing the need for handheld controllers in virtual or extended reality in favour of wearable devices.  

Over the next two years, the MAGNABLE team will work to develop a new human-machine interface which can produce high-resolution, low-noise scans of muscle activity by measuring muscles’ magnetic fields.

Currently, the most widely used method of monitoring muscle activity is electromyography (EMG), which takes its readings from electrodes placed on the skin.

The sensitivity of those readings are limited by the need to read the signals through muscle and skin, which dampens the clarity of the signal. That limitation makes It difficult for EMG to be used in human-machine interface devices like prosthetics.

One proposed solution is to surgically implant EMG sensors directly into muscle tissue to improve their ability to detect signals, but this kind of implantation carries risks of infection. 

An alternative to EMG is magnetomyography (MMG), which has the potential to provide improved resolution imagery without the requirement of invasive surgery. 

MMG is challenging to use for muscle activity monitoring because the amplitude of magnetic signals from muscles is small enough that the geomagnetic field can interfere with readings. 

To overcome that problem, the MAGNABLE system will build on recent developments from Glasgow University’s James Watt School of Engineering. At the School’s Microelectronics Lab, researchers have developed miniaturised magnetic sensors to measure the magnetic field with the sensitivity required to enable muscle activity monitoring.

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Principal investigator Professor Hadi Heidari of Glasgow University’s James Watt School of Engineering said: “MMG has a great deal of potential to produce the kind of high-resolution data that we’ll need in order to create highly capable neural interfaces which can be controlled by muscle movements, just like real limbs.

“The technology we’re developing could also be incorporated into arm bands or other wearable devices to enable realistic interactions with virtual and extended reality.” 

As the project progresses, they will build upon that breakthrough to develop a microchip which can read MMG data from muscles while screening out environmental background noise. 

Once the microchip is finalised, Glasgow spin-out Neuranics Ltd will look to bring it to market to enable new forms of human-machine interaction.

“I’m looking forward to solving some difficult challenges with my colleagues at the University… and Neuranics Ltd over the next couple of years, and making this technology available to the market,” Professor Heidari said in a statement. “Neuranics is a powerhouse which is set to disrupt the status quo in interfacing with the central, peripheral, and autonomic nervous systems.”

MAGNABLE is supported by the European Union’s Marie Skłodowska-Curie Actions