Moving magnetoencephalography towards real-world applications with a wearable system.
Imaging human brain function with techniques such as magnetoencephalography (MEG) typically requires a subject to perform tasks while their head remains still within a restrictive scanner. This artificial environment makes the technique inaccessible to many people, and limits the experimental questions that can be addressed.
Through a Wellcome-funded collaboration between the University of Nottingham and University College London (UCL), we have developed a MEG system that can be worn like a helmet, allowing free and natural movement during scanning. This is made possible by the integration of quantum sensors, which do not rely on superconducting technology, with a system for nulling background magnetic fields. The new system, which uses optically pumped magnetometers (OPMs), has been used to make MEG measurements while subjects make natural movements, including head nodding, stretching, drinking and playing a ball game.
This work formed the basis of a Letter to Nature that was published in March 2018 and also underpinned an exhibit, Quantum Sensing the Brain, at the 2018 Royal Society Summer Exhibition. The Nature publication gathered very significant media interest, featuring as the lead item on the BBC 6 O’Clock News on the day of publication, and its Altmetric score currently places it in the 99th percentile (ranked 234th) of the 256,609 tracked articles of a similar age in all journals, based on the online attention the article has received. The Royal Society Summer Exhibition, held 2-8 July in 2018, typically attracts 15,000 visitors, including 6,000 children. Our exhibit was one of 22 selected from 100 applications. The Quantum Sensing the Brain team, led by Elena Boto, a final year PhD student, and Dr Matt Brookes, our lead academic, produced a really striking exhibit, including a room-sized representation of the brain which showed real-time variations in illuminations based on the brain signals of one of the exhibitors, monitored using a wireless EEG head-set.
Following on from the work described in Nature, we have multiple publications that are in preparation, submitted or in press, including two papers in Neuroimage. One of these focuses upon the first use of OPM MEG in measuring language lateralisation in adults, and the other provides a detailed description of the novel field nulling system that makes all of the OPM-MEG measurements possible. The former is a precursor to measurements in children with epilepsy that we hope to make in collaboration with UCL and Great Ormond Street Hospital in the next year. While the latter prefaces the development of novel coil systems that we will install in a new magnetically shielded room (MSR) at the Sir Peter Mansfield Imaging Centre later this year. The new high-performance MSR will be built in collaboration with a UK company, Magnetic Shields Limited, which is funded by a grant from the ATEP scheme of the EPSRC Quantum Technologies Hub in Sensors and Metrology.
We are also now pursuing a wide range of additional applications of the wearable MEG system (for example in studying traumatic brain injury, spatial memory and childhood brain development), along with multiple new avenues of technical development to improve the system’s capabilities.