Article: Motor neuroprosthesis implanted with neurointerventional surgery improves capacity for activities of daily living tasks in severe paralysis: first in-human experience
Journal of Neurointerventional Surgery 2020; 0-7. First published on 28 October 2020
Thomas J Oxley,1,2 Peter E Yoo,1,2 Gil S Rind,1,2 Stephen M Ronayne,1,2 C M Sarah Lee,3 Christin Bird,1 Victoria Hampshire,2 Rahul P Sharma,4 Andrew Morokoff,1,5
Daryl L Williams,6 Christopher MacIsaac,7 Mark E Howard,8 Lou Irving,9 Ivan Vrljic,10 Cameron Williams,10 Sam E John,1,11 Frank Weissenborn,1,12 Madeleine Dazenko,3 Anna H Balabanski,13 David Friedenberg,14 Anthony N Burkitt,11 Yan T Wong,15 Katharine J Drummond,1,5 Patricia Desmond,1,10 Douglas Weber,16 Timothy Denison,2,17 Leigh R Hochberg,18 Susan Mathers,3 Terence J O’Brien,1,13 Clive N May,12 J Mocco,19 David B Grayden,11 Bruce C V Campbell,20,21 Peter Mitchell,10 Nicholas L Opie1,2
1. Vascular Bionics Laboratory, Departments of Medicine, Neurology and Surgery, Melbourne Brain Centre at the Royal Melbourne Hospital, The University of Melbourne, Melbourne, Victoria, Australia
2. Synchron, Inc, Campbell, California, USA
3. Neurology, Calvary Health Care Bethlehem, South Caulfield, Victoria, Australia
4. Interventional Cardiology, Cardiovascular Medicine Faculty, Stanford University, Stanford, California, USA
5. Neurosurgery, Melbourne Health, Parkville, Victoria, Australia
6. Anaesthesia, Melbourne Health, Parkville, Victoria, Australia
7. Intensive Care Unit, Melbourne Health, Parkville, Victoria, Australia
8. Institute for Breathing and Sleep, Austin Health, Heidelberg, Victoria, Australia
9. Respiratory Medicine, Melbourne Health, Parkville, Victoria, Australia
10. Radiology, Melbourne Health, Parkville, Victoria, Australia
11. Department of Biomedical Engineering, University of Melbourne, Melbourne, Victoria, Australia
12. Florey Institute of Neuroscience and Mental Health, University of Melbourne, Parkville, Victoria, Australia
13. Neurology, Melbourne Health, Parkville, Victoria, Australia
14. Battelle Memorial Institute, Columbus, Ohio, USA
15. Department of Electrical and Computer Systems Engineering, Monash University, Clayton, Victoria, Australia
16. Department of Mechanical Engineering and Neuroscience Institute, Carnegie Mellon University, Pittsburgh, Pennsylvania, USA
17. Institute of Biomedical Engineering, Oxford University, Oxford, Oxfordshire, UK
18. Center for Neurotechnology and Neurorecovery, Department of Neurology, Massachusetts General Hospital, Harvard Medical School, Harvard University, Cambridge, Massachusetts, USA
19. Neurosurgery, The Mount Sinai Health System, New York, New York, USA
20. Medicine, University of Melbourne, Parkville, Victoria, Australia
21. Neurology, Royal Melbourne Hospital, Melbourne, Victoria, Australia
This work was supported by research grants from US Defense Advanced Projects Agency (DARPA) Microsystems Technology Office contract N6601-12-1- 4045; Office of Naval Research (ONR) Global N26909-14-1-N020; USA Department of Defense Office of the Congressionally Directed Medical Research Programs (CDMRP), SC160158; Office of the Assistant Secretary of Defense for Health Affairs, Spinal Cord Injury Award Program W81XWH-17-1-0210; National Health and Medical Research Council of Australia (NHMRC) Grants GNT1161108, GNT1062532, GNT1138110; Australia Research Council (ARC) Linkage Grant LP150100038; Australian Federal Government, Department of Industry, Innovation and Science, GIL73654; Motor Neurone Disease Research Institute of Australia, GIA1844, Global Innovation Linkage Program, Australian Federal Government; and Synchron Inc. contributed to device fabrication
Establishing a communication trail between the brain and an external device is being put forward as a way to give back some functional independence to those with paralysis or disorders that reduce voluntary movement (ALS/motor neurone disease).
Research with similar technologies such as the Scalp EEG-based and near infrared spectroscopy brain computer interface (BCI) has shown potential. However, there are clinical hurdles for patients when using BCIs. Some require fiddly daily set ups that involve a caregiver or technicians providing assistance. Other issues include highly invasive implantation methods such as a burr hole craniotomy.
This research team hoped to investigate an implantable BCI that considers these clinical barriers and allow patients to control a digital device with their mind.
Brain computer interface (BCI): A computer system that takes signals from the brain, interprets and sends them to a device that performs the intended action.
Voluntary movement: Actions that were thought (e.g. moving your arm, walking)
Motor cortex: The part of the brain responsible for planning and carrying out voluntary movements
Signal transmission: The way in which information is sent between neurons
Paralysis: Loss of muscle function in the body
Amytrophic lateral sclerosis (ALS)/ Motor neurone disease: A gradual disease affecting the nerves in the brain and spine that reduces muscle control and leads to weakness
A novel endovascular Stentrode BCI was implanted in the brains of two participants with ALS. The device was implanted via catheter into a space next to the primary motor cortex, a part of the brain that controls movement.
A lead connects the device in the brain to an internal telemetery unit (ITU) in the chest. Signals from the ITU are sent wirelessly to an external device and computer that reads them. At home, participants underwent machine learning assisted training to control different mouse click commands such as no click, short click and long click. Long clicks were used to zoom in and for typing. The signals were combined with an eye tracker so participants could move the mouse cursor with their eyes. Some of the activities carried out included online shopping, typing text messages/emails and personal finance tasks.
Average click accuracy was 92.63% for the first participant with typing speed of 14 characters per minute. For the second participant click accuracy was 93.18% and typing speed of 20 characters per minute. Participants were able to engage with the range of computer tasks successfully.
Participants were able to regain some functional independence with the use of a novel endovascular neuroprosthesis. They were able to participate in a range of computer tasks such as online shopping and emails with high accuracy and independence.
Paralysis or other conditions that limit motor skills can significantly impact someone’s ability to perform daily tasks on their own. There are limited options for restoring these abilities. BCI systems are being researched as ways to translate brain activity into computer actions. This set up may help individuals boost their independence and communication skills.
Other variations of BCI have involved open brain surgeries and application in hospital/laboratory settings. This version of BCI is fully implanted in a way that is minimally invasive and wireless. It can also be used comfortably by participants in their homes which can enhance clinical outcomes.
Participants in this study are the first humans to have received a brain implant that can be inserted with a less invasive approach. The device shows great potential to help restore daily living skills in those with paralysis or reduced motor control. Other studies investigating BCIs have also involved humans, showing that it is possible to research and improve this technology in human participants. It is important that BCI research continues in humans, as it focusses on improving daily tasks such as emails, online shopping and banking that may be unsuitable to investigate in non-human models.