First human trial: Tiny device translates thought into action

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The Stentrode, a tiny device the size of a small paperclip, has been shown to help patients with severe upper limb paralysis to text, email and even shop online in the first human trial.

The device has been implanted successfully in two patients, who both suffer from severe paralysis due to amyotrophic lateral sclerosis (ALS) – also known as motor neurone disease (MND) – and neither had the ability to move their upper limbs.

The results found the Stentrode was able to wirelessly restore the transmission of brain impulses out of the body. This enabled the patients to successfully complete daily tasks such as online banking, shopping and texting, which previously had not been available to them.

The Royal Melbourne Hospital's Professor Peter Mitchell, neuro-intervention service director and principal investigator on the trial, said the findings were promising and demonstrate the device can be safely implanted and used within the patients.

"This is the first time an operation of this kind has been done, so we couldn't guarantee there wouldn't be problems, but in both cases the surgery has gone better than we had hoped," Mitchell said.

Mitchell implanted the device on the study participants through their blood vessels, next to the brain's motor cortex, in a procedure involving a small 'keyhole' incision in the neck.

"The procedure isn't easy, in each surgery there were differences depending on the patient's anatomy, however in both cases the patients were able to leave the hospital only a few days later, which also demonstrates the quick recovery from the surgery," Mitchell said.

Neuro-interventionalist and CEO of Synchron – the research commercial partner – associate Professor Thomas Oxley, said this was a breakthrough moment for the field of brain-computer interfaces.

"We are excited to report that we have delivered a fully implantable, take home, wireless technology that does not require open brain surgery, which functions to restore freedoms for people with severe disability," Oxley, who is also co-head of the Vascular Bionics Laboratory at the University of Melbourne, said.

The two patients used the Stentrode to control the computer-based operating system, in combination with an eye-tracker for cursor navigation. This meant they did not need a mouse or keyboard.

They also undertook machine learning-assisted training to control multiple mouse click actions, including zoom and left click. The first two patients achieved an average click accuracy of 92% and 93%, respectively, and typing speeds of 14 and 20 characters per minute with predictive text disabled.

University of Melbourne associate professor Nicholas Opie, co-head of the Vascular Bionics Laboratory at the University and founding chief technology officer of Synchron said the developments were exciting and the patients involved had a level of freedom restored in their lives.

"Observing the participants use the system to communicate and control a computer with their minds, independently and at home, is truly amazing," Opie said.

"We are thankful to work with such fantastic participants, and my colleagues and I are honoured to make a difference in their lives. I hope others are inspired by their success. "Over the last eight years we have drawn on some of the world's leading medical and engineering minds to create an implant that enables people with paralysis to control external equipment with the power of thought. We are pleased to report that we have achieved this."

The researchers caution that while it is some years away before the technology, capable of returning independence to complete everyday tasks is publicly available, the global, multidisciplinary team is working tirelessly to make this a reality.

The trial recently received a $A1.48m grant from the Australian commonwealth government to expand the trial to hospitals in New South Wales and Queensland, with hopes to enrol more patients.

Abstract
Background: Implantable brain–computer interfaces (BCIs), functioning as motor neuroprostheses, have the potential to restore voluntary motor impulses to control digital devices and improve functional independence in patients with severe paralysis due to brain, spinal cord, peripheral nerve or muscle dysfunction. However, reports to date have had limited clinical translation.
Methods: Two participants with amyotrophic lateral sclerosis (ALS) underwent implant in a single-arm, open-label, prospective, early feasibility study. Using a minimally invasive neurointervention procedure, a novel endovascular Stentrode BCI was implanted in the superior sagittal sinus adjacent to primary motor cortex. The participants undertook machine-learning-assisted training to use wirelessly transmitted electrocorticography signal associated with attempted movements to control multiple mouse-click actions, including zoom and left-click. Used in combination with an eye-tracker for cursor navigation, participants achieved Windows 10 operating system control to conduct instrumental activities of daily living (IADL) tasks.
Results: Unsupervised home use commenced from day 86 onwards for participant 1, and day 71 for participant 2. Participant 1 achieved a typing task average click selection accuracy of 92.63% (100.00%, 87.50%–100.00%) (trial mean (median, Q1–Q3)) at a rate of 13.81 (13.44, 10.96–16.09) correct characters per minute (CCPM) with predictive text disabled. Participant 2 achieved an average click selection accuracy of 93.18% (100.00%, 88.19%–100.00%) at 20.10 (17.73, 12.27–26.50) CCPM. Completion of IADL tasks including text messaging, online shopping and managing finances independently was demonstrated in both participants.
Conclusion: We describe the first-in-human experience of a minimally invasive, fully implanted, wireless, ambulatory motor neuroprosthesis using an endovascular stent-electrode array to transmit electrocorticography signals from the motor cortex for multiple command control of digital devices in two participants with flaccid upper limb paralysis.

Authors
Thomas J Oxley, Peter E Yoo, Gil S Rind, Stephen M Ronayne, C M Sarah Lee, Christin Bird, Victoria Hampshire, Rahul P Sharma, Andrew Morokoff, Daryl L Williams, Christopher MacIsaac, Mark E Howard, Lou Irving, Ivan Vrljic, Cameron Williams, Sam E John, Frank Weissenborn, Madeleine Dazenko, Anna H Balabanski, David Friedenberg, Anthony N Burkitt, Yan T Wong, Katharine J Drummond, Patricia Desmond, Douglas Weber, Timothy Denison, Leigh R Hochberg, Susan Mathers, Terence J O'Brien, Clive N May, J Mocco, David B Grayden, Bruce C V Campbell, Peter Mitchell, Nicholas L Opie

 

University of Melbourne material

 

Journal of NeuroInterventional Surgery abstract

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