Implanted device brings movement hope to paralysis patients

Thanks to the implantation of a tiny device, patients with upper limb paralysis are now able to text, email and shop online.

The paper-clip-sized device — called Stentrode — was developed by researchers from The University of Melbourne, The Royal Melbourne Hospital, The Florey Institute of Neuroscience and Mental Health, Monash University and Synchron Australia.

In a trial published in the Journal of NeuroInterventional Surgery, Stentrode was implanted successfully in two patients suffering from severe paralysis due to motor neuron disease (MND) — also known amyotrophic lateral sclerosis (ALS) — neither of whom had the complete ability to move their upper limbs. The device was able to wirelessly restore the transmission of brain impulses out of the body.

Professor Peter Mitchell, principal trial investigator and Neurointervention Service Director at The Royal Melbourne Hospital, said the findings were promising and demonstrate that 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,” Professor Mitchell said.

Professor Mitchell implanted the device in 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,” Professor Mitchell said.

Associate Professor Thomas Oxley, neurointerventionalist and CEO of research commercial partner Synchron, 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,” said Associate Professor Oxley, who is also co-head of the Vascular Bionics Laboratory at The University of Melbourne.

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 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,” Associate Professor 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 trial recently received a $1.48 million grant from the Australian Government to expand to hospitals in NSW and Queensland, with hopes to enrol more patients.

Although public availability of the technology is some years away, the researchers said a multidisciplinary team is working tirelessly to make the technology — capable of returning independence to complete everyday tasks — a reality.

Image caption: Associate Professor Nicholas Opie holding the device, Stentrode. Image credit: The University of Melbourne.