Stentrode (Stent-electrode recording array) is a small stent-mounted

electrode array An electrode array is a configuration of electrodes used for measuring either an electric current or voltage. Some electrode arrays can operate in a bidirectional fashion, in that they can also be used to provide a stimulating pattern of electric c ...

permanently implanted into a blood vessel in the brain, without the need for open brain surgery. It is in clinical trials as a brain–computer interface (BCI) for people with paralyzed or missing limbs, who will use their neural signals or thoughts to control external devices, which currently include computer operating systems. The device may ultimately be used to control

powered exoskeleton A powered exoskeleton, also known as power armor, powered armor, powered suit, cybernetic suit, cybernetic armor, exosuit, hardsuit, exoframe or augmented mobility, is a mobile machine that is wearable over all or part of the human body, provi ...

s, robotic

prosthesis In medicine, a prosthesis (plural: prostheses; from grc, πρόσθεσις, prósthesis, addition, application, attachment), or a prosthetic implant, is an artificial device that replaces a missing body part, which may be lost through trau ...

, computers or other devices. The device was conceived by

Australia Australia, officially the Commonwealth of Australia, is a Sovereign state, sovereign country comprising the mainland of the Australia (continent), Australian continent, the island of Tasmania, and numerous List of islands of Australia, sma ...

n neurologist Thomas Oxley, who has been developing the medical implant since 2010, using sheep for testing. Human trials started in November 2020 with two participants that suffer from

amyotrophic lateral sclerosis Amyotrophic lateral sclerosis (ALS), also known as motor neuron disease (MND) or Lou Gehrig's disease, is a neurodegenerative disease that results in the progressive loss of motor neurons that control voluntary muscles. ALS is the most comm ...

, a type of

motor neuron disease Amyotrophic lateral sclerosis (ALS), also known as motor neuron disease (MND) or Lou Gehrig's disease, is a neurodegenerative disease that results in the progressive loss of motor neurons that control voluntary muscles. ALS is the most comm ...

. The two patients were able to wirelessly control an operating system to text, email, shop, and bank using direct thought through the Stentrode brain-computer interface, marking the first time a brain-computer interface was implanted via the patient's blood vessels, eliminating the need for open brain surgery. The

FDA The United States Food and Drug Administration (FDA or US FDA) is a federal agency of the Department of Health and Human Services. The FDA is responsible for protecting and promoting public health through the control and supervision of food s ...

granted breakthrough designation to the device in August 2020.

Overview

Oxley began developing the implant in 2010, through his self-founded company Synchron. The small implant is an

made of

platinum Platinum is a chemical element with the symbol Pt and atomic number 78. It is a dense, malleable, ductile, highly unreactive, precious, silverish-white transition metal. Its name originates from Spanish , a diminutive of "silver". Platinu ...

that is mounted on a nitinol endovascular stent. The device measures about 5 cm long and a maximum of 4 mm in diameter. The implant is capable of two-way communication, meaning that it can both sense thoughts and stimulate movement, essentially acting as a

feedback Feedback occurs when outputs of a system are routed back as inputs as part of a chain of cause-and-effect that forms a circuit or loop. The system can then be said to ''feed back'' into itself. The notion of cause-and-effect has to be handled ...

loop within the brain, which offers potential applications for helping people with

spinal cord injuries A spinal cord injury (SCI) is damage to the spinal cord that causes temporary or permanent changes in its function. Symptoms may include loss of muscle function, sensation, or autonomic function in the parts of the body served by the spinal cor ...

and control robotic

prosthetic limbs In medicine, a prosthesis (plural: prostheses; from grc, πρόσθεσις, prósthesis, addition, application, attachment), or a prosthetic implant, is an artificial device that replaces a missing body part, which may be lost through trau ...

with their thoughts. The Stentrode device, developed by Oxley and a team at the University of Melbourne, is implanted via the jugular vein into a blood vessel next to cortical tissue near to the motor cortex and

sensory cortex The sensory cortex can refer informally to the primary somatosensory cortex, or it can be used as a term for the primary and secondary cortices of the different senses (two cortices each, on left and right hemisphere): the visual cortex on the occi ...

, so open

brain surgery Neurosurgery or neurological surgery, known in common parlance as brain surgery, is the medical specialty concerned with the surgical treatment of disorders which affect any portion of the nervous system including the brain, spinal cord and peri ...

is avoided. Insertion via the blood vessel avoids direct penetration and damage of the brain tissue. As for

blood clotting Coagulation, also known as clotting, is the process by which blood changes from a liquid to a gel, forming a blood clot. It potentially results in hemostasis, the cessation of blood loss from a damaged vessel, followed by repair. The mechanism o ...

concerns, Oxley says neurologists routinely use permanent stents in patients' brains to keep blood vessels open. Once in place, it expands to press the electrodes against the vessel wall close to the brain where it can record neural information and deliver currents directly to targeted areas. The signals are captured and sent to a wireless antenna unit implanted in the chest, which sends them to an external receiver. The patient would need to learn how to control a computer operating system that interacts with assistive technologies. The Stentrode technology has been tested on sheep and humans, with human trials being approved by the

St Vincent's Hospital, Melbourne St Vincent's Hospital is a major hospital in Fitzroy, Melbourne, Australia. It is operated by the St Vincent's Health service, previously known as the Sisters of Charity Health Service, Melbourne. It is situated at the corner of Nicholson Stree ...

Human Research Ethics Committee, Australia in November 2018.

Overview

See also

References