Stentrode (Stent-electrode recording array) is a small

stent In medicine, a stent is a tube usually constructed of a metallic alloy or a polymer. It is inserted into the Lumen (anatomy), lumen (hollow space) of an anatomic vessel or duct to keep the passageway open. Stenting refers to the placement of ...

-mounted

electrode array An electrode is an electrical conductor used to make contact with a nonmetallic part of a circuit (e.g. a semiconductor, an electrolyte, a vacuum or a gas). In electrochemical cells, electrodes are essential parts that can consist of a varie ...

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 A brain–computer interface (BCI), sometimes called a brain–machine interface (BMI), is a direct communication link between the brain's electrical activity and an external device, most commonly a computer or robotic limb. BCIs are often dire ...

(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 An exoskeleton is a wearable device that augments, enables, assists, or enhances motion, posture, or physical activity through mechanical interaction with and force applied to the user’s body. Other common names for a wearable exoskeleton in ...

s, robotic

prosthesis In medicine, a prosthesis (: prostheses; from ), or a prosthetic implant, is an artificial device that replaces a missing body part, which may be lost through physical trauma, disease, or a condition present at birth (Congenital, congenital disord ...

, computers or other devices. The device was conceived by Australian neurologist Thomas Oxley and built by Australian biomedical engineer

Nicholas Opie Nicholas Opie is an Australian biomedical engineer who co-founded Synchron in 2012. He invented the Stentrode alongside Thomas Oxley. Opie serves as the head of Vascular Bonic Laboratory at the University of Melbourne The University of Melb ...

, who have been developing the medical implant since 2010, using sheep for testing. Human trials started in August 2019 with participants who suffer from

amyotrophic lateral sclerosis Amyotrophic lateral sclerosis (ALS), also known as motor neuron disease (MND) or—in the United States—Lou Gehrig's disease (LGD), is a rare, Terminal illness, terminal neurodegenerative disease, neurodegenerative disorder that results i ...

, a type of

motor neuron disease Amyotrophic lateral sclerosis (ALS), also known as motor neuron disease (MND) or—in the United States—Lou Gehrig's disease (LGD), is a rare, terminal neurodegenerative disorder that results in the progressive loss of both upper and low ...

. Graeme Felstead was the first person to receive the implant. To date, eight patients have been implanted and are 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 ...

granted breakthrough designation to the device in August 2020. In January 2023, researchers demonstrated that it can record brain activity from a nearby blood vessel and be used to operate a computer with no serious adverse events during the first year in all four patients.

Overview

Opie began designing the implant in 2010, through Synchron, a company he founded with Oxley and cardiologist Rahul Sharma. The small implant is an

made of

platinum Platinum is a chemical element; it has Symbol (chemistry), symbol Pt and atomic number 78. It is a density, dense, malleable, ductility, ductile, highly unreactive, precious metal, precious, silverish-white transition metal. Its name origina ...

electrodes An electrode is an electrical conductor used to make contact with a nonmetallic part of a circuit (e.g. a semiconductor, an electrolyte, a vacuum or a gas). In electrochemical cells, electrodes are essential parts that can consist of a variety ...

embedded within a

nitinol Nickel titanium, also known as nitinol, is a metal alloy of nickel and titanium, where the two elements are present in roughly equal atomic percentages. Different alloys are named according to the weight percentage of nickel; e.g., nitinol 55 and ...

endovascular stent. The device measures about 5 cm long and a maximum of 8 mm in diameter. The implant is capable of two-way communication, meaning 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 handle ...

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. It is a destructive neurological and pathological state that causes major motor, sensory and autonomic dysfunctions. Symptoms of ...

and control robotic prosthetic limbs with their thoughts. The Stentrode device, developed by Opie and a team at the Vascular Bionics Laboratory within the Department of Medicine at the

University of Melbourne The University of Melbourne (colloquially known as Melbourne University) is a public university, public research university located in Melbourne, Australia. Founded in 1853, it is Australia's second oldest university and the oldest in the state ...

, is implanted via the

jugular vein The jugular veins () are veins that take blood from the head back to the heart via the superior vena cava. The internal jugular vein descends next to the internal carotid artery and continues posteriorly to the sternocleidomastoid muscle. Struc ...

into a blood vessel next to cortical tissue near to the

motor cortex The motor cortex is the region of the cerebral cortex involved in the planning, motor control, control, and execution of voluntary movements. The motor cortex is an area of the frontal lobe located in the posterior precentral gyrus immediately ...

and

sensory cortex The sensory cortex can refer sometimes 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 occ ...

, so open

brain surgery Neurosurgery or neurological surgery, known in common parlance as brain surgery, is the medical specialty that focuses on the surgical treatment or rehabilitation of disorders which affect any portion of the nervous system including the brain, s ...

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 thrombus, blood clot. It results in hemostasis, the cessation of blood loss from a damaged vessel, followed by repair. The process of co ...

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 Str ...

Human Research Ethics Committee, Australia in November 2018.

Overview

See also

References