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When administered through the jugular vein, a small “thought-controlled” device can record brain from a nearby blood vessel, thus eliminating the need for doctors to open the skull, a small trial shows.
The device, called the Stentrode, is designed to enable paralyzed people to operate assistive technology using only their thoughts. For example, trial participants used the device to generate text messages and emails, and for online banking and shopping, according to a new report published Monday (January 9) in the journal JAMA Neurology (opens in a new tab). (Early data from the study was also presented in March 2022 at the 74th Annual Meeting of the American Academy of Neurology in Seattle.)
While other mind-reading devices designed for similar purposes are usually placed on or in the brain during open-brain surgery, doctors can implant the Stentrode without having to split open the patient’s skull, study organizers wrote in a report.
“Blood vessels in the brain offer a less invasive route to accessing the motor cortex,” an area on the wrinkled surface of the brain involved in motor control, they wrote.
The team had previously shown that the Stentrode could be used in animals to both record signals from the brain and deliver electrical stimulation to the organ. Royal Melbourne Hospital (opens in a new tab) in Australia, an institution involved in the process. A recent human clinical trial — known as the Stentrode With Thought-Controlled Digital Switch (SWITCH) study — was the first to test the device in humans.
Related: First patient with new mind-reading device uses brain signals to write
The study involved four men of European descent with amyotrophic lateral sclerosis (ALS), a progressive disease that causes the death of nerve cells that control voluntary movement. At the time of enrollment, all study participants had severe paralysis of the upper limbs and varying degrees of lung function and speech impairment.
Each participant was placed with a Stentrode in the superior sagittal sinus, a large vein that drains fluid from the brain to the jugular vein and lies adjacent to the motor cortex. The device itself is made of a mesh-like material that contains 16 electrodes; doctors insert the device into the body using a catheter, and once in place, they expand the mesh so that it fits flush against the walls of the sinus, according to a March 2022 study. statement (opens in a new tab) from Synchron, the implantable brain-computer interface (BCI) company behind Stentrode. A wire runs from the electrodes to a small electronic device in the chest that wirelessly transmits the brain signals recorded by the device to a computer.
“All patients tolerated the procedure well and were usually discharged home within 48 hours,” co-lead investigator Dr. Peter Mitchell (opens in a new tab)director of neurointerventions at the Royal Melbourne Hospital, said in a separate article statement. The JAMA report noted that only one of the four patients stayed in the hospital for an additional day before being discharged.
The most common side effects were headaches and bruising at the incision sites, and no one experienced serious side effects during or after the procedure. And during the year-long follow-up period, no participant experienced a blood clot (thrombosis); blockage of blood vessels; “migration” of the device, meaning the movement of the device in the body; or any other serious side effects related to the device that could lead to death or permanent disability.
Moreover, “BCI maintained a stable signal throughout the study, and all participants successfully controlled the computer with BCI,” the authors stated.
“The safety and feasibility data from the first human study indicate that it is possible to record nerve signals from the blood vessel, and the favorable safety profile may promote wider and faster transmission of BCI to paralyzed individuals,” the team concluded.
