Engineers at Rice University have developed the smallest implantable brain stimulator ever demonstrated on a human patient. Thanks to the groundbreaking magnetoelectrodynamic power transfer technology, Jacob Robinson's Rice University laboratory has partnered with Motif Neurotech and clinicians Dr. Sameer Sheth and Sunil Dr. Sheth's co-developed pea-sized device can be wirelessly powered by an external transmitter and stimulate the brain through the dura mater – the protective membrane attached to the base of the skull.
Engineers at Rice University have developed the first miniature brain stimulator to work on a human patient. Photo credit: Jeff Fitlow/Rice University
The device, known as the "Digital Programmable Brain Therapy Device" (DOT), could revolutionize the treatment of drug-resistant depression and other psychiatric or neurological disorders because it offers an alternative therapy that provides greater autonomy and accessibility to patients than current neurostimulation-based therapies and is less invasive than other brain-computer interfaces (BCIs).
Robinson, a professor in the Department of Electrical and Computer Engineering and the Department of Biological Engineering at Rice University, said: "In this paper, we show our device, which is only the size of a pea, activates the motor cortex, which allows patients to move their hands. In the future, we can place implants in other parts of the brain, such as the prefrontal cortex, and we hope it will improve executive function in patients with depression or other conditions."
Existing implantable brain stimulation techniques are powered by relatively large batteries that need to be placed under the skin in other parts of the body and connected to the stimulation device by longer wires. This design limitation necessitates more surgeries, exposing patients to greater hardware implantation burdens, the risk of wire breakage or failure, and the need for future battery replacement surgeries.
Jacob Robinson and his research team at Rice University have developed the smallest implantable brain stimulator and demonstrated it in human patients, which will revolutionize the treatment of drug-resistant depression and other psychiatric or neurological disorders. Photo credit: Jeff Fitlow/Rice University
Joshua Woods, a graduate student in electrical engineering at Robinson's lab and lead author of the study, published in Science Advances, explains, "We eliminated the need for batteries by using an external transmitter to wirelessly power the device. Amanda Singer, a former graduate student in applied physics at Rice University and now at Motif Neurotech, is also the first author of the study.
The technology relies on a material that converts a magnetic field into electrical impulses. This conversion process is very efficient over a small scale and has a good tolerance for misalignment, which means it does not require complex or minor operations to activate and control. The device has a width of 9 mm and provides stimulation with 14.5 volts.
"Our implants get their full energy through this magnetoelectric effect," Robinson said. Robinson is the founder and CEO of Motif, a startup founded through the Rice University Biotech Launchpad, which is working to bring the device to market.
Motif is one of several neurotechnology companies that are exploring the potential of BCIs to revolutionize the treatment of neurological disorders. "Neurostimulation is key to achieving therapies in the field of mental health, as the side effects and lack of efficacy of medications leave many people without appropriate treatment options," Robinson said. "
Clinical testing and future directions
The researchers improvised, testing the device on a human patient, using it to stimulate the brain's motor cortex — the part of the brain responsible for movement — and produce a hand motor response. Next, they demonstrated the device's stable interface with the brain in pigs for a duration of 30 days.
"This has never been done before because the quality and intensity of the signal required to stimulate the brain through the dura mater was not possible before, and it was impossible for such a small implant to be transmitted by wireless power," Woods said. "
Robinson envisions using this technology at home. The doctor will prescribe the treatment and provide instructions on how to use the device, but the patient still has full control over the treatment: "Back at home, the patient puts on a hat or wearable device, powers and communicates with the implant, presses the 'Start' button on the iPhone or smartwatch, and the electrical stimulation from the implant activates a network of neurons inside the brain." "
Implant surgery involves a 30-minute minimally invasive procedure to implant the device into a bone above the brain. The implants and incisions are barely visible, and the patient can go home the same day.
Joshua Woods (from left), Jacob Robinson and Fatima Al Rushdan. Photo credit: Jeff Fitlow/Rice University
Schess, professor and vice chair for research in neurosurgery at Baylor College of Medicine, McNair Fellowship recipient and Karen Foundation Endowment Chair, said: "Pacemakers are a very routine part of cardiac care. In terms of neurological and psychiatric disorders, the counterpart is deep brain stimulation (DBS), which sounds scary and invasive. Deep brain stimulation is actually a fairly safe procedure, but it's still brain surgery, and its perceived risk sets a low ceiling on the number of people willing to take it and potentially benefit from it. That's where this technology comes in. A minor 30-minute procedure at an outpatient surgery center, which is nothing more than a skin procedure, is more acceptable than DBS. So if we can prove that it's as effective as more invasive alternative therapies, it's likely that this therapy will have a greater impact on mental health. "
But for disorders such as depression and obsessive-compulsive disorder, just a few minutes of stimulation per day is enough to bring about the desired change in the function of the target neuronal network.
Regarding next steps, Robinson said that in terms of research, he is "really interested in creating implant networks, as well as creating implants that can be stimulated and recorded so that they can provide adaptive, personalized therapies based on your own brain characteristics." From a therapeutic development perspective, Motif Neurotech is seeking approval from the U.S. Food and Drug Administration (FDA) to conduct long-term clinical trials in humans. Patients and caregivers can log on to the Motif Neurotech website to find out when and where these trials will begin.
编译来源：ScitechDaily