Brain Power

For certain cardiac problems, pacemakers have become a very common component of a patient’s treatment plan. After implantation, these devices can monitor the heart for abnormalities and automatically provide a jolt of electricity when needed to get things back on track. But that same basic model of supplying electrical current with precision to other parts of the body that are malfunctioning has not really taken off to the same extent.

The brain, in particular, could benefit from such an implant to treat conditions like depression and obsessive-compulsive disorder. But while neurostimulation has shown a great deal of promise in treating a number of neurological disorders, existing systems have many issues that limit their practicality. They tend to be highly invasive, which leaves most patients unwilling to even consider an implant. Even if medication is not working well, it may still seem like a better option than brain surgery, and all of the risks that come along with it.

Neurostimulation may become far more accessible in the future, thanks to the work of a team led by researchers at Rice University. They have developed a minimally-invasive implant, about the size of a pea, that can be surgically implanted in about 30 minutes. Rather than being inserted into the brain itself, this device is placed on the outside of the dura, which is a thick membrane that protects the brain. Furthermore, the implant does not require a battery, which means there are no wires running from it to another part of the body where a relatively large battery is housed.

The researchers call their device a Digitally programmable Over-brain Therapeutic (DOT). It is powered wirelessly via an external transmitter that generates magnetic fields. Within the implant, these magnetic fields are converted into electrical pulses via a highly efficient process involving the magnetoelectric effect. This enables it to deliver stimulation at up to 14.5 volts. And since no battery is involved, there are no wires running through the body that can break, and future surgeries for battery replacement are unnecessary.

To validate their system, the researchers temporarily implanted it in a human patient. The device was located over the motor cortex, which is responsible for movement. It was demonstrated that by turning on the neurostimulation, movements in the hand could be produced. Longer-term trials were conducted in pigs, which showed that the implant is stable and operates normally after a 30-day period.

It is envisioned that this device could be implanted in a simple outpatient procedure in which the patient goes home the same day. After that, the individual would be able to manage treatment on their own. They might, for example, put on a hat or other wearable device that provides the implant with power, and also communicates with it. From there, a smartphone app could be used to begin therapy.

In the future, the team would like to extend their work to encompass networks of implants. These implants might not only provide stimulation, but also sensing. In this way, the devices could monitor conditions and provide personalized therapies that respond to changing circumstances. But before that can happen, the implant will first need to be proven in long-term clinical trials in humans, which is what the researchers’ are currently focused on.