Wireless pacemaker for the brain that listen to and stimulate electric current in the brain

Wireless artifact-free neuromodulation device.

In a proposed device, two of the new chips would be embedded in a chassis located outside the head. Each chip could monitor electrical activity from 64 electrodes located into the brain while simultaneously delivering electrical stimulation to prevent unwanted seizures or tremors. (credit: Rikky Muller, UC Berkeley)
In a proposed device, two of the new chips would be embedded in a chassis located outside the head. Each chip could monitor electrical activity from 64 electrodes located into the brain while simultaneously delivering electrical stimulation to prevent unwanted seizures or tremors. (credit: Rikky Muller, UC Berkeley)

Engineers at the UC Berkeley have developed a new neurostimulator that can listen to and stimulate electric current in the brain at the same time. The device named WAND is expected to bring treatments to patients with diseases like epilepsy and Parkinson’s.

WAND, which stands for wireless artifact-free neuromodulation device, is both wireless and autonomous. Means, it can adjust the stimulation parameters on its own to prevent unwanted movements.

The device acts as a pacemaker for the brain that monitors brain’s electrical activity and delivers electrical simulation if it detects something amiss. Engineers noted that the device can be extremely effective at preventing debilitating tremors or seizures in patients with a variety of neurological conditions.

Rikky Muller assistant professor of electrical engineering and computer sciences at Berkeley said, “The process of finding the right therapy for a patient is extremely costly and can take years. Significant reduction in both cost and duration can potentially lead to greatly improved outcomes and accessibility. We want to enable the device to figure out what is the best way to stimulate for a given patient to give the best outcomes. And you can only do that by listening and recording the neural signatures.”

Former UC Berkeley postdoctoral associate Samantha Santacruz said, “In order to deliver closed-loop stimulation-based therapies, which is a big goal for people treating Parkinson’s and epilepsy and a variety of neurological disorders, it is very important to both perform neural recordings and stimulation simultaneously, which currently no single commercial device does.”

The WAND chip is designed with custom integrated circuits that can record the full signal from both subtle brain waves and strong electrical pulses delivered by the stimulator. (credit: Rikky Muller, UC Berkeley)
The WAND chip is designed with custom integrated circuits that can record the full signal from both subtle brain waves and strong electrical pulses delivered by the stimulator. (credit: Rikky Muller, UC Berkeley)

Engineers designed the WAND custom integrated circuits that can record the full signal from both the subtle brain waves and the strong electrical pulses. This chip design allows the WAND to subtract the signal from the electrical pulses, resulting in a clean signal from the brain waves.

Muller said, “Because we can actually stimulate and record in the same brain region, we know exactly what is happening when we are providing a therapy.”

In addition, scientists built a platform device with wireless and closed-loop computational capabilities that can be programmed for use in a variety of research and clinical applications.

During the experiments, the subjects were taught to use a joystick to move a cursor to a specific location. After a training period, the WAND device was capable of detecting the neural signatures that arose as the subjects prepared to perform the motion, and then deliver electrical stimulation that delayed the move.

WAND’s custom integrated circuits. (credit: Rikky Muller, UC Berkeley)
WAND’s custom integrated circuits. (credit: Rikky Muller, UC Berkeley)

Muller said, “While delaying reaction time is something that has been demonstrated before, this is, to our knowledge, the first time that it has been demonstrated in a closed-loop system based on a neurological recording only.”

“In the future we aim to incorporate learning into our closed-loop platform to build intelligent devices that can figure out how to best treat you, and remove the doctor from having to constantly intervene in this process.”

Andy Zhou and Benjamin C. Johnson of UC Berkeley join Santacruz as co-lead authors on the paper. Other contributing authors include George Alexandrov, Ali Moin and Fred L. Burghardt of UC Berkeley. This work was supported in part by the Defense Advanced Research Projects Agency (W911NF-14- 2- 0043) and the National Science Foundation Graduate Research Fellowship Program (Grant No. 1106400). Authors Benjamin C. Johnson, Jan M. Rabaey, Jose M. Carmena and Rikky Muller have financial interest in Cortera Neurotechnologies, Inc., which has filed a patent application on the integrated circuit used in this work.

The device is described in a study that appeared in Nature Biomedical Engineering.