Engineers at the University of California, Berkeley developed a novel neurostimulator that can listen to and stimulate electric current simultaneously in the brain, potential for delivering effective treatments to patients with diseases such as Parkinson’s and epilepsy.
The new wireless pacemaker device called ‘WAND’ functions like a pacemaker for the brain that monitors electrical activity of the brain as well as deliver electric stimulation when detecting something amiss.
Wireless Pacemaker type of devices can be highly effective at preventing debilitating tremors and seizures in patients with several neurological conditions. However, electrical seizures preceding the tremors and seizures are very subtle and both frequency and strength of electrical stimulation needed to them are equally low.
WAND stands for ‘Wireless Artifact-free Neuromodulation Device’ which is wireless and autonomous. Once the device learns to detect the signs of tremor or seizure, it can tune the stimulation parameters to halt the undesirable movements. Additionally, as it is a closed-loop that stimulates and records at the same time, the device can tune these parameters in real time.
The device is detailed in a research paper and published in the journal Nature Biomedical Engineering. It can register electrical activity for more than 128 channels, or from 128 points within the brain compared to 8 channels in other systems.
To demonstrate WAND, the researchers used it in rhesus macaques to detect and delay specific arm movements.
Ripples in a Pond
Stimulating and recording electrical signals in the brain at the same time is quite similar to observing small ripples in the pond, while also splashing the water with your feet – the electric signals from the brain are overwhelmed by the large electrical pulses delivered by the stimulation.
In the present-day scenario, deep brain stimulators sometimes stop recording while applying electrical stimulation, record at a region of the brain different from where the stimulation is delivered.
According to Samantha Santacruz, Assistant Professor at the University of Texas, it is essential to both perform both neural recordings and stimulation at the same time in order to deliver therapies based on closed-loop stimulation, which is an important goal for treating patients with epilepsy, Parkinson’s, and other neurological disorders. However, none of the existing commercial device can operate in such a way, she added.
The WAND custom integrated circuits were designed by a group of researchers led by Rikky Muller at Cortera Neurotechnologies. It can record the entire signal from subtle the brain waves as well as strong electrical pulses. Further, the chip design enables the device to remove the signal from the electrical pulses, resulting in a clean brain waves signal.
As the device allows to stimulate and record in the same region of the brain, the researchers know exactly what is happening while providing a therapy, Muller said.
In experiments, researchers showed that the WAND device is capable of detecting the neural signatures that appeared as the study subject prepared to perform a motion, and then provide electrical stimulation that delayed the motion.
It is for the first time that delaying of reaction time is demonstrated in a closed-loop system on the basis of neurological reading only, the researchers said.