Simultaneously stimulating and recording electrical signals in the brain is much like trying to see small ripples in a pond while also splashing your feet — the electrical signals from the brain are overwhelmed by the large pulses of electricity delivered by the stimulation. Currently, deep brain stimulators either stop recording while delivering the electrical stimulation or record at a different part of the brain from where the stimulation is applied — essentially measuring the small ripples at a different point in the pond from the splashing.
These devices can be extremely effective at preventing debilitating tremors or seizures in patients with a variety of neurological conditions. But the electrical signatures that precede a seizure or tremor can be extremely subtle, and the frequency and strength of electrical stimulation required to prevent them is equally touchy. It can take years of small adjustments by doctors before the devices provide optimal treatment. A new neurostimulator can listen to and stimulate electric current in the brain at the same time, potentially delivering fine-tuned treatments to patients with diseases like epilepsy and Parkinson’s.
The Wireless Artifact-free Neuromodulation Device (WAND) works like a “pacemaker” for the brain, monitoring the brain’s electrical activity and delivering electrical stimulation if it detects something amiss.
WAND is both wireless and autonomous, meaning that once it learns to recognize the signs of tremor or seizure, it can adjust the stimulation parameters on its own to prevent the unwanted movements. And because it is closed-loop — meaning it can stimulate and record simultaneously — it can adjust these parameters in real time.
WAND can record electrical activity over 128 channels or from 128 points in the brain, compared to eight channels in other closed-loop systems. WAND’s custom integrated circuits can record the full signal from both the subtle brain waves and the strong electrical pulses. This chip design allows WAND to subtract the signal from the electrical pulses, resulting in a clean signal from the brain waves.
Existing devices are tuned to record signals only from the smaller brain waves and are overwhelmed by the large stimulation pulses, making this type of signal reconstruction impossible. A platform device was built with wireless and closed-loop computational capabilities that can be programmed for use in a variety of research and clinical applications.