Posts Tagged neurostimulator

[NEWS] Wireless ‘pacemaker for the brain’ could be new standard treatment for neurological disorders

A grey-colored sits on an illustration of a brain

A new neurostimulator developed by engineers at UC Berkeley 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 device, named the WAND, works like a “pacemaker for the brain,” monitoring the brain’s electrical activity and delivering electrical stimulation if it detects something amiss.

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.

WAND, which stands for wireless artifact-free neuromodulation device, 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.

“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,” said Rikky Muller, an assistant professor of electrical engineering and computer sciences at Berkeley. “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.”

WAND can record electrical activity over 128 channels, or from 128 points in the brain, compared to eight channels in other closed-loop systems. To demonstrate the device, the team used WAND to recognize and delay specific arm movements in rhesus macaques. The device is described in a study that appeared today (Dec. 31) in Nature Biomedical Engineering.

A WAND chip in a hand

Ripples in a pond

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.

“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,” said former UC Berkeley postdoctoral associate Samantha Santacruz, who is now an assistant professor at the University of Texas in Austin.

Researchers at Cortera Neurotechnologies, Inc., led by Muller, 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 WAND to subtract the signal from the electrical pulses, resulting in a clean signal from the brain waves.

A close up picture of an integrated circuit

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.

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

In collaboration with the lab of electrical engineering and computer science professor Jan Rabaey, the team 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.

In experiments lead by Santacruz while a postdoc at UC Berkeley, and by electrical engineering and computer science professor Jose Carmena, 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 motion.

“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,” Muller said.

“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,” she said.

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.

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via Wireless ‘pacemaker for the brain’ could be new standard treatment for neurological disorders | Berkeley News

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[WEB SITE] Researchers study how neurostimulator can improve rehabilitation for stroke patients

 

Researchers at The Ohio State University Wexner Medical Center are among the first in the world studying how a specific type of neurostimulator can improve rehabilitation for stroke patients.

As part of the clinical trial, an electrical device called a vagus nerve stimulator is surgically implanted in the patient’s chest wall. The Vivistim device, which connects to the vagus nerve in the neck, is used to “rewire” circuits in the brain associated with certain motor functions. Stroke can result in the loss of brain tissue and negatively affect various bodily functions from speech to movement, depending on the location of the stroke.

In an earlier pilot study, this approach known as Paired Vagus Nerve Stimulation was shown to benefit approximately 85 percent of the people who received the nerve stimulation, said Dr. Marcie Bockbrader, research physiatrist for the Neurological Institute at The Ohio State University Wexner Medical Center.

“This nerve stimulation is like turning on a switch, making the patient’s brain more receptive to therapy,” Bockbrader said. “The goal is to see if we can improve motor recovery in people who have what is, in effect, a brain pacemaker implanted in their body. The idea is to combine this brain pacing with normal rehab, and see if patients who’ve been through all of the other usual therapies after a stroke can get even better.”

The study is recruiting patients who suffered a stroke and have been left with poor arm function as a result. The study is open to patients who have suffered a stroke at least nine months ago up to 10 years ago.


Each participant will receive three one-hour sessions of intensive physiotherapy each week for six weeks to help improve their arm function.

Half of the group will also receive an implanted vagus nerve stimulator. During rehabilitation therapy sessions, when a patient correctly performs an exercise, the therapist pushes a button to trigger the device to stimulate the vagus nerve. This neurostimulator signals the brain to remember that movement.

“We are trying to see if this neurostimulator could be used to boost the effective therapy, creating a sort of ‘supercharged therapy.’ We want to determine if patients can recover more quickly through the use of this stimulation,” Bockbrader said.

Previous research indicates that vagus nerve stimulation causes the release of the brain’s own chemicals, called neurotransmitters that will help the brain form new neural connections which might improve participant’s ability to use their arm.

Traditional vagus nerve stimulation has been used in the United States and around the world to treat more than 100,000 patients for epilepsy.

 

via Researchers study how neurostimulator can improve rehabilitation for stroke patients

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