Nerve stimulation in mice suggests new way to reduce delirium after surgery

October 11, 2018, Duke University Medical Center
Microscope images show immune cells in the brain called microglia in red. After injury, the immune system responds, activating microglia. In this study, stimulating the vagus nerve helped return microglia to a calmer state. Credit: Duke University

For adults over age 65, surgical complications can dampen not only their physical health but also their mental sharpness, with more than half of high-risk cases declining into delirium.

In research published this week in the journal Brain Stimulation, Duke University scientists show in a mouse model that a current treatment for seizures can also reverse , such as inflammation after surgery, and the subsequent confusion or cognitive decline that results.

The therapy involves minimally invasive stimulation of the vagus nerve using small electrical pulses comparable to a cell phone's vibrations.

The scientists used a Doppler ultrasound to guide the placement of a needle that delivers the electrical pulse, avoiding nearby delicate structures such as the carotid artery. Researchers hope to refine the technique into a completely non-invasive approach to preventing when seniors and other at-risk patients have surgery.

"Delirium is now recognized as the most common complication in older adults after surgery," said Niccolò Terrando, Ph.D., associate professor of anesthesiology at Duke and the study's senior author. "For most patients, it lasts a few days and resolves on its own. For some, it can lead to severe complications and even contribute to long lasting cognitive deficits, like dementia."

Terrando noted that these cognitive complications have a huge impact on quality of life and can be expensive, with health care costs for delirium reaching $164 billion a year according to the American Society of Anesthesiologists.

"So far, there is no therapy for this kind of cognitive after surgery," Terrando said. Anti-inflammatory drugs have many side effects and work broadly, he said, and they don't adequately target the inflammation in the that scientists believe triggers cognitive complications.

The vagus nerve helps the brain communicate with the heart, lungs, gut and other parts of the body. Vagus nerve stimulators have been surgically implanted in epilepsy patients for more than 20 years to reduce seizures.

In recent years, U.S. doctors have also prescribed at-home, non-invasive stimulators for severe headaches. However, there is not substantial evidence that the devices are stimulating the vagus nerve and not other structures near it, said Warren M. Grill, Ph.D., professor of biomedical engineering at Duke.

For the experimental model, mice with inflammation received one nerve-stimulating treatment lasting several minutes. The researchers monitored for signs of vagus activation, such as a slower heart rate and twitching of muscles around the larynx, and found improved cognitive outcomes and reduced brain after this treatment.

"This minimally invasive approach is already exceedingly benign, but in the long term it would be desirable to have an entirely non-invasive approach and we are beginning that work," Grill said.

Explore further: Depressed patients see quality of life improve with nerve stimulation

More information: William J. Huffman et al, Modulation of Neuroinflammation and Memory Dysfunction using Percutaneous Vagus Nerve Stimulation in Mice, Brain Stimulation (2018). DOI: 10.1016/j.brs.2018.10.005

Related Stories

Depressed patients see quality of life improve with nerve stimulation

August 21, 2018
People with depression who are treated with nerve stimulation experience significant improvements in quality of life, even when their depression symptoms don't completely subside, according to results of a national study ...

Electrical nerve stimulation could help patients regain motor functions sooner

May 2, 2018
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.

Single low-magnitude electric pulse successfully fights inflammation

May 13, 2015
The Feinstein Institute for Medical Research, the research arm of the North Shore-LIJ Health System, and SetPoint Medical Inc., a biomedical technology company, today released the results of research on the therapeutic potential ...

Vagus nerve stimulation promising in Crohn's disease

May 3, 2017
(HealthDay)—Vagus nerve stimulation may represent a new therapeutic option for patients with Crohn's disease (CD), according to a report published online April 18 in the Journal of Internal Medicine.

Researchers develop technique to monitor laryngeal and vagus nerves in surgery

July 2, 2017
In a first-of-its-kind study, Mount Sinai researchers have discovered a novel technique to monitor laryngeal and vagus nerve function while patients are under anesthesia during otolaryngology and neurosurgery procedures. ...

Severity of post-operative delirium relates to severity of cognitive decline

November 28, 2017
Researchers from the Harvard affiliated Hebrew SeniorLife Institute for Aging Research (IFAR), in collaboration with scientists from Beth Israel Deaconess Medical Center (BIDMC), Harvard Medical School (HMS), and Brown University, ...

Recommended for you

Research shows signalling mechanism in the brain shapes social aggression

October 19, 2018
Duke-NUS researchers have discovered that a growth factor protein, called brain-derived neurotrophic factor (BDNF), and its receptor, tropomyosin receptor kinase B (TrkB) affects social dominance in mice. The research has ...

Good spatial memory? You're likely to be good at identifying smells too

October 19, 2018
People who have better spatial memory are also better at identifying odors, according to a study published this week in Nature Communications. The study builds on a recent theory that the main reason that a sense of smell ...

How clutch molecules enable neuron migration

October 19, 2018
The brain can discriminate over 1 trillion odors. Once entering the nose, odor-related molecules activate olfactory neurons. Neuron signals first accumulate at the olfactory bulb before being passed on to activate the appropriate ...

Scientists discover the region of the brain that registers excitement over a preferred food option

October 19, 2018
At holiday buffets and potlucks, people make quick calculations about which dishes to try and how much to take of each. Johns Hopkins University neuroscientists have found a brain region that appears to be strongly connected ...

Gene plays critical role in noise-induced deafness

October 19, 2018
In experiments using mice, a team of UC San Francisco researchers has discovered a gene that plays an essential role in noise-induced deafness. Remarkably, by administering an experimental chemical—identified in a separate ...

Brain cells called astrocytes have unexpected role in brain 'plasticity'

October 18, 2018
When we're born, our brains have a great deal of flexibility. Having this flexibility to grow and change gives the immature brain the ability to adapt to new experiences and organize its interconnecting web of neural circuits. ...

0 comments

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.