Closed-loop stimulation promises fewer side effects

February 3, 2016, Albert Ludwigs University of Freiburg

Could potential side effects in the treatment of Parkinson's disease with stimulation be avoided with a closed-loop approach, which constantly adapts to the symptoms? This is one of the key questions Dr. Ioannis Vlachos and his colleagues Taskin Deniz, Prof. Dr. Ad Aertsen, and Prof. Dr. Arvind Kumar address in a study that was now published in the journal PLoS Computational Biology.

The approach developed at Bernstein Center Freiburg and BrainLinks-BrainTools cluster of excellence of Freiburg University offers a significant step forward in the research for innovative methods in the treatment of Parkinson's disease (PD): "There are currently only two common therapies to treat this disease. Either you can administer drugs or, if this does not work, one has to resort to , the so-called ," Vlachos explains. In the latter approach, which currently follows a method known as open-loop stimulation, an electrode is implanted in the patient's brain to provide a continuous train of stimulation pulses. "In principle, this resembles the approach of the cardiac pacemaker," says Vlachos. However, the symptoms of Parkinson's disease are not constant. And therefore, the researchers argue, constantly stimulating the brain with the same signal is not the most efficient treatment.

"In our closed-loop approach, the electrode provides a stimulus that adjusts to the momentary symptoms. Through this method we are hoping to avoid some side effects such as gait imbalance or speech impairment which occur in conventional DBS treatment", Vlachos explains.

In this new closed-loop approach, is recorded and fed to a neuroprosthetic device, which then adjusts the stimulation strength. The controller continuously monitors the brain activity that reflects the severity of the PD symptoms. The nature of the recorded activity determines the stimulation signal. If stronger stimulation is required, the control input gets stronger, if the activity becomes weaker, the stimulation is weakened, and if there is no pathological activity the device will not provide any stimulation. "This saves battery life and, hence, increases recharging and maintenance intervals – clearly an advantage for the patient carrying the battery," the researcher explains.

The same approach could be used for the treatment of other brain diseases such as epilepsy or schizophrenia. Moreover, Vlachos' method could also be used to devise controllers for non-invasive stimulation, such as transcranial stimulation techniques. This means that the brain can be stimulated from the outside, without the need to drill a hole into the skull and implant an electrode into the brain.

The closed-loop stimulation method developed by Vlachos and colleagues can further be adapted to influence brain activity to address basic science questions: "For instance, when animals attend to an input there is often an increase in oscillations. Using our controller, we can modulate the strength of oscillations and test if and how our attention is affected by such network oscillations." After promising results in computer simulations modeling the activity dynamics of large networks of neurons, the next step will be to verify the approach in animal models, before it can be tested in human patients.

Explore further: Portable stimulator being tested on Parkinson's patients

More information: Ioannis Vlachos et al. Recovery of Dynamics and Function in Spiking Neural Networks with Closed-Loop Control, PLOS Computational Biology (2016). DOI: 10.1371/journal.pcbi.1004720

Related Stories

Portable stimulator being tested on Parkinson's patients

January 20, 2015
Parkinson's disease is a slowly degenerative neurological disease that is expressed as impaired motor control, tremors, stiffness and, in later stages, problems with balance.

Next-generation brain stimulation may improve treatment of Parkinson's disease

October 19, 2011
Parkinson's disease (PD) is a devastating and incurable disease that causes abnormal poverty of movement, involuntary tremor, and lack of coordination. A technique called deep brain stimulation (DBS) is sometimes used to ...

New non-invasive method for brain research

June 24, 2013
Neuroscientists at the University of Tübingen have become the first to record neuromagnetic activity in the millisecond-by-millisecond range while the brain of a human subject was under stimulation by electric current. Electric ...

Responsive brain stimulation could improve life for Parkinson's sufferers

July 15, 2013
(Medical Xpress)—Researchers in Oxford have demonstrated a significant improvement in the treatment of advanced Parkinson's disease with deep brain stimulation.

Less-invasive method of brain stimulation helps patients with Parkinson's disease

October 16, 2012
Electrical stimulation using extradural electrodes—placed underneath the skull but not implanted in the brain—is a safe approach with meaningful benefits for patients with Parkinson's disease, reports the October issue ...

Low-frequency deep brain stimulation improves difficult-to-treat Parkinson's symptoms (Update)

January 27, 2015
Parkinson's disease patients treated with low-frequency deep brain stimulation show significant improvements in swallowing dysfunction and freezing of gait over typical high-frequency treatment. The study, published in Neurology ...

Recommended for you

Team seeks to create genetic map of worm's nervous system

December 10, 2018
How do you build a brain? What "rules" govern where neurons end up, how they connect to each other, and which functions they perform?

Classifying brain microglia: Which are good and which are bad?

December 6, 2018
Microglia are known to be important to brain function. The immune cells have been found to protect the brain from injury and infection and are critical during brain development, helping circuits wire properly. They also seem ...

Drawing is better than writing for memory retention

December 6, 2018
Older adults who take up drawing could enhance their memory, according to a new study.

Friend or foe? Brain area that controls social memory also triggers aggression

December 5, 2018
Columbia scientists have identified a brain region that helps tell an animal when to attack an intruder and when to accept it into its home. This brain area, called CA2, is part of the hippocampus, a larger brain structure ...

How the brain hears and fears

December 5, 2018
How is it that a sound can send a chill down your spine? By observing individual brain cells of mice, scientists at Cold Spring Harbor Laboratory (CSHL) are understanding how a sound can incite fear.

Adding new channels to the brain remote control

December 5, 2018
By enabling super-fast remote control of specific cells, light-activated proteins allow researchers to study the function of individual neurons within a large network—even an entire brain. Now one of the pioneers of 'optogenetics' ...

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.