Study finds factors that may cause fluctuations in deep brain stimulation levels over time

July 11, 2013

Deep brain stimulation therapy blocks or modulates electrical signals in the brain to improve symptoms in patients suffering from movement disorders such as Parkinson's disease, essential tremor and dystonia, but a new study suggests that several factors may cause electrical current to vary over time.

Led by Michele Tagliati, MD, director of Cedars-Sinai Medical Center's Movement Disorders Program, the study identified variables that affect impedance – resistance in circuits that affect intensity and wavelength of electrical current. Doctors who specialize in programming DBS devices fine-tune voltage, frequency and other parameters for each patient; deviations from these settings may have the potential to alter .

"Deep brain stimulation devices are currently designed to deliver constant, steady voltage, and we believe consistency and reliability are critical in providing therapeutic stimulation. But we found that we cannot take impedance stability for granted over the long term," said Tagliati, the senior author of a journal article that reveals the study's findings.

"Doctors with experience in DBS management can easily make adjustments to compensate for these fluctuations, and future devices may do so automatically," he added. "Although our study was not designed to link changes in impedance and voltage with , we believe it is important for patients to have regular, ongoing clinic visits to be sure they receive a steady level of stimulation to prevent the emergence of side effects or the re-emergence of symptoms."

Findings of the study – one of the largest of its kind and possibly the first to follow patients for up to five years – were published online ahead of print in Brain Stimulation. Researchers collected 2,851 impedance measurements in 94 patients over a period of six months to five years, evaluating fluctuations in individual patients and in individual electrodes. They looked at a variety of factors, including how long a patient had undergone treatment, the position of the implanted electrode, the side of the brain where the electrode was implanted, and even placement and function of contact positions along electrodes.

Medications usually are the first line of treatment for movement disorders, but if drugs fail to provide adequate relief or side effects are excessive, neurologists and neurosurgeons may supplement them with . Electrical leads are implanted in the brain, and an electrical pulse generator is placed near the collarbone. The device is then programmed with a remote, hand-held controller.

Explore further: Long-term study reports deep brain stimulation effective for most common hereditary dystonia

More information: Brain Stimulation, "Longitudinal Impedance Variability in Patients with Chronically Implanted DBS Devices," April 15 (Epub ahead of print).

Related Stories

Long-term study reports deep brain stimulation effective for most common hereditary dystonia

June 19, 2013
In what is believed to be the largest follow-up record of patients with the most common form of hereditary dystonia – a movement disorder that can cause crippling muscle contractions – experts in deep brain stimulation ...

In some dystonia cases, deep brain therapy benefits may linger after device turned off

February 12, 2013
Two patients freed from severe to disabling effects of dystonia through deep brain stimulation therapy continued to have symptom relief for months after their devices accidentally were fully or partly turned off, according ...

Parkinson's brain rhythms suggest better way to treat disease with deep brain stimulation

March 4, 2013
A team of scientists and clinicians at UC San Francisco has discovered how to detect abnormal brain rhythms associated with Parkinson's by implanting electrodes within the brains of people with the disease.

Referring doctors increasingly aware of deep brain stimulation therapy; more work remains

August 16, 2011
While deep brain stimulation has gained recognition by referring physicians as a treatment for Parkinson's disease and other movement disorders, just half of the patients they recommend are appropriate candidates to begin ...

Deep brain stimulation studied as last-ditch obesity treatment

June 13, 2013
(HealthDay)—For the first time, researchers have shown that implanting electrodes in the brain's "feeding center" can be safely done—in a bid to develop a new treatment option for severely obese people who fail to shed ...

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 ...

Recommended for you

New surgical strategy offers hope for repairing spinal injuries

July 28, 2017
Scientists in the UK and Sweden previously developed a new surgical technique to reconnect sensory neurons to the spinal cord after traumatic spinal injuries. Now, they have gained new insight into how the technique works ...

In witnessing the brain's 'aha!' moment, scientists shed light on biology of consciousness

July 27, 2017
Columbia scientists have identified the brain's 'aha!' moment—that flash in time when you suddenly become aware of information, such as knowing the answer to a difficult question. Today's findings in humans, combined with ...

Scientists block evolution's molecular nerve pruning in rodents

July 27, 2017
Researchers investigating why some people suffer from motor disabilities report they may have dialed back evolution's clock a few ticks by blocking molecular pruning of sophisticated brain-to-limb nerve connections in maturing ...

Social influences can override aggression in male mice, study shows

July 27, 2017
Stanford University School of Medicine investigators have identified a cluster of nerve cells in the male mouse's brain that, when activated, triggers territorial rage in a variety of situations. Activating the same cluster ...

Scientists become research subjects in after-hours brain-scanning project

July 27, 2017
A quest to analyze the unique features of individual human brains evolved into the so-called Midnight Scan Club, a group of scientists who had big ideas but almost no funding and little time to research the trillions of neural ...

Researchers reveal unusual chemistry of protein with role in neurodegenerative disorders

July 27, 2017
A common feature of neurodegenerative diseases is the formation of permanent tangles of insoluble proteins in cells. The beta-amyloid plaques found in people with Alzheimer's disease and the inclusion bodies in motor neurons ...

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.