Targeted deep brain stimulation to treat obsessive-compulsive disorder


Date:
July 6, 2020
Source:
Charite' - Universita"tsmedizin Berlin
Summary:
Researchers have further refined the use of deep brain stimulation
in the treatment of obsessive-compulsive disorder. By accurately
localizing electrode placement in the brains of patients, the
researchers were able to identify a fiber tract which is associated
with the best clinical outcomes following deep brain stimulation.



FULL STORY ==========================================================================
A group of researchers from Charite' -- Universita"tsmedizin Berlin
have further refined the use of deep brain stimulation in the treatment
of obsessive-compulsive disorder. By accurately localizing electrode
placement in the brains of patients, the researchers were able to
identify a fiber tract which is associated with the best clinical
outcomes following deep brain stimulation. The researchers' findings,
which have been published in Nature Communications*, may be used to
improve the treatment of obsessive-compulsive disorder.


==========================================================================
A person with obsessive compulsive disorder (OCD) experiences unwanted
thoughts and behaviors, the urge for which they find difficult or
impossible to resist.

More than 2 percent of people are affected by obsessive thoughts and
compulsive behaviors which severely impair daily activities. A treatment
option for severe cases is deep brain stimulation, a technique which
is also used in other disorders, such as Parkinson's disease. Deep
brain stimulation involves the implantation of tiny electrodes into
structures deep inside the brain. After implantation, these electrodes
deliver very weak electric currents to help rebalance brain activity. By stimulating different areas of the brain, such as a fiber tract within
the internal capsule or the subthalamic nucleus, this technique can
help improve clinical symptoms in some cases. Treatment success depends
on the accurate placement of electrodes and requires millimeter-level precision. The optimal stimulation target for patients with obsessive- compulsive disorders had not previously been identified.

For the first time, a team of researchers -- led by Dr. Andreas Horn
of Charite''s Department of Neurology with Experimental Neurology --
has been able to identify a specific nerve bundle which appears to be
the optimal target for stimulation. The researchers studied 50 patients
with obsessive-compulsive disorder who received treatment at a number of centers around the world. Using magnetic resonance imaging technology
both before and after electrode placement, the researchers were able
to visualize surrounding fibre tracts and test to see which of these
the electrodes were selectively stimulating. "Our analysis shows that
optimal results are linked to a very specific nerve bundle.

Reliable evidence for this link was found across the cohorts of patients examined in Cologne, Grenoble, London and Madrid," explains Dr. Horn.

The researchers initially examined two cohorts of patients, both of
which received deep brain stimulation to the internal capsule or the subthalamic nucleus. These brain structures have a variety of connections
to other areas of the brain. And yet, a specific tract situated between
the prefrontal cortex and the subthalamic nucleus was identified as a
suitable target for stimulation in both of these groups. Precise electrode localizations allowed the researchers to reliably predict treatment
outcomes in both of these groups. These results were then replicated
in two further, independent cohorts. When comparing their results with
other studies, the researchers showed that the target areas described
were also located within the tract-target identified in this study.

Describing the way in which these findings could help with electrode implantation, the study's first author, Ningfei Li, says: "Our results
do not alter the original target area, they simply helped us to define
it more precisely. What this means is that: so far, we have had to steer
our boat toward an island which was shrouded in fog. Now, we can make
out the island itself and perhaps even the pier, so we can aim for it
with greater accuracy." All 3D structural analysis data have been made publicly available to researchers around the world. No Charite' patients
with obsessive-compulsive disorder are receiving treatment using this
invasive method of deep brain stimulation. However, the participating
research centers continue to share their knowledge and are developing
protocols for additional studies to test the newly defined target areas.


========================================================================== Story Source: Materials provided by
Charite'_-_Universita"tsmedizin_Berlin. Note: Content may be edited for
style and length.


========================================================================== Journal Reference:
1. Ningfei Li, Juan Carlos Baldermann, Astrid Kibleur, Svenja Treu,
Harith
Akram, Gavin J. B. Elias, Alexandre Boutet, Andres M. Lozano,
Bassam Al- Fatly, Bryan Strange, Juan A. Barcia, Ludvic Zrinzo,
Eileen Joyce, Stephan Chabardes, Veerle Visser-Vandewalle,
Mircea Polosan, Jens Kuhn, Andrea A. Ku"hn, Andreas Horn. A
unified connectomic target for deep brain stimulation in
obsessive-compulsive disorder. Nature Communications, 2020; 11
(1) DOI: 10.1038/s41467-020-16734-3 ==========================================================================

Link to news story: https://www.sciencedaily.com/releases/2020/07/200706113924.htm

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