WASHINGTON -- A closed-loop deep brain stimulation system may
diminish dyskinesia and improve symptom control for Parkinson's patients,
researchers reported here.
In a preliminary study of only two Parkinson's patients,
stimulation automatically adjusted based on a signal recorded from the motor
cortex, Nicole Swann, PhD, of the University of California San Francisco, and
colleagues reported during a press briefing at the Society
for Neuroscience meeting.
That led to the additional benefit of energy
savings, she said. "We were able to save energy without decreasing how
well symptoms were controlled. Patients are getting the same benefit as if they
were receiving stimulation all the time, but now with energy savings."
Deep brain stimulation (DBS) for Parkinson's
disease has been available for about 2 decades. It's an effective therapy, but
"it's not perfect," Swann said, noting that patients can still
develop involuntary movements, or dyskinesia, while on the therapy.
A
next step for DBS would be to have a closed-loop system where the device
monitors for brain signals indicative of both symptoms and side effects, and
adjusts stimulation as needed.
Swann's
group used the Activa PC DBS system (Medtronic), which includes an implanted
recording device that picks up signals from the motor cortex. Specifically, it
tracks a previously identified narrowband gamma oscillation (about 80 Hz)
that's associated with dyskinesia.
If
the signal is high, that means the patient is likely to be having dyskinesia,
so the device reduces stimulation. If the signal is low, that's indicative of
symptoms, so more stimulation is delivered.
Overall, they found that the system was indeed
able to adjust stimulation based on recorded activity. Neither of the two
patients reported discomfort, adverse events, or worsening symptoms during the
single experimental session.
Both patients had a reduction in device energy
usage (45% and 38%, respectively), and that energy was saved without affecting how
well symptoms were controlled, Swann said.
Currently,
it is possible for Parkinson's patients to regulate their stimulation to some
degree, she noted. They have a controller and they can increase or decrease the
voltage or frequency as needed, but "many patients don't use this,"
she said.
"For
some it's personal preference, or hesitancy -- they don't want to mess with
it," she said. "Other times, it's just not sensitive enough. So there
are patients who can benefit from having automatically adjusted stimulation."
Since
it's still very early days for the technology, Swann said it's critical to do
additional studies, especially to see if the offerings can be improved upon.
For instance, can automatically adjusted stimulation lead to an improvement in
symptoms "rather than just maintaining efficacy while saving energy?"
Helen Mayberg, MD, of
Emory University in Atlanta, called the device a "true implementation of a
closed-loop system in human beings being treated with stimulation for
Parkinson's disease."
"This is where
the technology is going," said Mayberg, who was not involved in the study.
Swann disclosed no relevant relationships with industry.
Primary Source
Society for Neuroscience
https://www.medpagetoday.com/meetingcoverage/sfn/69323
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