A new technique for delivering deep brain stimulation (DBS) may provide a way to individualize this therapy, and lessen side effects, for some people with Parkinson’s disease (PD). A study published in the July edition of Lancet Neurology found that the technique, which can deliver more focused electrical stimulation at higher levels, safely improved PD symptoms.
Deep brain stimulation (DBS) is a standard therapy for people with PD who have disabling wearing-off periods, tremors, and dyskinesias (involuntary movements). Since DBS came into use in the 1990s, the basic technique of surgically implanting an electrode into the brain, most often in an area called the subthalamic nucleus (STN), has remained the same. One shortcoming, however, is that the electrical current used to ease symptoms can spread beyond the targeted brain area. This can cause side effects including speech difficulties and impulse control disorders.
Researchers led by Lars Timmermann, M.D., at the University Hospital in Cologne, Germany, tested a new DBS device, which delivers electrical stimulation through “multiple-source current steering.” Using eight individually-programmed electrical contacts, electrical stimulation can be focused to a better-defined area in the brain than with DBS devices used now. Forty people with PD participated in the study. They were, on average, 60 years old and had been living with PD for 12 years. DBS electrodes were surgically implanted in both sides of study participants’ brains. At three, six and 12 months after implantation, researchers evaluated the movement symptoms of each participant using a standard rating scale, the United Parkinson’s Disease Rating Scale, or UPDRS III. Participants also kept diaries of their symptoms and answered questionnaires about their quality of life.
- Six months after DBS surgery, participants’ movement symptoms had improved remarkably: on average by 62 percent.
- Participants experienced 3.5 hours a day more of “on” time at the six-month evaluation compared to baseline.
- On average, participants also reduced their use of antiparkinsonian drugs by half.
- A year after DBS surgery, study participants maintained these improvements and reported an improved quality of life.
- Three serious adverse events were attributed to either the device or the surgery, e.g., infection at implant site, a number on par with other clinical trials of DBS and were resolved. One participant died from pneumonia six months after surgery unrelated to the DBS device or procedure.
What Does It Mean?
Many people with PD have benefited from DBS. Yet in the nearly 20 years that the surgery has been available for use in humans, there has been very few changes in the stimulating equipment. There is clear room for improvement, to make DBS even more effective and to lessen potential side effects.
Several new DBS approaches are under study. The research reported here represents a step forward for the one known as multiple-source current steering. Multiple-source current steering allows for a highly customized approach to DBS and has the potential to offer benefits over the older, well-established technology. In this small, phase II clinical trial, using a device manufactured by Boston Scientific, the researchers showed that this device was safe and effective.
However, the study authors caution that the placebo effect may have exaggerated the benefits reported, since neither participants nor their doctors were “blinded” to the treatment. Further trials, with larger numbers of participants, are needed to further investigate the potential benefits of this approach to DBS. In fact, the manufacturer has launched a larger, 310 participant, multi-center, double-blinded trial of its Vercise® DBS system in the US, where it is still an experimental device (it is already approved in Europe).
Timmerman L, Jain R, Chen L, Maarouf M, Barbe MT, Allert N, Brücke T, Kaiser I, Beirer S, Sejio F, Suarez E, Lozano B, Haegelen C, Vérin M, Porta M, Servello D, Gill S, Whone A, Van Dyck N, Alesch F. Multiple-source current steering in subthalamic nucleus deep brain stimulation for Parkinson’s disease (the VANTAGE study): a non-randomised, prospective, multicentre, open-label study. The Lancet Neurology (2015) 14:693–701. http://dx.doi.org/10.1016/S1474-4422(15)00087-3
Tagliati M. Multiple-Source Current Steering: A New Arrow in the DBS Quiver. The Lancet Neurology (2015) 14:670-671. http://dx.doi.org/10.1016/S1474-4422(15)00099-X