AAN 2026 | Optimal targets for DBS in Parkinson’s disease and guidance for selecting between them
Alfonso Fasano, MD, PhD, FAAN, University of Toronto, Toronto, Canada, discusses the evolving understanding of deep brain stimulation (DBS) targets in Parkinson’s disease, emphasizing that subthalamic nucleus (STN) and globus pallidus interna (GPI) stimulation offer comparable efficacy but suit different patient profiles. He highlights the importance of individualized target selection based on symptoms, medication goals, and patient characteristics to optimize outcomes and minimize side effects. This interview took place at the 78th American Academy of Neurology (AAN) Annual Meeting in Chicago, IL.
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Transcript
The approved targets for Parkinson’s surgery are basically three. The VIM in the thalamus that can be treated with lesions or DBS, but also the subthalamus and the globus pallidus pars interna that we call STN or GPI respectively. And STN and GPI are the main targets these days for deep brain stimulation. They’re officially approved. And because we’ve been using them for a few years now, or actually more than a few years, it’s been three decades at this point, we have a better understanding of what they can do...
The approved targets for Parkinson’s surgery are basically three. The VIM in the thalamus that can be treated with lesions or DBS, but also the subthalamus and the globus pallidus pars interna that we call STN or GPI respectively. And STN and GPI are the main targets these days for deep brain stimulation. They’re officially approved. And because we’ve been using them for a few years now, or actually more than a few years, it’s been three decades at this point, we have a better understanding of what they can do. So especially in the early eras of deep brain stimulation, most people will have said that STN-DBS is the only procedure for Parkinson’s disease. Then there’s been a renewed interest in the States for a variety of reasons towards GPI-DBS, and so this led to the debate whether STN or GPI was the better target for Parkinson’s patients. So this inspired a number of well-done studies, randomizing patients to either target. And now we have a better understanding based on evidence of what these two targets, when stimulated, can achieve. And in short, it’s not that one is better than the other. We know what’s the best candidate for each target. So the job of the neurologist and neurosurgeon is to identify the right candidate for each target. STN is particularly useful when we want to achieve a great effect on bradykinesia by reducing the amount of medications, levodopa taken by the patients. So anytime our goal is to keep the doses of medications low, we prefer STN. An example of this will be people having psychiatric complications coming from drugs or people of a younger age where we can lower the medication use stimulation for many years and then 10/15 years later we can increase again the medication so it gives us the opportunity to use a scalable approach in the years to come. At the same time STN-DBS can also induce dyskinesias. It can induce depression or mania because it’s a small target, so we can obtain more side effects. So it’s less forgiving as a target. The reason why we try to do it mainly in super healthy, younger individuals. GPI instead is more forgiving. It’s a bigger target. We can target just a motor section of the nucleus, and we achieve mainly motor results from it. It’s certainly the greatest option for dyskinesias, but because it’s not so effective for bradykinesia, people don’t reduce the medication typically too much. So it’s an ideal target for people who are a little bit more frail on the older age of the spectrum, so where we want to achieve some improvement of quality of life without risking a worsening of cognition, balance, freezing of gait. So like I said, we now know that they’re effective. Actually, the studies comparing them concluded that they’re equal. But in reality, we know that for each candidate, we have a better solution, either STN or GPI. And I should say that in some cases in the past, we started with one target and then we had to add the other targets. For example, GPI initially, then bradykinesia worsens. We cannot increase medication too much. Then you will add STN-DBS. But we also had STN-DBS treated patients who developed dyskinesias because of the stimulation. And then we had to do GPI-DBS on top to take care of the dyskinesias. Not common, but in theory, it’s not either or. In some people, it’s also both.
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Disclosures
Dr. Fasano has received personal compensation in the range of $5,000-$9,999 for serving as a Consultant for Abbott. Dr. Fasano has received personal compensation in the range of $10,000-$49,999 for serving as a Consultant for Abbvie. Dr. Fasano has received personal compensation in the range of $500-$4,999 for serving as a Consultant for Ipsen. Dr. Fasano has received personal compensation in the range of $10,000-$49,999 for serving as a Consultant for Medtronic. Dr. Fasano has received personal compensation in the range of $5,000-$9,999 for serving as a Consultant for Boston Scientific. Dr. Fasano has received personal compensation in the range of $500-$4,999 for serving on a Scientific Advisory or Data Safety Monitoring board for Abbott. Dr. Fasano has received personal compensation in the range of $5,000-$9,999 for serving on a Scientific Advisory or Data Safety Monitoring board for Medtronic. Dr. Fasano has received personal compensation in the range of $500-$4,999 for serving on a Scientific Advisory or Data Safety Monitoring board for Ceregate. Dr. Fasano has received personal compensation in the range of $0-$499 for serving on a Scientific Advisory or Data Safety Monitoring board for Inbrain Neuroelectronics. Dr. Fasano has received personal compensation in the range of $500-$4,999 for serving on a Scientific Advisory or Data Safety Monitoring board for Syneos Health. Dr. Fasano has received personal compensation in the range of $0-$499 for serving on a Scientific Advisory or Data Safety Monitoring board for Annovis. Dr. Fasano has received personal compensation in the range of $0-$499 for serving on a Scientific Advisory or Data Safety Monitoring board for CADTH. Dr. Fasano has received personal compensation in the range of $500-$4,999 for serving as an Editor, Associate Editor, or Editorial Advisory Board Member for International Parkinson and Movement Disorders Society. The institution of Dr. Fasano has received research support from Boston Scientific. The institution of Dr. Fasano has received research support from Medtronic. The institution of Dr. Fasano has received research support from Abbvie. The institution of Dr. Fasano has received research support from Canadian Institutes of Health Research (CIHR). The institution of Dr. Fasano has received research support from Michael J Fox Foundation. The institution of Dr. Fasano has received research support from Bluerock Therapeutics. Dr. Fasano has received publishing royalties from a publication relating to health care. Dr. Fasano has a non-compensated relationship as a Medical Advisory Committee with CenteR for Advancing Neurological Innovation to Application (CRANIA) that is relevant to AAN interests or activities. Dr. Fasano has a non-compensated relationship as a Medical Advisory Committee with HopeNET that is relevant to AAN interests or activities. Dr. Fasano has a non-compensated relationship as a Medical Advisory Committee with International Essential Tremor Foundation that is relevant to AAN interests or activities. Dr. Fasano has a non-compensated relationship as a Member with Tremor Research Group that is relevant to AAN interests or activities. Dr. Fasano has a non-compensated relationship as a Co-Chair with Tremor Study Group of the IPMDS that is relevant to AAN interests or activities. Dr. Fasano has a non-compensated relationship as a Vice-Chair with NPH Study Group of the IPMDS that is relevant to AAN interests or activities. Dr. Fasano has a non-compensated relationship as a Vice-Chair with Industry Committee of the IPMDS that is relevant to AAN interests or activities.
