Parkinson’s therapy: “For me, the surgery was a game changer”
15.04.2026
Parkinson’s is considered a disease of old age. But that is not always the case. Ilias Triantafyllakis was 25 years old when he received the diagnosis. The symptoms worsened rapidly; one drug therapy failed, another caused severe side effects. Ten years later, the young man underwent surgery at Charité – Universitätsmedizin Berlin. Fine electrodes now send impulses to specific centers in his brain. Deep brain stimulation has dramatically improved the life of the father of a family. He can move smoothly, sleep better, and think clearly again. Now the stimulation is intended to “learn” to adapt to different situations throughout the day.
“How are you? Did you get here well?” asked Prof. Andrea Kühn, shaking hands with Dr. Ilias Triantafyllakis in a brightly lit examination room at the Clinic for Neurology with Experimental Neurology. “I slept well - actually better than at home.” He laughed. His children, aged two and four, had not been able to wake him during his overnight stay at the clinic. The fact that Ilias Triantafyllakis can once again sleep through the night is thanks to a neurosurgical procedure at Charité a little over one year ago.
Two thin wires, as fine as needles, now lead into the interior of his brain. At their ends are tiny probes that can read brain signals and regularly send mild electrical impulses to a specific region of the diencephalon - the subthalamic nucleus, which is responsible, among other things, for transmitting movement signals.
“The operation was a game changer for me,” said Ilias Triantafyllakis. “Even very simple things work again- like being able to read three books in a row to my children.” He had come to the clinic to take the next step. His stimulator, a matchbox-sized device under his right collarbone connected to the electrodes in his brain, was to be switched to what is known as adaptive mode. This means that the previously constant, high-frequency impulses - which he could not feel at all - would in the future adjust to his needs: increasing during stress or when medication is insufficient, and decreasing when his mobility is fine or while he is at rest.
“Our patients initially benefit from deep brain stimulation itself,” explained Andrea Kühn, who heads the Movement Disorders and Neuromodulation section as well as the Collaborative Research Center ReTune at Charité and is a NeuroCure principal investigator. “In Parkinson’s patients, we can usually reduce symptoms by about half. At the same time, medication doses can also be halved, so overall patients feel significantly better.” Together with her team and partners around the world, the neuroscientist continues to develop this technology. She has been a pioneer in characterizing the rhythm of neuronal activity in the relevant brain circuits and in optimizing the interplay between electrode placement, impulse strength, and medication - for Parkinson’s syndrome as well as other neurological movement disorders such as dystonia, tremor, or tics. At present, she is investigating whether personalizing therapy in the form of adaptive deep brain stimulation can further improve outcomes and when it is most useful.
Looking back: The first symptoms and a long search
“It was January 7, 2015.” A fateful day. Without hesitation, Ilias Triantafyllakis named the date. “The day of my state exam (Staatsexamens), right before the test.” The law student received his Parkinson’s diagnosis from his doctor. It was a shock. “I was incredibly young and had just started my PhD.” A few days earlier, during Christmas with his family in Athens, it had begun. His left leg became stiff and immobile and could only be dragged along. Soon he found it difficult to coordinate the left and right sides of his body. “I was extremely slow in everything.” This form of Parkinson’s syndrome is called akinetic-rigid - characterized by stiff muscles and slowed movement.
Parkinson’s disease still cannot be cured. Brain cells that produce the neurotransmitter dopamine - often referred to as the “happiness hormone” - die irreversibly, disrupting brain circuits responsible for movement. This process cannot be stopped. However, the symptoms of the disease can be alleviated. In Ilias Triantafyllakis’s case, the first treatment attempt with a medication intended to replace the missing dopamine in the brain failed. Instead, a feared side effect occurred: he developed a gambling addiction. His brain increasingly craved reward stimuli - sometimes stock speculation, sometimes sports betting.
Exhausted physically and financially, a change in medication was supposed to help. But the next drug, a precursor to dopamine, also caused serious side effects. It did not provide continuous relief; so-called “on” and “off” phases alternated, and involuntary movements were added. “My muscles were either stiff or I was overactive,” recalled Triantafyllakis, who by then was working in banking. When his second child was born, the burden became too great. “I had a full-time job, and on some days I could barely sit upright at my desk.” His neurologist suggested deep brain stimulation and referred the young man to Charité.
A new life with brain stimulation
“I wasn’t afraid,” said Ilias Triantafyllakis. “I trust science.” Once again, it was January 7 - this time in 2025, exactly ten years after his Parkinson’s diagnosis. In a procedure lasting several hours, experienced neurosurgeons at Charité placed two probes precisely in their target area, the subthalamic nucleus, a region deep in the brain about the size of a fingernail. A few days later, a second procedure followed: the stimulator and connecting cables were implanted under the skin, similar to a pacemaker. A study team at the Clinic for Neurology with Experimental Neurology continued to monitor the father closely, documenting every change and fine-tuning the stimulation.
The precise positioning of the probes is crucial for the effectiveness of deep brain stimulation. It is calculated based on individual radiological imaging data by experienced neurosurgeons such as Dr. Gerd-Helge Schneider at Charité. © Götz Schleser
“My life has improved incredibly since then,” said Ilias Triantafyllakis, reflecting on his decision. “Since the operation, I’ve been able to exercise again - before that, it was difficult. The fluctuations between immobility and excessive movement have almost completely disappeared. I can do much more, especially with my children and my wife. And I sleep through the night again. Before, it was only four hours at a time because my muscles would stiffen.” In addition, he now requires only a small fraction of his previous medication dose. The frequent dosing throughout the day and the diminishing effectiveness of dopamine replacement had become an increasing burden for him.
The stimulation learns to adapt
Back in the examination room on the fourth floor of the Charité ward building, Ilias Triantafyllakis walked slowly, shuffling back and forth. Study physician Dr. Victoria Witzig checked his mobility: “Left arm?” “Nothing, doesn’t work at all.” “Turn?” “Can’t.” “Open and close your hand?” “Right works. Left doesn’t.” The symptoms of the disease had returned in full intensity - tremor, brain fog, lack of concentration, immobility. This time, it was intentional. The stimulation had been switched off, and medication paused for 12 hours under clinical supervision. The goal was to record brain activity without therapeutic intervention and then determine the upper and lower limits for the future adaptive stimulation.
Ilias Triantafyllakis hoped that the fluctuations in his mobility that still occasionally occurred under continuous stimulation would disappear once the electrical impulses were delivered exactly when his brain needed them. “I could imagine it becoming more dynamic - and maybe the remaining twenty percent improvement will come on top.” This is possible because adaptive deep brain stimulation is a so-called closed-loop system - a brain–computer interface that Andrea Kühn and her team have helped develop. “The electrodes detect rhythmic fluctuations in brain activity in a specific frequency range and read them out. The system uses this information to activate impulses in real time,” explained the neurologist. “This technology is still very new and can only be implemented in a few specialized centers. But we are already seeing improvements in patients who have been switched to it.”
Trust in science: Dr. Victoria Witzig and Dr. Jonathan Kaplan have been supporting Ilias Triantafyllakis since his operation. © Götz Schleser
Whether adaptive deep brain stimulation is truly superior to continuous stimulation will be examined by Andrea Kühn and her study team starting this summer in a large comparative trial. Around 50 patients in Berlin, Würzburg, Düsseldorf, and other centers across Germany will take part. A specialized outpatient clinic for this new, intelligent form of Parkinson’s therapy has already been established at Charité since the beginning of this year.
Victoria Witzig adjusted a control on the tablet in her hand while watching her patient. “I’ll increase it now. Left: 3 milliamps…” “Oh, cool… ah…” Ilias Triantafyllakis laughed with relief. “Right…” His stimulator was active again and would in future respond individually to different situations, sometimes sending stronger, sometimes weaker impulses. He tapped his index finger and thumb together rhythmically - first slowly, then faster. “With you, it’s always like a switch. The symptoms suddenly disappear.” The study physician and Andrea Kühn once again checked arm mobility, balance, and gait. It was a careful fine-tuning of the electrical impulses in tenths of a milliampere, repeated again and again until the optimal setting was reached.
Around 200 Parkinson’s patients at Charité have received a stimulator in the past six years that can, in principle, be switched to adaptive stimulation. Andrea Kühn and her team have already guided 23 of them through this process. Most report additional improvements in their daily lives. This impression is supported by the results of a Charité study from 2025 involving the first eight patients, as well as by a subsequent international approval study published in the summer of 2025 in the journal JAMA Neurology. “I have always been fascinated by the human brain, even though we still do not fully understand how it works,” said Andrea Kühn. “If we can help our Parkinson’s patients live with as few limitations as possible through adaptive deep brain stimulation, that is a major step forward. For the first time, neurotechnology in Parkinson’s allows us to respond directly to brain rhythms - essentially reading the brain’s language and using that information to adjust treatment.”
Ten days later, Ilias Triantafyllakis spun his four-year-old daughter through the hallway of their apartment. They played and laughed together. “I feel as if I am almost no longer ill,” he said. “The disease had taken up so much space in my life - and in my children’s lives.”
His wife Berdice confirmed that deep brain stimulation had brought great benefits to him and the entire family. “It has given us a good life. We have truly gained a lot.” He could already feel that the newly adapted form of stimulation suited his dynamic lifestyle even better. Further fine-tuning by the Charité study team is still needed. Finding the exact right settings is challenging. It requires experience, but also intuition, because the human brain is complex and not a computer. Nevertheless, brain stimulators are becoming part of routine medical care. Soon, they may be as common as pacemakers are today.
Additional Information
Collaborative Research Center TRR 295 ReTune
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