A new neurophysiological marker called Evoked Resonant Neural Activity (ERNA) could transform how doctors fine-tune deep brain stimulation (DBS) surgery for Parkinson's disease, making the procedure faster and more precise without relying on patient feedback during the operation. In a recent study published in April 2026, researchers found that ERNA outperformed traditional methods at identifying the optimal stimulation sites in the brain.

What Is ERNA and How Does It Work?

ERNA is a large-amplitude neural signal that emerges when doctors apply electrical stimulation to specific brain regions, such as the subthalamic nucleus (STN), a key target in Parkinson's treatment. Unlike other brain signals used in DBS programming, ERNA produces a distinctive oscillating waveform that decays after stimulation stops. The signal appears to reflect activity in brain networks involved in movement control and is particularly strong in the dorsolateral region of the STN, the area most critical for treating Parkinson's symptoms.

What makes ERNA especially valuable is its size. The signal measures several hundred microvolts, making it much larger and easier to detect than other neurophysiological markers, even when patients are under general anesthesia during surgery. This robustness is crucial because most patients prefer to be asleep during DBS implantation rather than awake, which is the traditional approach.

"ERNA is evoked by stimulation, and ERNA may be especially relevant in asleep DBS surgeries where general anesthesia is being used, and these are the types of surgeries that patients prefer," explained Dr. Mitra Afshari, an associate editor of the Movement Disorder Society podcast.

Dr. Mitra Afshari, Associate Editor, Movement Disorder Society Podcast

How Does ERNA Compare to Current Methods?

Currently, doctors rely on beta oscillations, a type of brain rhythm between 13 and 30 hertz, to guide DBS programming. Beta power is the basis of today's closed-loop DBS systems, which sense dysfunction in real time and deliver stimulation only when needed. However, traditional DBS programming is largely based on trial-and-error clinical judgment, with surgeons testing multiple contact points along the electrode to find the best location.

In a 2022 retrospective study, researchers compared three approaches for predicting which electrode contact would ultimately be chosen for chronic stimulation in 47 Parkinson's patients. The results were striking: ERNA correctly predicted the optimal contact 80 percent of the time, compared to 67 percent for anatomical landmarks and just 50 percent for beta power. This earlier finding prompted the team to investigate ERNA's potential in more advanced surgical scenarios.

Dr. Kanae J. Nagao, a neurologist at the University of Melbourne and lead researcher on the recent work, noted that ERNA offers advantages beyond raw accuracy. Because of its large amplitude, ERNA provides better spatial resolution when surgeons use directional leads, which have multiple independent current controls that allow for more precise targeting of stimulation.

"We're not trying to say ERNA is better or is going to replace local field potentials. We're trying to look at adding a tool for DBS programming that could be potentially useful in a different aspect, especially trying to improve the efficiency of that initial DBS programming period, which is really quite arduous for patients," stated Dr. Kanae J. Nagao.

Dr. Kanae J. Nagao, Neurologist, Florey Department of Neuroscience, University of Melbourne

Why Does ERNA Matter for Parkinson's Patients?

The initial DBS programming phase is notoriously challenging for patients. Surgeons must test numerous electrode contacts to find the sweet spot that maximizes symptom relief while minimizing side effects. This process is time-consuming, uncomfortable, and often requires patients to be awake so doctors can assess their tremor, rigidity, and movement in real time. A faster, more objective method could significantly reduce surgical time and patient burden.

ERNA's ability to work reliably under general anesthesia is particularly important. Because the signal remains robust even when patients are sedated, surgeons can use ERNA to guide programming decisions without waking patients during surgery. This aligns with patient preferences and reduces the stress and discomfort associated with awake DBS procedures.

How to Optimize DBS Programming With ERNA

• Intraoperative Recording: ERNA can be rapidly recorded during surgery in the operating room, minimizing disruption to the surgical workflow and allowing real-time assessment of electrode placement.
• Spatial Mapping: The relative amplitudes of ERNA at each electrode contact remain preserved under general anesthesia, enabling surgeons to map the spatial distribution of the signal and identify the optimal stimulation site with high precision.
• Directional Lead Compatibility: ERNA's large amplitude makes it ideal for use with modern directional leads that have multiple independent current controls, allowing surgeons to fractionate current with greater spatial resolution than would be possible with smaller neural signals.

What Happens Next for ERNA Research?

The April 2026 study published in the Movement Disorders journal represents a significant step forward, but researchers emphasize that ERNA is not meant to replace existing methods. Instead, it offers a complementary tool that could streamline the initial programming phase and potentially improve lead placement decisions. Future work will likely explore ERNA's utility in other movement disorders beyond Parkinson's disease, such as dystonia, where abnormal muscle contractions cause involuntary movements.

The research team, led by Dr. Wesley Thevathasan at the University of Melbourne, continues to investigate the neurobiological mechanisms underlying ERNA. Understanding exactly how ERNA reflects brain network activity could unlock even broader applications in neuromodulation and movement disorder treatment.

For Parkinson's patients considering DBS, the emergence of ERNA as a programming tool offers hope for shorter surgeries, faster recovery, and more precise symptom control. As this technology matures and becomes more widely available, it could reshape the standard of care for one of the most effective treatments for advanced Parkinson's disease.