Timing of brain surgery critical for certain Parkinson's patients

The timing of Deep Brain Stimulation (DBS) surgery is a critical factor in preserving cognitive function for Parkinson's disease patients with a specific genetic mutation, according to a new study by an international team of researchers. 

The groundbreaking findings, published recently in the medical journal Movement Disorders, the official peer-reviewed journal of the International Parkinson and Movement Disorder Society, offer vital new guidance for doctors and patients navigating the complex decisions surrounding Parkinson's treatment. The team was co-led by Dr. Gian Pal, chief of Neurology and director of the Movement Disorders Program at Hackensack Meridian Neuroscience Institute at JFK University Medical Center, and associate professor of Neurology at the Hackensack Meridian School of Medicine.

Deep Brain Stimulation is a surgical procedure that has revolutionized Parkinson's care, offering profound relief from disabling tremors, stiffness, and involuntary movements when standard medications work unreliably. DBS is a life-changing surgical procedure that acts like a pacemaker for the brain, relieving severe tremors and stiffness when medications no longer work. 

DBS uses a surgically implanted battery to send steady, mild electrical pulses to the specific areas affected by Parkinson's. These rhythmic pulses act like noise-canceling headphones, overriding the chaotic brain signals that cause tremors and stiffness so patients can move smoothly again.

Patients who carry a mutation in the GBA1 gene-the most common genetic risk factor for Parkinson's disease-often experience significant physical symptoms earlier in life, making them prime candidates for DBS, but are also predisposed to cognitive problems.

Because of their vulnerability to cognitive problems, doctors have started to approach DBS cautiously in people with Parkinson's disease carrying GBA1 mutations. There is a debate regarding whether GBA1 carriers might face an accelerated loss of memory and executive function (cognitive decline) after undergoing DBS, or whether their cognitive problems are a natural part of their disease and unrelated to DBS, making the decision to operate complex.

To better understand factors that might influence DBS risk in GBA1 carriers, Dr. Pal and colleagues wanted to understand how timing of surgery might affect cognitive outcomes. Researchers analyzed data from 343 patients across 10 medical centers in the United States and Europe. They compared cognitive outcomes over time between patients with and without the GBA1 mutation who underwent DBS surgery either early or late in the course of their disease.

The research team uncovered that the risk of cognitive decline in genetically predisposed patients is heavily dependent on exactly when the surgery is performed. Patients with the GBA1 mutation who received DBS in the later stages of their disease experienced a significantly faster decline in their cognitive abilities compared to those who received the surgery earlier. In those without the genetic mutation, timing of DBS did not affect the cognitive outcome.

Importantly, the study identified a crucial window for intervention. The data showed performing DBS within the first seven to eight years of a patient's Parkinson's diagnosis is a vital cutoff point. Intervening before this threshold allows patients to extend their period of improved physical mobility, while also delaying the onset of significant cognitive decline. The severity of the specific genetic mutation a patient carried did not change this overall pattern-timing was the ultimate deciding factor.

This discovery represents a major shift in how neurologists and neurosurgeons might evaluate candidates for DBS. The study's authors emphasize that possessing a GBA1 genetic variant should never disqualify a patient from receiving the life-changing physical benefits of brain surgery. But this additional data can help patients and families better understand the potential benefits and risks of this surgical intervention.

The findings also highlight the critical importance of early genetic testing for Parkinson's patients. By identifying a GBA1 mutation early in the disease process, patients and their care teams can proactively consider DBS as a treatment option sooner rather than later, optimizing both their physical mobility and their long-term mental sharpness.

This new research could pave the way for a more personalized approach to Parkinson's care, where a patient's unique genetic blueprint directly informs the safest and most effective timeline for their treatment.

We may be approaching a turning point in how we use deep brain stimulation for Parkinson's disease. For decades, DBS decisions have largely been based on a patient's symptoms and clinical characteristics. Our research suggests that a patient's genetics-and importantly, the timing of surgery-may also matter. The future of DBS may not simply be deciding who should receive it, but identifying the right window to intervene for each individual patient. That moves us closer to truly personalized treatment for Parkinson's disease.

Dr. Gian Pal, chief of Neurology and director of the Movement Disorders Program at Hackensack Meridian Neuroscience Institute at JFK University Medical Center