Age is a consideration, not a cutoff, for DBS surgery
For many years, Deep Brain Stimulation (DBS) was primarily offered to Parkinson's disease (PD) patients under the age of 70 due to concerns about risks and complications in older adults. However, medical perspectives have evolved significantly. The focus has moved from chronological age to biological age and overall health status. This shift has opened up DBS as a viable treatment option for a broader age range of patients with movement disorders like Parkinson's disease and essential tremor.
Evolving perspectives on age and DBS
Multiple studies have challenged the traditional age cutoff for DBS surgery. Research published in 2018 in the Journal of Neurosurgery compared long-term outcomes in PD patients over and under 70 and found no significant differences in motor function improvement, suggesting older age should not be an automatic exclusion criterion. A 2022 study on elderly PD patients (aged 75 and older) found that while DBS is effective for motor symptoms, those with longer disease duration may experience fewer long-term improvements in daily living activities. These findings emphasize that candidacy is less about a specific number and more about the individual's overall condition and disease progression.
Average age for DBS across different studies
Research studies on DBS cohorts provide a range of average ages, reflecting both the specific patient population being studied and the evolving acceptance of DBS for older patients. For instance, a 2017 study on PD patients aged 70 and older had an average age of 72.45 at the time of surgery. A broader database analysis of PD patients between 2000 and 2009 showed an average age of 61.2, but notably, 17.1% of those patients were over 75. For essential tremor (ET), another condition treated by DBS, one study reported a mean age of 68.42 years at the time of surgery. These varying averages highlight the importance of individual assessment rather than relying on a single number.
Critical factors influencing DBS candidacy
Instead of a rigid age limit, a multidisciplinary team evaluates several key factors to determine if a patient is a suitable candidate for DBS. This comprehensive assessment ensures the best possible outcomes and minimizes risks.
- Levodopa responsiveness: A strong, consistent response to levodopa medication is a primary indicator of a positive response to DBS. The ideal time for surgery is when a patient still responds to medication but struggles with fluctuations in motor control or dyskinesia.
- Overall health: The patient's general physical health is a major consideration. The surgical team assesses for other serious medical conditions or comorbidities, such as heart disease or significant lung issues, that could increase surgical risk.
- Cognitive and psychiatric health: A comprehensive neuropsychological evaluation is crucial. Patients with significant cognitive decline, dementia, or uncontrolled psychiatric conditions like depression or psychosis are generally not considered good candidates, as these issues may not improve and could even worsen after surgery.
- Severity and type of symptoms: DBS is most effective for motor symptoms such as tremor, stiffness, slowness of movement, and medication-induced dyskinesias. It is less effective for problems like freezing of gait, balance issues, or dementia.
- Disease duration: The length of time a patient has had the disease can also be a factor. While a longer duration doesn't necessarily exclude a patient, it may correlate with a higher burden of symptoms that don't respond well to DBS.
Comparing DBS candidacy factors for Parkinson's and Essential Tremor
| Feature | Parkinson's Disease (PD) Candidacy | Essential Tremor (ET) Candidacy |
|---|---|---|
| Symptom Focus | Motor symptoms like tremor, rigidity, bradykinesia, and medication-induced dyskinesias. | Disabling tremor (postural and action) that interferes with daily life activities like eating and writing. |
| Medication Response | A strong, positive response to levodopa medication is a key predictor of DBS success. | Tremor is refractory, meaning it has not responded adequately to standard medications like propranolol and primidone. |
| Timing | Typically considered after 4+ years of diagnosis when medication fluctuations or dyskinesia become problematic. | Consideration often occurs when tremor becomes severe enough to significantly impact quality of life despite medication trials. |
| Non-motor Symptoms | Severity of non-motor symptoms like dementia and balance issues significantly impacts candidacy and long-term outcomes. | Cognitive impairment and other non-motor issues are also assessed, as they can occur in some ET patients. |
The shifting age window for DBS
The optimal window for DBS has expanded. Previously, many centers were hesitant to operate on patients over 70 or 75, often citing concerns about increased risk. However, robust studies with long-term follow-up have demonstrated that age alone is not a reliable predictor of surgical outcomes or complications. Biological factors, including cognitive function, comorbidity burden, and surgical tolerance, are more telling. This has led to a more personalized approach to patient selection.
The importance of personalized assessment
Because every patient's journey with a movement disorder is unique, a personalized assessment is vital. An older patient with well-preserved cognitive function and few comorbidities may be a far better candidate than a younger patient with significant cognitive impairment and other health issues. This nuanced approach ensures that DBS is offered to individuals who are most likely to experience significant, life-enhancing benefits from the procedure.
Conclusion
In summary, there is no single average age for DBS surgery, and the focus is increasingly on a patient’s overall health rather than their chronological age. Clinical studies show that older patients can benefit significantly from DBS, with surgical outcomes and complications not necessarily tied to age. Critical factors like responsiveness to medication, general health, and cognitive function play a much more important role in determining candidacy than age alone. For individuals considering DBS, an in-depth evaluation by a specialized medical team is the most crucial step in determining eligibility and predicting potential outcomes. For more detailed information on surgical considerations, consulting authoritative sources like The Michael J. Fox Foundation is recommended, which can be a valuable resource for anyone navigating DBS decisions. The Michael J. Fox Foundation
