What Are the Downsides to Deep Brain Stimulation?

Deep brain stimulation (DBS) can dramatically reduce tremor, rigidity, and other movement symptoms in conditions like Parkinson’s disease and essential tremor, but it comes with a real list of trade-offs. These range from immediate surgical risks like bleeding in the brain to longer-term problems with speech, mood, cognition, and the sheer logistical burden of living with implanted hardware that needs regular maintenance. Some downsides are well-known to movement-disorder specialists; others catch patients and families off guard because they were never clearly discussed before surgery.

Surgical Risks at the Time of the Procedure

The most serious immediate risk is bleeding inside the skull. Any time a surgeon passes electrodes through brain tissue, there is a chance of puncturing a blood vessel. In one large single-center series of more than 700 patients, symptomatic intracranial hemorrhage occurred in about 1.1% of cases, and asymptomatic bleeding visible only on postoperative imaging was seen in an additional 3.4%.¹ Male sex and a history of high blood pressure appear to raise the odds.² Ischemic stroke during surgery is rarer, occurring in well under 1% of procedures, and death related to the operation has been reported but is uncommon.³ Postoperative confusion, temporary breathing difficulty, and seizures round out the list of early complications, each affecting a small but real fraction of patients.

Speech and Gait Problems

Of all the stimulation-related side effects, speech difficulty is the one that patients report most often and that researchers have studied most closely. In Parkinson’s disease patients with subthalamic nucleus stimulation, most speech problems are mild or moderate, but a fraction turn out to be persistent. One long-term retrospective study found that roughly 17% of patients experienced speech impairment that was either not reversible or of unknown reversibility, and about 12% experienced the same for gait problems.⁴ The good news is that many speech and gait effects are tied directly to stimulation settings and can improve within minutes of turning the stimulator off.⁵ The bad news is that turning stimulation down to fix speech may let other symptoms creep back in. Clinicians often describe programming visits as a balancing act: dialing settings to minimize tremor without making speech slurred or walking unsteady.

Other stimulation-related nuisances include muscle contractions, tingling or numbness, eyelid twitching, and visual disturbances. These tend to be manageable through programming adjustments, but they add to the list of things that need to be monitored and fine-tuned over time.⁶

Cognitive Changes and Verbal Fluency Decline

The cognitive picture after DBS is uneven. Most patients do not experience a broad collapse in thinking ability, but specific cognitive skills do take a hit. Verbal fluency, the ability to quickly generate words starting with a given letter or belonging to a given category, shows consistent decline after subthalamic DBS. A meta-analysis covering hundreds of patients found moderate-sized drops in both phonemic and semantic verbal fluency.⁷ A separate controlled study found that DBS patients also showed significant decline in verbal memory compared to Parkinson’s patients who did not undergo surgery, along with trends toward slower information processing and difficulty inhibiting automatic responses.⁸

These findings point to disruption in frontostriatal circuits, the networks connecting the frontal lobes to deeper brain structures. For many patients, the verbal fluency dip is noticeable but tolerable compared to the motor benefits they gain. For others, especially those whose work or daily life depends heavily on verbal agility, this trade-off deserves careful thought before surgery.

Psychiatric and Mood Effects

Depression, mania, emotional blunting, and suicidal thinking are all documented after DBS, though rates vary depending on the condition being treated and the brain target chosen. A meta-analysis pooling a decade of data on DBS for Parkinson’s disease, dystonia, and essential tremor found that depression occurred in roughly 2–4% of patients and mania in about 1–2%. The completed suicide rate, however, stood out at 0.16–0.32%, which the authors flagged as high enough to warrant routine pre-surgical screening and close postoperative monitoring.⁹

When DBS is used for treatment-resistant depression itself, the psychiatric adverse event profile is different. A scoping review of DBS for depression found that about 18% of patients experienced worsening depressive symptoms, about 9% developed or worsened anxiety, and the completed suicide rate reached 2.5%.¹⁰ Those numbers are not directly comparable to the movement-disorder figures because the patient population begins with severe psychiatric illness, but they underline that mood effects are not a minor footnote.

Why does a procedure targeting motor circuits affect mood at all? The subthalamic nucleus and surrounding regions connect to limbic and prefrontal areas involved in emotion regulation. Stimulating one circuit can spill into adjacent ones. Additionally, in Parkinson’s patients, dopaminergic medications are often reduced after DBS. The sudden drop in medication that was previously providing some mood support can unmask or worsen depression and apathy.

Hardware Complications and Revision Surgeries

DBS hardware is implanted in the body for years, and like any long-term implant, it can fail. Lead fractures, connector erosion, and device malfunction are all documented. In one national center’s case series spanning a decade, X-rays confirmed outright lead fractures in some patients while others showed high impedance levels across all contacts, suggesting internal damage invisible on imaging.¹¹ A phenomenon called Twiddler’s syndrome, where patients unconsciously rotate the pulse generator under the skin, can coil or kink the lead wires and cause the system to stop working.

Infections at any point along the hardware, from the scalp incision to the chest pocket housing the pulse generator, occur in roughly 2–5% of patients across various studies.³ Treating a DBS infection sometimes means removing the entire system, which brings its own crisis: original symptoms come roaring back, and medication needs ramp up sharply.¹²

Over half of patients in one large cohort required at least one repeat hardware surgery, most commonly to replace a depleted battery in the pulse generator. About 11% needed repeat intracranial electrode surgery, and a small fraction had their systems removed entirely.¹³ Rechargeable generators have reduced the frequency of battery-change surgeries, but they come with their own burden: patients must remember to charge the device regularly, which can become harder as the underlying disease progresses.

Impulse Control and Behavioral Changes

Impulse control disorders, including pathological gambling, compulsive shopping, binge eating, and hypersexuality, are common in Parkinson’s disease even without surgery, largely because of dopaminergic medications. The relationship between DBS and these behaviors is genuinely complicated. Reducing medication after DBS can improve pre-existing impulse control problems. But new impulse control disorders also emerge after surgery in some patients. One study found that 17 patients developed new impulse control diagnoses after DBS, with unilateral stimulation accounting for the majority.¹⁴ The overall effect of DBS on impulse control has been called a “double-edged sword” in the literature: the same intervention can both help and harm, depending on the patient and how medications are managed afterward.¹⁵

The Ongoing Burden of Programming and Follow-Up

DBS is not a set-it-and-forget-it treatment. After surgery, patients need repeated programming sessions where a clinician adjusts stimulation settings to find the best balance of benefit and side effects. In the first year alone, patients average about seven programming visits. That rate drops to roughly three per year afterward, but it never reaches zero.¹³ For patients who live far from a DBS center or who have limited mobility, these visits represent a significant practical challenge. Some patients need travel assistance, overnight stays, or time off work.

This management burden also extends to caregivers, who often coordinate travel, accompany the patient to appointments, and monitor for changes between visits. The cumulative demand over years of DBS therapy is something that rarely features prominently in pre-surgical counseling.

MRI Restrictions

Living with implanted DBS hardware changes your relationship with medical imaging. The main concern with MRI is that the electromagnetic fields can heat the electrode tips inside the brain, which risks tissue damage. Studies in both human patients and phantom models have confirmed that the electrode tip is where temperature rises are most pronounced, and that the risk increases at higher field strengths and with certain coil configurations.¹⁶ Even switching from a head-only transmit coil to a body-transmit coil can significantly increase heating at the electrode tips.¹⁷

Newer DBS systems have been designed to be conditionally MRI-compatible, meaning scans can be performed safely under specific technical conditions. But “conditionally compatible” is not the same as “no restrictions.” Patients and radiology departments both have to follow a narrow set of rules, including specific absorption rate limits and coil types. In practice, some imaging centers simply decline to scan patients with DBS implants, which can complicate the diagnosis of unrelated conditions like suspected stroke or cancer.

What Happens When Stimulation Stops Suddenly

An underappreciated risk of DBS is what happens when it abruptly stops working, whether from a depleted battery, a fractured lead, or removal for infection. In some Parkinson’s patients, sudden loss of stimulation triggers a life-threatening akinetic crisis, sometimes called malignant DBS withdrawal syndrome. Symptoms include severe rigidity, inability to move, high fever, and altered consciousness, resembling a condition caused by abrupt withdrawal of dopaminergic drugs.¹⁸

What makes this particularly dangerous is that the standard rescue treatment, increasing dopaminergic medication, does not reliably work. Case reports describe patients who only recovered after stimulation was physically restored by replacing the pulse generator. Delayed restoration or failure to recognize the syndrome can be fatal.¹⁹ Risk factors appear to include long disease duration, many years of stimulation, and older age. This effectively means that the longer someone benefits from DBS, the more dependent on it they become, and the more dangerous an unplanned interruption gets.

Loss of Benefit Over Time

Some patients notice that DBS becomes less effective years after implantation. This raises the question of whether the brain adapts to the stimulation (tolerance) or whether the underlying disease is simply progressing. For essential tremor patients with thalamic stimulation, a secondary analysis found statistically significant long-term reductions in how well DBS controlled hand function and daily activities, with evidence of genuine tolerance in some measures.²⁰ But other researchers have argued that tolerance is probably over-reported in the literature and that disease progression, suboptimal lead placement, and programming that has not been updated adequately may explain most of the worsening.²¹

In Parkinson’s disease, the situation is a bit different because DBS primarily addresses the motor symptoms that are responsive to dopaminergic medication. As the disease advances and non-motor symptoms like balance problems, cognitive decline, and autonomic dysfunction take center stage, DBS cannot address those newer symptoms. Patients and families sometimes interpret this as the stimulation “wearing off” when in reality the disease has moved into territory DBS was never designed to reach.

Personality, Relationships, and the Expectation Gap

Some of the most difficult downsides of DBS are the hardest to quantify. Qualitative research with patients and caregivers has revealed that unanticipated changes in personality and sense of self can follow surgery. Some changes are positive: patients feel more like themselves again after years of progressive disability. But others are negative, and they can strain relationships in ways neither the patient nor their partner anticipated.²² A caregiver who has spent years adapting to their partner’s limitations may struggle to adjust when those limitations suddenly change. Meanwhile, the patient may not recognize the personality shifts that others see in them.

Research on dispositional personality traits has not found dramatic measurable changes after DBS, but work on narrative identity, how people tell the story of who they are, suggests that self-image disruptions may be more common than standardized tests capture.²³ This is an area where the science is still catching up to patient experience.

Expectations also play a measurable role in how satisfied patients are after surgery. A systematic review found that patients who went into DBS expecting improvements in symptoms that DBS cannot directly address, like mental state, were more likely to report disappointment with their motor outcomes and quality of life afterward, even when objective motor scores had improved.²⁴ Having unrealistic expectations before surgery can color the entire experience after it.

Access Disparities and Who Gets Left Out

DBS is an expensive, specialized procedure concentrated in large academic medical centers. That creates access problems that function as a systemic downside. Patients living in higher-income neighborhoods with greater educational attainment are more likely to receive DBS. Insurance type matters, too: patients with private insurance are more likely to undergo the procedure, while those on Medicaid face lower rates of referral and treatment. Clinician avoidance of administrative burden and lower reimbursement from government-funded insurance may contribute to the gap.²⁵ The result is that many patients who could benefit from DBS never get the chance to weigh its downsides in the first place, because they are never offered it.

Pediatric and Emerging Uses

As DBS expands beyond its traditional base in adult Parkinson’s disease and essential tremor into conditions like childhood dystonia and psychiatric disorders, new risks emerge. In children, the growing skull creates a unique problem: bone growth at the burr hole site can push the electrode upward over time, causing lead migration that does not occur in adults. The developing nervous system also raises questions about long-term effects of chronic stimulation on brain maturation that simply have not been studied at scale yet.

For psychiatric indications like obsessive-compulsive disorder and treatment-resistant depression, the evidence base is far thinner than for movement disorders. Sample sizes in clinical trials are small, follow-up periods are shorter, and the adverse event profiles are still being mapped. The psychiatric applications are promising but carry extra uncertainty about both safety and efficacy that patients deserve to hear about clearly before consenting.

The Brain’s Physical Response to the Implant

A question patients sometimes ask is whether the electrode sitting in brain tissue for years causes local damage. Post-mortem studies have examined this by looking at brain tissue around DBS leads. What they find is a thin collar of gliosis, essentially scar tissue formed by the brain’s support cells, surrounding the electrode track. In one study, this gliotic collar averaged roughly 120–160 microns in thickness, and there was no significant difference in the amount of gliosis between patients who had lived with DBS for under five years versus those who had it for more than a decade.²⁶ That is reassuring in the sense that the brain does not seem to mount an escalating inflammatory response over time. But the gliosis that does form can affect electrode impedance and may contribute to the gradual changes in stimulation thresholds that clinicians observe.