For adults aged 18 and over whose focal seizures continue despite properly tried medication, and whose seizures cannot be treated by removing a single area of brain, deep brain stimulation of the anterior nucleus of the thalamus can substantially reduce how often seizures happen. It is a treatment that makes epilepsy smaller, not one that makes it disappear: most patients have fewer and less severe seizures, most continue taking medication, and lasting freedom from seizures is uncommon.
At a glance
- Usual target
- Anterior nucleus of the thalamus (ANT), both sides
- Who it is for
- Adults 18 and over, focal (partial-onset) seizures continuing despite adequate trials of at least two suitable medications
- Usually considered when
- Seizures start in more than one place, come from both sides, or arise in an area that cannot safely be removed — or resective surgery has been declined or has not worked
- Realistic aim
- Fewer and less severe seizures, fewer injuries, fewer emergency admissions
- Not the aim
- A cure, or stopping medication
- Time to benefit
- Months; in the published trials the effect continued to grow over years
- Age policy in this practice
- Deep brain stimulation is the neuromodulation option preferred for adults 18 and over
Why stimulate rather than remove the focus
When seizures come from one clearly identified area that can be removed without unacceptable cost to speech, memory or movement, removing it is the better operation: it offers a real chance of freedom from seizures, which stimulation does not. Deep brain stimulation is for the patients that route does not fit — seizures starting in several places, seizures coming from both temporal lobes, a focus sitting in eloquent cortex, a previous resection that did not work, or a patient who does not want resective surgery.
So the first question at assessment is never "should we stimulate?" It is "can this epilepsy be cured by surgery?" Stimulation is discussed once the answer to that is no.
What the evidence shows
Anterior thalamic stimulation is the best-studied DBS approach in epilepsy. It was tested in a double-blind randomised trial in which every patient received an implant and half had the stimulation switched on, so that neither patient nor assessor knew who was being stimulated.
| Stage | Result |
|---|---|
| Blinded phase (3 months) | The stimulated group had a 29% greater reduction in seizures than the implanted-but-not-stimulated group (p = 0.002) |
| 2 years | Median seizure frequency reduced by 56%; 54% of patients had at least half their seizures removed |
| 7 years | Median seizure frequency reduced by 75% |
| Focal to bilateral tonic-clonic seizures at long-term follow-up | Reduced by 71% |
Fisher R, Salanova V, Witt T, et al. Electrical stimulation of the anterior nucleus of thalamus for treatment of refractory epilepsy. Epilepsia 2010;51:899–908. Salanova V, Sperling MR, Gross RE, et al. The SANTÉ study at 10 years of follow-up: effectiveness, safety, and sudden unexpected death in epilepsy. Epilepsia 2021;62:1306–1317. doi:10.1111/epi.16895
What it does not do — said plainly
- It does not cure epilepsy. Complete and lasting freedom from seizures is uncommon with thalamic stimulation.
- It does not replace medication. Doses may be simplified over time, but patients should expect to continue treatment.
- It does not work immediately. The benefit builds over months and the trial data show it continuing to improve for years.
- It is not free of psychological effects. In the randomised trial, depression and memory complaints were reported more often by stimulated patients than by controls. Anyone considered for this operation is screened for mood and memory beforehand and followed for both afterwards — this is not an optional part of the programme.
Assessment before surgery
No decision is made from a clinic letter. A candidate for epilepsy neuromodulation is assessed the way a candidate for resective surgery is assessed, because the first purpose of that work is to find out whether resection is possible:
- Video-EEG monitoring long enough to record the patient's habitual seizures.
- High-resolution epilepsy-protocol MRI, reviewed specifically for a structural cause.
- Functional imaging where the MRI is unrevealing or the electroclinical picture is discordant.
- Neuropsychological assessment of memory, language and mood.
- Review at a multidisciplinary epilepsy surgery meeting with neurology, neurophysiology, neuroradiology, neuropsychology and neurosurgery present.
- A clear record of which medications were tried, at what dose, and why each was stopped — seizures that have not had two properly conducted drug trials are not yet drug-resistant.
Why adults only
The randomised evidence for anterior thalamic stimulation, and the regulatory approvals that followed it, are in adults. Children with drug-resistant epilepsy are managed along a different pathway, in paediatric epilepsy surgery centres, with different options and different thresholds. In this practice, deep brain stimulation is offered from the age of 18.
Ask whether DBS is an option for your epilepsy
Frequently asked questions
Can deep brain stimulation cure epilepsy?
No. It reduces how often seizures happen and how severe they are. In the long-term follow-up of the randomised trial the median reduction in seizure frequency was 75% at seven years, but lasting freedom from seizures is uncommon and medication is normally continued.
Is DBS better than removing the part of the brain causing seizures?
No — where a single focus can be removed safely, resective surgery offers a real chance of freedom from seizures and is the better operation. Stimulation is for patients in whom resection is not possible, has been declined, or has already been tried without success.
Who is a candidate for epilepsy DBS in this practice?
An adult aged 18 or over with focal seizures that have continued despite adequate trials of at least two appropriate medications, who has been assessed at an epilepsy surgery meeting and in whom resection is not the right answer.
How long before seizures improve?
Months rather than weeks. The published trial data show the effect increasing over the first years of stimulation rather than appearing immediately after surgery.
Will I still need my epilepsy medication?
Yes. Medication is normally continued, though the regimen can sometimes be simplified once seizures are better controlled. Nothing is changed without the treating neurologist.