TMS for Epilepsy

TMS and seizure disorders — a complex relationship

Here’s the paradox. High-frequency TMS can potentially trigger seizures — it’s the main safety risk of any TMS treatment. But low-frequency TMS does the opposite. It dials down cortical excitability. It may actually help prevent seizures.

That makes epilepsy both a contraindication for standard high-frequency TMS and a potential treatment target for low-frequency protocols. Same technology, opposite effects, depending on how you use it.

How low-frequency TMS may help

Low-frequency (0.5-1 Hz) rTMS reduces neural excitability in the area being stimulated. For epilepsy, that means calming the seizure focus — the patch of overexcitable brain tissue where seizures start.

It works best when:

• The seizure focus sits near the cortical surface (where TMS can actually reach it)
• The focus is well-localized (pinpointed by EEG or MRI)
• The patient has drug-resistant focal epilepsy — meaning medications haven’t been enough

Evidence

The research is mixed, but there are signals worth paying attention to:

• A 2020 Cochrane review found low-frequency rTMS reduced seizure frequency in some patients with focal epilepsy, though evidence quality was rated low-to-moderate
• Studies that targeted the seizure focus directly (guided by EEG) showed better results than protocols without precise targeting
• Responding patients saw 20-40% reductions in seizure frequency
• Effects are often temporary, requiring repeated treatment courses

Why this remains investigational

A few honest obstacles:

• Results across studies are inconsistent — some show clear benefit, others don’t
• Nobody has locked down the optimal stimulation parameters (frequency, pulse count, treatment duration)
• Standard TMS coils can’t reach deep seizure foci — and many seizure foci are deep
• Patient selection criteria haven’t been standardized

Safety considerations

• Low-frequency TMS (1 Hz) for epilepsy has a favorable safety profile
• High-frequency TMS (10 Hz+) is generally contraindicated in active epilepsy — the seizure trigger risk is real
• Patients should be monitored during sessions with EEG if available
• Anti-epileptic medications should continue during TMS treatment
• Close collaboration between your epileptologist and TMS provider is non-negotiable. This is not a situation for going it alone.

Current status

TMS for epilepsy is not part of standard clinical practice. If you’re interested:

• Talk to your epileptologist (not just a general neurologist) — they’ll understand the nuances
• Look for clinical trials specifically for drug-resistant focal epilepsy
• Do not undergo standard high-frequency TMS protocols if you have epilepsy. The risk of triggering seizures is real and documented.
• Specialized low-frequency protocols should only happen at centers with genuine epilepsy expertise