Noninvasive Brain Stimulation as Focal Epilepsy Treatment in the Hospital, Clinic, and Home

Introduction

Noninvasive brain stimulation (NIBS) provides a treatment option for patients not eligible for surgical intervention or who seek low-risk approaches and may be used in the hospital, clinic and at home. Our objective is to summarize our single-center experience with multiple NIBS approaches for the treatment of focal epilepsy.

Methods

A retrospective chart review identified drug resistant focal epilepsy patients who received NIBS as an epilepsy treatment at Mayo Clinic in Rochester, MN. Patients were typically treated as follows: (1) for TMS, 1 Hz stimulation was applied for five consecutive days in the neuromodulation clinic, (2) for outpatient tDCS, stimulation was applied for five consecutive days in the clinic, followed by optional treatment at home (3) for inpatient tDCS, stimulation was applied for three consecutive days. We analyzed continuous EEG data for the inpatient tDCS cohort and available HD-EEG data for outpatient cohorts to quantify changes in interictal epileptiform discharges (IEDs) as a result of stimulation. Outcomes were assessed at 1-month for TMS and outpatient tDCS and 1-week for inpatient tDCS.

Results

24 patients were treated with TMS (n=10) and tDCS (n=14, 9 as outpatients). The median age was 40 years (range 15-73). The median seizure reduction following stimulation was 50%. 14 patients (58 %) were responders to treatment (TMS=4/10, tDCS Outpatient =7/9, tDCS Inpatient=3/5). Five outpatient tDCS participants elected to continue treatment at home. 4 TMS and 4 outpatient tDCS underwent high density EEG before and after 5 days of therapy. Following stimulation, IED rate was reduced in 4/5 inpatient tDCS patients, 4/4 outpatient tDCS patients, and 4/4 TMS patients. Two patients experienced an increase in seizure frequency (1 following TMS and 1 following outpatient tDCS), which returned to baseline 4-6 weeks after stimulation treatments were discontinued.

Conclusions

TMS and tDCS are potential treatment approaches for drug resistant focal epilepsy patients in the hospital, clinic, and home. They have a favorable safety profile and can lead to a reduction in IEDs rates and seizures. These results suggest further studies are needed to examine NIBS as treatment for epilepsy.

Plain Language Summary

Noninvasive brain stimulation, such as transcranial magnetic stimulation and transcranial direct current stimulation, offer new treatment options for patients with focal seizures. This study reviewed the experience at Mayo Clinic using noninvasive brain stimulation in the hospital, clinic and at-home settings to treat seizures. Results showed an overall 50% median seizure reduction, and 58% of patients had at least a 50% reduction in seizures. Noninvasive brain stimulation is a promising treatment approach with a favorable safety profile.

Key Points

• Transcranial Magnetic Stimulation (TMS) and Transcranial Direct Current Stimulation (tDCS) may reduce seizures in a variety of settings

• TMS and tDCS can lead to a reduced interictal epileptiform discharge rate (IED)

• tDCS has the potential to be utilized safely at home by focal epilepsy patients

• Noninvasive brain stimulation is well tolerated and safe in focal epilepsy patients