Repetitive transcranial magnetic stimulation in the treatment of epilepsia partialis continua

Abstract

Objective: Repetitive transcranial magnetic stimulation (rTMS) is a technique for noninvasive focal brain stimulation by which small intracranial electrical currents are generated by a fluctuating extracranial magnetic field. In clinical epilepsy, rTMS has been applied most often interictally to reduce seizure frequency. Less often, rTMS has been used to terminate ongoing seizures, as in instances of epilepsia partialis continua (EPC). Whether ictal rTMS is effective and safe in the treatment of EPC has not been extensively studied. Here, we describe our recent experience with rTMS in the treatment of EPC, as an early step toward evaluating the safety and efficacy of rTMS in the treatment of intractable ongoing focal seizures.

Methods: Seven patients with EPC of mixed etiologies were treated with rTMS applied over the seizure. rTMS was delivered in high-frequency (20-100 Hz) bursts or as prolonged low-frequency (1 Hz) trains. The EEG was recorded for three of the seven patients.

Results: rTMS resulted in a brief (20-30 min) pause in seizures in three of seven patients and a lasting (>or=1 day) pause in two of seven. A literature search identified six additional reports of EPC treated with rTMS where seizures were suppressed in three of six. Seizures were not exacerbated by rTMS in any patient. Generally mild side effects included transient head and limb pain, and limb stiffening during high-frequency rTMS trains.

Conclusions: Our clinical observations in a small number of patients suggest that rTMS may be safe and effective in suppressing ongoing seizures associated with EPC. However, a controlled trial is needed to assess the safety and anticonvulsive efficacy of rTMS in the treatment of EPC.

Figures

Figure 1. EEG of patient with EPC undergoing rTMS

EEG was recorded with a conventional 10–20 international scalp electrode configuration, filtered 1–70 Hz, and displayed in a referential montage. “*” demarcates typical left temporal sharp waves. (a) 100 Hz rTMS was at 100% MO with figure-8 coil for 0.05 seconds (arrow). EEG following rTMS shows transiently-reduced sharp wave frequency. (b) Typical sharp waves (*) precede 1 Hz rTMS (arrow), and are absent (c) following rTMS.

Figure 1. EEG of patient with EPC undergoing rTMS

EEG was recorded with a conventional 10–20 international scalp electrode configuration, filtered 1–70 Hz, and displayed in a referential montage. “*” demarcates typical left temporal sharp waves. (a) 100 Hz rTMS was at 100% MO with figure-8 coil for 0.05 seconds (arrow). EEG following rTMS shows transiently-reduced sharp wave frequency. (b) Typical sharp waves (*) precede 1 Hz rTMS (arrow), and are absent (c) following rTMS.

Figure 1. EEG of patient with EPC undergoing rTMS

EEG was recorded with a conventional 10–20 international scalp electrode configuration, filtered 1–70 Hz, and displayed in a referential montage. “*” demarcates typical left temporal sharp waves. (a) 100 Hz rTMS was at 100% MO with figure-8 coil for 0.05 seconds (arrow). EEG following rTMS shows transiently-reduced sharp wave frequency. (b) Typical sharp waves (*) precede 1 Hz rTMS (arrow), and are absent (c) following rTMS.