Abstracts

Rationale: Transcranial magnetic stimulation (TMS) is a noninvasive modality of focal brain stimulation in which a fluctuating magnetic field induces an electrical current within the cortex. Each pulse stimulates a small area of tissue and can be used to probe brain states as well as to influence cortical excitability. TMS has been used for depression, migraine, and presurgical motor and language mapping, and is being investigated for its potential as a therapeutic tool in epilepsy. We present a case of a patient with focal epilepsy, refractory to multiple medication trials, who has experienced a remarkable period of seizure freedom after TMS therapy¹.

1. Tsuboyama M, Kaye HL, Rotenberg A. Review of Transcranial Magnetic Stimulation in Epilepsy. Clin Ther. 2020;42(7):1155-1168.

Methods: The patient is a 48-year-old man with focal epilepsy, intractable since onset at age 12. He had experienced an exacerbation of his seizure frequency from once a month to 50-60 times daily for two months prior to presentation. The seizures lasted 20-30 seconds, with semiology of feeling unwell and anxious, an illusory auditory sensation, diplopia and oscillopsia, loss of motor control, and inability to follow commands. Brain MRI showed a focal cortical dysplasia in the left occipital lobe with surrounding cortical enhancement. CSF evaluation was negative for inflammatory markers or the presence of disease-causing antibodies. He was admitted to the Epilepsy Monitoring Unit (EMU), where focal seizures were recorded occurring 7-8 times per hour, arising maximally from the left occipital head region at electrode O1. Medication loads with levetiracetam and lacosamide did not improve seizures. He was subsequently treated with 1 Hz repetitive TMS (rTMS) targeting the left occipital region over the next five days (1800 pulses/day) while undergoing continuous EEG monitoring.

Results: Stimulation for 5 consecutive days was well-tolerated. Seizure frequency was 7-8/hour prior to stimulation. By day 3, seizure frequency was 0-5 per hour, and by day 5 it was 0-4. He was discharged to home after completion of stimulation, having been on his home medications for seven days. Ambulatory EEG on day 31 showed no seizure activity over 24 hours. EEG signal processing showed decrease in seizure detections, spike frequency, and alpha power over the left occipital region over the course of the recordings. One month follow-up MRI showed resolution of cortical enhancement.

After dismissal from the hospital, the patient was seizure-free for six months, and was able to stop one antiseizure medication and reduce another. He receives 3 days of 1 Hz rTMS every 2-3 months. At last follow up of 11 months, he was experiencing auras approximately every two weeks without progression to disabling seizures.

Conclusions: In this patient with refractory lesional focal epilepsy, rTMS was well-tolerated and effective in controlling seizures whereas medications were not. TMS influences cortical excitability, is a promising non-invasive means of treating focal epilepsy, and has measurable effects on EEG. Further investigation is needed to determine useful biomarkers for noninvasive brain stimulation.

Funding: Please list any funding that was received in support of this abstract.: Research supported by NIH NINDS K23NS112339 (BNL).