Effects of 1 Hz Repetitive Transcranial Magnetic Stimulation on Cortical Excitability and Seizure Reduction in Intractable Neocortical Epilepsy

Cho, Hyun Ji; Kim, Hee Jin; Lee, Mina; Choi, Kyung Gyu; Lee, Hyang Woon

Abstract

BACKGROUND
& OBJECTIVES: Repetitive transcranial magnetic stimulation (rTMS) can modulate the excitability of cortical networks, possibly reduce the excitability by low frequency stimulation. In this study, we are conducting a study using 1 Hz rTMS in patients with intractable neocortical epilepsy. We wish to see whether 1Hz rTMS induces considerable changes in the cortical excitability and whether it leads to a significant reduction in seizure frequency in individual patients. METHODS: Patients with intractable neocortical epilepsy were recruited, and 1 Hz rTMS (110% of resting motor threshold, 1800 stimuli twice a day) was delivered to the seizure focus for 5 consecutive days. Resting motor threshold (r-MT), MEP amplitudes at different intensities, intracortical inhibition (ICI) and intracortical facilitation (ICF) were measured as TMS indices for motor cortical excitability. TMS measures were repeated before and after daily rTMS session, and again after 2 weeks. RESULTS: Four patients (aged 15 to 53, 3 females and 1 male, 2 TLE and 2 FLE) were described here:cortical excitability in 2 neocortical TLE patients showed lower r-MT and reduced ICF in ipsilateral hemisphere to epileptic focus. One of them with cortical dysplasia showed increased r-MT and ICI, and decreased ICF after daily rTMS session. This patient was seizure-free for 10 weeks, after which the seizure frequency returned to the baseline. CONCLUSIONS: Our preliminary data shows that 1 Hz rTMS may decrease cortical excitability and/or intracortical facilitation, and increase intracortical inhibition after daily rTMS. These findings suggest possible therapeutic effects of low frequency rTMS for patients with intractable neocortical epilepsy.