Challenges in epilepsy include reliable diagnostics and the evaluation of the efficacy of treatment. Transcranial magnetic stimulation (TMS) is a used to evaluate cortical excitability and may provide a biomarker for the likelihood of seizures. We use robot-guided TMS with EMG and high-density EEG. Patients are recruited from the Medisch Spectrum Twente. To assist in a better understanding of clinical findings, we use computational models to explore pathophysiological processes involved in changes in cortical excitability and transitions to seizures.