International Journal of Neural Systems, Vol. 23, No. 1 (2013) 1250035 (16 pages) c  World Scientiﬁc Publishing Company DOI: 10.1142/S0129065712500359 TRANSCRANIAL MAGNETIC STIMULATION (TMS) MODULATES EPILEPTIFORM DISCHARGES IN PATIENTS WITH FRONTAL LOBE EPILEPSY: A PRELIMINARY EEG-TMS STUDY VASILIOS K. KIMISKIDIS ∗,‡ , DIMITRIS KUGIUMTZIS † , SOTIRIOS PAPAGIANNOPOULOS ∗ and NIKOLAOS VLAIKIDIS ∗ ∗ Department of Neurology III, Medical School Aristotle University of Thessaloniki, Thessaloniki 54124, Greece † Department of Mathematical, Physical and Computational Sciences Faculty of Engineering, Aristotle University of Thessaloniki Thessaloniki 54124, Greece ‡ kimiskid@med.auth.gr Accepted 19 September 2012 Published Online 7 December 2012 Background: TMS is being increasingly used as a noninvasive brain stimulation technique for the ther- apeutic management of partial epilepsies. However, the acute eﬀects of TMS on epileptiform discharges (EDs, i.e. interictal epileptiform activity and subclinical electrographic seizure patterns) remain unex- plored. Objective: To investigate whether TMS can modulate EDs in partial epilepsy. Methods: In Experiment Set 1, the safety of the TMS protocol was investigated in 10 well-controlled by anti-epileptic drugs (AEDs) epileptic patients. In Experiment Set 2, the eﬀects of TMS on EDs were studied in three subjects with intractable frontal lobe epilepsies, characterized by particularly frequent EDs. TMS was applied over the electrographic focus with a circular and a ﬁgure of eight coil while recording EEG with a 60-channel TMS-compatible EEG system. The eﬀectiveness of TMS in aborting EDs was investigated using survival analysis and brain connectivity analysis. Results: The TMS protocol was well-tolerated. TMS was an eﬀective method to abort EDs even when adjusting for its latency with respect to ED onset (CMH test, p< 0.0001). While the eﬀective brain connectivity around the epileptic focus increased sig- niﬁcantly during EDs (p< 0.01), with TMS administration the increase was not statistically signiﬁcant. Conclusion: TMS can modulate EDs in patients with epileptogenic foci in the cortical convexity and is associated with reversal of ED-induced changes in brain connectivity. Keywords : Transcranial magnetic stimulation; electroencephalogram; epileptiform discharges; brain connectivity. 1. Introduction Brain stimulation is a rapidly evolving technique with multiple therapeutic applications in Neurol- ogy and Psychiatry. With regard to epilepsy, deep brain stimulation (DBS) of various subcortical tar- gets, such as the anterior thalamic nucleus, 1 has proved to be an eﬀective means of controlling seizures in drug-resistant patients with partial and secon- darily generalized seizures. On the other hand, DBS is an invasive procedure associated with a number of side eﬀects including intracranial hemorrhage, implant site infection, psychic adverse events and cognitive dysfunction. Accordingly, noninvasive tech- niques, such as transcranial magnetic stimulation ‡ Corresponding author. 1250035-1 Int. J. Neur. Syst. 2013.23. Downloaded from www.worldscientific.com by 221.172.141.253 on 06/22/14. For personal use only.