Klinische Neurophysiologie 2014; 45 - V28
DOI: 10.1055/s-0034-1371207

Ictal local field potential recordings in anterior thalamus (ANT) and nucleus accumbens (NAC) in patients with temporal lobe epilepsy (TLE)

C Kluge 1, F Marquardt 1, J Voges 2, S Rampp 3, H Stefan 3, A Kowski 4, M Holtkamp 4, HJ Heinze 1, FC Schmitt 1
  • 1O.-v.-Guericke University, Dpt. of Neurology, Magdeburg, Deutschland
  • 2O.-v.-Guericke University, Dpt. of Stereotactic Neurosurgery, Magdeburg, Deutschland
  • 3University Hospital Erlangen, Department of Neurology, Epilepsy Center, Erlangen, Deutschland
  • 4Charité – Universitätsmedizin, Epilepsy-Center Berlin-Brandenburg, Berlin, Deutschland

Rationale: Deep brain stimulation (DBS) of the ANT has recently been established as a therapeutic strategy for medically refractory focal epilepsy. However, the mechanistic underpinnings of this novel treatment option are still not sufficiently understood, partly because under normal clinical conditions the analysis of propagation of epileptic activity is restricted to information derived either from surface or intracranial EEG recordings restricted to the accessible cortical structures.

Methods: We had the opportunity to analyse ictal local field potentials recorded simultaneously from implanted DBS leads in both the ANT and the NAC concurrently with surface EEG in three patients treated for intractable TLE with DBS. Several connectivity measures were used, which quantitatively assess information exchange between distant network nodes (especially directional phase locking, supplemented through directed transfer entropy analyses), and related them to the electroclinical context of the patients.

Results: We were able to trace the synchronization in the network sampled and found that in two out of three patients epileptic activity occurred first in the subcortical brain structures (ANT in patients 1 and 2) and then progressed to the other parts of the brain, including the contralateral hemisphere. In patient 3 seizure onset was observed concurrently both in ANT and NAC.

Conclusion: Our analyses demonstrate how physiological activity becomes superseded by pathologic synchronization as the seizure develops. They provide a contribution to understanding the contribution of the ANT and NAC to seizure propagation in patients with temporal lobe epilepsy.