Assessing Deep Brain Stimulation Efficacy in Epilepsy: Target Accuracy and Thalamic Pathology

Brisbane Convention & Exhibition Centre 

The anterior and centromedian thalamic nuclei (ATN, CM) are commonly targeted regions in deep brain stimulation (DBS) for epilepsy (Fig 1A). The motivation for this target strategy is related to the circuits they are involved in. On the one hand, the ATN, which plays a vital role in seizure propagation of focal epilepsy with a mesial temporal focus, is a core node of the Papez circuit that is central to the functional dynamics of the entire limbic structures. On the other hand, the CM, often associated with generalized epilepsy, is also the core of the cerebello-thalamic-cortical (CTC) circuit characterized by diffuse cortical projections [1]. While the efficacy of targeting these nuclei has been previously replicated, the details of the biological substrates that may affect its outcomes remain poorly understood. Here, we sought to address this question by assessing i) the relation between DBS target accuracy and seizure reduction, ii) pathological effects on the thalamic nuclei and their white matter bundles based on the morphological analysis and track density imaging (TDI) and finally iii) the clinical utility of these neuroimaging features to classify responder and non-responder groups (RG/NRG).