A Computational Modeling Study of Focal Electrically Administered Seizure Therapy and Frontoparietal Electroconvulsive Therapy

OBJECTIVES: Modification of the electrode placement with electroconvulsive therapy (ECT) impacts on patient outcomes, including cognitive effects. The investigation of alternative right unilateral placements (RUL) has the potential to further improve ECT outcomes by reducing cognitive side effects.

METHODS: This study investigated differences in the intracerebral distribution of current density comparing the standard d'Elia right unilateral positioning (temporoparietal [TP]) with two recently developed RUL placements, focal electrically administered seizure therapy (FEAST) and frontoparietal (FP) stimulation. The strength of the electrical fields (E-fields) was compared in brain regions of interest (ROIs) implicated in both clinical and cognitive outcomes. Computational modeling was conducted in the head models of five participants with major depression who had received RUL ECT.

RESULTS: Results showed that the FEAST and FP placements were associated with significantly less bilateral stimulation effects in regions hypothesized to be associated with memory, whereas the FP and TP placements produced significantly greater bilateral stimulation effects in some regions hypothesized to be associated with efficacy. FEAST, using a smaller anterior electrode, produced significantly greater E-fields in some ROIs associated with memory and efficacy, although those differences were much smaller in magnitude.

CONCLUSIONS: These findings suggest that both FEAST and FP may result in a superior clinical profile relative to TP. Future clinical studies are required to confirm the differences in clinical outcomes associated with the novel RUL placements.