Enhanced Spatial Targeting in ECT Utilizing FEAST

Study Design: This study will focus on refining FEAST methods by implementing a fixed-current titration and dosing method (800mA; 0.3 ms), testing the optimal directionality of current flow, and confirming specificity of induction of seizures in right orbitofrontal cortex. Twenty patients in an episode of major depression will be enrolled in the initial open-label study. Patients are kept on current medications for at least 2 weeks prior to initiation of therapy and throughout the treatment course. Patients are allowed PRN lorazepam limited to 3 mg/d but not within 10 hours of a FEAST session. Patients will undergo routine clinical care pre-ECT evaluations which include chemistry laboratory tests, a chest x-ray and an EKG. Patient will also undergo a brain MRI needed for 3D finite element modeling (FEM) to compute individual electric fields for each participant enrolled.

Once treatment is initiated, patients receive a dose 6 times initial ST at all treatments except the first, where ST is determined. If insufficient improvement (<40% change from baseline HRSD-24 item, or IDS-SR) after six treatments, the dose will increase by 50% in charge (9 times initial ST). Patients will undergo 6 channel EEG during all treatments. Sessions 2, 3 and 4 will be cross-randomized across FEAST (with typical electrodes placement and current flow directionality configurations), RP FEAST and RC FEAST to allow a direct comparison of induced seizure focality. To ensure that each possible treatment sequence (ABC, ACB, BAC, BCA, CAB, CBA, where A=regular FEAST, B=RP FEAST, C=RC FEAST) during visits 2-4 is represented with approximately equal frequency, participants will be allocated to treatment sequence using a block randomization scheme with a block size of 6 participants. Within each block, each treatment sequence appears exactly once, in random order (e.g. 123456, 352641, etc.). In this way, the number of participants allocated to a particular sequence never differs by more than one from any other sequence.

The primary measure right frontal to motor connectivity (seizure drive) and time for orientation recovery obtained following these sessions will permit direct comparison between normal configuration, RP FEAST and RC FEAST as well. Preliminary data generated by the investigators suggest that RP polarity FEAST will elicit the most focal seizure with the shortest time for reorientation and fewest amnestic side effects.

Study Procedures: All clinical procedures performed through Fairview will be documented in EPIC and duplicated in the research team's RedCap database for later analysis. Treatments are given in the morning, 3 times per week. Pharmacological agents are standardized: atropine (0.4 mg IV), methohexital (0.75 mg/kg) and succinylcholine (0.75-1.0 mg/kg). [If methohexital is unavailable, thiopental will be substituted (2.0 mg/kg]. Patients are oxygenated by mask (100% O2) prior to anesthesia and until resumption of spontaneous respiration. Standardized procedures are used to reduce impedance at ECT and EEG electrode sites. The d'Elia unilateral placement[69] is used for conventional RUL ECT. FEAST will involve the 1.25" circular anterior electrode being centered at the measured FP2 position by the 10/20 EEG system, with the posterior cathode electrode (1"x2.5") tangential to the mid-sagittal plain and centered at vertex. FEAST is delivered with a modified MECTA Spectrum 5000Qrelative to the commercial device with the capacity for unidirectional stimulation.

A baseline appointment, scheduled at the Treatment Resistant Depression Clinic in Saint Louis Park, will be initially scheduled with potential participants to complete the informed consent process as well as baseline assessments for: MINI-7, HRSD-24, Clinical Global Impression (CGI), Inventory of Depressive Symptoms - Self Report (IDS-SR), SSI, SSI-W, Short Form (SF-36), and the Quality of Life questionnaire. Participants will also undergo a baseline MRI that will consist of individual T1- and T2-weighted MRI scans which will be acquired with isotropic voxel resolution of 0.8 mm through resources located in the CMRR building. These structural data will be processed in the SimNIBS software to create a 3D volume conductor model of the subject's head. These MRI images will be constructed into 3D FEM models to compute non-invasive brain stimulation and electric fields for each participant enrolled.