CET- REM (Correlating ECT Response to EEG Markers)

Single-center study to determine the relationship between changes in depression symptoms and electroencephalographic (EEG) patterns induced by electroconvulsive therapy (ECT)

Electroconvulsive therapy (ECT) is an effective treatment for many psychiatric illnesses, including major depressive disorder. While effective, objective markers have not been developed to predict clinical outcome trajectories following ECT. This is important given the risks and costs incurred during a full treatment course. Electroencephalography (EEG) is typically employed to monitor the generation and termination of ECT-induced seizures but leverage of markers toward prognostication remains a future goal. The investigators have characterized two distinct EEG patterns associated with ECT-induced generalized seizures and have two sleep markers that may serve as markers for predicting response to treatment. Central Positive Complexes (CPCs) are large ictal complexes with a scalp topology of voltage declining from the top of the head. CPCs are localized to cortical areas that are involved in the formation of sleep spindles and slow wave sleep. A pattern of low-voltage activity, known as post-ictal generalized electroencephalographic suppression (PGES), is frequently used to document termination of these seizures. Additionally, two EEG markers of sleep microstructure may have utility given their association with synaptic plasticity, a process presumably invoked over the course of ECT-induced recovery from psychiatric illness as pathologic neural circuitry undergoes reconfiguration. These two markers, sleep spindles and slow waves show altered expression patterns in patients with psychiatric disorders, and thus may be useful as objective markers of ECT responsiveness. None of the above EEG markers have been explored for an association to interval changes in disease severity over the course of ECT. This project will incisively probe the relationships between temporal trajectories of major depressive disorder severity and longitudinal measurements of ictal and postictal EEG markers. Ninety patients will be followed for up to 22 ECT sessions. Bedside clinical instruments will allow assessments of depression severity. High-density (65-electrode) EEG caps will be acquired before and up to 30 minutes following ECT electrical stimulation. Duration of CPCs will be determined using a novel automated algorithm. Duration of PGES will be evaluated using recently validated automated algorithms. Wireless wearable devices will address previous barriers to the longitudinal study of sleep microstructure in the outpatient ECT setting. Slow wave activity and density of sleep spindles will be evaluated at the first cycle of N3 and N2 sleep, respectively. For a subset of patients, feasibility will be assessed for the potentiation of slow wave activity through closed loop acoustic stimulation.

Eligibility Criteria:
Inclusion Criteria:

* Age 18 years or greater
* Referral for ECT index course for treatment-resistant depression (unipolar major depressive disorder or bipolar depression), major depressive disorder with psychotic symptoms, schizophrenia or schizoaffective being treated for a depressed episode, unspecified depression

Exclusion Criteria:

* Schizophrenia or schizoaffective disorder not being treated for a depressed episode.