Cognitive Recovery After Electroconvulsive Therapy and General Anesthesia

Seizures are often associated with loss of consciousness, possibly through effects on
sub-cortical arousal systems, disruption of cortical-subcortical interactions, and ultimately
through depressed neocortical function. Furthermore, people are often confused in the
post-ictal state even when consciousness returns after a seizure. Disrupted cognitive
function during the postictal phase has not been fully characterized but presents short and
long-term implications. Many experience an acute disorder of attention, consciousness, and
cognition, referred to as delirium. Memory deficits are also common. The neurobiology for
these phenomena are incomplete and challenging to test, as seizures are typically sporadic
and vary in intensity and character. In contrast, the setting of electroconvulsive therapy
(ECT) provides the opportunity to study the reconstitution of consciousness and cognition
following seizures in an elective and predictable context.

There is no standard agent used to induce general anesthesia during ECT. Ketamine is
receiving greater attention as an infusion for treating depression and for its potential
benefits on improving ECT efficacy and expediting cognitive recovery. Further data are needed
to determine whether ketamine may improve recovery of cognitive function relative to
etomidate, a commonly used anesthetic for general anesthesia during ECT.

The investigators will evaluate the cognition function and electroencephalographic patterns
that accompany the recovery from ECT and general anesthesia. Twenty patients with refractory
depression will be randomized in this interventional single-blinded randomized crossover
trial. Each patient will complete seven study visits. The first visit will be conducted
during the dose-charge titration ECT treatment with etomidate anesthesia. After this session,
patients will be randomized to three sessions each week for two weeks (six treatments total).
Over the first week patients will be randomized in order for three treatment arms: (1)
etomidate general anesthesia and ECT, (2) ketamine general anesthesia and ECT, and (3)
ketamine alone. Patients will be blinded to the treatment arm for each session. Baseline and
post-treatment measurements of cognition and ECT will be acquired on each of the six
treatment sessions.

Patients that agree will have a MRI.

Inclusion Criteria:

- Treatment resistant depression requiring outpatient ECT

- Planned right unilateral ECT stimulation

- English speaking

- Able to provide written informed consent

Exclusion Criteria:

- Known brain lesion or neurological illness that causes cognitive impairment

- Schizophrenia

- Schizoaffective disorder

- Blindness or deafness or motor impediments that may impair performance for cognitive
testing battery

- Inadequate ECT seizure duration with etomidate