ECT Pulse Amplitude and Medial Temporal Lobe Engagement

Phase 4

Completed

Conditions: Major Depressive Disorder

Interventions: Device: MECTA Spectrum 5000Q Amplitude

Registration Number: NCT02999269

Lead Sponsor: University of New Mexico

Brief Summary: Electroconvulsive therapy (ECT) remains the gold-standard treatment for patients with depressive episodes. During a typical four-week ECT series, most depressive episodes will respond to treatment and people will improve their level of functioning (return to work or family). Independent of the antidepressant effect of ECT, many patients experience transient memory impairment. This investigation will examine the impact of one ECT parameter (pulse amplitude or current) on brain changes (structure of connections within the brain) and clinical outcomes. The goal of this investigation is to determine the optimal parameter for an individual patient that will maintain the clinical response (reduce depression severity) and minimize side effects (eliminate memory issues related to treatment).

Detailed Description: Electroconvulsive therapy (ECT) remains the gold-standard treatment for patients with depressive episodes. During a typical four-week ECT series, most depressive episodes remit, and formerly suicidal or psychotically depressed patients will resume their premorbid levels of functioning. Independent of the antidepressant effect of ECT, many patients experience debilitating but transient cognitive effects such as attention and memory deficits. These unwanted side effects are particularly troubling for older patients who are more likely to have existing cognitive deficits. Both the stimulus delivery (electrode placement, pulse amplitude, and pulse width) and seizure induction appear to work in synergy, but the underlying mechanism of action for successful response has yet to be fully elucidated. Moreover, further work is needed to understand the relationship between clinical improvement and cognitive impairment. This investigation will examine the clinical and neurocognitive impact of targeted medial temporal lobe engagement as a function of pulse amplitude, one of several variable factors influencing the ECT charge. The ECT charge is measured in millicoulombs (mC) and derived from multiplying pulse train duration, pulse-pair frequency, pulse width, and pulse amplitude. Pulse amplitude determines the induced electric field strength in the brain and is presently fixed at 900 milliamperes (mA) with no clinical or scientific justification. The central hypothesis of this investigation is that the optimal pulse amplitude for an individual patient will enhance neuroplasticity (clinical response) while minimizing the disruption of dominant hemisphere hippocampal cognitive circuitry (resulting in cognitive stability). The preliminary data informs the dosage range between 600 and 800 mA. Pulse amplitudes outside of this range compromise efficacy (500 mA) or may increase risk of cognitive impairment (900 mA). The first aim of this investigation will identify the electric field strength and neuroplasticity associated with clinical response. Critically, this aim will establish the neuroplasticity threshold, which is defined as the electric field strength necessary to induce neuroplasticity. The second aim will detect the neural correlates of ECT-mediated cognitive changes, which may be related to disrupted dominant hemisphere long-term potentiation. The third aim will use data-driven dual regression to predict the optimal pulse amplitude for an individual patient. This contribution will be significant because the electric field, when manipulated by pulse amplitude, can subsequently maximize hippocampal neuroplasticity (efficacy) and minimize disrupted connectivity (cognitive stability) thus improving clinical outcomes.

Recruitment & Eligibility

Status: COMPLETED

Sex: All

Target Recruitment: 62

Inclusion Criteria

Diagnosis of major depressive disorder (with or without psychotic features)
the clinical indications for ECT including treatment resistance or a need for a rapid and definitive response
Hamilton Depression Rating Scale 24-item (HDRS-24) > 21
age range between 50 and 80 years of age
right-handedness

Exclusion Criteria

Defined neurological or neurodegenerative disorder (e.g., history of head injury with loss of consciousness > 5 minutes, epilepsy, Alzheimer's disease)
other psychiatric conditions (e.g., schizophrenia, schizoaffective disorder, bipolar disorder)
current drug or alcohol use disorder, except for nicotine; and 4) contraindications to MRI.

Study & Design

Study Type: INTERVENTIONAL

Study Design: PARALLEL

Arm && Interventions

Group	Intervention	Description
600 mA Right Unilateral ECT	MECTA Spectrum 5000Q Amplitude	MECTA Spectrum 5000Q Amplitude
800 mA Right Unilateral ECT	MECTA Spectrum 5000Q Amplitude	MECTA Spectrum 5000Q Amplitude
700 mA Right Unilateral ECT	MECTA Spectrum 5000Q Amplitude	MECTA Spectrum 5000Q Amplitude

Primary Outcome Measures

Name	Time	Method
Depression Severity	post-ECT Hamilton Depression Rating Scale -24 item. The time frame is 4 weeks after study initiation.	Hamilton Depression Rating Scale - 24 item. Scores range from 0 to 76 (higher scores indicate more depression severity)
Cognition	post-ECT Hopkins Verbal Learning Trial-Revised (percent retention score, range 0 - 100, higher is better). The time frame is 4 weeks after study initiation.	Hopkins Verbal Learning Trial-Revised (percent retention score, range 0 - 100, higher is better)

Secondary Outcome Measures