EEG effects of ECT: Implications for rTMS

Abstract

Electroconvulsive therapy (ECT) involves the use of electrical stimulation to elicit a series of generalized tonic–clonic seizures for therapeutic purposes and is the most effective treatment known for major depression. These treatments have significant neurophysiologic effects, many of which are manifest in the electroencephalogram (EEG). The relationship between EEG data and the response to ECT has been studied since the 1940s, but for many years no consistent correlates were found. Recent studies indicate that a number of specific EEG features recorded during the induced seizures (ictal EEG) as well as before and after a course of treatment (interictal EEG) are related to both the therapeutic efficacy and cognitive side effects. Similar to ECT, repetitive transcranial magnetic stimulation (rTMS), which involves focal electromagnetic stimulation of cortical neurons, has also been studied as an antidepressant therapy and also appears to have neurophysiologic effects, although these have not been as fully investigated as is the case with ECT. Given the similarity of these treatments, it is natural to consider whether advances in understanding the electrophysiologic correlates of the ECT response might have implications for rTMS. The present article reviews the literature on the EEG effects of ECT and discusses the implications in terms of the likely efficacy and side effects associated with rTMS in specific anatomic locations, the potential for producing an antidepressant response with rTMS without eliciting seizure activity, eliciting focal seizures with rTMS, and the possibility of using rTMS to focally modulate seizure induction and spread with ECT to optimize treatment. Depression and Anxiety 12:157–165, 2000. © 2000 Wiley‐Liss, Inc.

Effect of a Course of Electroconvulsive Therapy on Interictal Bispectral Index Values

“…A number of interictal EEG changes have been reported consistently after a course of ECT (for a succinct summary, please refer to Krystal et al 12 ). Specifically, there is an increase in the amount of slow wave activity, 13,14 which is frontally predominant.…”

EFFICACY AND ACCEPTABILITY OF HIGH FREQUENCY REPETITIVE TRANSCRANIAL MAGNETIC STIMULATION (rTMS) VERSUS ELECTROCONVULSIVE THERAPY (ECT) FOR MAJOR DEPRESSION: A SYSTEMATIC REVIEW AND META-ANALYSIS OF RANDOMIZED TRIALS

“…rTMS can either decrease or increase cortical excitability in relatively focal areas depending on the parameters of stimulation, and frequencies ≥ 5 Hz (high frequency rTMS [HF‐rTMS]) are usually excitatory . Interestingly, several human and animal studies have observed a number of similar effects produced by rTMS and ECT on the endocrine system, sleep parameters, and in certain behavioral and biochemical measures, all of which are associated with potential antidepressant properties …”

“…[7,8] Interestingly, several human and animal studies have observed a number of similar effects produced by rTMS and ECT on the endocrine system, sleep parameters, and in certain behavioral and biochemical measures, all of which are associated with potential antidepressant properties. [9][10][11][12][13] HF-rTMS is nonconvulsive, requires no anaesthesia, has a mild side effects profile (e.g., local discomfort at the place of stimulation), and may even improve cognitive performance. [14][15][16][17] As a result, it is being increasingly investigated as a potential treatment for several neuropsychiatric disorders, [18,19] and a number of recent meta-analyses have confirmed its overall efficacy and safety for treating MD.…”

Magnetic Seizure Therapy of Treatment-Resistant Depression in a Patient With Bipolar Disorder

“…1 Most importantly, it is the most effective treatment known for major depression. 2 The application of ECT sometimes results in severe cognitive side effects. Declarative memory impairment after ECT has often been reported and is well investigated.…”