Effects of Stimulus Intensity and Electrode Placement on the Efficacy and Cognitive Effects of Electroconvulsive Therapy
Department of Biological Psychiatry, New York State Psychiatric Institute, NY 10032. New England Journal of Medicine
(Impact Factor: 55.87).
03/1993; 328(12):839-46. DOI: 10.1056/NEJM199303253281204
The efficacy of electroconvulsive therapy in major depression is established, but the importance of the electrical dosage and electrode placement in relation to efficacy and side effects is uncertain.
In a double-blind study, we randomly assigned 96 depressed patients to receive right unilateral or bilateral electroconvulsive therapy at either a low electrical dose (just above the seizure threshold) or a high dose (2.5 times the threshold). Symptoms of depression and cognitive functioning were assessed before, during, immediately after, and two months after therapy. Patients who responded to treatment were followed for one year to assess the rate of relapse.
The response rate for low-dose unilateral electroconvulsive therapy was 17 percent, as compared with 43 percent for high-dose unilateral therapy (P = 0.054), 65 percent for low-dose bilateral therapy (P = 0.001), and 63 percent for high-dose bilateral therapy (P = 0.001). Regardless of electrode placement, high dosage resulted in more rapid improvement (P < 0.05). Compared with the low-dose unilateral group, the high-dose unilateral group took 83 percent longer (P < 0.001) to recover orientation after seizure induction, whereas the combined bilateral groups took 252 percent longer (P < 0.001). During the week after treatment, there was three times more retrograde amnesia about personal information with bilateral therapy (P < 0.001). There were no differences between treatment groups in cognitive effects two months after treatment. Forty-one of the 70 patients who responded to therapy (59 percent) relapsed, and there were no differences between treatment groups.
Increasing the electrical dosage increases the efficacy of right unilateral electroconvulsive therapy, although not to the level of bilateral therapy. High electrical dosage is associated with a more rapid response, and unilateral treatment is associated with less severe cognitive side effects after treatment.
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- "Conversely, this finding was not corroborated in a recent trial (Sienaert et al., 2010) in which the reorientation time was measured at three time points and not continuously after the resumption of spontaneous respiration . Although mean PRT tended to be longer with more efficacious treatments in studies comparing electrode placements and dosing regimens (McCall et al., 2000; Sackeim et al., 1993, 2000), no study has investigated this relationship. Given that the time to recover from disorientation may reflect seizure adequacy, we hypothesize that elderly depressed patients with longer PRTs early in the ECT course are more likely to respond to treatment compared to those who reach orientation sooner. "
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No study has previously investigated whether the speed of recovery from disorientation in the post-ictal period may predict the short-term treatment outcome of electroconvulsive therapy (ECT).
This longitudinal cohort study included 57 elderly patients with unipolar or bipolar major depression, aged 60-85 years, treated with formula-based ECT. Treatment outcome was assessed weekly during the ECT course using the 17-item Hamilton Rating Scale for Depression (HRSD17). The post-ictal reorientation time (PRT) was assessed at the first and third treatments.
Longer PRTs at the first and third treatments predicted a more rapid decline and a lower end-point in continuous HRSD17 scores (p=0.002 and 0.019, respectively). None of the patients who recovered from disorientation in less than 5min met the remission criterion, defined as an HRSD17 score of 7 or less. A greater increment in stimulus dosage from the first to the third ECT session rendered a smaller relative decline in PRT (p<0.001).
The limited number of subjects may reduce the generalizability of the findings.
The speed of recovery from disorientation at the first and third sessions seems to be a predictor of the treatment outcome of formula-based ECT, at least in elderly patients with major depression. It remains to be clarified how the PRT may be utilized to guide stimulus dosing.
Available from: Veronica Galvez
- "In addition, the choice of ECT electrode placements is important , as montages that minimize the degree of temporal lobe stimulation, including right unilateral (RUL), have been found beneficial for reducing memory side effects (Sackeim et al., 1993; Sobin et al., 1995; Dunne and McLoughlin, 2012). This empirical research is supported by findings from a large community study that showed that these ECT treatment factors explained a large degree of variability in patient outcomes between different hospitals (Sackeim et al., 2007). "
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ABSTRACT: Loss of personal memories experienced prior to receiving electroconvulsive therapy (ECT) is common and distressing and in some patients can persist for many months following treatment. Improved understanding of the relationships between individual patient factors, ECT treatment factors and clinical indicators measured early in the ECT course may help clinicians minimise these side effects through better management of the ECT treatment approach. In this study we examined the associations between the above factors for predicting retrograde autobiographical memory changes following ECT treatment.
Seventy four depressed participants with major depressive disorder were administered ECT three times a week using either a right unilateral (RUL) or bitemporal (BT) electrode placement and brief or ultrabrief pulse width ECT. Verbal fluency and retrograde autobiographical memory (assessed using the Columbia Autobiographical Memory Interview - Short Form, AMI-SF) were tested at baseline and after the last ECT treatment. Time to re-orientation was measured immediately following the third and sixth ECT treatments.
Results confirmed the utility of measuring time to re-orientation early during the ECT treatment course as a predictor of greater retrograde amnesia and the importance of assessing baseline cognitive status for identifying patients at greater risk for developing later side effects. With increased number of ECT treatments, older age was associated with increased time to re-orientation. Consistency of verbal fluency performance was moderately correlated with change in AMI-SF scores following RUL ECT.
ECT treatment techniques associated with lesser cognitive side effects should be particularly considered for patients with lower baseline cognitive status or older age.
© The Author 2015. Published by Oxford University Press on behalf of CINP.
- "Although alternative therapies have been developed during recent years, such as vagus nerve stimulation, repetitive transcranial magnetic stimulation, and deep brain stimulation, the use of ECT has not yet been superseded.3 Encouragingly, more and more methods have been explored to alleviate ECT-induced memory deficits and to improve the final cognitive outcomes of psychiatric patients after ECT, including ECT parameter setting, electrode placement, and drug assistance.4,5 Anesthesia is required for modern ECT (modified ECT [MECT]) to enhance its safety by preventing its complications, such as fracture, asphyxia, and cardiovascular instability.6 "
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Although a rapid and efficient psychiatric treatment, electroconvulsive therapy (ECT) induces memory impairment. Modified ECT requires anesthesia for safety purposes. Although traditionally found to exert amnesic effects in general anesthesia, which is an inherent part of modified ECT, some anesthetics have been found to protect against ECT-induced cognitive impairment. However, the mechanisms remain unclear. We investigated the effects of propofol (2,6-diisopropylphenol) on memory in depressed rats undergoing electroconvulsive shock (ECS), the analog of ECT in animals, under anesthesia as well as its mechanisms.
Chronic unpredictable mild stresses were adopted to reproduce depression in a rodent model. Rats underwent ECS (or sham ECS) with anesthesia with propofol or normal saline. Behavior was assessed in sucrose preference, open field and Morris water maze tests. Hippocampal long-term potentiation (LTP) was measured using electrophysiological techniques. PSD-95, CREB, and p-CREB protein expression was assayed with Western blotting.
Depression induced memory damage, and downregulated LTP, PSD-95, CREB, and p-CREB; these effects were exacerbated in depressed rats by ECS; propofol did not reverse the depression-induced changes, but when administered in modified ECS, propofol improved memory and reversed the downregulation of LTP and the proteins.
These findings suggest that propofol prevents ECS-induced memory impairment, and modified ECS under anesthesia with propofol improves memory in depressed rats, possibly by reversing the excessive changes in hippocampal synaptic plasticity. These observations provide a novel insight into potential targets for optimizing the clinical use of ECT for psychiatric disorders.
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