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: 54.42). 03/1993; 328(12):839-46. DOI: 10.1056/NEJM199303253281204
Source: PubMed

ABSTRACT 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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    • "Almost all anesthetic agents have anticonvulsant properties because of their effects on the gamma-aminobutyric acid receptors and may, therefore, influence seizure variables and clinical outcome of ECT (Tan and Lee, 2009; Vaidya et al., 2012). Stimulation parameters, such as electrical dosage and electrode placement, are also known to affect response to ECT (Sackeim et al., 1993). Factors affecting the seizure threshold, such as age, sex, concomitant medication with anticonvulsive or proconvulsant properties and electrode placement, could affect both the quality and duration of seizures (Chung, 2002; Sackeim et al., 1991). "
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    ABSTRACT: OBJECTIVE: To compare the effects of propofol and etomidate on the stimulus variables and efficacy of electroconvulsive therapy (ECT) in depressed inpatients. METHOD: This retrospective study included 54 inpatients (aged 18-75 years) who met the DSM-IV criteria for major depression and were treated with bilateral ECT. For the first part of the study, the primary outcome was the mean stimulus charge per ECT session. For the second part, the main outcome measure was the proportion of patients achieving full remission. RESULTS: Propofol-treated patients showed a higher mean stimulus charge (etomidate 227.58 ± 130.44, propofol 544.91 ± 237.56, p<0.001) despite the lack of a significant difference in starting threshold doses. The propofol group had a shorter mean electroencephalogram (etomidate 69.41 ± 22.50, propofol 42.95 ± 22.26, p<0.001) and motor (etomidate 46.11 ± 14.38, propofol 22.89 ± 7.13, p<0.001) seizure duration and a higher mean number of inadequate seizures (etomidate 0.12 ± 0.15, propofol 0.47 ± 0.26), p<0.001). No significant differences were found between the groups for the effects of the anesthetics on the efficacy of ECT. LIMITATIONS: Our study is limited by a retrospective design and the small number of patients treated with propofol restricted the sample size. CONCLUSIONS: Anesthesia with propofol has a significant reducing effect on seizure duration during the course of ECT which results in more inadequate seizures, despite the use of a higher mean stimulus charge. Regarding the possible effect of the anesthetics on ECT, randomized clinical trials with sufficient power to detect differences is warranted.
    Progress in Neuro-Psychopharmacology and Biological Psychiatry 06/2013; 45. DOI:10.1016/j.pnpbp.2013.06.003 · 4.03 Impact Factor
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    • "In conclusion, our data suggests that the application of right dorsolateral prefrontal cortex anodal tDCS in combination with pharmacological treatment maybe beneficial in acute stages of mania in patients with bipolar disorder type I. This is relevant, since unlike ECT, in which higher electrical doses lead to greater risks of cognitive side-effects [14], no significant side-effects have been described with tDCS, even with repeated sessions [4] [5]. Given the characteristics of this case, this approach needs also to be investigated in patients with sexual disinhibition regardless the cause, such as in patients with schizophrenia or substance abuse [15], as well as in patients with epilepsy [16], multiple sclerosis [17] and dementia [18]. "
    Brain Stimulation 11/2012; 6(4). DOI:10.1016/j.brs.2012.10.008 · 5.43 Impact Factor
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    • "In this study, we tested a short form of the autobiographical memory interview (Sackeim et al., 1993; Weiner et al., 1986). Time to full reorientation was shorter after MST treatment as compared to ECT treatment. "
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    ABSTRACT: Major depression is a common mental health problem and associated with significant morbidity and mortality, including impaired social and physical functioning and increased risk for suicide. Electroconvulsive therapy (ECT) is highly efficacious in treatment-resistant depressive disorders, but cognitive side effects are frequently associated with the treatment. Magnetic seizure therapy (MST) is a form of convulsive therapy, using magnetic fields in order to induce therapeutic seizures. First studies suggested that cognitive side effects of MST, including postictal recovery time, are more benign than those resulting from ECT treatment. In this open-label study we tested the hypothesis that MST is associated with clinically significant antidepressant effects in treatment-resistant depression (TRD) as an add-on therapy to a controlled pharmacotherapy. Twenty patients suffering from TRD were randomly assigned to receive either MST or ECT starting from July 2006 until November 2008. Primary outcome measure was antidepressant response assessed by Montgomery Åsberg Depression Scale. Secondary outcome measures included Hamilton Depression Rating Scale, Hamilton Anxiety Scale, Beck Depression Inventory and 90-Item Symptom Checklist. Antidepressant response (improvement of 50% in MADRS ratings) was statistically significant and of similar size in both treatment groups. Cognitive side effects were observed in neither group. Characteristics in MST- and ECT-induced seizures were comparable, especially regarding ictal activity and postictal suppression. Thus, MST may be a potential alternative to ECT if efficacy and safety are validated in larger clinical trials.
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