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The Cognitive Effects of Electroconvulsive Therapy: A Critical Review
Abstract
In this article, we discuss the neurocognitive domains affected by electroconvulsive therapy (ECT), moderators of ECT-related cognitive change, and cognitive outcomes in high-risk populations, as well as compare the cognitive effects ECT to other common treatments for refractory depression. Despite ECT being one of the oldest and most common treatments for refractory depression, various approaches to ECT (ie, strength, wavelength, and electrode placement), use of clinical convenience samples, and employment of varied and often inadequate methods of neurocognitive assessment have contributed to ongoing confusion regarding the nature and severity of post-treatment cognitive side effects. Although findings suggest that most healthy adults return to neurocognitive baseline within a few days after treatment, older adults and those with premorbid neurological impairment may be at an increased risk of prolonged mental status changes post-ECT. Employment of comprehensive neuropsychological batteries versus screening measures may assist in further understanding the nature and course of post-treatment cognitive side effects.
... The 2019 review demonstrated that there is no evidence that ECT works for its primary target group, depressed older people. There is evidence, however, that older people are particularly likely to end up with memory loss (Mosti & Brook, 2019;Sackeim et al., 2007). For many years, NICE Guidelines have stated: 'The risks associated with ECT may be greater in older people; exercise particular caution when considering ECT treatment in this group' (NICE, 2009). ...
Objectives:
To assess progress towards improving the administering of electroconvulsive therapy (ECT) in England since an audit covering 2011, 2013, and 2015. The same information was gathered, for 2019, on usage, demographics, consent, and adherence to national guidelines and the Mental Health Act.
Design and methods:
Freedom of Information Act requests were sent to 56 National Health Service Trusts.
Results:
Thirty-seven trusts (66%) provided data. The gradual decline in the use of ECT in England has levelled off at about 2,500 people per year. There was a 47-fold difference between the Trusts with the highest and lowest rates per capita. Most recipients are still women (67%) and over 60 (58%). Only one Trust could report how many people received psychological therapy prior to ECT, as required by government (NICE) guidelines. More than a third of ECT (37%) is still given without consent, with 18% of Trusts non-compliant with legislation concerning second opinions. There were slight declines, compared to a previous audit, in the use of standardized depression scales, down to 30%, and standardized measures of cognitive dysfunction, down to 24%. Only six Trusts provided any data for positive outcomes and seven for adverse effects. None provided data on efficacy or adverse effects beyond the end of treatment. Twelve Trusts used identical sentences to each other, verbatim, in response to one or more questions.
Conclusions:
Given the apparent failure of current monitoring and accrediting of ECT clinics in England, by the Royal College of Psychiatrists' ECT Accreditation Service (ECTAS), an independent government sponsored review is urgently needed.
Practitioner points:
Psychologists and other mental health staff should ensure that people are offered evidence-based psychological treatments before being offered E.C.T. All staff should ensure that patients are fully informed of the high risk of memory loss and the smaller risk of cardiovascular failure and mortality. Individuals receiving ECT should be closely monitored for adverse cognitive effects, and treatment immediately terminated if these become apparent. Because of increased risk of memory loss for women and older people, the use of ECT should be kept to a minimum and avoided where possible, with these two groups.
Background
Depressive episodes (DEP) characterized by abnormalities in cognitive functions and mood is a leading cause of disability. Electroconvulsive therapy (ECT), which involves a brief electrical stimulation of the anesthesia brain, is one of the most effective treatments used in patients with DEP due to its rapid efficacy.
Methods
In this work, we investigated how dynamic brain functional connectivity responds to ECT and whether the dynamic responses are associated with treatment outcomes and side effects in patients. We applied a fully automated independent component analysis (ICA)-based pipeline to 110 patients with DEP (including diagnosis of unipolar depression or bipolar depression) and 60 healthy controls (HCs). The dynamic functional connectivity was analyzed by a combination of the sliding window approach and clustering analysis.
Results
Five reoccurring connectivity states were identified, and DEP had fewer occurrences in one brain state (state 1) with strong positive and negative connectivity. DEP patients changed the occupancy of two states (states 3 and 4) after ECT, resulting in significantly different occurrences of one additional state (state 3) compared to HC. We further found that DEP patients had diminished global meta-state dynamism, two of which recovered to normal after ECT. Interestingly, the changes in dynamic connectivity characteristics were associated with the changes in memory recall and Hamilton Depression Rating Scale of DEP after ECT.
Conclusions
These converging results extend current findings on subcortical-cortical dysfunction and dysrhythmia in DEP and demonstrate that ECT might cause remodeling of brain functional dynamics that enhance the neuroplasticity of the diseased brain.
Background
Electroconvulsive therapy (ECT) is still being administered to approximately a million people annually. There have been no ECT versus simulated ECT (SECT) studies since 1985. The five meta-analyses of ECT versus SECT studies all claim that ECT is more effective than SECT for its primary target, severe depression. This review assesses the quality of those meta-analyses and of the 11 studies on which they are based.
Methods
The meta-analyses were evaluated primarily in terms of whether they considered the quality of the studies they included, but also in terms of whether they addressed efficacy beyond end of treatment. The methodological rigor of the 11 studies included by one or more of the meta-analyses was assessed using a 24-point Quality scale developed for this review.
Results
The five meta-analyses include between 1 and 7 of the 11 studies. The metaanalyses pay little or no attention to the multiple limitations of the studies they include. The 11 studies have a mean Quality score of 12.3 out of 24. Eight scored 13 or less. Only four studies describe their processes of randomization and testing the blinding. None convincingly demonstrate that they are double-blind. Five selectively report their findings. Only four report any ratings by patients. None assess Quality of Life. The studies are small, involving an average of 37 people. Four of the 11 found ECT significantly superior to SECT at the end of treatment, five found no significant difference and two found mixed results (including one where the psychiatrists reported a difference but patients did not). Only two higher Quality studies report follow-up data, one produced a near-zero effect size (.065) in the direction of ECT, and the other a small effect size (.299) in favor of SECT.
Conclusions
The quality of most SECT–ECT studies is so poor that the meta-analyses were wrong to conclude anything about efficacy, either during or beyond the treatment period. There is no evidence that ECT is effective for its target demographic—older women, or its target diagnostic group—severely depressed people, or for suicidal people, people who have unsuccessfully tried other treatments first, involuntary patients, or adolescents. Given the high risk of permanent memory loss and the small mortality risk, this longstanding failure to determine whether or not ECT works means that its use should be immediately suspended until a series of well designed, randomized, placebo-controlled studies have investigated whether there really are any significant benefits against which the proven significant risks can be weighed.
Objective:
To determine if antidepressant drug usage is associated with cognitive impairment or dementia, including Alzheimer disease (AD).
Method:
We conducted a systematic search of Medline, PubMed, PsycINFO, Web of Science, Embase, CINAHL, and the Cochrane Library. An initial screen by abstracts and titles was performed, and relevant full articles were then reviewed and assessed for their methodologic quality. Crude effect estimates were extracted from the included articles and a pooled estimate was obtained using a random effects model.
Results:
Five articles were selected from an initial pool of 4,123 articles. Use of antidepressant drugs was associated with a significant twofold increase in the odds of some form of cognitive impairment or dementia (OR = 2.17). Age was identified as a likely modifier of the association between antidepressant use and some form of cognitive impairment or AD/dementia. Studies that included participants with an average age equal to or greater than 65 years showed an increased odds of some form of cognitive impairment with antidepressant drug usage (OR = 1.65), whereas those with participants less than age 65 revealed an even stronger association (OR = 3.25).
Conclusions:
Antidepressant drug usage is associated with AD/dementia and this is particularly evident if usage begins before age 65. This association may arise due to confounding by depression or depression severity. However, biological mechanisms potentially linking antidepressant exposure to dementia have been described, so an etiological effect of antidepressants is possible. With this confirmation that an association exists, clarification of underlying etiologic pathways requires urgent attention.
Objectives:
The aims of the present study were to describe the short-term rate of subjective memory worsening (SMW) and identify factors of importance for SMW in a large clinical sample treated for depression with electroconvulsive therapy (ECT).
Methods:
This register-based study included 1212 patients from the Swedish National Quality Register for ECT. Subjective memory worsening was defined as a 2-point worsening on the memory item of the Comprehensive Psychopathological Rating Scale from before to within 1 week after treatment. Associations between patient characteristics and treatment factors were examined using logistic regression.
Results:
Subjective memory worsening was experienced in 26%. It was more common in women than in men (31% vs 18%; P < 0.001) and more common in patients aged 18 to 39 years than in patients 65 years or older (32% vs 22%; P = 0.008). Patients with less subjective memory disturbances before ECT had a greater risk of SMW. Patients in remission after ECT had a lower risk of SMW. A brief pulse width stimulus gave higher risk of SMW compared with ultrabrief pulse (odds ratio, 1.61; 95% confidence interval, 1.05-2.47).
Conclusions:
Subjective memory worsening is reported by a minority of patients. However, young women are at risk of experiencing SMW. Ultrabrief pulse width stimulus could be considered for patients treated with unilateral electrode placement who experience SMW. Each patient should be monitored with regard to symptoms and adverse effects, and treatment should be adjusted on an individual basis to maximize the clinical effect and with efforts to minimize the cognitive adverse effects.This is an open-access article distributed under the terms of the Creative Commons Attribution-Non Commercial-No Derivatives License 4.0 (CCBY-NC-ND), where it is permissible to download and share the work provided it is properly cited. The work cannot be changed in any way or used commercially without permission from the journal.
Cognitive dysfunction is often present in major depressive disorder (MDD). Several clinical trials have noted a pro-cognitive effect of antidepressants in MDD. The objective of the current systematic review and meta-analysis was to assess the pooled efficacy of antidepressants on various domains of cognition in MDD.
Trials published prior to April 15, 2015, were identified through searching the Cochrane Central Register of Controlled Trials, PubMed, Embase, PsychINFO, Clinicaltrials.gov, and relevant review articles. Data from randomized clinical trials assessing the cognitive effects of antidepressants were pooled to determine standard mean differences (SMD) using a random-effects model.
Nine placebo-controlled randomized trials (2,550 participants) evaluating the cognitive effects of vortioxetine (n=728), duloxetine (n=714), paroxetine (n=23), citalopram (n=84), phenelzine (n=28), nortryptiline (n=32) and sertraline (n=49) were identified. Antidepressants had a positive effect on psychomotor speed (SMD 0.16; 95% C.I. 0.05-0.27; I² = 46%) and delayed recall (SMD 0.24; 95% C.I. 0.15-0.34; I² = 0%). The effect on cognitive control and executive function did not reach statistical significance. Of note, after removal of vortioxetine from the analysis, statistical significance was lost for psychomotor speed. Eight head-to-head randomized trials comparing the effects of selective serotonin reuptake inhibitors (SSRIs) (n=371), selective serotonin and norepinephrine reuptake inhibitors (SNRIs) (n=25), tricyclic antidepressants (TCAs) (n=138) and norepinephrine and dopamine reuptake inhibitors (NDRIs) (n=46) were identified. No statistically significant difference in cognitive effects was found when pooling results from head-to-head trials of SSRIs, SNRIs, TCAs and NDRIs. Significant limitations were the heterogeneity of results, limited number of studies and small sample sizes.
Available evidence suggests that antidepressants have a significant positive effect on psychomotor speed and delayed recall.
© The Author 2015. Published by Oxford University Press on behalf of CINP.
Some studies suggest better overall outcomes when right unilateral electroconvulsive therapy (RUL ECT) is given with an ultrabrief, rather than brief, pulse width.
The aim of the study was to test if ultrabrief-pulse RUL ECT results in less cognitive side effects than brief- pulse RUL ECT, when given at doses which achieve comparable efficacy. One hundred and two participants were assigned to receive ultrabrief (at 8 times seizure threshold) or brief (at 5 times seizure threshold) pulse RUL ECT in a double-blind, randomized controlled trial. Blinded raters assessed mood and cognitive functioning over the ECT course.
Efficacy outcomes were not found to be significantly different. The ultrabrief group showed less cognitive impairment immediately after a single session of ECT, and over the treatment course (autobiographical memory, orientation).
In summary, when ultrabrief RUL ECT was given at a higher dosage than brief RUL ECT (8 versus 5 times seizure threshold), efficacy was comparable while cognitive impairment was less.
© The Author 2014. Published by Oxford University Press on behalf of CINP.
Cognitive functions of adolescents treated with ECT for mood disorder were evaluated at long-term follow-up.
At an average of 3.5 years (SD=1.7) after the last ECT, 10 subjects treated during adolescence with bilateral ECT for severe mood disorder completed a clinical and cognitive evaluation, including the California Verbal Learning Test and Squire's Subjective Memory Questionnaire. The same assessments were given to 10 psychiatric comparison subjects matched for sex, age, and diagnosis.
All cognitive test scores of the patients treated with ECT were similar to those of the comparison subjects and did not differ from norms from the community. Six of the 10 ECT-treated patients reported having had memory losses immediately after the ECT course, but only one complained of subjective memory impairment at follow-up.
The results suggest that adolescents given ECT for severe mood disorder do not suffer measurable cognitive impairment at long-term follow-up.
Despite ongoing controversy, there has never been a large-scale, prospective study of the cognitive effects of electroconvulsive therapy (ECT). We conducted a prospective, naturalistic, longitudinal study of clinical and cognitive outcomes in patients with major depression treated at seven facilities in the New York City metropolitan area. Of 751 patients referred for ECT with a provisional diagnosis of a depressive disorder, 347 patients were eligible and participated in at least one post-ECT outcome evaluation. The primary outcome measures, Modified Mini-Mental State exam scores, delayed recall scores from the Buschke Selective Reminding Test, and retrograde amnesia scores from the Columbia University Autobiographical Memory Interview-SF (AMI-SF), were evaluated shortly following the ECT course and 6 months later. A substantial number of secondary cognitive measures were also administered. The seven sites differed significantly in cognitive outcomes both immediately and 6 months following ECT, even when controlling for patient characteristics. Electrical waveform and electrode placement had marked cognitive effects. Sine wave stimulation resulted in pronounced slowing of reaction time, both immediately and 6 months following ECT. Bilateral (BL) ECT resulted in more severe and persisting retrograde amnesia than right unilateral ECT. Advancing age, lower premorbid intellectual function, and female gender were associated with greater cognitive deficits. Thus, adverse cognitive effects were detected 6 months following the acute treatment course. Cognitive outcomes varied across treatment facilities and differences in ECT technique largely accounted for these differences. Sine wave stimulation and BL electrode placement resulted in more severe and persistent deficits.
The present study aimed to systematically compare the cognitive outcomes of high-frequency repetitive transcranial magnetic stimulation (HF-rTMS) and electroconvulsive therapy (ECT) in head-to-head studies with major depression (MDD) patients. A systematic literature search identified six studies with 219 MDD patients that were too heterogeneous to reliably detect meaningful differences in acute cognitive outcomes after ECT vs. HF-rTMS. Cognitive effects of brain stimulation vary depending on the timeframe and methods of assessment, stimulation parameters, and maintenance treatment. Thus, acute and longer-term differences in cognitive outcomes both need to be investigated at precisely defined timeframes and with similar instruments assessing comparable functions.
This study presents a comprehensive case series of adolescents who received electroconvulsive therapy (ECT) for treatment-resistant depression.
Conducting a chart review, we identified 13 adolescents who had ECT for treatment of depression over a 5-year interval (2008-2013) at a Canadian tertiary care psychiatric hospital. Details about participants' clinical profile, index course of ECT, outcome, side effects, and comorbidities were extracted and analyzed.
Thirteen adolescents aged 15 to 18 years, received a mean of 14 (SD, 4.5) ECT sessions per patient. Based on the Beck Depression Inventory-II at baseline and after treatment with ECT, a reliable improvement was observed in 10 patients, with 3 achieving full recovery. Through mixed effects linear modeling, we found a decrease of 0.96 points (95% CI, -1.31 to -0.67, P < 0.001) on the Beck Depression Inventory-II total score for every ECT treatment received. The Montreal Cognitive Assessment was used for monitoring of cognitive function throughout the treatment. Adverse effects included transient subjective cognitive impairment (n = 11), headache (n = 10), muscular pain (n = 9), prolonged seizure (n = 3), and nausea and/or vomiting (n = 3).
A clinically significant improvement was observed for 10 (77%) adolescents receiving ECT for treatment-resistant depression. These observations suggest that ECT is a potential treatment option for refractory depression in selected adolescents. More data are needed to draw conclusions about efficacy and possible predictors of treatment response.
Depression is associated with cognitive impairment and dementia, but whether treatment for depression with antidepressants reduces the risk for cognitive decline is unclear. We assessed the association between antidepressant use and cognitive decline over 6 years.
Participants were 3,714 adults aged 50 or older enrolled in the nationally-representative Health and Retirement Study (HRS) and with self-reported antidepressant use. Depressive symptoms were assessed using the 8-item Center for Epidemiologic Studies Depression Scale. Cognitive function was assessed at four time-points (2004, 2006, 2008, 2010) through using a validated 27-point scale. Change in cognitive function over the 6-year follow-up period was examined using linear growth models, adjusted for demographics, depressive symptoms, comorbidities, functional limitations and antidepressant anticholinergic activity load.
At baseline, cognitive function did not differ significantly between the 445 (12.1%) participants taking antidepressants and those not taking antidepressants (mean 14.9%, 95% CI: 14.3-15.4 vs. mean 15.1%, 95% CI: 14.9-15.3). During the 6-year follow up period, cognition declined in both users and nonusers of antidepressants, ranging from -1.4 change in mean score in those with high depressive symptoms and taking antidepressants to -.5 change in mean score in those with high depressive symptoms and not taking antidepressants. In adjusted models, people taking antidepressants declined at the same rate as those not taking antidepressants. Results remained consistent across different levels of baseline cognitive function, age, and duration of antidepressant use (prolonged versus short-term).
Antidepressant use did not modify the course of 6-year cognitive change in this nationally- representative sample.
Copyright © 2015 Elsevier Inc. All rights reserved.
Maintenance electroconvulsive therapy (m-ECT) is effective in preventing recurrences of depressive episodes. There is little information on long-term m-ECT extending over several years and its impact on cognitive functions. This study was an attempt to determine the efficacy and side effects of long-term m-ECT.
Depressive episodes and admissions before m-ECT for a period equal to the duration of m-ECT and during m-ECT were compared using medical records. Cognitive functions assessed by Mini-Mental State Examination (MMSE) before and after m-ECT were compared along with the review of Neuropsychiatry Unit Cognitive Assessment Tool (NUCOG).
17 patients had m-ECT that extended from 6 to 153 months (mean 39, SD=44.46). The average number of episodes before and during m-ECT was 2.47 (SD=2.23) and 0.88 (SD=1.31) respectively (Wilcoxon ranked test Z=3.06, r=0.55, two-tailed p=0.002). Average number of admissions dropped from 2.05 (SD=1.88) to 0.23 (SD=0.43) during m-ECT (Z=3.471, r=0.71, p=0.001). The average time to recurrence was 24.24 months (SD=25.20) with longest depression free survival of 105 months. There was no significant difference in MMSE score before and after the commencement m-ECT or progressive deterioration in NUCOG score.
This study was limited by retrospective nature of data collection, small sample size, confounding effects of antidepressants along with m-ECT and absence of a highly sensitive cognitive screening tool that can capture all types of cognitive impairments following m-ECT.
In a naturalistic setting the efficacy of m-ECT may extend over several years while cognitive functions remain largely unaffected.
Thirty-seven inpatients with major depression were assessed for postictal and interictal disorientation after they received 8 of 12 ECTs. In 20 patients, four of the eight assessments were after simulated ECT only. Only real, but not simulated, ECT produced postictal disorientation. Postictal disorientation was greatest after the first treatment, less after the second, and did not change in later assessments. It was shortest for person, longer for place, and longest for time, and showed a temporal time gradient. Interictal disorientation increased with the number of treatments. Two electrical stimulus variables (seizure duration and electrical stimulus intensity) correlated with the length of postictal disorientation. The influence of seizure duration and stimulus variables were independent of each other. The influence of the electrical stimulus variables was independent of the influence of demographic variables. These, however, did affect the length of postictal disorientation.
(C) Lippincott-Raven Publishers.
Neurocognitive functioning is well known to be affected after ECT. However quantified data about the severity of the cognitive impairment after ultrabrief pulse and brief pulse ECT are limited, which makes it hard to judge its clinical relevance.
To review all prospective studies using right unilateral (ultra) brief pulse index electroconvulsive therapy published up until February 2011 which used at least one instrument for cognitive assessment before and after ECT. The severity and persistence of neurocognitive side effects immediately (one to seven days post ECT), between one and six months and after six months post ECT were assessed by calculating effect sizes using Cohen's d.
Ten studies fulfilled the inclusion criteria and provided detailed information to compute effect sizes. The results indicate loss of autobiographical memory and impairment of verbal fluency, anterograde verbal and non-verbal memory immediately after brief pulse RUL ECT. To a lesser extent impairment of working memory and reduced speed of processing is found. Autobiographical memory is the only domain still being impaired between one and six months post ECT, but improved in this period. Verbal fluency normalized to baseline performance between one and six months post ECT whereas anterograde verbal and non-verbal memory normalized or even improved. Speed of processing improved within six months after ECT. Long-term data on these cognitive domains were not available. Based on two of the ten included studies the results suggest that ultrabrief pulse RUL ECT causes less decline in autobiographical and anterograde memory after ECT than brief pulse RUL ECT.
This review may be limited because of the small number of included studies and due to unreliable effect sizes. Furthermore, few data were available for non-memory domains and cognitive functioning after six months.
Loss of autobiographical memory is still present between one and six months after unilateral brief pulse ECT. Ultrabrief pulse RUL ECT shows less decline in autobiographical memory. Other neurocognitive impairments after brief pulse RUL ECT seem to be transient.
Bifrontal (BF) placement of electrodes in electroconvulsive therapy (ECT) has emerged as an alternative option to the conventional bitemporal (BT) and right unilateral electrode placement in view of fewer cognitive adverse effects. However, the results have been contradictory in terms of clinical efficacy.
We studied the records of all patients referred for ECT between the months of August 2008 and July 2010 (n=1575). One hundred and five of these patients had received BF-ECT. These records were compared with the records of 105 patients who received BT-ECT. For each patient who received BF-ECT, the very next person posted for BT-ECT was taken as the control. All patients received bilateral ECTs at 1.5-times the threshold stimulus dose. The number of ECTs administered, duration of hospital stay after ECT initiation, seizure threshold and failure to achieve adequate seizures were compared. Two raters who achieved good inter-rater reliability assessed the initial severity using the clinical global impression scale and clinical improvement using a Likert scale.
The speed of response, as assessed by the number of ECTs received and the duration of hospital stay after ECT initiation was similar in the two groups. In addition, both groups were comparable in terms of clinical improvement scores on the Likert scale. BF-ECT patients also had a significantly higher seizure threshold, which remained significant in spite of controlling for age. This study is chart based, with its inherent limitations. Standard outcome measures were not used. Cognitive adverse effects were not studied.
BF-ECT performed similar to BT-ECT with regard to therapeutic efficacy. Given the consistent results of the former, with fewer cognitive side-effects, the findings of the present study support BF-ECT as the first line for electrode application.
To study cognitive performance in depressed geriatric inpatients with or without preexisting cognitive impairment who received a first course of electroconvulsive therapy (ECT).
Forty-four elderly inpatients with major depressive disorder (ICD-10 criteria) were included in a prospective consecutive case series of a university hospital. The patients were divided into 3 groups (no cognitive impairment [NCI], mild cognitive impairment [MCI], dementia) and rated for cognitive performance with the MMSE before first ECT, after sixth ECT, and 6 weeks and 6 months after ECT termination. Affective symptoms were rated by 21-item Hamilton Depression Rating Scale (HDRS-21) before and 6 weeks after ECT. Analysis of variance or Kruskal-Wallis tests on ECT-induced MMSE and HDRS-21 score changes were compared to baseline. Binary logistic regression was used for predictor analysis. The study was conducted from April 2004 to April 2008.
After initial nonsignificant cognitive deterioration in all 3 groups, the NCI group improved cognitively 6 weeks (P = .018) and 6 months (P = .027) after ECT. The MCI group improved in cognition 6 months (P = .036) after ECT. In the dementia group, mean MMSE scores also improved numerically over the course of ECT without significance. Dementia patients with antidementia treatment improved in cognition to a clinically relevant extent after the sixth ECT. Dementia subjects without antidementia treatment deteriorated. After the sixth ECT, 70.0% of dementia patients (P = .004) presented a cognitive decline, and 68.8% of MCI patients (P < .001) presented a decline 6 weeks after ECT. Six months after ECT, one-third of the dementia patients (P < .036) still had a cognitive decline. Affective symptoms remitted after ECT in all 3 groups (P < .001). Pre-ECT cognitive deficits were the best predictor of MMSE decline (6 weeks after ECT, P = .007; 6 months after ECT, P = .055).
ECT is effective and well tolerated in geriatric depressed inpatients regardless of preexisting cognitive impairment. Cognitive deficits were transient.
Electroconvulsive therapy (ECT) is the most acutely effective treatment for depression, but is limited by cognitive side effects. However, research on their persistence, severity, and pattern is inconsistent. We aimed to quantify ECT-associated cognitive changes, specify their pattern, and determine progression.
MEDLINE, EMBASE, PsycArticles, PsychINFO, PsychLIT, and reference lists were systematically searched through January 2009. We included all independent, within-subjects design studies of depressed patients receiving ECT where cognition was assessed using standardized tests. Main outcome was change in performance after ECT relative to pretreatment scores with respect to delay between finishing ECT and cognitive testing. We explored potential moderators' influence, e.g., electrode placement, stimulus waveform.
Twenty-four cognitive variables (84 studies, 2981 patients) were meta-analyzed. No standardized retrograde amnesia tests were identified. Significant decreases in cognitive performance were observed 0 to 3 days after ECT in 72% of variables: effect sizes (ES) ranging from -1.10 (95% confidence interval [CI], -1.53 to -.67) to -.21 (95% CI, -.40 to .01). Four to 15 days post-ECT, all but one CI included zero or showed positive ES. No negative ES were observed after 15 days, with 57% of variables showing positive ES, ranging from .35 (95% CI, .07-.63) to .75 (95% CI, .43-1.08). Moderators did not influence cognitive outcomes after 3 days post-ECT.
Cognitive abnormalities associated with ECT are mainly limited to the first 3 days posttreatment. Pretreatment functioning levels are subsequently recovered. After 15 days, processing speed, working memory, anterograde memory, and some aspects of executive function improve beyond baseline levels.
Electroconvulsive therapy (ECT) is an effective treatment for major depression. Optimising efficacy and minimising cognitive impairment are goals of ongoing technical refinements.
To compare the efficacy and cognitive effects of a novel electrode placement, bifrontal, with two standard electrode placements, bitemporal and right unilateral in ECT.
This multicentre randomised, double-blind, controlled trial (NCT00069407) was carried out from 2001 to 2006. A total of 230 individuals with major depression, bipolar and unipolar, were randomly assigned to one of three electrode placements during a course of ECT: bifrontal at one and a half times seizure threshold, bitemporal at one and a half times seizure threshold and right unilateral at six times seizure threshold.
All three electrode placements resulted in both clinically and statistically significant antidepressant outcomes. Remission rates were 55% (95% CI 43-66%) with right unilateral, 61% with bifrontal (95% CI 50-71%) and 64% (95% CI 53-75%) with bitemporal. Bitemporal resulted in a more rapid decline in symptom ratings over the early course of treatment. Cognitive data revealed few differences between the electrode placements on a variety of neuropsychological instruments.
Each electrode placement is a very effective antidepressant treatment when given with appropriate electrical dosing. Bitemporal leads to more rapid symptom reduction and should be considered the preferred placement for urgent clinical situations. The cognitive profile of bifrontal is not substantially different from that of bitemporal.
In the past decade, a growing bulk of evidence has accumulated to suggest that patients suffering from major depression (MD) present some cognitive disturbances, such as impairment in attention, working memory, and executive function, including cognitive inhibition, problem- and task-planning. If the results of short-term memory assessment in depressed patients are equivocal, a general consensus exists that memory problems are secondary to attentional dysfunctions, and reflect the inability to concentrate. Moreover, both unipolar and bipolar patients show evidence of impaired verbal learning that has been commonly interpreted as reflecting an inability to transfer information from short-term to long-term storage. According to some authors, there would be a gender-related as well age-related specificity of some disturbances. Depressed patients also show impairments of executive functions and their recent exploration through brain imaging techniques has recently permitted to formulate some general hypotheses on the possible involvement of different brain areas in MD.
While electroconvulsive therapy (ECT) in major depression is effective, cognitive effects limit its use. Reducing the width of the electrical pulse and using the right unilateral electrode placement may decrease adverse cognitive effects, while preserving efficacy.
In a double-masked study, we randomly assigned 90 depressed patients to right unilateral ECT at 6 times seizure threshold or bilateral ECT at 2.5 times seizure threshold, using either a traditional brief pulse (1.5 ms) or an ultrabrief pulse (0.3 ms). Depressive symptoms and cognition were assessed before, during, and immediately, two, and six months after therapy. Patients who responded were followed for a one-year period.
The final remission rate for ultrabrief bilateral ECT was 35 percent, compared with 73 percent for ultrabrief unilateral ECT, 65 percent for standard pulse width bilateral ECT, and 59 percent for standard pulse width unilateral ECT (all P's<0.05 after covariate adjustment). The ultrabrief right unilateral group had less severe cognitive side effects than the other 3 groups in virtually all primary outcome measures assessed in the acute postictal period, and during and immediately following therapy. Both the ultrabrief stimulus and right unilateral electrode placement produced less short- and long-term retrograde amnesia. Patients rated their memory deficits as less severe following ultrabrief right unilateral ECT compared to each of the other three conditions (P<0.001).
The use of an ultrabrief stimulus markedly reduces adverse cognitive effects, and when coupled with markedly suprathreshold right unilateral ECT, also preserves efficacy. (ClinicalTrials.gov number, NCT00487500.).
A newly designed remote memory test has been used to assess the temporal dimension of prolonged retrograde amnesia. Patients given a course of electroconvulsive treatments for relief of depressive illness exhibited a temporal gradient of retrograde amnesia after five treatments. Memories acquired up to about 3 years before treatment were impaired, but memories acquired 4 to 17 yearss before treatment were not affected. The results suggest that the neural substrate of memory gradually changes with the passage of time after learning and that resistance to amnesic treatment can continue to develop for years.
ECT might be utilized in two ways. Firstly, the ECT-induced postictal confusional state might be used to retrieve 'forgotten' information. Secondly, review of the literature suggests that psychogenic amnesia may be precipitated by a depressive episode, as in the present case. Since ECT has known anti-depressive efficacy, its utilization may eliminate psychogenic amnesia with a depressive etiology.
A group of 231 psychiatric patients were evaluated (with the Wechsler Adult Intelligence Scale and the Halstead-Reitan Neuropsychological Test Battery) before and after electroconvulsive therapy. Improvement during the course of therapy was shown in 96% of the measures and significant improvement (p less than 0.05) occurred in 37.5% of the measures, indicating generally improved functioning. The performance of these patients on the pre-ECT testing was generally in the range characteristic of patients with documented brain damage, but the score improved during the course of treatment to the borderline normal level.
Substantial progress has been made in identifying how the treatment parameters used in ECT impact on cognitive side effects. However, there is limited information regarding individual differences in vulnerability to these side effects. The authors examined patients' pretreatment global cognitive status and postictal orientation recovery time as potential predictors of the magnitude of retrograde amnesia for autobiographical memories after ECT.
Seventy-one inpatients with major depressive disorder were randomly assigned to four ECT conditions that varied in electrode placement (right unilateral versus bilateral) and stimulus dosage (low versus high intensity). Orientation recovery time was assessed at virtually every session during the course of ECT. Global cognitive status was assessed with the modified Mini-Mental State examination before treatment, during the week after termination of treatment, and 2 months after treatment ended. Retrograde amnesia was assessed at these same time points with the Autobiographical Memory Interview.
Pre-ECT global cognitive status and the duration of postictal disorientation were strong predictors of the magnitude of retrograde amnesia in the week after the course of ECT and at 2-month follow-up. In general, these relationships were maintained regardless of technical parameters in the administration of the ECT.
Patients who manifest global cognitive impairment before treatment and patients who experience prolonged disorientation in the acute postictal period may be the most vulnerable to persistent retrograde amnesia for autobiographical information.
Past research focused on characterizing the cognitive deficits caused by ECT, understanding their causes, and defining ways of ameliorating the deficits. Future research includes the following recommendations. IN CHARACTERIZING THE DEFICITS: more accurately defining the time course to recovery; finding out whether specific memory tasks and specific patients show long-lasting effects; and defining specific components of memory and non-memory deficits (e.g., associative memory, incidental everyday memory, inattention). IN UNDERSTANDING THE CAUSES: determining whether seizure activity in certain brain structures is associated with specific cognitive deficits; finding out in which ways electric dose, electrode placement, seizure duration, and seizure threshold interact in causing the deficits; evaluating the effects of mediating variables such as blood pressure rise; and assessing the influence of background variables such as age, sex, and brain abnormality. IN AMELIORATING THE DEFICITS: continuing the search for effective medication; defining ways of reducing the number of treatments (twice weekly ECT, caffeine or thyroxine modified treatment); and manipulating dose in relation to electrode placement.
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.
Controversy persists about the use of right unilateral (RUL) and bilateral (BL) electroconvulsive therapy (ECT). While RUL ECT results in less severe short-term and long-term cognitive effects, there is concern that it is less efficacious than BL ECT.
In a double-blind study, 80 depressed patients were randomized to RULECT, with electrical dosages 50%, 150%, or 500% above the seizure threshold, or BL ECT, with an electrical dosage 150% above the threshold. Depression severity and cognitive functioning were assessed before, during, immediately after, and 2 months after ECT. Compared with baseline, responders had at least a 60% reduction in symptom scores 1 week after ECT, and were monitored for relapse for 1 year.
High-dosage RUL and BL ECT were equivalent in response rate (65%) and approximately twice as effective as low-dosage (35%) or moderate-dosage (30%) unilateral ECT. During the week after the randomized phase, BL ECT resulted in greater impairment than any dosage of unilateral ECT in several measures of anterograde and retrograde memory. Two months after ECT, retrograde amnestic deficits were greatest among patients treated with BL ECT. Thirty-three (53%) of the 62 patients who responded to ECT relapsed, without treatment group differences. The relapse rate was greater in patients who had not responded to adequate pharmacotherapy prior to ECT and who had more severe depressive symptoms after ECT.
Right unilateral ECT at high dosage is as effective as a robust form of BL ECT, but produces less severe and persistent cognitive effects.
Electroconvulsive therapy (ECT) is used increasingly in the older adult population for major depression, particularly when depression is not responsive to medications, when antidepressants are not tolerated due to side effects, or when depression is accompanied by life-threatening complications such as severe weight loss or catatonia where a rapid definitive response is required. ECT is considered a low-risk procedure that can be successfully done in medically ill older adults, but it is associated with a brief period of increased blood pressure and pulse leading to increased myocardial oxygen demand. ECT may cause delirium, particularly in the cognitively impaired older. As successful management of older patients undergoing a course of ECT often involves geriatricians and other medical practitioners, this review provides an update on the indications for ECT, how it is done, the common complications seen after the procedure, and its efficacy. Finally, specific recommendations for management are made.
Electroconvulsive therapy (ECT) is an effective treatment for a variety of psychiatric syndromes. However, one of its adverse secondary effects is neurocognitive dysfunction. The aim of this paper is to review different subtypes of memory dysfunction associated with ECT from a neuropsychological perspective. Declarative memory is clearly impaired after ECT. Immediate memory, however, is broadly preserved. Few studies have addressed procedural and incidental memory. Selective memory is impaired, probably due to the disruption of specific brain regions. Some of the possible neurobiological bases of ECT memory dysfunction are discussed in this paper. Synaptic plasticity, the cerebral neurotransmission system, and cerebral metabolism are examined in relation to the dysfunction and subsequent recovery of each memory subtype.
In severe depression, studies of regional cerebral blood flow (rCBF) by SPECT have not produced uniform results. The association between changes in SPECT and electroconvulsive therapy (ECT) has shown somewhat conflicting data. No data are available on benzodiazepine receptor function SPECT studies in ECT.
Twenty drug-resistant adult inpatients fulfilling the DSM-IIIR criteria for major depression were studied by SPECT (rCBF by relative ECD uptake in all, and benzodiazepine receptor function by iomazenil uptake in five subjects) before and 1 week after clinically successful bitemporal ECT. Clinical and neuropsychological test scores were used as references for the possible changes in SPECT.
An increased perfusion after ECT was observed in right temporal and bilateral parietal cortices, whereas no reductions in relative ECD uptake were seen after ECT. Iomazenil-SPECT revealed a highly significant increase in the benzodiazepine receptor uptake in all studied cortical regions except temporal cortices.
Clinically successful ECT was associated with changes in vascular perfusion and GABAergic neurotransmission, providing new evidence for the mechanism of action of ECT and for the neurobiology of severe drug-resistant depression.
Neuropsychological abnormalities of lateralization have been reported after right unilateral electroconvulsive therapy (ECT), that may reflect temporary disruption of the treated hemisphere. A visuospatial task sensitive to lateralization of spatial attention was administered in a test-retest design to patients with unipolar major depression and a group of age and gender matched controls. The patient group underwent right unilateral ECT between the two test sessions. The patient and control groups did not differ significantly at the initial baseline testing. After ECT, the patient group showed a significant shift of attentional bias toward the left, while the control group showed no significant shift in the second session relative to the first. The results suggest that approximately 1 h after termination of ictus there is a leftward attentional bias, possibly reflecting a change in right hemisphere cerebral activity.
Thirty-seven inpatients with major depression were assessed for postictal and interictal disorientation after they received 8 of 12 ECTs. In 20 patients, four of the eight assessments were after simulated ECT only. Only real, but not simulated, ECT produced postictal disorientation. Postictal disorientation was greatest after the first treatment, less after the second, and did not change in later assessments. It was shortest for person, longer for place, and longest for time, and showed a temporal time gradient. Interictal disorientation increased with the number of treatments. Two electrical stimulus variables (seizure duration and electrical stimulus intensity) correlated with the length of postictal disorientation. The influence of seizure duration and stimulus variables were independent of each other. The influence of the electrical stimulus variables was independent of the influence of demographic variables. These, however, did affect the length of postictal disorientation.
Continuation and maintenance electroconvulsive therapy (ECT) are used to prevent relapse of depression after a successful course of index ECT. Such a course of treatment is typically extended for as long as a year. However, some patients seem to require longer courses of maintenance ECT. Little is known about the outcomes of long-term use (> 1 year) of maintenance ECT. We reviewed our maintenance ECT practice for the year 2000 and found that 43 patients had been receiving maintenance ECT for more than a year. This retrospective study reviews the outcomes of these patients. All patients had depression associated with either unipolar or bipolar disorder or schizoaffective disorder. These patients had multiple medication or psychotherapy trials or both and multiple hospitalizations before receiving maintenance ECT. Effects on depressive symptoms, level of functioning, health care use, frequency of hospitalizations, and cognition are discussed. We conclude that extended maintenance ECT is efficacious and well tolerated and reduces hospital use for a population of chronically depressed patients refractory to medication.
Cognitive dysfunction is common in older persons suffering from a major depression. However, the degree to which this dysfunction is reversible with successful treatment of the depression remains uncertain. The present study examined the effects that treatment (randomized double-blind design) with either an SSRI (paroxetine) or a tricyclic antidepressant (nortriptyline) had on cognition in older depressed patients. The patients' performance was compared to that of a group of normal controls of similar age and education. Patients and controls were administered measures of working memory, information-processing speed, episodic memory and attention five times over the course of a 12 week trial. At baseline, the patients performed more poorly than the elderly controls on all cognitive measures. While the patients' performance did improve over the course of their treatment, the magnitude of this improvement did not exceed that produced in the elderly controls by practice alone. The same pattern of results was evident in both intent-to-treat and responder analyses. Thus, there was no evidence that the depressed patients' cognitive performance normalized after response to antidepressant therapy. Neither the patients' age at onset nor their baseline level of cognitive functioning influenced the amount by which their performance improved over the 12 week trial. There was no difference between paroxetine and nortriptyline in the amount of cognitive change associated with treatment. The present results suggest that cognitive dysfunction persists in older depressed patients even after their mood disorder has responded to antidepressant medications.
This study examined cognitive side effects of maintenance electroconvulsive (ECT) in comparison with maintenance pharmacotherapy after index ECT.
Clinical outcome data and neuropsychological measurements were compared in 11 maintenance ECT patients and 13 control patients treated with maintenance pharmacotherapy after index ECT. Data were gathered in a prospective naturalistic study during follow-up.
There were no significant differences in patient characteristics and effects of index ECT between groups. In control patients treated with maintenance pharmacotherapy, cognitive function as well as depression ratings remained stable. During maintenance ECT neuropsychological test performance and depression ratings improved slightly but not significantly.
Neuropsychological functioning during the maintenance phase of treatment did not differ between the two treatment groups. Cognitive function remained stable during maintenance ECT.
This explorative study investigated the interaction between electroconvulsive therapy (ECT) treatment-effect, reduced depression, and neuropsychological outcome in relation to age. Follow-up neuropsychological assessment was conducted with depressive patients treated with ECT. From a potential sample of 45 patients, the neuropsychological measures (pre-ECT, three times post-ECT, up to 12 months) and clinical data from the remaining 21 patients who completed all assessments were evaluated (mean age=56.76; SD=14.12; range, 33-79). ECT resulted in a decrease in the depression scores. A distinct impact of ECT and depression decrease on cognitive domains was found. Depression alleviation was mainly associated with improvement in cognitive domains such as memory, information processing, and executive function. ECT improved cognitive domains such as information processing and perception. Short-term cognitive improvement was greater in older patients but showed an increase similar to that at long-term follow-up in younger patients (<60). Current findings provide evidence that ECT may improve cognitive functioning in nondemented elderly, which has strong clinical relevance concerning the use of ECT.
Few studies have been conducted comparing complaints of memory problems using objective and subjective memory scales in depressed patients who received electroconvulsive therapy (ECT) + pharmacotherapy or treatment with pharmacotherapy only. Patients who suffer from depression according to the Diagnostic and Statistical Manual of Mental Disorder (Fourth Edition) criteria and who were admitted within the past 5 years before this study in a general psychiatric hospital were screened for inclusion. Objective retrograde amnesia was assessed using the Autobiographical Memory Interview and the Amsterdam Media Questionnaire (AMQ). Subjective retrograde amnesia was assessed using the Squire Subjective Memory Questionnaire and the ECT Retrograde Amnesia and Perception Scale (ERAPS), a newly developed scale. Twenty of the 84 patients who received ECT + pharmacotherapy and 30 of the 196 patients who received pharmacotherapy only participated in the study. Patients' ERAPS memory scores were compared with proxies' ERAPS memory scores of the patients to assess the reliability of memory complaints. The ECT + pharmacotherapy group was found to suffer more from memory problems using the AMQ 1990 test. There was also a difference for the proxy's ERAPS memory score, reflecting the conviction of proxies from the ECT + pharmacotherapy patients that these patients suffer more memory problems due to the illness, treatment with pharmacotherapy, or ECT. The differences could not be explained by the influence of determinants for retrograde amnesia. ECT + pharmacotherapy patients did not attribute their memory problems mainly to ECT but put equal "blame" on the depressive illness, treatment with pharmacotherapy, and ECT. The analyses suggest that the AMQ 1990s test is (more) sensitive in registering retrograde amnesia than the other scales used in the study.
In most studies right unilateral electroconvulsive therapy (ECT) has been shown to cause fewer cognitive side effects but less antidepressant efficacy compared with bi(fronto)temporal ECT at certain intensities.
To compare the short-term efficacy and side effects of right unilateral ECT and bifrontal ECT.
In a double-blind randomised controlled clinical trial, 92 patients diagnosed with pharmaco-resistant major depression received either six right unilateral ECT treatments (250% stimulus intensity of titrated threshold) or six bifrontal ECT (150% of threshold) treatments over a 3-week period. Concomitant psychotropic medications were continued during ECT treatments. The severity of depression and cognitive status was assessed prior to the first ECT and one day after the sixth ECT using the 21-item Hamilton Depression Rating Scale and the modified Mini Mental State Examination.
Eight patients did not complete the course of the study due to minor side effects or withdrawal of consent. The mean Hamilton Depression score decreased from 27 to 17 points in both groups of 46 patients, resulting in 12 responders (primary endpoint defined as a decrease >50%) in each patient group (95% confidence interval for the odds ratio from 0.35 to 2.8). There was no reduction in the modified Mini Mental State score (mean score 86 of 100 points).
Both bifrontal and right unilateral electrode placements in ECT were reasonably safe and moderately efficacious in reducing symptoms of pharmaco-resistant major depression.
Electroconvulsive therapy (ECT) is a highly effective treatment for depression but its use is limited by the risk of cognitive side effects. This study explored the potential of a novel approach, ultrabrief pulsewidth (0.3 ms) right unilateral (RUL-UB) ECT, to minimise cognitive effects while preserving efficacy.
Mood and neuropsychological functioning were objectively rated in 30 patients over a course of RUL-UB ECT at 6 times seizure threshold. Results (mood outcomes, ECT treatment parameters) were compared with a retrospectively assessed group of 30 age and gender matched patients who received RUL ECT (1.0 ms pulsewidth, 3.5 times seizure threshold) at the same hospital.
Six treatments of RUL-UB ECT resulted in relatively few cognitive side effects, compared to reports of previous studies. The number of responders did not differ between groups but significantly more treatments were required in the RUL-UB group, suggesting a slower speed of response.
Patients were not randomised to the two forms of ECT and data was obtained retrospectively in the RUL ECT comparison group.
This study suggests that RUL-UB ECT can be effective in treating depression while incurring lesser cognitive side effects than a commonly used form of RUL ECT, but a greater number of treatments may be required for response.
Electroconvulsive therapy (ECT) as a single course or in maintenance form (M-ECT) is an effective treatment in depressed elderly. However, ECT may have adverse effects on cognition.
To review all studies from 1980-2006 on ECT and cognition in the elderly with a minimum age of 55 years or a mean age of 55 years, and with valid measurements of cognition before and after ECT.
Nine out of the 15 eligible studies were focused exclusively on the elderly. Three studies reported verbal learning- and recall problems post ECT, while three studies found positive effects of ECT on memory, speed of processing and concentration. Global cognitive functioning in patients with cognitive impairment improved in all studies. At follow up, most studies reported improvement of cognitive functions. Learning verbal information and executive functioning were impaired in M-ECT patients whereas global cognition remained stable after M-ECT over a year.
To date research of ECT on cognitive functioning in the elderly is very limited. Small sample size, lack of controls, use of a single screening instrument and a short follow up period may explain the conflicting results. Given the clinical importance, more extensive research on cognition in elderly treated with ECT is urgently needed.
To review studies that examined the impact of electroconvulsive therapy (ECT) on cognitive functioning in depressed older people.
Studies were systematically retrieved using PsychINFO and MEDLINE, with additional articles sourced from lists of references. Given our aged-care focus, study participants had a minimum mean age of 60 years, with no single participant younger than 50 years.
Twenty-seven studies met our criteria. Apart from evidence of interictal slowing of information processing speed, there were mixed results with regard to the impact of ECT on other cognitive domains. Factors contributing to this variability in results include the lack of discrimination between unilateral, bilateral, or mixed electrode placement; the inclusion of patients with dementia; the small sample sizes; and the use of tests insensitive to subtle cognitive changes.
The effect of ECT in elderly recipients' cognition remains unclear, and further research with more critically selected methods is required. In the meantime, we recommend that clinicians regularly administer brief focused cognitive tests before, during, and after treatment to monitor progress.
The adverse cognitive effects of electroconvulsive therapy are important limitations in the use of this treatment that continues to be a significant therapeutic strategy after 7 decades of use. Among the approaches to mitigation of these side effects are considerations involving the prescription and manipulation of the electrical stimulus itself. The impact of the following electrical factors on the cognitive outcomes of electroconvulsive therapy are surveyed: efficiency of the stimulus as expressed in electrical waveform; targeting of the stimulus, the major concept underlying electrode placement; stimulus dosing; and frequency and number of treatments. The current state of development of knowledge in these areas is summarized, and methods to achieve the best cognitive outcomes without sacrificing clinical efficacy are discussed. Future trends in the further optimization of the electrical stimulus are briefly mentioned.
In the last 20 years, an increasing number of articles have been published about effects of electroconvulsive therapy (ECT) on memory. Here, we review autobiographical memory studies in particular because there have been conflicting reports about the extent and persistence of ECT effects and the period before treatment from which memories are most likely to be affected.
Five psychological and medical databases (MEDLINE, PubMed, PsychINFO, ScienceDirect, and Web of Knowledge) were searched from 1980 to 2007, yielding 15 studies of ECT and autobiographical memory.
Evidence suggests that autobiographical memory impairment does occur as a result of ECT. Objective measures found memory loss to be relatively short term (<6 months posttreatment), whereas subjective accounts reported amnesia to be more persistent (>6 months post-ECT). Electroconvulsive therapy predominantly affects memory of prior personal events that are near the treatment (within 6 months). Autobiographical memory loss is reduced by using brief pulse ECT rather than sine wave-unilateral positioning of electrodes rather than bilateral-and by titrating electrical current relative to the patient's own seizure threshold.
Further research is required to determine memory loss associated with ECT, controlling for the direct effects of the depressive state.
Cognitive impairment remains a common side effect of brief pulse electroconvulsive therapy (ECT), and its minimization has been the motivation for many different treatment modifications over the decades. The level of impairment has been shown to vary according to different technical parameters of ECT including, but not limited to, electrode placement, dosage, and waveform, as well as patient factors, such as age and premorbid intellect. Most past research has focused the assessment on memory impairments associated with ECT. Specifically, ECT can result in both anterograde and retrograde memory impairments. However, the study of non-memory cognitive functions after ECT has been relatively neglected. Furthermore, although considerable recovery has been observed within weeks of treatment completion, data are lacking in the longer term. The following article presents an overview of what is currently known about the pattern and recovery of cognitive side effects of ECT. Controversies within the literature and areas requiring further research are highlighted.