Changes in regional cerebral blood flow abnormalities in late-life depression following response to electroconvulsive therapy

Depressive Pseudodementia with Reversible AD-like Brain Hypometabolism: A Case Report and a Review of the Literature

Recent European guidelines recommend using brain FDG-PET to differentiate between Alzheimer's disease (AD) and depressive pseudodementia (DP), with specific hypometabolism patterns across the former group, and typically normal or frontal hypometabolism in the latter. We report the case of a 74 years-old man with DP (MMSE 16/30), whose FDG-PET visual rating and semiquantitative analysis closely mimicked the typical AD pattern, showing severe hypometabolism in bilateral precuneus, parietal and temporal lobes, and sparing frontal areas, suggesting the diagnosis of moderate AD. Shortly after starting antidepressant polytherapy, he underwent formal NPS testing, which revealed moderate impairment of episodic memory and mild impairment on executive and visuospatial tests, judged consistent with neurodegenerative dementia and concomitant depression. Over the following two years, he improved dramatically: repeated NPS assessment did not show significant deficits, and FDG-PET showed restoration of cerebral metabolism. The confirmation of PET findings via semiquantitative analysis, and their reversion to normality with antidepressant treatment, proved the non-neurodegenerative origin of the initial AD-like FDG-PET abnormalities. We review similar cases and provide a comprehensive analysis of their implications, concluding that reversible FDG-PET widespread hypometabolism might represent a biomarker of pseudodementia. Therefore, we suggest caution when interpreting FDG-PET scans of depressed patients with cognitive impairment.

Association between increased theta cordance and early response to ECT in late-life depression

OBJECTIVES

More than half of patients with major depression who do not respond to initial antidepressants become treatment resistant (TRD), and while electroconvulsive therapy (ECT) is effective, it involves anesthesia and other medical risks that are of concern in geriatric patients. Past studies have suggested that theta cordance (TC), a correlate of cerebral metabolism measured by electroencephalography, could guide treatment decisions related to patient selection and engagement of the therapeutic target.

METHODS/DESIGN

Eight patients with late-life treatment resistant depression (LL-TRD) underwent magnetoencephalography (MEG) at baseline and following seven sessions of ECT. We tested whether the mean and regional frontal cortex TC were able to differentiate early responders from nonresponders.

RESULTS

Five patients whose depression severity decreased by >30% after seven sessions were considered early responders. We found no baseline differences in mean frontal TC between early responders compared with nonresponders, but early responders exhibited a significant increase in TC following ECT. Further, we found that compared with nonresponders, early responders exhibited a greater change in TC specifically within the right prefrontal cortex.

CONCLUSIONS

These results support the hypothesis that increases in frontal TC are associated with antidepressant response. We expand on previous findings by showing that this change is specific to the right prefrontal cortex. Validation of this neural marker could contribute to improved ECT outcomes, by informing early clinical decisions about the acute efficacy of this treatment.

Severity-dependent and -independent brain regions of major depressive disorder: A long-term longitudinal near-infrared spectroscopy study

BACKGROUND

Long-term longitudinal studies are necessary to establish neuroimaging indicators which contribute to the detection of severity changes over time in patients with major depressive disorder (MDD).

METHODS

One hundred sixty-five patients with MDD underwent clinical assessments and near-infrared spectroscopy (NIRS) examination at the initial evaluation (T0). After 1.5 years, 45 patients who visited for the follow-up evaluation (T1.5) were included in the analysis. The authors conducted analyses using the 17-item Hamilton Rating Scale for Depression (HAMD) scores and mean oxy-hemoglobin concentration ([oxy-Hb]) changes during a cognitive task in NIRS at T0 (T0_HAMD, T0_[oxy-Hb]) and at T1.5 (T1.5_HAMD, T1.5_[oxy-Hb]), and their intra-individual longitudinal changes (ΔHAMD = T1.5_HAMD - T0_HAMD, Δ[oxy-Hb] = T1.5_[oxy-Hb] - T0_[oxy-Hb]).

RESULTS

For severity-dependent regions, the Δ[oxy-Hb] in the right inferior frontal gyrus (IFG) was negatively correlated with the ΔHAMD. For severity-independent regions, the intra-class correlation coefficients between T0_ and T1.5_[oxy-Hb] were moderate in the bilateral middle frontal gyri (MFG).

LIMITATIONS

The percentage of patients included in the follow-up examination was relatively small.

CONCLUSIONS

Brain activation in the right IFG and the bilateral MFG as measured by NIRS may differentially indicate clinical severity and trait-related abnormalities in MDD.

Trajectories in Cerebral Blood Flow Following Antidepressant Treatment in Late-Life Depression: Support for the Vascular Depression Hypothesis

OBJECTIVE

Studies have identified longitudinally that there exists an association between depression, cerebral blood flow (CBF), and white matter hyperintensities that are thought to be due to vascular pathologies in the brain. However, the changes in CBF, a measure that reflects cerebrovascular integrity, following pharmacotherapy are not well understood. In this study, we investigated the dynamic CBF changes over the course of antidepressant treatment and the association of these changes with depressive symptoms.

METHODS

We used pseudocontinuous arterial spin labeling to investigate CBF changes in a sample of older patients (≥ 50 years of age; N = 46; 29 female) with a DSM-IV diagnosis of major depressive disorder. Participants had 5 magnetic resonance imaging scans (at baseline, the day after receiving a placebo, the day after receiving a first dose of venlafaxine, a week after starting venlafaxine treatment, and at the end of trial [12 weeks]). Montgomery-Asberg Depression Rating Scale (MADRS) was used to evaluate depression severity and treatment outcome. We investigated the association between changes in depression severity with changes in voxel-wise CBF while adjusting for potential confounding factors.

RESULTS

Increased CBF in the middle and posterior cingulate between baseline and end of treatment was significantly associated with percent decrease in MADRS score, independent of sex and Mini-Mental State Examination score (5,000 permutations, cluster forming threshold P < .005, family-wise error P < .05). No significant effects were detected between baseline and other scans (ie, placebo, acute [single dose], or subacute [after a week]).

CONCLUSIONS

Regional CBF increases were associated with decreases in depressive symptoms. This observation is consistent with the vascular depression hypothesis in late-life depression.

TRIAL REGISTRATION

ClinicalTrials.gov identifiers: NCT00892047 and NCT01124188.

The Effect of Electroconvulsive Therapy on Hypoperfusion in Psychotic Bipolar Depression: A Case Study

The pharmacological treatment of bipolar depression has low response rates. Twenty percent to 30% of patients have an insufficient response to medication. The guidelines suggest that electroconvulsive therapy (ECT) is the next step. The aim of this case study is to evaluate the effect of ECT on the perfusion of the brain in bipolar depression, while monitoring effects on mood and cognition. We present a case study of 56-year-old female patient who suffered from a psychotic depression and cognitive impairment. Before ECT, she took several antidepressants and atypical antipsychotics, but there was no improvement in her symptoms. By using single-photon emission computed tomography, we obtained the status of the regional cerebral blood flow and found a decreased perfusion in the anterior part of the left temporal lobe, the posterior part of the right temporal lobe, and in the left gyrus frontalis inferior. This is consistent with previous findings. Electroconvulsive therapy resulted in a resolution of the patient's depression and an improvement in her neurocognitive performance. Markedly, this was only in visual learning and working memory, domains in which the patient was already relatively stronger pre-ECT treatment. A new single-photon emission computed tomography, 4 weeks after the last ECT course, showed normalization of the regional cerebral blood flow.

The Normalization of Brain ¹⁸F-fluorodeoxy-D-glucose Positron Emission Tomography Hypometabolism following Electroconvulsive Therapy in a 55-year-old Woman with Treatment-resistant Late Onset Depression: A Case Report

Major depressive disorder, especially in later life, has heterogeneous clinical characteristics and treatment responses. Symptomatically, psychomotor retardation, lack of energy, and apathy tends to be more common in people with late-onset depression (LOD). Despite recent advances in psychopharmacologic treatments, 20% to 30% of patients with mood disorders experience inadequate responses to medication, often resulting in a trial of electroconvulsive therapy (ECT). However, the therapeutic mechanism of ECT is still unclear. By using ¹⁸F-fluorodeoxy-D-glucose positron emission tomography-computed tomography (¹⁸F-FDG PET/CT), we can obtain the status of brain metabolism in patients with neuropsychiatric disorders and changes during psychiatric treatment course. The object of this case report is evaluating the effect of ECT on brain metabolism in treatment-refractory LOD by PET/CT and understanding the mode of action of ECT. In this case report, we presented a 55-year-old female patient who suffered psychotic depression that was resistant to pharmacological treatment. Several antidepressants and atypical anti-psychotics were applied but there was no improvement in her symptoms. The patient presented not only depressed mood and behaviors but also deficit in cognitive functions. We found decreased diffuse cerebral metabolism in her brain ¹⁸F-FDG PET/CT image. ECT resulted in amelioration of the patients’ symptoms and another brain PET imaging 7 weeks after the last ECT course showed that her brain metabolism was normalized.

A long-term longitudinal follow-up of depressed patients treated with ECT with special focus on development of dementia

BACKGROUND

In this study, the long term effects of ECT on patients with depression were investigated through repeated rCBF and EEG measures as well as clinical characteristics over several years. The aim of the investigation was to establish an association with the eventual development of dementia.

METHOD

A cohort of forty-nine patients (21 men and 28 women) with a mean age of 61 years underwent ECT. A subsequent evaluation from medical records and three rating-scales for diagnosis of Alzheimer´s disease (AD), fronto-temporal dementia (FTD), and for vascular dementia (VaD), revealed that 17 patients (8 men and 9 women), had developed dementia. These cases were compared to the 32 patients (13 men and 19 women), who had not developed dementia.

RESULT

Initially, the dementia group, compared to those without dementia, showed a lower hemispheric CBF (left side; p=.029, right side; p=.033), and a lower mean occipital EEG frequency (p=.048). After the first ECT-series, an increase in general disorientation (p=.015), personal disorientation (p=.009), and subsequently, spatial disorientation (p=.021), were seen in the dementia group. There were no differences in the clinical response or remissions after treatment in the groups.

LIMITATIONS

The small sample-size, which did not allow for the comparison of characteristics between different dementias.

CONCLUSION

Depressed older patients who later developed dementia showed lower hemispheric mean level of CBF and EEG mean frequency before ECT and higher personal and spatial disorientation following ECT.

Magnetic seizure therapy in treatment-resistant depression: clinical, neuropsychological and metabolic effects

BACKGROUND

Magnetic seizure therapy (MST), despite being in an early phase of clinical research, has been demonstrated to be associated with antidepressant efficacy. However, safety, tolerability and efficacy data in connection with functional brain activity from larger samples are lacking. The aim of this study was to determine clinical and cognitive effects of MST and the influence of MST on regional brain glucose metabolism.

METHOD

Twenty-six patients suffering from treatment-resistant depression (TRD) underwent MST. Ten patients underwent a randomized trial and 16 patients an open-label study design. The primary outcome criterion was the severity of depressive symptoms assessed with the Hamilton Depression Rating Scale (HAMD). Depressive symptoms, tolerability and cognitive safety, along with social functioning and quality of life parameters, were assessed using various rating scales. A clinical follow-up visit 6 months following the completion of a course of MST and [18F]-fluorodeoxyglucose positron emission tomography (FDG-PET) scans of 12 patients were analysed.

RESULTS

A significant response to MST was demonstrated by 69% of the patient sample, with 46% meeting remission criteria. Anxiety ratings were significantly reduced in responders and their quality of life was improved. Half of the responders relapsed within 6 months. No cognitive side-effects were observed. FDG-PET scans showed a metabolic increase in the frontal cortex bilaterally and a decrease in the left striatum.

CONCLUSIONS

Robust antidepressant and anti-anxiety efficacy of MST was demonstrated, and found to be associated with localized metabolic changes in brain areas that are strongly implicated in depression. Thus, MST presents an effective, well-tolerated and safe treatment option for patients unable to respond to other forms of therapy for depression.

A review of longitudinal electroconvulsive therapy: neuroimaging investigations

Electroconvulsive therapy (ECT) is the most effective treatment for a depressive episode but the mechanism of action and neural correlates of response are poorly understood. Different theories have suggested that anticonvulsant properties or neurotrophic effects are related to the unique mechanism of action of ECT. This review assessed longitudinal imaging investigations (both structural and functional) associated with ECT response published from 2002 to August 2013. We identified 26 investigations that used a variety of different imaging modalities and data analysis methods. Despite these methodological differences, we summarized the major findings of each investigation and identified common patterns that exist across multiple investigations. The ECT response is associated with decreased frontal perfusion, metabolism, and functional connectivity and increased volume and neuronal chemical metabolites. The general collective of longitudinal neuroimaging investigations support both the anticonvulsant and the neurotrophic effects of ECT. We propose a conceptual framework that integrates these seemingly contradictory hypotheses.

Electroconvulsive Treatment: Hypotheses about Mechanisms of Action

No consensus has been reached on the mode of action of electroconvulsive treatment (ECT). We suggest that two features may aid in the delineation of the involved mechanisms. First, when effective, ECT would be likely to affect brain functions that are typically altered in its primary recipient group, people with severe depression. Central among these are the frontal and temporal lobes, the hypothalamus-pituitary-adrenal (HPA) stress axis, and the mesocorticolimbic dopamine system. Second, the involved mechanisms should be affected for a time period that matches the average endurance of clinical effects, which is indicated to be several days to a few weeks. To identify effects upon frontal and temporal lobe functioning we reviewed human studies using EEG, PET, SPECT, and fMRI. Effects upon the HPA axis and the dopamine system were assessed by reviewing both human and animal studies. The EEG studies indicate that ECT decelerates neural activity in the frontal and temporal lobes (increased delta and theta wave activity) for weeks to months. Comparable findings are reported from PET and SPECT studies, with reduced cerebral blood flow (functional deactivation) for weeks to months after treatment. The EEG deceleration and functional deactivation following ECT are statistically associated with reduced depression scores. FMRI studies indicate that ECT flattens the pattern of activation and deactivation that is associated with cognitive task performance and alters cortical functional connectivity in the ultra slow frequency range. A common finding from human and animal studies is that ECT acutely activates both the HPA axis and the dopamine system. In considering this evidence, we hypothesize that ECT affects the brain in a similar manner as severe stress or brain trauma which activates the HPA axis and the dopamine system and may compromise frontotemporal functions.

Frontocingulate dysfunction in depression: toward biomarkers of treatment response

Increased rostral anterior cingulate cortex (rACC) activity has emerged as a promising predictor of treatment response in depression, but neither the reliability of this relationship nor the mechanisms supporting it have been thoroughly investigated. This review takes a three-pronged approach to these issues. First, I present a meta-analysis demonstrating that the relationship between resting rACC activity and treatment response is robust. Second, I propose that the rACC plays a key role in treatment outcome because of its 'hub' position in the default network. Specifically, I hypothesize that elevated resting rACC activity confers better treatment outcomes by fostering adaptive self-referential processing and by helping to recalibrate relationships between the default network and a 'task-positive network' that comprises dorsolateral prefrontal and dorsal cingulate regions implicated in cognitive control. Third, I support this hypothesis by reviewing neuropsychological, electrophysiological, and neuroimaging data on frontocingulate dysfunction in depression. The review ends with a discussion of the limitations of current work and future directions.

Antipsychotic effect of electroconvulsive therapy is related to normalization of subgenual cingulate theta activity in psychotic depression

OBJECTIVE

Electroconvulsive therapy (ECT) is one of the most effective options available for treating depressive and psychotic symptoms in a variety of disorders. While the exact mechanism of ECT is unclear, it is known to increase metabolism and blood flow specifically in the anterior cingulate cortex (ACC). The ACC is a cortical generator of theta rhythms, which are abnormal in patients with depression and psychotic disorders. Since patients with psychotic depression are known to respond particularly robustly to ECT, we investigated whether the therapeutic effect of ECT in this population was related to normalization of abnormal theta activity in the ACC.

METHOD

We obtained 19-lead electroencephalography (EEG) data from 17 participants with psychotic depression before and 2-3 weeks after a full course of ECT. EEG data was analyzed with quantitative measures and low-resolution electromagnetic tomography (LORETA) compared to an age-adjusted normative database.

RESULTS

Quantitative EEG analyses revealed that theta band (4-7 Hz) activity was the only frequency band that changed with ECT. LORETA analyses revealed that the primary site of theta activity change was within the subgenual ACC (Brodmann area 25). There was a positive association between increased subgenual ACC theta activity and decreased psychotic symptoms. The degree of low theta activity in the subgenual ACC prior to ECT predicted the antipsychotic response of ECT.

CONCLUSIONS

The antipsychotic effect of ECT is related to normalization of subgenual ACC theta hypoactivity.

Preliminary evidence differentiating ADHD using brain SPECT imaging in older patients

The objective of this study was to differentiate ADHD patients from a healthy comparison group using high resolution brain SPECT imaging in older patients. Using extensive chart reviews of structured interviews, DSM-IV criteria, and psychiatrist-given diagnoses, we identified 27 patients over age 50 with ADHD, either combined or inattentive types. Patients were compared to an age-matched group of healthy subjects with brain SPECT imaging at rest and during concentration using semiquantitative visual readings. Significantly lower cortical activity is noted in the ADHD group, particularly in the prefrontal poles, orbits, and parietal lobes. Older ADHD patients can be discerned from healthy subjects using brain SPECT. The results support the executive dysfunction model of ADHD.

Dissociable recruitment of rostral anterior cingulate and inferior frontal cortex in emotional response inhibition

The integrity of decision-making under emotionally evocative circumstances is critical to navigating complex environments, and dysfunctions in these processes may play an important role in the emergence and maintenance of various psychopathologies. The goal of the present study was to examine the spatial and temporal dynamics of neural responses to emotional stimuli and emotion-modulated response inhibition. High-density event-related brain potentials (ERPs) were measured as participants (N=25) performed an emotional Go/NoGo task that required button presses to words of a "target" emotional valence (i.e., positive, negative, neutral) and response inhibition to words of a different "distractor" valence. Using scalp ERP analyses in conjunction with source-localization techniques, we identified distinct neural responses associated with affective salience and affect-modulated response inhibition, respectively. Both earlier (approximately 300 ms) and later (approximately 700 ms) ERP components were enhanced with successful response inhibition to emotional distractors. Only ERPs to target stimuli differentiated affective from neutral cues. Moreover, source localization analyses revealed right ventral lateral prefrontal cortex (VLPFC) activation in affective response inhibition regardless of emotional valence, whereas rostral anterior cingulate activation (rACC) was potentiated by emotional valence but was not modulated by response inhibition. This dissociation was supported by a significant Region x Trial Type x Emotion interaction, confirming that distinct regional dynamics characterize neural responses to affective valence and affective response-inhibition. The results are discussed in the context of an emerging affective neuroscience literature and implications for understanding psychiatric pathologies characterized by a detrimental susceptibility to emotional cues, with an emphasis on major depressive disorder.

Metabolic correlates of antidepressant and antipsychotic response in patients with psychotic depression undergoing electroconvulsive therapy

OBJECTIVES

Although electroconvulsive therapy (ECT) is a very effective treatment of depression and psychosis, the mechanisms by which this occurs are not fully delineated. The objective of this study was to investigate the functional alterations in brain metabolism in response to ECT through the use of positron emission tomography assessment of cerebral glucose metabolism before and after a course of ECT.

METHODS

Ten subjects with psychotic depression were studied with positron emission tomography using [F]fluorodeoxyglucose before and between 2 and 3 weeks after a course of ECT. Statistical parametric mapping and region of interest analyses of the anterior cingulate cortex (ACC) subregions (dorsal, rostral, subcallosal, and subgenual) and hippocampus were used to determine glucose metabolic changes from ECT. The Hamilton Depression Rating Scale and the Scale for Assessing Positive Symptoms were the primary measures used for assessing clinical changes from ECT.

RESULTS

Electroconvulsive therapy led to significant increases in the left subgenual ACC and hippocampal metabolism, which were directly correlated with each other and to a reduction in depression as measured by total Hamilton Depression Rating Scale scores. Better antidepressant responders had increased, whereas poorer responders had a decreased left subgenual ACC and hippocampal metabolism. The decrease in positive symptoms was also correlated with increased left hippocampal metabolism.

CONCLUSIONS

The antidepressant effect of ECT was correlated with increased metabolism in the left subgenual ACC and hippocampus, whereas the antipsychotic effect of ECT was only correlated with increased left hippocampal metabolism. This finding has implications to better understand the mechanism of antidepressant and antipsychotic effects of ECT.

Aging, grey matter, and blood flow in the anterior cingulate cortex

The anterior cingulate cortex (ACC) is thought to be the neuroanatomical interface between emotion and cognition. Because effective emotion-cognition interactions are essential to optimal decision making, clarifying how the functionality of the ACC changes in older age using functional imaging holds great promise for ultimately understanding what contributes to the psychological changes occurring in late life. However, the interpretation of functional imaging studies is complicated by the fact that aging is associated with changes in grey matter volume and in the cerebral vasculature. In the present study, we obtained high-resolution structural magnetic resonance (MR) imaging data and quantitative blood flow images to examine the association between aging, blood flow, and grey matter volume in the ACC. Twenty-six healthy individuals between 25 and 79 years of age underwent quantitative [15O]water positron emission tomography (PET) imaging. The ACC was traced onto tissue-classified images derived from T1- and T2-weighted MRIs using previously defined methods. The ACC was divided into dorsal, rostral, and subgenual regions. Age was negatively correlated with blood flow in dorsal and rostral ACC regions. Effects were weaker but in a similar direction for the subgenual ACC. While older age and lower blood flow were both associated with smaller rostral ACC grey matter volumes, mediation analysis revealed that grey matter volume only partially mediated the effect of age on blood flow in the rostral ACC. Neural alterations not detectable on MR images may lead to reduced blood flow due to fewer and/or less metabolically active neurons. Alternatively, lower blood flow may be a cause, rather than a consequence, of smaller grey matter volume in the ACC.

Regional cerebral blood flow changes in depression after electroconvulsive therapy

A large number of studies have documented regional cerebral blood flow (rCBF) abnormalities in depression. A smaller yet significant number of studies have examined changes in rCBF before and after treatment. The findings, however, have been variable with regard to changes before and after electroconvulsive therapy (ECT). A consecutive series of patients (n=10) with drug-resistant major depressive episode according to DSM-IV with 17-item Hamilton Rating Scale for Depression (HRSD) scores greater than or equal to 14 gave their informed consent and were studied with technetium-99m ethyl cysteinate dimer single-photon emission computed tomography (99mTc-ECD SPECT) before and after a course of ECT. The results were analyzed with statistical parametric mapping version 99. No region showed significant positive correlations between rCBF patterns of changes and HRSD changes, but three clusters emerged as showing significant negative correlations. These regions corresponded with left frontopolar gyrus, left amygdala, globus pallidus and nucleus accumbens, and left superior temporal gyrus. It was speculated that ECT affected both the prefrontal cortex, commonly assumed to be involved in depression, and the amygdala, known to play a central role in the processing of emotional stimuli, through the limbic-cortical-striatal-pallidal-thalamic circuit.

Resolution of SPECT-determined anterior cerebral hypoperfusion correlated with maintenance ECT-derived improvement in residual symptoms in a case of late-life psychotic depression

A 70-year-old widow with recurrent psychotic depression was successfully treated with maintenance electroconvulsive therapy (ECT) for 4 years up to the present. Anterior cerebral hypoperfusion visualized by single photon emission computerized tomography (SPECT) before ECT persisted (second SPECT study 14 days after the last ECT session) despite a response to the first course of acute ECT. Only mild symptoms remained. Relapse occurred 2 weeks after the post-ECT SPECT study. The hypoperfusion improved after response to a second course of acute ECT (per SPECT 5 days after the last ECT session), and perfusion was normalized after 2-year maintenance ECT (per SPECT 14 days after the last ECT session). The normalization coincided with improvement in depressive symptoms remaining after the second course of acute ECT. We speculate that the effectiveness of maintenance ECT might have been in part the result of the improvement in residual symptoms and that resolution of the persistent anterior hypoperfusion, which might underlie medical refractoriness, illness chronicity, and relapse tendency in late-life depression, might have been associated with the improvement in residual symptoms achieved by maintenance ECT.

Resting anterior cingulate activity and abnormal responses to errors in subjects with elevated depressive symptoms: a 128-channel EEG study

Depression has been associated with dysfunctional executive functions and abnormal activity within the anterior cingulate cortex (ACC), a region critically involved in action regulation. Prior research invites the possibility that executive deficits in depression may arise from abnormal responses to negative feedback or errors, but the underlying neural substrates remain unknown. We hypothesized that abnormal reactions to error would be associated with dysfunctional rostral ACC activity, a region previously implicated in error detection and evaluation of the emotional significance of events. To test this hypothesis, subjects with low and high Beck Depression Inventory (BDI) scores performed an Eriksen Flanker task. To assess whether tonic activity within the rostral ACC predicted post-error adjustments, 128-channel resting EEG data were collected before the task and analyzed with low-resolution electromagnetic tomography (LORETA) using a region-of-interest approach. High BDI subjects were uniquely characterized by significantly lower accuracy after incorrect than correct trials. Mirroring the behavioral findings, high BDI subjects had significantly reduced pretask gamma (36.5-44 Hz) current density within the affective (rostral; BA24, BA25, BA32) but not cognitive (dorsal; BA24', BA32') ACC subdivision. For low, but not high, BDI subjects pretask gamma within the affective ACC subdivision predicted post-error adjustments even after controlling for activity within the cognitive ACC subdivision. Abnormal responses to errors may thus arise due to lower activity within regions subserving affective and/or motivational responses to salient cues. Because rostral ACC regions have been implicated in treatment response in depression, our findings provide initial insight into putative mechanisms fostering treatment response.

Interictal slow-wave focus in left medial temporal lobe during bilateral electroconvulsive therapy

The interictal state between two electroconvulsive therapy (ECT) sessions is clinically characterised by possible cognitive adverse effects like mild amnestic syndrome. ECT-induced amnestic deficits can persist for several weeks after ECT. Electrophysiologically, slowing of brain electrical activity in the interictal state has often been reported. Especially, for bilateral ECT a correlation between enhanced left frontotemporal theta activity and retrograde amnesia has been demonstrated. This study focuses on the topographic distribution of cortical slow-wave oscillations during the interictal state of a bilateral ECT cycle. Twelve patients with major depression have been investigated with 32-channel resting EEG 24 h after the 6th ECT session. As controls, 8 major depressive patients were investigated prior to antidepressive treatment. The generating sources of slow-wave activity are estimated within the theta frequency band with low-resolution brain electromagnetic tomography. Source analysis revealed a distinct pattern of theta activity in the depth of the left temporal lobe (fusiform and parahippocampal gyri, Brodmann areas 37 and 36, respectively; p< 0.05) during the interictal state. This finding suggests a dysfunction of the left medial temporal lobe memory system during the interictal state of a bilateral ECT cycle. It will further be discussed whether it is possible to obtain information about activity of deep brain structures like the hippocampal formation from scalp-recorded signals.

Time course of cerebral blood flow changes following electroconvulsive therapy in depressive patients-measured at 3 time points using single photon emission computed tomography

Although electroconvulsive therapy (ECT) has been employed for treating depression for more than 60 years, its mechanisms of action are yet unknown. To clarify the ECT effects on brain function, we examined cerebral blood flow (CBF) using single photon emission computed tomography at 3 time points--few days before an ECT course (Pre) and approximately 5 days (Post 1) and 1 month (Post 2) after the last ECT session. Eight depressive patients completed the study. In all the patients, the depressive symptoms improved after the ECT course, and major cognitive impairment was not observed at any time point. At Pre, the regional CBF (rCBF) in the widespread areas in the frontal lobe and limbic regions including cingulate cortex and parahippocampal gyrus was lower in the patients than in the normal controls. At Post 1 and Post 2, the rCBF in the frontal and limbic regions continued to be lower in the patients than in the controls although the successive recovery of decreased rCBF in the frontal region was observed. Regarding the time course among the patients, the rCBF in the right medial frontal region significantly increased (toward normal) at Post 2, not at Post 1. These findings suggest that depressive patients have decreased CBF in the frontal and limbic regions, and the medial frontal region plays a crucial role in ECT and recovery from depression. Further, patients who have undergone ECT treatment for depression should be carefully observed because brain functions continue to change even after a successful ECT course.

HPA axis normalization, estimated by DEX/CRH test, but less alteration on cerebral glucose metabolism in depressed patients receiving ECT after medication treatment failures

OBJECTIVE

To examine the clinical effects of electroconvulsive therapy (ECT) on depressed patients with medication treatment failures, we investigated the alterations in hypothalamic-pituitary-adrenocortical (HPA) function and regional cerebral metabolism rate of glucose (rCMRGlu) after ECT in these patients.

METHOD

Before and after ECT, the combined dexamethasone/corticotrophin-releasing hormone (DEX/CRH) test was administered to seven patients who were referred for ECT. In the same patients, (18)F-fluorodeoxyglucose positron emission tomography ((18)F-FDG PET) was also assessed.

RESULTS

Cortisol response in the DEX/CRH test significantly decreased after a successful ECT. A significant hypometabolism in various frontal regions and hypermetabolism in the parietal regions of these patients when compared with controls remained after ECT.

CONCLUSION

Depressed patients who failed trials of antidepressant medication showed a remission with ECT that was accompanied by resolution of HPA dysregulation. However, measures of cerebral brain metabolism did not resolve.

Evaluation of cingulate gyrus blood flow in patients with liver cirrhosis

Although neuropsychological tests are commonly applied to detect minimal hepatic encephalopathy (HE) in patients with liver cirrhosis (LC), they provide no information about the cerebral regions involved. Recently, it has been reported that some populations of alcoholic cirrhotics, with mild HE, have reduced cerebral metabolic rate for glucose in bifrontal cortices and in the anterior cingulate gyrus. We evaluated the degree of reduction in blood flow at the anterior cingulate gyrus and the frontal lobes in cirrhotic patients who underwent single photon emission computed tomography (SPECT). Data were obtained from 47 cirrhotic patients and 47 subjects without LC. Three radiologists unaware of the results of laboratory tests visually evaluated the transaxial, coronal, and sagittal views of SPECT. The area and the degree of blood flow reduction in the anterior cingulate gyrus and frontal lobes were scored. Reduced blood flow in the anterior cingulate gyrus was observed in most LC patients. In patients without overt HE, poor performance in neuropsychological tests was correlated with reduced cerebral blood flow in the anterior cingulate gyrus. Blood flow in the anterior cingulate gyrus as measured by SPECT may be a simple and good indicator of cerebral functional changes in patients with LC.

Pretreatment neurophysiologic function and ECT response in depression

OBJECTIVES

Recent brain imaging studies have provided evidence that brain function assessed prior to treatment of depression may be associated with eventual treatment response. The present study tested the hypothesis that brain activity in midline apical quantitative EEG (QEEG) electrodes would be associated with therapeutic response to electroconvulsive therapy (ECT).

METHODS

Ten treatment-refractory patients with unipolar or bipolar depression received a Hamilton Rating Scale for Depression (Ham-D) at baseline, during, and following ECT treatment. Resting, eyes-closed, 35-lead QEEG recordings were done 1 day before the initial ECT treatment. Data were analyzed using QEEG power and cordance.

RESULTS

The mean of the theta-band pretreatment cordance from the central brain region was strongly associated with percentage decrease in Ham-D score over the course of treatment (r = 0.80, P = 0.005). QEEG cordance from other brain regions and power from all brain regions did not show an association with clinical improvement.

CONCLUSIONS

Depressed subjects with higher pretreatment central cordance appear to be more likely to experience therapeutic benefits of ECT. The location of central electrodes over the cingulate cortex may indicate that pretreatment cingulate activity is associated with response to ECT.

No evidence for oxidative damage in the hippocampus after acute and chronic electroshock in rats

Although several advances has occurred over the past 20 years concerning the use of electroconvulsive therapy (ECT), little progress has been made in the mechanisms underlying its therapeutic or adverse effects. Thus, this work was performed in order to determine the level of oxidative damage and antioxidant enzyme activities early and late after acute and chronic electroconvulsive shock (ECS). We demonstrated a decrease in lipid peroxidation in the hippocampus immediately after and up to 30 days after a single or multiple electroconvulsive shock. This was also true for protein carbonyls in the acute protocol. We demonstrated an increase in catalase (CAT) and superoxide dismutase (SOD) activities at different time points after single and multiple electroconvulsive shock. Our findings, for the first time, demonstrated that after electroconvulsive shock, there is an increase in antioxidant enzyme activities and we cannot demonstrate oxidative damage in the hippocampus.

No brain perfusion impairment at long-term follow-up in elderly patients treated with electroconvulsive therapy for major depression

No functional neuroimaging study has previously assessed the long-term effects of electroconvulsive therapy (ECT) on brain perfusion. In this study, long-term follow-up brain perfusion in elderly patients treated with ECT for severe unipolar major depression was assessed. In 14 elderly major depressed patients who were ECT remitters, 22 elderly major depressed patients who were pharmacological treatment remitters and 25 age- and sex-matched healthy controls, a medication-free brain 9mTc-HMPAO-SPECT was performed after a minimum period of 12 months of euthymia and, in the case of the ECT remitters, at least 12 months after the last ECT session. Brain perfusion ratios in major depressed patients administered ECT were similar to those in major depressed patients receiving pharmacological treatment and in control subjects. This result suggests that elderly patients given ECT for severe unipolar major depression do not suffer brain perfusion abnormalities at long-term follow-up. Our study adds new evidence in favor of the safety of the ECT, particularly in elderly subjects.

Safety and feasibility of magnetic seizure therapy (MST) in major depression: randomized within-subject comparison with electroconvulsive therapy

Magnetic seizure therapy (MST) is a novel means of performing convulsive therapy using rapidly alternating strong magnetic fields. MST offers greater control of intracerebral current intensity than is possible with electroconvulsive therapy (ECT). These features may result in a superior cognitive side effect profile for MST, while possibly retaining the efficacy of ECT. The objective of this study was to determine whether MST and ECT differ in seizure characteristics, and acute objective and subjective cognitive side effects. A total of 10 inpatients in a major depressive episode referred for ECT were enrolled in this randomized, within-subject, double-masked trial. Seizure threshold was determined with MST and ECT in the first two sessions of a course of convulsive therapy, with order randomized. The remaining two sessions consisted of suprathreshold stimulation with MST and ECT. A neuropsychological battery and side effect rating scale were administered by a masked rater before and after each session. Tonic-clonic seizures were elicited with MST in all patients. Compared to ECT, MST seizures had shorter duration, lower ictal EEG amplitude, and less postictal suppression. Patients had fewer subjective side effects and recovered orientation more quickly with MST than ECT. MST was also superior to ECT on measures of attention, retrograde amnesia, and category fluency. Magnetic seizure induction in patients with depression is feasible, and appears to have a superior acute side effect profile than ECT. Future research will be needed to establish whether MST has antidepressant efficacy.

New developments in electroconvulsive therapy and magnetic seizure therapy

New findings regarding the mechanisms of action of electro-convulsive therapy (ECT) have led to novel developments in treatment technique to further improve this highly effective treatment for major depression. These new approaches include novel placements, optimization of electrical stimulus parameters, and new methods for inducing more targeted seizures(eg, magnetic seizure therapy [MST]). MST is the use of transcranial magnetic stimulation to induce a seizure. Magnetic fields pass through tissue unimpeded, providing more control over the site and extent of stimulation than can be achieved with ECT. This enhanced control represents a means of focusing the treatment on target cortical structures thought to be essential to antidepressant response and reducing spread to medial temporal regions implicated in the cognitive side effects of ECT. MST is at an early stage of development. Preliminary results suggest that MST may have some advantages over ECT in terms of subjective side effects and acute cognitive functioning. Studies designed to address the antidepressant efficacy of MST are underway. As with all attempts to improve convulsive therapy technique, the clinical value of MST will need to be established through controlled clinical trials. This article reviews the experience to date with MST, and places this work in the broader context of other means of optimizing convulsive therapy in the treatment of depression.

Update on magnetic seizure therapy: a novel form of convulsive therapy

Magnetic seizure therapy (MST) refers to the use of transcranial magnetic stimulation to induce a seizure for therapeutic purposes. MST is under investigation as a means of improving the safety profile of electroconvulsive therapy (ECT). Although both MST and ECT induce seizures through electrical stimulation of the brain, the electric field induced by MST is more focal and limited than that induced by ECT. Because magnetic fields pass through tissue unimpeded, there is greater control over the site and extent of stimulation with MST than can be achieved with ECT. This enhanced control represents a means of focusing the treatment on target cortical structures thought to be essential to antidepressant response and of reducing spread to medial temporal regions implicated in the cognitive side effects of ECT. MST is currently at an early stage of development. This article reviews the experience with MST in animal models and initial human investigations. Preliminary results have demonstrated the feasibility of performing MST in the clinical setting, and there are suggestions that MST may have advantages over ECT in terms of subjective side effects and some measures of acute cognitive functioning. The antidepressant efficacy of MST is not yet known, but studies designed to address that critical issue are underway. As with all attempts to refine convulsive therapy techniques (such as modifications in stimulation parameter configurations and electrode placement), the ultimate clinical value of MST will need to be established through controlled clinical trials.