A preliminary study of the effects of electroconvulsive therapy on regional brain glucose metabolism in patients with major depression

Correlation Between ECT Quality Measures and Likelihood to Transition From Acute to Continuation and Maintenance ECT

OBJECTIVES

To evaluate the association between 3 ECT quality measures (seizure duration, Postictal Suppression Index [PSI], and heart rate response) and therapeutic compliance as indicated by transitioning from acute to continuation to maintenance phases of ECT.

METHODS

This was a retrospective chart review of patients who received ECT between July 2016 and July 2019. ECT quality measures were lagged by 1 ECT session to examine the effect of the prior session's quality measure on progressing to a higher ECT phase at the subsequent ECT session. Associations with therapeutic compliance were analyzed using mixed-effects ordinal regression and mixed-effects partial proportional odds models.

RESULTS

Seizure duration was associated with 8% higher adjusted odds of progressing to out of the acute phase (95% confidence interval [CI]: 2% to 15%, P = 0.007) and 18% higher adjusted odds of progressing to the maintenance phase (95% CI: 10% to 28%, P < 0.001); PSI was associated with 9% higher adjusted odds of progressing out of the acute phase (95% CI: 3% to 16%, P = 0.005), whereas heart rate response was not statistically associated with therapeutic compliance. Greater therapeutic compliance was also associated with bilateral electrode placement and older age.

CONCLUSIONS

Longer seizure duration was associated with greater therapeutic compliance across all ECT phases, PSI was associated with progressing out of the acute phase, and heart rate response was not associated with therapeutic compliance. Our findings assist ECT psychiatrists in optimizing ECT quality measures to promote better compliance with ECT.

Bifrontal electroconvulsive therapy changed regional homogeneity and functional connectivity of left angular gyrus in major depressive disorder

Electroconvulsive therapy (ECT) is a rapid and effective treatment for MDD. However, the mechanism of ECT for MDD has not been clarified. In this study, we used resting-state functional magnetic resonance imaging (rs-fMRI) to explore the mechanism of ECT. Two groups of subjects were recruited: healthy controls (HCs) and MDD patients who received bifrontal ECT. MDD patients and HCs underwent rs-fMRI scans and clinical assessments (Hamilton Depression Rating Scale, Rey-Auditory Verbal Learning Test (RAVLT), and the verbal fluency test). Regional homogeneity (ReHo) and functional connectivity were evaluated for the analysis of rs-fMRI data. The results showed that ReHo values in the left angular gyrus (LAG) significantly increased in MDD patients after ECT, and the functional connectivity of the LAG with bilateral inferior temporal gyrus, bilateral middle frontal gyrus, left superior frontal gyrus, left middle temporal gyrus, left precuneus, left posterior cingulate gyrus, and right angular gyrus was found to be strengthened after ECT. The scores of delayed recall trial in the RAVLT of MDD patients were related to the functional connectivity of the LAG with the left inferior temporal gyrus and the left posterior cingulate gyrus. It indicated LAG palyed an important role in the mechanism of ECT in MDD.

A longitudinal study on deep brain stimulation of the medial forebrain bundle for treatment-resistant depression

Deep brain stimulation (DBS) to the superolateral branch of the medial forebrain bundle (MFB) has been reported to lead to rapid antidepressant effects. In this longitudinal study, we expand upon the initial results we reported at 26 weeks (Fenoy et al., 2016), showing sustained antidepressant effects of MFB DBS on six patients with treatment-resistant depression (TRD) over 1 year. The Montgomery-Åsberg Depression Rating Scale (MADRS) was used as the primary assessment tool. Deterministic fiber tracking was used to individually map the target area; analysis was performed to compare modulated fiber tracts between patients. Intraoperatively, upon stimulation at target, responders reported immediate increases in energy and motivation. An insertional effect was seen during the 4-week sham stimulation phase from baseline (28% mean MADRS reduction, p = 0.02). However, after 1 week of initiating stimulation, three of six patients had a > 50% decrease in MADRS scores relative to baseline (43% mean MADRS reduction, p = 0.005). One patient withdrew from study participation. At 52 weeks, four of remaining five patients have > 70% decrease in MADRS scores relative to baseline (73% mean MADRS reduction, p = 0.007). Evaluation of modulated fiber tracts reveals significant common orbitofrontal connectivity to the target region in all responders. Neuropsychological testing and ¹⁸F-fluoro-deoxyglucose-positron emission tomography cerebral metabolism evaluations performed at baseline and at 52 weeks showed minimal changes and verified safety. This longitudinal evaluation of MFB DBS demonstrated rapid antidepressant effects, as initially reported by Schlaepfer et al. (2013), and supports the use of DBS for TRD.

How Electroconvulsive Therapy Works?: Understanding the Neurobiological Mechanisms

Electroconvulsive therapy (ECT) is a time tested treatment modality for the management of various psychiatric disorders. There have been a lot of modifications in the techniques of delivering ECT over decades. Despite lots of criticisms encountered, ECT has still been used commonly in clinical practice due to its safety and efficacy. Research evidences found multiple neuro-biological mechanisms for the therapeutic effect of ECT. ECT brings about various neuro-physiological as well as neuro-chemical changes in the macro- and micro-environment of the brain. Diverse changes involving expression of genes, functional connectivity, neurochemicals, permeability of blood-brain-barrier, alteration in immune system has been suggested to be responsible for the therapeutic effects of ECT. This article reviews different neurobiological mechanisms responsible for the therapeutic efficacy of ECT.

Reversal of cerebral glucose hypometabolism on positron emission tomography with electroconvulsive therapy in an elderly patient with a psychotic episode

AB, a 74-year-old Caucasian woman, was admitted for acute onset of psychosis, anxiety, and cognitive impairment. Pharmacotherapy was unsuccessful and the patient was referred for electroconvulsive therapy (ECT). Pre-ECT, ¹⁸ F-fluorodeoxyglucose-positron emission tomography (PET)/computed tomography showed extensive frontal, parietal, and temporal cortical hypometabolism suggestive of a neurodegenerative disease. After eight ECT sessions, the psychotic and anxiety symptoms as well as the cognitive impairment resolved. The rapid improvement in symptoms was more suggestive of a psychotic episode rather than dementia. Two days after the ECT course, ¹⁸ F-fluorodeoxyglucose-PET/computed tomography showed improvements in cerebral cortical hypometabolism, especially in the left parietal cortex, left temporal/occipital cortex. and bifrontal regions. At a follow-up visit 2 months after the ECT course, the psychotic episode was still in remission, and ¹⁸ F-fluorodeoxyglucose-PET/computed tomography continued to show improved cerebral cortical hypometabolism in these areas. This case illustrated the effect of ECT in reversing cerebral glucose hypometabolism on PET. The improvement in cerebral glucose hypometabolism may represent the neurophysiological mechanism of ECT in the treatment of a psychotic episode. Improved cerebral glucose hypometabolism was present 2 months post-ECT, which suggests that ECT caused sustained functional neural changes.

Subgenual cingulate cortical activity predicts the efficacy of electroconvulsive therapy

Electroconvulsive therapy (ECT) is the most effective treatment for depression, yet its mechanism of action is unknown. Our goal was to investigate the neurobiological underpinnings of ECT response using longitudinally collected resting-state functional magnetic resonance imaging (rs-fMRI) in 16 patients with treatment-resistant depression and 10 healthy controls. Patients received bifrontal ECT 3 times a week under general anesthesia. We acquired rs-fMRI at three time points: at baseline, after the 1st ECT administration and after the course of the ECT treatment; depression was assessed with the Hamilton Depression Rating Scale (HAM-D). The primary measure derived from rs-fMRI was fractional amplitude of low frequency fluctuation (fALFF), which provides an unbiased voxel-wise estimation of brain activity. We also conducted seed-based functional connectivity analysis based on our primary findings. We compared treatment-related changes in HAM-D scores with pre- and post-treatment fALFF and connectivity measures. Subcallosal cingulate cortex (SCC) demonstrated higher BOLD signal fluctuations (fALFF) at baseline in depressed patients, and SCC fALFF decreased over the course of treatment. The baseline level of fALFF of SCC predicted response to ECT. In addition, connectivity of SCC with bilateral hippocampus, bilateral temporal pole, and ventromedial prefrontal cortex was significantly reduced over the course of treatment. These results suggest that the antidepressant effect of ECT may be mediated by downregulation of SCC activity and connectivity. SCC function may serve as an important biomarker of target engagement in the development of novel therapies for depression that is resistant to treatment with standard medications.

Effect of electroconvulsive therapy on gray matter volume in major depressive disorder

BACKGROUND

Although the clinical efficacy of electroconvulsive therapy (ECT) is well established, the underlying mechanisms of action remain elusive. The aim of this study was to elucidate structural changes of the brain following ECT in patients with major depressive disorder (MDD).

METHOD

Fifteen patients with MDD underwent magnetic resonance imaging scanning before and after ECT. Their gray matter volumes were compared between pre- and post-ECT.

RESULTS

There were significant volume increases after ECT in the bilateral medial temporal cortices, inferior temporal cortices, and right anterior cingulate. Further, the increase ratio was correlated with the clinical improvement measured by the Hamilton Depression Rating scale.

LIMITATION

All subjects were treated with antidepressants that could have a neurotoxic or neuroprotective effect on the brain.

CONCLUSIONS

We found that there were significant increases of gray matter volume in medial temporal lobes following ECT, suggesting that a neurotrophic effect of ECT could play a role in its therapeutic effect.

Electroconvulsive therapy treatment in patients with somatic symptom and related disorders

OBJECTIVE

Medically unexplained somatic complaints are highly prevalent, and lead to significant impairment and disability. The number of effective treatment modalities for somatic symptom and related disorders (SSDs) or somatoform disorders (SDs) remains limited. To date, there is no formal indication for electroconvulsive therapy (ECT) in SSD or SD. We report on the largest case series to date regarding the effectiveness of ECT in patients with SSD and SD.

METHODS

A retrospective chart review of all patients treated with an index course of ECT at the Neuropsychiatric Program at the University of British Columbia Hospital from 2000 to 2010 was conducted. The primary outcomes consisted of changes in pseudoneurologic symptoms, pain symptoms, cardiopulmonary symptoms, and gastrointestinal symptoms. Complaints were examined pre- and post-ECT.

RESULTS

Twenty-eight participants were included in this study. Twenty-one participants received right unilateral ECT. Six received bifrontal ECT. One received bitemporal ECT. Eighteen of 21 participants reported improvement in pseudoneurologic symptoms; eleven of 14 participants reported improvement in pain symptoms; one participant reported improvement in cardiopulmonary symptoms; and one of two participants reported improvement in gastrointestinal symptoms. This paper discusses the putative mechanism of action of ECT in the treatment of SD/SSD.

CONCLUSION

This retrospective study suggests that ECT could be included as part of the existing treatment for refractory SSD and SD, particularly in refractory cases with comorbid mood disorders.

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.

Clinical effects of electroconvulsive therapy in severe depression and concomitant changes in cerebral glucose metabolism--an exploratory study

OBJECTIVE

Electroconvulsive therapy (ECT) is an effective mode of treatment--especially for severe depression and for depression refractory to pharmacotherapy, nevertheless the mode of action of ECT is far from being fully understood. This study assessed the effects of a series of ECT in depressive subjects on cerebral glucose metabolism measured by FDG-PET scans pre- and post-therapy in thus far the largest group of 12 patients.

METHODS

Our analysis included careful repeated evaluation of clinical changes in mood and behaviour by standardised questionnaires, which allowed testing for a potential correlation between clinical and cerebral metabolic changes. PET scanning was done within a predefined time window and we used predefined ROIs with counts normalized to the pons activity.

RESULTS

We observed few changes in cerebral glucose metabolism over time. There was a marginal increase in the left temporal and a trend for a decrease in left frontobasal areas subsequent to treatment in our sample. FDG uptake patterns remained remarkably stable in all the other predefined ROIs pre- and post-treatment. There were no significant correlations between changes in relative metabolic rates and changes in depression scores and parameters derived from neurocognitive testing.

CONCLUSIONS

Our study thus cannot support the view that FDG-PET can assess the functional brain changes that are likely to occur subsequent to ECT in such a scenario, but this may be related to limited sensitivity given the sample size. Future studies thus might wish to challenge this notion in larger patient samples to clarify this issue.

Global decrease of serotonin-1A receptor binding after electroconvulsive therapy in major depression measured by PET

Electroconvulsive therapy (ECT) is a potent therapy in severe treatment-refractory depression. Although commonly applied in psychiatric clinical routine since decades, the exact neurobiological mechanism regarding its efficacy remains unclear. Results from preclinical and clinical studies emphasize a crucial involvement of the serotonin-1A receptor (5-HT(1A)) in the mode of action of antidepressant treatment. This includes associations between treatment response and changes in 5-HT(1A) function and density by antidepressants. Further, alterations of the 5-HT(1A) receptor are consistently reported in depression. To elucidate the effect of ECT on 5-HT(1A) receptor binding, 12 subjects with severe treatment-resistant major depression underwent three positron emission tomography (PET) measurements using the highly selective radioligand [carbonyl-(11)C]WAY100635, twice before (test-retest variability) and once after 10.08±2.35 ECT sessions. Ten patients (~83%) were responders to ECT. The voxel-wise comparison of the 5-HT(1A) receptor binding (BP(ND)) before and after ECT revealed a widespread reduction in cortical and subcortical regions (P<0.05 corrected), except for the occipital cortex and the cerebellum. Strongest reductions were found in regions consistently reported to be altered in major depression and involved in emotion regulation, such as the subgenual part of the anterior cingulate cortex (-27.5%), the orbitofrontal cortex (-30.1%), the amygdala (-31.8%), the hippocampus (-30.6%) and the insula (-28.9%). No significant change was found in the raphe nuclei. There was no significant difference in receptor binding in any region comparing the first two PET scans conducted before ECT. This PET study proposes a global involvement of the postsynaptic 5-HT(1A) receptor binding in the effect of ECT.

Quantification of Tc-99m-ethyl cysteinate dimer brain single photon emission computed tomography images using statistical probabilistic brain atlas in depressive end-stage renal disease patients: Correlation with disease severity and symptom factors

This study adapted a statistical probabilistic anatomical map of the brain for single photon emission computed tomography images of depressive end-stage renal disease patients. This research aimed to investigate the relationship between symptom clusters, disease severity, and cerebral blood flow. Twenty-seven patients (16 males, 11 females) with stages 4 and 5 end-stage renal disease were enrolled, along with 25 healthy controls. All patients underwent depressive mood assessment and brain single photon emission computed tomography. The statistical probabilistic anatomical map images were used to calculate the brain single photon emission computed tomography counts. Asymmetric index was acquired and Pearson correlation analysis was performed to analyze the correlation between symptom factors, severity, and regional cerebral blood flow. The depression factors of the Hamilton Depression Rating Scale showed a negative correlation with cerebral blood flow in the left amygdale. The insomnia factor showed negative correlations with cerebral blood flow in the left amygdala, right superior frontal gyrus, right middle frontal gyrus, and left middle frontal gyrus. The anxiety factor showed a positive correlation with cerebral glucose metabolism in the cerebellar vermis and a negative correlation with cerebral glucose metabolism in the left globus pallidus, right inferior frontal gyrus, both temporal poles, and left parahippocampus. The overall depression severity (total scores of Hamilton Depression Rating Scale) was negatively correlated with the statistical probabilistic anatomical map results in the left amygdala and right inferior frontal gyrus. In conclusion, our results demonstrated that the disease severity and extent of cerebral blood flow quantified by a probabilistic brain atlas was related to various brain areas in terms of the overall severity and symptom factors in end-stage renal disease patients.

Corticolimbic balance shift of regional glucose metabolism in depressed patients treated with ECT

BACKGROUND

Although the clinical efficacy of electroconvulsive therapy (ECT) has been well established in patients with pharmacotherapy-resistant depression, the physiological mechanism and changes in regional cerebral function after ECT are unclear.

METHODS

We recruited 16 depressed patients who underwent ECT, and 11 healthy controls. The change in cerebral glucose metabolism was evaluated before and after a series of ECT using [18F]-fluorodeoxyglucose positron emission tomography (FDG-PET).

RESULTS

Before ECT, the patient group showed significant hypometabolism in the superior frontal gyrus, and hypermetabolism in the inferior temporal gyri compared with healthy controls, and these abnormalities remained after ECT. Comparisons between pre- and post-ECT metabolic activity revealed decreased regional metabolism in the frontotemporal neocortical areas after ECT, while increased metabolism was found in the right medial temporal structures including amygdala and pons. In addition, a decrease in glucose metabolism in the fronto-temporo-parietal regions correlated with an increase in glucose metabolism in the right medial temporal regions across subjects.

LIMITATIONS

There was considerable variability in the interval between the last ECT and FDG-PET scan. Depressed subjects were maintained on medication. The subjects included both major depressive disorder and bipolar disorder patients, as well as both ECT responders and non-responders.

CONCLUSION

Depression refractory to pharmacotherapy might have functional deficits in specific circumscribed frontal and temporal structures. ECT resolves the clinical symptoms without largely affecting these brain metabolic abnormalities. In contrast, ECT shifts the balance of corticolimbic function, which might explain how ECT ameliorates symptoms of depression in patients.

Electroconvulsive therapy and its different indications

In spite of recent developments in the pharmacotherapy of depressive disorders, the delay until clinical improvement can be achieved, and the considerable rate of nonresponse and nonremission, are major problems which remain unresolved. Electroconvulsive therapy (ECT) is a nonpharmacologic biological treatment which has been proven to be a highly effective treatment option, predominantly for depression, but also for schizophrenia and other indications. Though there is a lack of controlled investigations on long-term treatments, ECT can also be used for relapse prevention during maintenance therapies. The safety and tolerability of electroconvulsive treatment have been enhanced by the use of modified stimulation techniques and by progress in modern anesthesia. Thus, today a safe treatment can also be offered to patients with higher somatic risks. ECT still represents an important option, especially in the therapy of treatment-resistant psychiatric disorders after medication treatment failures. Earlier consideration of ECT may reduce the rate of chronic and difficult-to-treat psychiatric disorders.

Changes in brain metabolism after ECT-positron emission tomography in the assessment of changes in glucose metabolism subsequent to electroconvulsive therapy--lessons, limitations and future applications

BACKGROUND

Electroconvulsive therapy (ECT) has been used as an effective treatment option in severe and treatment resistant cases of depression for decades. However the mode of action of ECT is still not fully understood. Advances in neuroimaging created new possibilities to understand the functional changes of the human brain.

METHODS

Literature review of studies assessing possible changes in cerebral glucose metabolism pre- and post-ECT by PET, identified by PubMed.

RESULTS

Studies were limited by small sample size, inhomogeneous study population with uni- and bipolar depressive patients and methodological inconsistencies. Despite considerable variance, reduction in glucose metabolism after ECT in bilateral anterior and posterior frontal areas represented the most consistent findings.

CONCLUSIONS

Future research into this issue should include larger and more consistent cohorts of patients. Assessing clinical improvement of depression after ECT should allow to correlate changes in brain glucose metabolism with functional scores. Follow up PET scans after six or twelve months should be performed to test if changes in brain metabolism are persistent.

Transcranial and deep brain stimulation approaches as treatment for depression

Given that a considerable portion of depressed patients does not respond to or remit during pharmacotherapy, there is increasing interest in non-pharmacological strategies to treat depressive disorders. Several brain stimulation approaches are currently being investigated as novel therapeutic interventions beside electroconvulsive therapy (ECT), a prototypic method in this field with proven effectiveness. These neurostimulation methods include repetitive transcranial magnetic stimulation (rTMS), magnetic seizure therapy (MST), vagus nerve stimulation (VNS), deep brain stimulation (DBS) and transcranial direct current stimulation (tDCS). It is via different neuroanatomically defined "windows" that the various approaches access the neuronal networks showing an altered function in depression. Also, the methods vary regarding their degree of invasiveness. One or the other method may finally achieve antidepressant effectiveness with minimized side effects and constitute a new effective treatment for major depression.

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.

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.

Enhanced attention-dependent auditory processing by electroconvulsive therapy in psychotic depression

There is a lack of knowledge about the effect of electroconvulsive therapy (ECT) on auditory event-related potentials (ERPs) in severe psychotic depression. The aim of this study was to investigate both the effect of ECT on attention-dependent ERP (P300) and the correlation of P300 values with depression level. We recorded the auditory ERPs of 23 patients expressing psychotic symptoms and fulfilling the DSM-III-R criteria for treatment-resistant severe major depressive episode before and a week after successful bitemporal ECT. The clinical status was assessed with Hamilton (Ham-D) and Montgomery and Asberg (MADRS) depression scales. ECT was clinically very effective with these scales. On the level of auditory processing, ECT increased P300 amplitude with no significant effect on latency. Small amplitudes over the left hemisphere before treatment were associated with bigger Ham-D-score decrement. ECT produces a significant increase in brain activity at the level of attention-dependent auditory processing in severe depression. The change in electrical responses seems to represent a largely independent variable from the clinical assessment scales, even if the recovery rate was remarkable, because the change in overall symptom scores did not correlate with the P300 changes.

Changes in brain metabolism associated with remission in unipolar major depression

OBJECTIVE

Functional brain correlates of remission in patients with major depressive disorder (MDD) are measured with positron emission tomography (PET) and 18F-fluorodeoxyglucose.

METHOD

Glucose metabolism was measured in patients (n = 41) with moderate to severe MDD during acute depression and in the remitted state defined as a period of asymptomatic condition over 12 weeks. Data analyses used a region-of-interest (ROI) approach and statistical parametric mapping (SPM).

RESULTS

There were significant decreases in metabolism upon remission with respect to the baseline scan in left prefrontal, anterior temporal and anterior cingulate cortex and bilateral thalamus (SPM analysis) and bilateral putamen and cerebellum (SPM and ROI analyses). There was a significant asymmetry in prefrontal and anterior cingulate cortex metabolism with lower metabolism in the left hemisphere that persisted despite clinical remission.

CONCLUSION

These findings support the hypothesis that selective monoamine reuptake inhibition leads to an attenuation of a brain circuit that mediates depressive symptomatology.

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.

ECT of major depressed patients in relation to biological and clinical variables: a brief overview

The knowledge that spontaneous or induced convulsions can improve mental disorders has been present for several centuries. electroconvulsive therapy (ECT) has undergone fundamental changes since its introduction, and in the last 15-20 years there has been a legitimate renewal of interest for this therapy. Today the indications for use of ECT seem well codified, and its technique and practices have evolved considerably. It is now firmly established as an important and effective method of treating certain severe forms of depression. However, still very little is known about the mechanism of ECT. In this paper, first, we will give a short overview as to how far we have got concerning ECT in relation to various clinical and biological variables. Second, we will describe ECT in relation to electroencephalographic (EEG) technique and clinical outcome as well as give some proposals as to how to go on with the data analysis of EEG. In conclusion, the superior effect of ECT compared to other antidepressives in severe depression may depend on neurochemical and neurobiological cascade effects initiated by repeated treatments. Above all, ECT offers a unique experimental opportunity to study how neuromodulation of the major transmitter systems may be involved in brain dynamics and alteration of connectivity.

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

The impact of electroconvulsive therapy (ECT) on the regional cerebral blood flow (rCBF) abnormalities in late-life depression is still unknown and the clinical significance of these findings in late-life depression has not been fully discussed. Using single photon emission computed tomography (SPECT) with 99mTc-hexamethylpropylene amine oxime (99mTc-HMPAO), we examined the changes of rCBF patterns in nine late-life patients with major depressive episodes before and following response to ECT compared with nine age- and sex-matched healthy volunteers. Statistical comparisons were made on both region-of-interest (ROI) and voxel-by-voxel bases. In ROI-based analyses, a mean rCBF was significantly decreased in the patients before ECT compared with the control, significantly increased (normalized) in the patients 2 weeks after ECT compared with that before ECT, and still increased in the patients 12 weeks after ECT compared with that before ECT. In voxel-by-voxel analyses, a significant rCBF reduction was found in the bilateral pre- and subcallosal anterior cingulate cortex, the bilateral caudal orbitofrontal cortex, the right insular cortex and the right posterior middle frontal gyrus in patients before ECT compared with the control, and similar rCBF patterns were shown at 2 weeks and 12 weeks after ECT. We propose the hypothesis that a mean rCBF reduction may have a state-related property while persistent anterior paralimbic hypoperfusion may have a trait-like property, which relates to the relapse vulnerability as well as a tendency toward medication failure and illness chronicity in late-life depression.