Brain Networks After ECT: New Small Study From China
Out on PubMed, from investigators in China, is this study:
Changes in brain network properties in major depressive disorder following electroconvulsive therapy: a combined static and dynamic functional magnetic resonance imaging study.
Ann Palliat Med. 2022 Jan 14:apm-21-2723. doi: 10.21037/apm-21-2723. Online ahead of print.PMID: 35073711
The abstract is copied below:
Background: Major depressive disorder (MDD) is a common and intractable mood disorder. Electroconvulsive therapy (ECT) is a common means of brain electrical stimulation for the treatment of MDD, but the neurobiological mechanism of its clinical symptom relief effect is still to be explored. This study aims to explore how ECT plays a role in depression remissions by investigating the changes of static and dynamic brain network characteristics in MDD patients before and after ECT.
Methods: Resting-state functional magnetic resonance imaging (fMRI) scans were obtained from nine MDD patients twice before and after a full course of ECT, all of whom responded to ECT as defined by at least a 50% reduction from baseline Hamilton Depression Scale (HAMD) scores. Both static and dynamic characteristics of the functional brain network were compared between the pre- and post-ECT scans for all participants, and the correlations between changes in clinical symptoms and altered network metrics were also investigated.
Results: The clustering coefficient and local efficiency in static brain networks were increased significantly, while the global flexibility of dynamic brain networks was decreased significantly after ECT. Several regions of interest (ROIs) that changed significantly at the local level were also identified, which involved regions of the cerebellum, hippocampus as well as frontal and temporal cortices. Although not significant, the decrease of HAMD scores were associated with trends of changed network metrics after ECT.
Conclusions: Our results suggest that ECT may alleviate the depressive symptoms of MDD by decreasing the randomness of the brain network as reflected by changes in both static and dynamic network properties and that the temporal gyrus, frontal gyrus, hippocampus, and cerebellar regions may play key roles in such mechanisms. These findings have important implications for our understandings of ECT and depression. However, this study is limited by a relatively small sample size and the results should be confirmed in larger samples.
Keywords: Electroconvulsive therapy (ECT); brain network; depression; dynamic brain network; graph theory.
And from the text:
Electroconvulsive therapy (ECT) provides effective and tolerable treatment to relieve depressive symptoms in patients with MDD (7-9), especially for patients who failed to respond to conventional pharmacotherapies (10,11). Because of such advantages, the use of ECT in psychiatric hospitals has largely increased over the past few years in China, the United States and the rest of the world (12). However, the ECT is not effective for all patients (13), and the underlying mechanisms are still poorly understood. To uncover the physiological markers of ECT response and advance the future treatment optimization, there is an urgent need to know how ECT plays a role in the treatment of MDD.
Conclusions
Briefly, this study explores the neurobiological mechanism by which ECT may play its role in relieving depressive symptoms in MDD by investigating the changes in both static and dynamic brain network properties after ECT. We found that the clustering coefficient and local efficiency in static brain networks were increased, while the flexibility of the dynamic brain network was decreased after ECT. Several ROIs that changed significantly at the local level were also identified, which involved regions of the cerebellum, hippocampus as well as frontal and temporal cortices. Moreover, although not significant, the decrease of HAMD scores were associated with trends of changes in all network metrics after ECT. Our results suggest that ECT may alleviate the depressive symptoms of MDD by decreasing the randomness of brain network as reflected by changes in both static and dynamic network metrics, which might extend our knowledge of mechanisms underlying ECT for the clinical treatments of MDD. However, this study is limited by a relatively small sample size and the results should be confirmed in larger samples.
So here is another very small (n=9) neuroimaging study from China. The conclusion is that ECT normalizes both static and dynamic brain networks, whatever that means. The images in the figures are lovely. Is one to believe that this stuff is cutting edge, gobbledygook, or something in between? Perhaps one interesting thing is that the cerebellum is involved, it's not just for movement/balance anymore. Will a zillion small, unreplicated neuroimaging studies lead to the full understanding of the mechanism of action of ECT? I am not holding my breath.
Connectivity mavens will want to read this in full (~15 minutes), others can look at the pictures and turn the pages...
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