ساختار مغز سالمندان افسرده و پاسخ به الکتروشوک درمانی

Electroconvulsive therapy (ECT) is the treatment of choice in severe geriatric depression. High remission rates may be influenced by specific brain morphology characteristic of geriatric depression. Our objective was to identify the relationship between brain structure, symptom profile, and ECT response. In a naturalistic cohort of 55 patients with a major depressive disorder, structural magnetic resonance imaging (MRI) was performed before ECT. Voxel-based morphometry was applied to determine regional differences in gray matter (GM) volume between patients and 23 matched healthy controls. Depressed patients with psychotic symptoms showed significantly higher remission rates and smaller regional GM volume of the left inferior frontal gyrus (IFG). Patients with late onset depression showed smaller regional GM volume of the bilateral lateral temporal cortex. Larger size of response in the whole patient group was related to smaller pretreatment regional GM volume of the right lateral temporal cortex, whereas faster speed of response was related to smaller pretreatment regional GM volume of the right IFG. ECT is most effective in depressed patients with psychotic symptoms. In this study the presence of psychotic symptoms was related to pretreatment smaller GM volume of the left IFG and bilateral temporal cortex. Smaller volume of the IFG pretreatment was related to faster treatment response, and smaller volume of the right lateral temporal cortex pretreatment was related to larger response to ECT. These results are possibly explained by the connectivity between these brain regions and an interconnected network that is particularly activated by the ECT-induced seizures.

Electroconvulsive therapy (ECT) is a safe and effective treatment in severe geriatric depression (Stek et al., 2007) with remission rates ranging from 50% to 70% (Tew et al., 1999 and Oudega et al., 2011). Accumulating evidence suggests that differences in symptom profiles of geriatric depressed patients contribute to ECT response, i.e., geriatric depressed patients with psychotic symptoms (PS) have higher response rates to ECT than do geriatric depressed patients without PS (Parker et al., 1992 and Birkenhäger et al., 2003). It is unclear, however, whether differences in symptom profiles and ECT response relate to specific neurobiological characteristics, such as differences in brain structure. The combined study of symptom profile, brain structure, and ECT response may add to our understanding of this differential ECT response and its underlying mechanisms of effect. The mechanism of action in ECT is yet to be discovered. A previous study of our group showed an association between medial temporal lobe atrophy (MTA) and poor ECT response (Oudega et al., 2011), suggesting that the medial temporal lobe is involved in the ECT mechanism. Furthermore, single photon emission computed tomography (SPECT) studies evaluated the network that is activated during ECT, showing specific strong activation of the frontal, parietal and temporal cortices after initiation of ECT-induced seizures (Blumenfeld et al., 2003 and McNally and Blumenfeld, 2004). Structural magnetic resonance imaging (MRI) studies in patients with geriatric depression compared with healthy subjects, using the region of interest (ROI) approach, showed smaller gray matter (GM) volume of the medial temporal (Steffens et al., 2000), parietal (Andreescu et al., 2008), and prefrontal (Kumar et al., 2000) cortices. Results of whole-brain voxel-based morphometry (VBM) studies in patients with geriatric depression, compared with healthy subjects, are inconclusive, showing no difference at all (Koolschijn et al., 2010) or smaller GM volume of the lateral (Yuan et al., 2008) and medial (Bell-McGinty et al., 2002; Egger et al., 2008) temporal cortices, mygdala, orbitofrontal (Egger et al., 2008), superior frontal, and post-central cortices (Yuan et al., 2008). Studies of brain structure in geriatric depression in relation to specific symptom profiles such as the presence of PS or late onset depression (LOD) (age of onset above 55 years of age) are sparse. Only one study, using a ROI approach, evaluated 19 geriatric depressed patients with PS versus 26 geriatric depressed patients without PS (Kim et al., 1999), finding smaller GM volume of the prefrontal cortex in psychotic depression. Other studies found no difference between elderly patients with LOD and healthy controls (Colloby et al., 2011) or smaller GM volume of the insula and posterior cingulate gyrus (Hwang et al., 2010). So far, no study has reported on the relationship between symptom profile, brain structure, and ECT response in severe geriatric depression. We used VBM in a naturalistic cohort of 55 patients with severe geriatric depression to evaluate this relationship. We hypothesized that alterations of frontal, parietal, and temporal GM volume would relate to ECT response, since these regions are involved in the network that is activated during ECT-induced seizures (Blumenfeld et al., 2003 and McNally and Blumenfeld, 2004).