EEG Microstate Parameters and Neuroinflammatory Biomarkers in Patients With Treatment-Resistant Major Depressive Disorder Receiving ECT

Condition(s) studied

Investigational drug(s) / intervention(s)

Electroconvulsive Therapy: ECT will be administered using the Thymatron System IV Integrated ECT Device under general anesthesia, in accordance with standard clinical protocols. Treatments will be delivered using bilateral electrode placement with brief-pulse square-wave stimulation, and if side effects are seen, right unilateral electrode placement will be applied. The duration of treatment, number of sessions, and stimulation parameters will be determined according to each patient's clinical condition.

Study summary

This study aims to investigate the neurophysiological and inflammatory changes associated with electroconvulsive therapy (ECT) in patients diagnosed with Major Depressive Disorder who are resistant to at least two antidepressant treatments, using microstate analysis derived from resting-state electroencephalography (EEG) recordings. Within this scope, EEG recordings obtained before and after ECT will be compared to determine the relationships between changes in microstate parameters and inflammatory marker levels, clinical variables, and psychometric scale scores reflecting clinical improvement.

Peripheral blood samples collected from the same patient group will be analyzed for complete blood count parameters as well as levels of interleukin-1 alpha (IL-1α), interleukin-1 beta (IL-1β), interleukin-2 (IL-2), interleukin-6 (IL-6), interleukin-8 (IL-8), interleukin-10 (IL-10), tumor necrosis factor-alpha (TNF-α), soluble glycoprotein 130 (sgp-130), soluble interleukin-6 receptor (sIL-6R), interferon gamma-induced protein 10 kDa (IP-10), and C-reactive protein (CRP). In addition, inflammatory indices, including the Neutrophil-to-Lymphocyte Ratio (NLR), Platelet-to-Lymphocyte Ratio (PLR), and Monocyte-to-Lymphocyte Ratio (MLR), will be calculated. The association between baseline levels of these biomarkers and treatment response will be evaluated. Moreover, changes in biomarker levels following ECT will be statistically examined in relation to clinical scale scores and EEG microstate parameters.

Although microstate analysis and inflammatory biomarkers have each been extensively investigated in psychiatric disorders, studies evaluating these two biomarkers together, particularly with the inclusion of healthy control participants, remain limited. In this regard, the present study aims to evaluate the effects of ECT on patients with treatment-resistant depression using objective neurophysiological indicators, to contribute to the understanding of the pathophysiology of depression at the level of brain networks, and to provide a scientific basis for the development of personalized treatment approaches in the future.

Eligibility

Primary outcome measure(s)

• Clinical Response and Remission Assessed by the Montgomery-Åsberg Depression Rating Scale — These assessments will be repeated within 1 week before ECT starts and at 14+6 days and 8 weeks + 6 days after ECT cessation.
  Before ECT initiation and 2 and 8 weeks after the cessation of ECT sessions, depressive symptom severity will be assessed using the Montgomery-Åsberg Depression Rating Scale. Montgomery-Åsberg Depression Rating Scale total score ranges from 0 to 60, with higher scores indicating greater severity of depressive symptoms. Change in total score from baseline will be assessed following electroconvulsive therapy (ECT).Clinical response will be defined as a ≥50% reduction in MADRS total score from baseline. Remission will be defined as a MADRS total score ≤7.
• Clinical Response Assessed by Hamilton Depression Rating Scale — These assessments will be repeated within 1 week before ECT starts and at 14+6 days and 8 weeks + 6 days after ECT cessation.
  Before ECT initiation and 2 and 8 weeks after the cessation of ECT sessions, depressive symptom severity will be assessed using the Hamilton Depression Rating Scale. The total score of scale ranges from 0 to 52, with higher scores indicating greater severity of depressive symptoms. Change in Hamilton Depression Rating Scale total score from baseline will be assessed following electroconvulsive therapy (ECT).Clinical response will be defined as a ≥50% reduction in total score from baseline. Remission will be defined as a total score ≤7.
• EEG Microstate Duration — These assessments will be repeated within 1 week before ECT starts and 14+6 days and 8 weeks + 6 days after ECT cessation.
  Participants will be instructed to remain relaxed, quiet, and motionless during EEG recording. EEG acquisition will consist of 5 minutes with eyes open followed by 5 minutes with eyes closed. Raw EEG data will undergo preprocessing, including artifact removal, band-pass filtering, and re-referencing. Microstate analysis will be performed using MICROSTATELAB v2.1, an EEGLAB extension. Four canonical microstate classes (A, B, C, and D) will be identified. For each microstate class, duration will be calculated as the mean time for which the microstate remains stable following its onset and will be reported in milliseconds (ms).
• EEG Microstate Occurrence — These assessments will be repeated within 1 week before ECT starts and 14+6 days and 8 weeks + 6 days after ECT cessation.
  Participants will be instructed to remain relaxed, quiet, and motionless during EEG recording. EEG acquisition will consist of 5 minutes with eyes open followed by 5 minutes with eyes closed. Raw EEG data will undergo preprocessing, including artifact removal, band-pass filtering, and re-referencing. Microstate analysis will be performed using MICROSTATELAB v2.1, an EEGLAB extension. Four canonical microstate classes (A, B, C, and D) will be identified. For each microstate class, occurrence will be calculated as the mean number of times the microstate occurs per second and will be reported in Hertz (Hz).
• EEG Microstate Coverage — These assessments will be repeated within 1 week before ECT starts and 14+6 days and 8 weeks + 6 days after ECT cessation.
  Participants will be instructed to remain relaxed, quiet, and motionless during EEG recording. EEG acquisition will consist of 5 minutes with eyes open followed by 5 minutes with eyes closed. Raw EEG data will undergo preprocessing, including artifact removal, band-pass filtering, and re-referencing. Microstate analysis will be performed using MICROSTATELAB v2.1, an EEGLAB extension. Four canonical microstate classes (A, B, C, and D) will be identified. For each microstate class, coverage will be calculated as the percentage of the total EEG recording time occupied by that microstate class and will be reported as a percentage (%).
• EEG Microstate Transition Probability — These assessments will be repeated within 1 week before ECT starts and 14+6 days and 8 weeks + 6 days after ECT cessation.
  Participants will be instructed to remain relaxed, quiet, and motionless during EEG recording. EEG acquisition will consist of 5 minutes with eyes open followed by 5 minutes with eyes closed. Raw EEG data will undergo preprocessing, including artifact removal, band-pass filtering, and re-referencing. Microstate analysis will be performed using MICROSTATELAB v2.1, an EEGLAB extension. Four canonical microstate classes (A, B, C, and D) will be identified. For each pair of microstate classes, transition probability will be calculated as the proportion of transitions from a given microstate class to a specific subsequent microstate class relative to all transitions originating from that microstate class. Transition probability will be reported as a proportion ranging from 0 to 1.

Trial sites (1)

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