Neural Noise

Theta-cordance as biomarker of iTBS treatment response in treatment-resistant depression

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  • EEG theta-cordance can serve as a biomarker of treatment response to intermittent theta burst stimulation (iTBS) in patients with treatment-resistant depression.1
  • The finding is relevant to stimulation biomarkers and EEG signal processing in psychiatry.1 1

Weekly enrichment (2026-07-20)

  • The study retrospectively analyzed 30 inpatients with major depressive disorder who received 10 sessions of left-sided intermittent theta burst stimulation (iTBS) over two weeks, with resting-state 19-channel EEG processed to compute theta cordance (plus delta/alpha/beta) in predefined cortical clusters before and after treatment.2
  • Depression severity was rated with the Hamilton Depression Rating Scale (HAM-D) and the Major Depression Inventory (MDI), and correlations linked baseline values and pre/post change scores to symptom improvement.2
  • Baseline prefrontal theta cordance was not associated with clinical outcome, arguing against its use as a pre-treatment predictor for iTBS in this sample.23
  • Treatment-related change was region-specific: responders showed greater occipital decreases in theta cordance (OC p = 0.036; MLOC p = 0.009) and a non-significant trend toward left-frontal increases (MLFC p = 0.072), with exploratory alpha and delta effects also emerging.23
  • The authors (Reissmann, Rupprecht, Langguth and colleagues, University of Regensburg) concluded theta cordance may serve as a dynamic, region-specific EEG marker to monitor and personalize iTBS, warranting prospective validation.3
  • Theta cordance is a QEEG measure introduced by Leuchter and Cook that combines absolute and relative EEG power and correlates with regional cerebral perfusion/metabolism; a 2002 double-blind study of 51 depressed adults found medication responders uniquely showed prefrontal cordance decreases at 48 hours and 1 week, before clinical differences emerged at 4 weeks.4
  • In treatment-resistant depression, earlier work found that an early (week-1) prefrontal theta cordance reduction predicted venlafaxine response — 11 of 12 responders versus 5 of 13 non-responders decreased (p = 0.01), with positive and negative predictive values of 0.7 and 0.9.5
  • Across antidepressant classes, week-1 prefrontal theta cordance reduction has shown comparable predictive accuracy — in a 142-patient study, ROC AUCs were 0.77 (SSRI), 0.77 (SNRI), and 0.87 (NDRI/bupropion) — situating the iTBS findings within a broader cordance biomarker literature.6

Footnotes

  1. https://www.sciencedirect.com/science/article/pii/S1388245726002099?dgcid=rss_sd_all ↩ ↩2 ↩3

  2. https://doi.org/10.1016/j.clinph.2026.2111710 ↩ ↩2 ↩3 ↩4

  3. https://epub.uni-regensburg.de/78929/ ↩ ↩2 ↩3

  4. https://www.nature.com/articles/1395884 ↩

  5. https://www.cambridge.org/core/journals/european-psychiatry/article/abs/early-reduction-in-prefrontal-theta-qeeg-cordance-value-predicts-response-to-venlafaxine-treatment-in-patients-with-resistant-depressive-disorder/CF52FD18D93B21A5CF8B15577C8735C3 ↩

  6. https://doi.org/10.1016/j.eurpsy.2017.01.1973 ↩

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