# Assessing an electroencephalography (EEG) biomarker of response to transcranial magnetic stimulation for major depression

> **NIH VA I01** · WHITE RIVER JUNCTION VA MEDICAL CENTER · 2021 · —

## Abstract

Major Depressive Disorder (MDD) is highly prevalent among Veterans and associated with significant cost,
disability and mortality. Although evidence-based medications and psychotherapies are available to treat MDD,
full and sustained remission is uncommon. Transcranial magnetic stimulation (TMS) is an FDA-cleared
intervention that offers a novel strategy for treating patients with treatment-resistant depression (TRD). TMS is
available within the VA through the VA Clinical TMS Pilot Program. TMS is based in a neural circuit paradigm
of MDD positing that stimulation at a key node (e.g., dorsolateral prefrontal cortex) can restore function within a
network of brain regions involved in mood regulation. Although a substantial number of TRD patients respond
well to TMS, many do not. This suggests some patients have a form of neural network dysfunction that is more
amenable to TMS. Resting electroencephalography (EEG) provides a safe, convenient and reliable way to
measure focal brain electrical activity and neural network function. Prior studies have identified EEG markers
associated with response to antidepressant medications, but limited research has been conducted to identify
EEG markers predictive of an antidepressant response with TMS. This is a critical gap, since TMS likely
operates via direct modulation of neural network activity, such that baseline differences in neural
network function should help identify which patients are more or less likely to respond to TMS.
Investigators in our group have identified putative predictive EEG-based biomarkers for response to TMS for
TRD. One of these (differential patterns of gamma oscillations) may specifically predict response to 10 Hz TMS
applied to the left dorsolateral prefrontal cortex, the type of TMS received by >80% of Veterans receiving TMS
in the TMS Pilot Program. Another (changes in theta cordance early in the course of treatment) may predict
eventual response to TMS; this potential biomarker was identified by Dr. Andrew Leuchter (a consultant on this
grant) and has been shown to also predict response to antidepressant medications and deep brain stimulation
for TRD. By adding baseline (pretreatment) and weekly resting EEG assessment to the VA National
Clinical TMS Pilot Program, the goals of this study are to: (1) test a potential response biomarker
measured at baseline in a large sample of Veterans receiving TMS to treat depression (N=400); (2)
assess whether a second putative biomarker (early changes in theta cordance during treatment)
predict eventual response to TMS; (3) leverage this large sample to identify other potential biomarkers
(such as markers of early versus late response to TMS, markers of response to other TMS parameters
(e.g., 5 Hz, 1 Hz or theta burst TMS), and markers of change with treatment that may speak to
mechanism); and (3) create an infrastructure to rapidly identify and test additional EEG-based
biomarkers of treatment response in patients with depression and other p...

## Key facts

- **NIH application ID:** 9933192
- **Project number:** 1I01CX002088-01
- **Recipient organization:** WHITE RIVER JUNCTION VA MEDICAL CENTER
- **Principal Investigator:** Amit Etkin
- **Activity code:** I01 (R01, R21, SBIR, etc.)
- **Funding institute:** VA
- **Fiscal year:** 2021
- **Award amount:** —
- **Award type:** 1
- **Project period:** 2020-10-01 → 2024-09-30

## Primary source

NIH RePORTER: https://reporter.nih.gov/project-details/9933192

## Citation

> US National Institutes of Health, RePORTER application 9933192, Assessing an electroencephalography (EEG) biomarker of response to transcranial magnetic stimulation for major depression (1I01CX002088-01). Retrieved via AI Analytics 2026-05-22 from https://api.ai-analytics.org/grant/nih/9933192. Licensed CC0.

---

*[NIH grants dataset](/datasets/nih-grants) · CC0 1.0*