TMS-EEG Hyperexcitability May Predict Postoperative Delirium
Delirium is a sudden and serious change in mental status that often affects older adults after surgery. It can cause confusion, memory issues, and longer hospital stays. Despite how common it is, predicting who will experience delirium has remained a challenge. A recent study brings new hope by using a cutting-edge tool called TMS-EEG to measure brain excitability before surgery.
TMS-EEG, short for transcranial magnetic stimulation combined with electroencephalography, stimulates specific areas of the brain and records how the brain responds. It’s like knocking on a door and listening closely to how the house reacts. In this case, researchers used it to see how different regions of the brain reacted to stimulation—before any surgery took place.
What the Study Found
Researchers studied 92 older adults who were scheduled for elective surgeries. Before the procedures, they used TMS to gently stimulate three key brain regions: the left dorsolateral prefrontal cortex, the inferior parietal lobule (IPL), and the superior parietal lobule (SPL). At the same time, EEG recorded the brain’s responses to this stimulation.
After surgery, patients were closely monitored for signs of delirium using a well-known diagnostic tool called the Confusion Assessment Method (CAM). Twelve patients (13%) developed delirium.
The most interesting finding? Before their surgeries, those who went on to experience delirium already showed signs of TMS-EEG hyperexcitability in the parietal areas of their brain. This means their brain activity was more intense or overly reactive when stimulated. The frontal region, often linked to decision-making and planning, did not show the same overactivity.
Why This Matters for Mental Health and Aging
This study suggests that people who develop delirium may already have underlying brain vulnerabilities—before surgery even starts. The researchers believe this fits into a broader theory: delirium may be triggered by stress in people with abnormal brain function that isn’t always obvious in day-to-day life.
TMS-EEG may eventually become a tool to screen for brain health before surgery, helping identify those at higher risk of postoperative complications like delirium. If confirmed by more research, this could lead to better care plans, preventive strategies, and a deeper understanding of how delirium overlaps with conditions like dementia.
Looking Ahead
This kind of translational research—where neuroscience meets clinical care—highlights the promise of interventional psychiatry. TMS-EEG is more than a diagnostic tool; it might one day help prevent cognitive decline in vulnerable populations.
Understanding how the brain responds to stimulation before surgery could help healthcare professionals make safer choices for older patients. As tools like TMS-EEG become more accessible, we may be able to personalize care in ways we never could before.
Citations:
- Tseng, Y-H., Ozdemir, R., Rodionov, A., et al. (2025). Preoperative parietal TMS-EEG hyperexcitability in patients with subsequent postoperative delirium. Brain Stimulation, 18(5). https://doi.org/10.1016/j.brs.2025.05.040
- Inouye, S. K., & Marcantonio, E. R. (2017). Delirium in older persons. The New England Journal of Medicine, 377(15), 1456-1466. https://www.nejm.org/doi/full/10.1056/NEJMra1605216