Neural Noise- An updated international expert review addresses the clinical utility and future prospective of TMS–EEG.1
- TMS–EEG is a combined stimulation–recording method for assessing cortical excitability and connectivity.1 1
Weekly enrichment (2026-07-20)
- The article is a consensus review, “Clinical utility and prospective of TMS–EEG: Updated review from an international expert group,” published in Clinical Neurophysiology (doi:10.1016/j.clinph.2025.2111487); it updates the 2019 Tremblay et al. guidelines (Clin Neurophysiol 2019;130:802–844) and was authored by a large international expert group led by Ziemann and Ilmoniemi.2
- TMS–EEG combines TMS perturbation with simultaneous EEG recording to infer causal input–output relationships in cortical circuits, going beyond observational techniques such as resting-state EEG or functional MRI.2
- Core physiological readouts include TMS-evoked potentials (TEPs) and derived measures such as TMS-related oscillations, effective-connectivity metrics, and complexity estimates like the Perturbational Complexity Index (PCI).2
- Pharmacological work links TEP components to excitation/inhibition balance: the N15–P25 complex is regulated by ion-channel drugs, the N45 is modulated by GABA-A and NMDA agents (increasing with greater inhibition), and the P60 is depressed by AMPA-receptor inhibition.2
- PCI as a diagnostic biomarker for disorders of consciousness detected minimally conscious state with 94.7% sensitivity (Casarotto et al., 2016) and shows good-to-high test–retest reliability (>0.7); the review places PCI in the late-stage-3/early-stage-4 phase of biomarker development, approaching clinical translation.2
- In treatment-resistant depression, TEP-derived alpha/theta connectivity of the left DLPFC classified youth with TRD versus controls with up to 83% accuracy (Dhami et al., 2020).2
- Peripheral-evoked potentials (PEPs) are a major confound because, like TEPs, they are time-locked to the pulse and neuronal in origin; offline strategies such as ICA, SSP-SIR, and regression are used to reduce them but rest on debated assumptions.2
- A parallel 2026 Frontiers integrative review (literature searched to October 2025) emphasizes TEPs, global/local mean field power (GMFP/LMFP), and time-frequency indices across Alzheimer’s disease, depression, epilepsy, and stroke, and calls for larger controlled studies.3
- Reliability-focused reviews report that late TEP components are more reliable than early ones, and that the absence of standardized, high-reliability protocols still limits routine clinical use.4 5