Abstract Number: Esoc2026a362 Therapeutic Effect of Electromagnetic Stimulation Upon Functional Outcomes in Post-Stroke Rehabilitation: Delta-to-Alpha Ratio as an Informative Non-Invasive Recovery Metric

Abstract Background and aims The Delta-to-Alpha Ratio (DAR) and Theta-to-Alpha Ratio (TAR) are electroencephalography (EEG) biomarkers that reflect pathological slow-wave activity post stroke and are associated with motor recovery. This study investigated whether DAR and TAR can serve as sensitive, non-invasive indicators of treatment response during neurorehabilitation, and as operational tools to guide therapeutic monitoring. Methods We conducted a longitudinal study with 21 ischemic stroke patients (13 receiving electromagnetic stimulation, 8 receiving control intervention) who underwent 15 sessions over two months. Resting-state EEG data was recorded from eight scalp electrodes. DAR and TAR were computed per session. A Linear Mixed-Effects Model (LMM) was used to analyze interaction effects between treatment group and session number. Validation was conducted on an independent dataset to assess generalizability. Results LMM analysis revealed a significant session-by-treatment interaction for both DAR (beta = -0.406, p = 0.008) and TAR (beta = -0.044, p = 0.001). Patients in the active group demonstrated a significantly steeper decline in both biomarkers over time, consistent with the restoration of cortical network activity. Control participants showed no significant change across sessions. Conclusions DAR and TAR are sensitive to treatment-related neurophysiological effects and align with functional improvement trajectories. These findings support the use of DAR and TAR as dynamic, objective readouts for post-stroke recovery. Their simplicity, reproducibility, and clinical interpretability suggest strong potential as tools for routine monitoring, personalization of therapy, and neurologist engagement in stroke rehabilitation. Conflict of interest Itay Inbar: Nothing to disclose Figure 1 - belongs to Background and aims