Abstract WP360: An Automated Transcranial Device for Detecting Hemispheric Bioimpedance Asymmetry During Stroke: Normative Human Baselines, Stability, and Stroke Modeling Data

Introduction: Rapid detection of ischemic/hemorrhagic stroke at the bedside a critical unmet need, particularly in prehospital and resource-limited settings where advanced neuroimaging is unavailable. The STEDI device is a portable, automated bioimpedance device designed to detect hemispheric asymmetries associated with intracranial pathology. Here, we establish normative baselines in healthy adults, evaluate test–retest stability, and validate the ability of STEDI using stroke phantom and simulation models. Methods: Seventy-nine healthy adult volunteers (267 trials) underwent transcranial impedance measurements. A hemispheric bioimpedance asymmetry ratio (Left÷Right) was calculated per subject. Test–retest reproducibility was assessed with repeat sessions on separate days. Hemispheric asymmetry was modeled with a head phantom, constructed from two compartments with a septum to mirror human hemispheres, with either fluid with the same conductivity as human brain (symmetric) or one fluid with conductivity of human brain and the other with conductivity of blood (asymmetric/stroke), and computationally simulated using Ansys software. Comparative analysis was performed between normative human, benchtop phantom, and Ansys data. Results: Normative human data demonstrated a tight asymmetry distribution (mean ratio 1.015 ± 0.049; median 1.021). Test–retest reproducibility across days showed minimal bias on Bland-Altman analysis (p=0.42). Left versus right raw impedance values were strongly correlated (Pearson r=0.96, n=267, Figure 1). Tukey multiple comparisons demonstrated no statistical significance between head size and bioimpedance ration (p>0.35 for all comparisons). In contrast, benchtop phantom and Ansys simulations produced markedly asymmetric ratios (benchtop: left 1.557, right 0.615; Ansys: left 1.634, right 0.628), which were well separated from the normative distribution yet highly correlated to each other. These results demonstrate the ability of STEDI to distinguish stroke-analog asymmetry from healthy human baselines (Figure 2). Conclusions: STEDI established a reproducible normative bioimpedance baseline in healthy volunteers and demonstrated robust test–retest stability. Stroke analog modeling using phantom and computational methods confirmed that pathological asymmetry is readily separable from the narrow physiological range. These findings support the translational potential of STEDI as an automated, portable device for rapid stroke detection and triage.