ABSTRACT NUMBER: ESOC2026A2283 IMPROVING DETECTION OF APHASIA AND SPATIAL NEGLECT: TWO-CENTER PROSPECTIVE VALIDATION OF A DUAL-PURPOSE NIHSS ITEM 9

Abstract Background and aims The National Institutes of Health Stroke Scale (NIHSS) is central to acute stroke assessment but underrepresents right-hemisphere deficits such as spatial neglect (SN). Standard NIHSS Item 11 primarily captures extinction and lacks sensitivity for the broader behavioral manifestations of SN, contributing to underestimation of right-hemisphere stroke severity. We evaluated the diagnostic accuracy and feasibility of a refined NIHSS Item 9 (n-NIHSS-9), designed to enable simultaneous screening for aphasia and SN using the “Cookie Theft” picture. Methods In this prospective, two-center observational study, consecutive adults with hemispheric stroke were assessed ≤7 days from onset. The n-NIHSS-9 was compared with the Star Cancellation Test (SCT) and Line Bisection Test (LBT). The simplified Catherine Bergego Scale (sCBS) served as the reference standard. Diagnostic accuracy metrics and non-completion rates were recorded. Results Of 632 patients (51.7% male; mean age 70.4 ± 12.9), SN prevalence was 27.5% (left-sided 19.7%; right-sided 7.8%). The n-NIHSS-9 showed 84.75% sensitivity (95% CI 76.97–90.70), 96.92% specificity (95% CI 94.69–98.40), and 93.57% accuracy relative to sCBS. Administration time was < 30 seconds. Non-completion of the n-NIHSS among patients with SN was 7% (mainly aphasia). The SCT also showed high sensitivity (76.77%) but more instances of non-completion (11.71%), while the LBT showed lower sensitivity (37.50%) and the highest non-completion (14.71%). Conclusions The n-NIHSS-9 provides a brief, feasible method for incorporating structured SN screening into the standard NIHSS examination. Its diagnostic performance and minimal time burden may support earlier and more balanced detection of hemispheric stroke deficits in routine practice. Conflict of interest Ieva Celpacenko: nothing to disclose, Vaidas Matijosaitis: nothing to disclose, Antanas Vaitkus: nothing to disclose, Tadas Vanagas: nothing to disclose, Haukur Hjaltason: nothing to disclose, Eysteinn Ívarsson: nothing to disclose, Marianne Elisabeth Klinke: nothing to disclose Figure 1 - belongs to Methods