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Objectives: To separate posterior-circulation stroke (PCS) and vestibular-neuritis (VN) using quantitative vestibular tests., Methods: Patients were prospectively recruited from the emergency room within 72 h of presentation. Video-nystagmography (VNG), three-dimensional video head-impulse testing (vHIT), vestibular-evoked myogenic potentials (VEMPs), and subjective visual-horizontal (SVH) were performed., Results: There were 128 PCS and 134 VN patients. Common stroke-territories were: posterior-inferior cerebellar artery, basilar-perforators, multi-territory and anterior-inferior cerebellar artery (41.4%, 21.1%, 14.1%, 7.8%). VN included superior, inferior and pan-neuritis (53.3%, 4.2%, and 41.5%). Most VN and stroke patients presented with acute vestibular syndrome (96.6%, 61.7%). In VN, we recorded horizontal (98.5%) or vertical/torsional spontaneous nystagmus (1.5%) and in PCS, absent-nystagmus (53.9%), horizontal (32%) or vertical/torsional (14.1%) nystagmus. The mean slow-phase velocity of horizontal nystagmus was faster in VN than PCS (11.8 ± 7.2 and 5.2 ± 3.0°/s, p < 0.01). Ipsilesional horizontal-canal (HC) vHIT-gain was lower in VN than in stroke (0.47 ± 0.24, 0.92 ± 0.20, p < 0.001). Ipsilesional catch-up saccades occurred earlier, and their amplitude, prevalence, and velocity were greater in VN than PCS (p < 0.01). Ipsilesional SVH deviation > 2.5° occurred more often in VN than in stroke (97.6% and 24.3%, p < 0.01). Abnormal bone-conducted ocular-VEMP asymmetry ratio was more common in VN than PCS (50% and 14.4%, p < 0.01). Using the ten best discriminators (VNG, vHIT, SVH, and oVEMP metrics), VN was separated from PCS with a sensitivity of 92.9% and specificity of 89.8%. Adding VNG and vHIT to the bedside head-impulse-nystagmus-and-test-of-skew (HINTS) test enhanced sensitivity and specificity from 95.3% and 63.4% to 96.5% and 80.6%., Conclusion: Quantitative vestibular testing helps separate stroke from vestibular neuritis and, when used, could improve diagnostic accuracy in the emergency room., (© 2022. Crown.)

Objectives: To compare acute nystagmus characteristics of posterior circulation stroke (PCS) and acute vestibular neuritis (AVN) in the emergency room (ER) within 24 h of presentation. Methods: ER-based video-nystagmography (VNG) was conducted, recording ictal nystagmus in 101 patients with PCS (on imaging) and 104 patients with AVN, diagnosed on accepted clinical and vestibular test criteria. Results: Patients with stroke in the brainstem (38/101, affecting midbrain (n = 7), pons (n = 19), and medulla (n = 12)), cerebellum (31/101), both (15/101) or other locations (17/101) were recruited. Common PCS territories included posterior-inferior-cerebellar-artery (41/101), pontine perforators (18/101), multiple-territories (17/101) and anterior-inferior-cerebellar-artery (7/101). In PCS, 44/101 patients had no spontaneous nystagmus. Remaining PCS patients had primary position horizontal (44/101), vertical (8/101) and torsional (5/101) nystagmus. Horizontal nystagmus was 50% ipsiversive and 50% contraversive in lateralised PCS. Most PCS patients with horizontal nystagmus (28/44) had unidirectional "peripheral-appearing" nystagmus. 32/101 of PCS patients had gaze-evoked nystagmus. AVN affected the superior, inferior or both divisions of the vestibular nerve in 55/104, 4/104 and 45/104. Most (102/104) had primary position horizontal nystagmus; none had gaze-evoked nystagmus. Two inferior VN patients had contraversive torsional-downbeat nystagmus. Horizontal nystagmus with SPV ≥ 5.8 °/s separated AVN from PCS with sensitivity and specificity of 91.2% and 83.0%. Absent nystagmus, gaze-evoked nystagmus, and vertical-torsional nystagmus were highly specific for PCS (100%, 100% and 98.1%). Conclusion: Nystagmus is often absent in PCS and always present in AVN. Unidirectional 'peripheral-appearing' horizontal nystagmus can be seen in PCS. ER-based VNG nystagmus assessment could provide useful diagnostic information when separating PCS from AVN. [ABSTRACT FROM AUTHOR]