Impact of Clinician Training Background and Stroke Location on Bedside Diagnostic Test Accuracy in the Acute Vestibular Syndrome – A Meta-Analysis

Objective: Acute dizziness/vertigo is usually due to benign inner-ear causes but is occasionally due to dangerous neurologic ones, particularly stroke. Because symptoms and signs overlap, misdiagnosis is frequent and overuse of neuroimaging is common. We assessed the accuracy of bedside findings to differentiate peripheral vestibular from central neurologic causes. Methods: We performed a systematic search (MEDLINE and Embase) to identify studies reporting on diagnostic accuracy of physical examination in adults with acute, prolonged dizziness/vertigo (“acute vestibular syndrome” [AVS]). Diagnostic test properties were calculated for findings. Results were stratified by examiner type and stroke location. Results: We identified 6,089 citations and included 14 articles representing 10 study cohorts (n = 800). The Head Impulse, Nystagmus, Test of Skew (HINTS) eye movement battery had high sensitivity 95.3% (95% confidence interval [CI] = 92.5–98.1) and specificity 92.6% (95% CI = 88.6–96.5). Sensitivity was similar by examiner type (subspecialists 94.3% [95% CI = 88.2–100.0] vs non-subspecialists 95.0% [95% CI = 91.2–98.9], p = 0.55), but specificity was higher among subspecialists (97.6% [95% CI = 94.9–100.0] vs 89.1% [95% CI = 83.0–95.2], p = 0.007). HINTS sensitivity was lower in anterior cerebellar artery (AICA) than posterior inferior cerebellar artery (PICA) strokes (84.0% [95% CI = 65.3–93.6] vs 97.7% [95% CI = 93.3–99.2], p = 0.014) but was “rescued” by the addition of bedside hearing tests (HINTS+). Severe (grade 3) gait/truncal instability had high specificity 99.2% (95% CI = 97.8–100.0) but low sensitivity 35.8% (95% CI = 5.2–66.5). Early magnetic resonance imaging (MRI)-diffusion-weighted imaging (DWI; within 24–48 hours) was falsely negative in 15% of strokes (sensitivity 85.1% [95% CI = 79.2–91.0]). Interpretation: In AVS, HINTS examination by appropriately trained clinicians can differentiate peripheral from central causes and has higher diagnostic accuracy for stroke than MRI-DWI in the first 24–48 hours. These techniques should be disseminated to all clinicians evaluating dizziness/vertigo. ANN NEUROL 2023;94:295–308.