Plasma neurofilament light chain and glial fibrillary acidic protein in the differential diagnosis of acute vertigo in the emergency department

BACKGROUND: Distinguishing posterior circulation stroke (PCS) from peripheral or other causes of acute vertigo can be challenging. Blood biomarkers, such as plasma neurofilament light chain (pNfL) and glial acidic fibrillary protein (pGFAP), have been associated with (even small) stroke lesions and could support patient selection for neuroimaging and inpatient evaluation in acute vertigo. METHODS: This prospective study included consecutive patients presenting with acute vertigo to a neurological emergency department. All patients received neurological examination, laboratory testing and neuroimaging. pNfL and pGFAP were measured using Single Molecule Array (SIMOA) technique. pNfL and pGFAP levels were compared between PCS and patients with non-central vertigo. RESULTS: 102 patients were included (mean age 57.9 years, 57.8% female). pNfL Z-scores were higher in PCS compared to non-central vertigo patients (median 2.1, IQR = 1.5 versus 0.7, IQR = 1.9; p = 0.004). pNfL Z-score ≥ 1.0 was associated with PCS (OR 8.8, 95% CI 2.4-32.7), yielding a sensitivity of 84.2%, specificity of 62.4% and negative predictive value of 94.6%. pGFAP Z-scores were higher in PCS patients than in non-central vertigo patients (median 1.3, IQR = 2.8 versus 0.6, IQR = 1.5; p = 0.016). pGFAP Z-score ≥ 1.0 was associated with PCS (OR 3.5, 95% CI 1.3-9.8), yielding a sensitivity of 57.9%, specificity of 71.8% and negative predictive value of 88.4%. Respective associations remained robust after correcting for symptom duration. DISCUSSION: pNfL and pGFAP levels were higher in PCS compared to patients with non-central causes of vertigo. With its high negative predictive value, pNfL appears especially clinically useful to rule out PCS in acute vertigo.