Otolin-1 for differentiating central and peripheral causes of acute continuous dizziness

Patients with isolated acute-onset continuous dizziness (iAOCD) are commonly seen at the emergency department (ED). Distinguishing peripheral vestibular disorders from central causes remains challenging. Existing diagnostic tools, including bedside examination and neuroimaging, have important limitations. Otolin-1, an inner ear-specific glycoprotein, has been proposed as a biomarker of peripheral vestibular pathology. This study evaluated whether otolin-1 could serve as a diagnostic biomarker for this differentiation.

This study analyzed samples from a prospective multicenter cohort of adult patients who were seen at the ED with acute onset, continuous dizziness without focal neurological deficits. Patients were included within 24 hours of symptom onset. Otolin-1 plasma concentrations were measured using an enzyme-linked immunosorbent assay. Final diagnoses (central versus peripheral) were determined by an expert panel based on clinical assessment, diffusion-weighted magnetic resonance imaging and 3-month follow-up.

We analyzed 245 patients (179 peripheral, 66 central). Median otolin-1 concentrations did not differ significantly between peripheral and central causes (517.6 [IQR 443.7-592.8] pg/mL vs 487.9 [424.9-644.4] pg/mL; p = 0.349). No significant differences were observed in hyperacute (<4.5 hours after symptom onset) or acute (4.5-24 hours after symptom onset) subgroups. Similarly, otolin-1 concentrations did not differ between central iAOCD and specific peripheral diagnoses. Substantial overlap in concentration ranges was observed across all comparisons. Receiver operating characteristic analysis similarly showed no useful discrimination (AUC 0.539, 95% CI 0.455-0.623).

Otolin-1 does not differentiate between central and peripheral causes of iAOCD in the ED setting. Although biologically linked to inner ear pathology, otolin-1 lacks sufficient discriminatory value as a stand-alone diagnostic biomarker.