Revisiting Diagnostic Criteria for Bilateral Vestibulopathy: A New Comprehensive Instrumental Model

Background: Bilateral vestibulopathy (BVP) is a disabling condition characterized by a deficit in vestibular function on both sides. Current diagnostic criteria consider instrumental data only from horizontal canals, excluding vertical canals and otolithic function, with the possibility of not including some variants of BVP. This study aims to evaluate vestibular functions in people with chronic vestibular syndrome through a comprehensive battery of tests. Methods: This diagnostic accuracy study included patients who met criteria for probable BVP. The index test included a thorough evaluation of the vestibular system, using the video Head Impulse Test (vHIT) to measure the gain of the angular vestibulo-ocular reflex (aVOR) in all six semicircular canals and the cervical and ocular vestibular-evoked myogenic potentials (VEMPs) to assess otolith function. The diagnostic criteria established by the Barany Society were considered the standard reference, including only the horizontal vHIT as an instrumental assessment. Results: 78 patients (41 male, age 61.40 ± 12.99) were enrolled. The Barany criteria showed a low ability to rule out BPV (sensitivity = 46%). The median Dizziness Handicap Inventory (DHI) varied from 66 to 69 among the models studied, and a significant difference in DHI scores between positive and negative tests was observed for the Barany criteria and the six-canals vHIT model. Conclusions: Our findings highlight the potential to transform BPV diagnostic criteria. The identification of new bilateral vestibular dysfunction variants through improved diagnostic tools calls for revising current criteria, with promising implications for patient care and understanding of etiological and prognostic aspects.