Instrumental Analysis of Dynamic Vestibular Function in BPPV

Background: Instrumental vestibular findings in acute benign paroxysmal positional vertigo (BPPV) may help characterize vestibular function beyond positional nystagmus; however, their pathological and prognostic significance remains uncertain. We evaluated video head impulse test (vHIT) and cervical vestibular evoked myogenic potential (c-VEMP) findings relating to acute idiopathic BPPV. Methods: This retrospective observational case series included 40 adults evaluated within 72 h of symptom onset. Positional testing identified the affected semicircular canal. Patient-level vHIT gains, corrective saccades, c-VEMP latencies, raw peak-to-peak amplitudes, and interaural asymmetry ratios were summarized descriptively. Contralateral measurements provided within-patient comparisons; no independent healthy control group was included. Results: The cohort comprised 20 women and 20 men (mean age: 59.35 ± 8.31 years). Posterior, lateral, and anterior canal BPPV were diagnosed in 32 (80%), 6 (15%), and 2 (5%) patients, respectively, with right-posterior-canal involvement in 18 patients (45%). Reduced vHIT gain accompanied by corrective saccades in the affected canal trace was observed in five patients (12.5%: 3 posterior, 1 lateral, and 1 anterior). Bilateral c-VEMPs were recordable in all patients. Mean affected vs. contralateral p13 latencies were 16.41 vs. 15.93 ms, n23 latencies were 24.57 vs. 23.92 ms, and raw peak-to-peak amplitudes were 50.66 vs. 58.18 µV. These raw amplitude values could not be independently validated as electromyography-normalized measures. Conclusions: Most patients did not meet functional deficit criteria on vHIT in the affected canal traces. The c-VEMP findings describe the tested sacculocollic pathway but require established normative reference values and electromyographic amplitude normalization for categorical diagnostic interpretation. These cross-sectional observations do not imply structural canal integrity, functional reversibility, treatment efficacy, or recurrence risk.