Differences in vestibulo-ocular reflex time constants in patients with vestibular migraine versus vestibular neuritis/labyrinthitis.

Objective: Recurrent dizziness, vertigo, and imbalance, as well as nausea or vomiting, can be induced by central or peripheral vestibular pathology. Vestibular migraine (VM) is a central pathology in which migraines reciprocally interact with vestibular nuclei. Vestibular neuritis and labyrinthitis (VN/L) are peripheral diseases involving inflammation of structures in the vestibular nerve or labyrinth. Because VM and VN/L in early stages can produce similar symptoms, diagnosis may require prolonged clinical evaluation. It has been suggested that differences in a patient's Vestibulo-Ocular Reflex (VOR) measured during the rotary chair step rotation test (RCS Test) can differentiate VM from peripheral pathologies, allowing for faster diagnosis. We sought to compare VOR time constants (VORTs) in patients with VM versus VN/L, with the goal of exploring potential diagnostic value.

Study Design: Retrospective chart review of patients seen at a hospital balance center between January 2010 and June 2019.

Setting: Tertiary referral center.

Patients: 68 patients (mean age = 58.15, 65 % female, 35 % male) were placed into two groups based on clinical diagnosis codes: 1) VM or 2) VN/L.

Main Outcome Measure(s): Primary variable of VORT, evoked by rotational step testing.

Results: Patients in the VM group demonstrated statistically significant elevated VOR Ts outside the normed range of 10-19.5 compared to those in the VN/L group (p = 0.0003) while patients in the VN/L group demonstrated statistically significant shortened VOR Ts (p = 0.0443) with the two populations having distinctly different VOR T profiles.

Conclusions: Our results support the conclusion that elevated VOR Ts are a sign of central vestibular pathology and highlight the benefit of utilizing rotary chair testing early in the diagnostic process as a powerful diagnostic tool when evaluating dizzy patients for central versus peripheral vestibular dysfunction. Our results suggest more particularly that elevated VOR Ts can be utilized to identify patients with vestibular migraine, thus offering differentiation from patients with peripheral vestibular dysfunction earlier in the process of diagnosis, with an opportunity for earlier intervention.