Enhanced Eye Velocity in Head Impulse Testing—A Possible Indicator of Endolymphatic Hydrops

Introduction: On video head impulse testing (vHIT) of semicircular canal function, some patients reliably show enhanced eye velocity and so VOR gains >1.0. Modeling imaging indicate this could be due to endolymphatic hydrops. Oral glycerol reduces membranous labyrinth volume cochlear symptoms hydrops, we tested whether oral reduced the vHIT velocity. Study Design: Prospective clinical study retrospective analysis patient data. Methods: Patients with during horizontal were enrolled ( n = 9, 17 ears) given orally 86% glycerol, 1.5 mL/kg body weight, dissolved 1:1 in physiological saline. Horizontal was performed before intake (time 0), then at intervals 1, 2, 3 h after intake. Control 4, 6 received water same intervals. To provide an objective index used a measure gain which captures is clear on inspecting records. We call initial it defined as: (the ratio peak value time velocity). The responses other who showed routine analyzed try identify how enhancement occurred. Results: found that caused, average, significant reduction response, whereas caused no systematic change. impulses compensatory saccade-like response increasing Conclusion: following consistent hypothesis may by