Respuesta oculomotora al test de autorrotación cefálica vertical en pacientes con vértigo posicional paroxístico benigno del conducto posterior

Abstract

ObjectiveTo evaluate the eye movement response to the head auto-rotation test (HART) in the vertical plane in patients with benign paroxysmal positional vertigo. Patientsand methodsDesign:A transversal, descriptive study Setting upOutpatient clinic in a general Hospital Individuals34 posterior canal BPPV cases with a video-oculographíc diagnosis, older than 18 years old, 7 of them were not able to perform the HART. InterventionHART was performed by a an electrooculographic system with simultaneous recording of head movement by an acelerometer in the vertical plane (Vorteq, Micromedical Instruments). The HART with eyes fixation was performed 3 times to determine its reliability. Main outcome measuresGain, asymmetry and phase for the vertical VOR respectively. A statistical analysis was carried out to determine the test reliability and the number of individuals with an abnormal result. ResultsGain is the only variable that showed a reproducible result in the HART for the active head movement at 1-2 Hz (testretest reliability 0.83-0.89). The values of gain showed a moderate correlation at the frequencies 1-3 Hz (correlation 0.60-0.87). Asymmetry and phase were not reproducible variables (correlation0.55). Thirteen of 27 (48%) patients presented a decrease of the vertical gain, another 13 showed normal values and one case showed raised values. ConclusionGain is the only useful variable in the vertical HART. Forty-eight percent of patients with posterior canal BPPV have a reduced vertical gain, suggesting an impairment of inferior vestibular nerve function.