6.: A video-oculographic study of acute vestibular neuritis

Abstract

The clinical signs of vestibular neuritis (VN) are spontaneous nystagmus and a positive horizontal head impulse test (hHIT). Both of these signs can be subtle and difficult to determine, especially for non-experts. Also, a normal hHIT may be due to covert saccades. Spontaneous nystagmus resolves, but many patients never recover normal vestibulo-ocular reflex (VOR) gain. Some patients with apparent acute VN have a normal examination within 24 hours. We aimed to quantify with a video oculographic device the VOR gain and catch up saccades early in acute VN, and repeat measurements daily during their hospital admission. We enrolled adults with acute VN presenting to the emergency department within 24 hours of symptom onset. We recorded the eye movement response to rapid head impulses using the ICS Impulse video-oculographic device (GN Otometrics, Taastrup, Denmark) on each day of their hospital admission. There were nine patients with acute VN. They had marked variation in initial VOR gains. Four patients had VOR gains in the normal range, despite having signs and symptoms of VN. Most patients’ VOR gains increased during their admission, but five remained in the abnormal range. Patients with lower VOR gains were less likely to improve into the normal range. We also observed a reduction in the VOR gain on the unaffected side in those patients. No patient with initially abnormal VOR gain recovered normal VOR gain and resolution of physical signs. Early video head impulse testing in the emergency department and each day of admission is feasible and well tolerated in acute VN. Quantitation of VOR gain acutely could have implications for the diagnosis of VN or pseudoneuritis, and could help select patients for corticosteroid treatment or further investigation.