Patterns of vestibular function in patients with dizziness after COVID-19 vaccination; dual tertiary referral center study

BackgroundAlthough dizziness is a common symptom after vaccination, the mechanism, and prognosis are not well understood.Aims/ObjectivesThis study aimed to investigate patients with dizziness after COVID-19 vaccination by analyzing objective information.MethodsA retrospective study of patients who visited the outpatient clinics of two institutes with a complaint of dizziness occurring within 72 h after a COVID-19 vaccination.ResultsIn most cases, patients experienced only a single event of dizziness, and the subjective symptom was relieved after a few weeks. All patients decreased gain of vestibular ocular reflex (VOR). The vestibular function test results showed signs of central vestibulopathy in some cases. We separated patients into two groups; the direction-fixed nystagmus (DFN) group and the direction-changing nystagmus (DCN) group. All patients showed decreased gain on the rotational chair test (RCT). The DFN group showed an 80% decrease in video head impulse test (vHIT) gain, whereas the DCN group only showed a decrease of 25%. In RCT, 66% of the DFN group showed asymmetry compared to 20% showing asymmetry in the DCN group.Conclusion and significanceThe patients who suffered from dizziness after the COVID-19 vaccination exhibited decreased VOR gain and in some cases signs of central vestibulopathy.