Spontaneous nystagmus in horizontal canal benign paroxysmal positional vertigo

Objective Benign paroxysmal positional vertigo of horizontal semicircular canal (HSC-BPPV) is characterized by either geotropic or apogeotropic nystagmus induced by head roll test. Some patients also present with spontaneous nystagmus. The aim of this study is to examine the clinical manifestation of spontaneous nystagmus in HSC-BPPV and evaluate the effect on the treatment outcome. Patients and methods Electronystagmography and video eye movement recordings of 125 patients diagnosed as HSC-BPPV were reviewed retrospectively. Presence of spontaneous nystagmus was analyzed and treatment outcome after repositioning therapy was compared. Results Overall, spontaneous nystagmus was observed in 19 patients (15.2%) with HSC-BPPV at initial presentation. In canalolithiasis group (n = 64), the treatment outcome did not differ between patients with or without spontaneous nystagmus. However, in cupulolithiasis group (n = 61), patients presenting with spontaneous nystagmus (n = 10) required more repositioning therapy sessions. Conclusion The presence of spontaneous nystagmus at initial presentation may implicate poorer treatment outcome in cupulolithiasis HSC-BPPV patients.