No abstract

Canalolithiasis and cupulolithiasis are known to be a primary etiology of benign paroxysmal positional vertigo (BPPV). In lateral canal type BPPV (L-BPPV), direction-changing geotropic or apogeotropic nystagmus is present. In many cases, the latency is long in canalolithiasis and short in cupulolithiasis. However, there are a few cases that do not fit in this general notion. Physiological factors, including volume, number, friction and viscosity of the otoconial debris, and velocity of the moving debris may well affect the latency of nystagmus. Horizontal nystagmus induced by an utricular disorder is another potential factor that may contribute to horizontal nystagmus of L-BPPV. The nystagmus pattern in L-BPPV is not simple, but sometimes complex, thus making its diagnosis difficult.

No abstract

Vestibular evoked myogenic potentials which are induced around the eyes are known as ocular vestibular evoked myogenic potentials (oVEMPs) and are useful for the clinical examination of vestibular function. Cervical vestibular evoked myogenic potentials (cVEMPs) have been used as a test of the vestibulo-collic reflex, particularly the sacculocollic reflex. In Ramsay Hunt syndrome, facial palsy of the eighth cranial nerve spreads from the geniculate ganglion via the vestibulofacial and vestibulocochlear anastomoses. Other studies have also reported that vertigo in patients with Ramsay Hunt syndrome is mostly induced by superior vestibular neuritis. We identified oVEMPs in patients with unilateral facial palsy and analyzed the association of oVEMPs with clinical usefulness, recovery of facial palsy, and pathology of Ramsay Hunt syndrome. Seventeen patients with facial palsy were enrolled in this study. There were 6 cases of Bell's palsy and 11 cases of Ramsay Hunt syndrome. Vertigo in patients with Ramsay Hunt syndrome was induced by superior vestibular neuritis rather than inferior vestibular neuritis, as was indicated by the frequent impairment of oVEMPs. There was a tendency for patients with a low electroneurography (ENoG) value, and patients who had improved slowly, to show abnormal oVEMPs.