[Inferior vertical nystagmus: is magnetic resonance imaging mandatory?]

The presentation of a down-beating nystagmus force to discard vascular pathology of brain and cervical joint with magnetic resonance imagine (MRI). Recent studies support the low profitability of this study and is subjected that this oculomotor sign has a peripheral origin especially when the patient has a benign paroxysmal positional vertigo (BPPV) with affection of the superior semicircular canal.

To evidence the profitability of MRI in a population of patients with positional down-beating nystagmus.

We present a retrospective study with 42 consecutive patients. A complete clinical history and physical examination was performed. All of them perform vestibular tests (caloric and rotatory), cranial and cervical MRI.

Fifty-two percent of patients present clinical manifestations and physical exploration compatible with BPPV. MRI was normal in 67%. We found spondylopathy in 26% and vascular cerebral pathology in 5%. Prevalence of type I Arnold-Chiari malformation was 9% in our population. None of them was founded when the main symptom was suggestive of BPPV. Results obtained of vestibular tests didn't contribute additional information to give an ethiologic diagnosis.

The profitability of vestibular tests and MRI in our population with down beating nystagmus was very low. We must evaluate the real necessity of this test with the clinical context.