title: When paroxysmal positioning vertigo isn't benign.
abstract: The electronystagmographic auditory brainstem response and magnetic resonance imaging findings for a 33-year-old male with a 3.5 cm left vestibular schwannoma are presented. Of particular interest was the presence of an unusual positioning nystagmus following the Dix-Hallpike maneuver in the right head-hanging position. The patient demonstrated a nystagmus that was immediate in onset and not fatigueable upon repeated positioning. During positioning, the patient experienced a vertical bobbing sensation and dysphoria, but not rotational vertigo. Most importantly, the nystagmus had a predominant downbeating vertical component. the case illustrates the diagnostic significance of downbeating nystagmus elicited by the Dix-Hallpike maneuver.
authors.affiliation: Department of Otolaryngology-Head and Neck Surgery, Henry Ford Hospital, Detroit, Michigan 48202, USA.
authors.forename: G P
authors.initials: GP
authors.lastname: Jacobson
authors.forename: J A
authors.initials: JA
authors.lastname: Butcher
authors.forename: C W
authors.initials: CW
authors.lastname: Newman
authors.forename: E M
authors.initials: EM
authors.lastname: Monsell
mesh_terms: D000328:Adult; D001299:Audiometry; D004584:Electronystagmography; D007839:Functional Laterality; D006319:Hearing Loss, Sensorineural / Q000175:diagnosis / Q000503:physiopathology; D006801:Humans; D008279:Magnetic Resonance Imaging; D008297:Male; D009464:Neuroma, Acoustic / Q000150:complications / Q000175:diagnosis / Q000473:pathology; D009759:Nystagmus, Pathologic; D014717:Vertigo / Q000175:diagnosis* / Q000209:etiology; D000159:Vestibulocochlear Nerve / Q000473:pathology