Diagnostic problems in patients with benign paroxysmal positional vertigo.

The steps of the examination procedure applied for a correct diagnosis of benign paroxysmal positional vertigo (BPPV) are reviewed. A precise diagnosis is important in view of treatment of this type of vertigo by rehabilitation therapy. Clinical experience supports the concept that the diagnosis has to be based not only on a typical history, but also on the presence of a reproducible vertigo and paroxysmal positioning nystagmus. In the procedure applied in the department, this nystagmus can be reproduced by the Dix-Hallpike maneuver under Frenzel's glasses, during electronystagmography (ENG) recording in the position tests, or it can be present in the vestibular habituation training test battery (a battery of 19 maneuvers applied for defining the adequate exercises in the rehabilitation treatment for BPPV). Analysis of the reviewed data in 95 patients showed that one third of the patients described the vertigo in a rather atypical way, while the further testing revealed a typical BPPV. This experience denies any absolute reliability to only history. In fact, only the finding of such a paroxysmal positioning nystagmus is conclusive for confirming BPPV. However, also the presence of such a nystagmus appeared not to be a constant datum, so that in some patients more than one examination was necessary to come to a reliable diagnosis. It is obvious that, for detecting a paroxysmal positioning nystagmus, ENG is less reliable than the Dix-Hallpike maneuver under Frenzel's glasses.