Reliability of examination data in the diagnosis of benign paroxysmal positional vertigo.

A practical clinical view of the reliability of the data obtained in the several steps of the examination procedure is discussed to obtain an objective basis for the selection of patients with provoked vertigo (benign paroxysmal positioning vertigo [BPPV]) 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 upon a typical history, but also upon the presence of a reproducible vertigo and paroxysmal positional nystagmus (ppn). Such a ppn can be reproduced not only as a "classic" nystagmus by the Dix-Hallpike maneuver, but also as a positional nystagmus and vertigo during electronystagmographic recording in the position tests and in the vestibular habituation training (VHT)-test battery (a battery of 19 maneuvers applied for defining the adequate exercises in the rehabilitation treatment of BPPV). The ppn is not a constant reproductible sign in every patient, and in some, only one of these tests confirms the BPPV. This experience is confirmed by the analysis of the reviewed data in 95 patients, which showed that one third of the patients described their vertigo in a rather atypical way, whereas further testing revealed a BPPV. In this way any absolute reliability of history has to be denied. In fact, only the finding of a ppn is conclusive for confirming BPPV. However, as in former experiences, here too, the presence of such a ppn appeared not to be a constant datum, so that in some patients more than one examination was necessary to come to a reliable diagnosis. Patients in whom only vertigo could be reproduced, never confirmed by nystagmus, were excluded as an atypical ppv group.