The diagnostic framework of peripheral positional vertigo and dizziness (PPVD): a new concept based on the observation of alcohol-induced posterior canal light cupula.

The aim of the authors is to document positional alcohol nystagmus type I (PAN I) elicited by positioning in pitch plane in order to activate/inhibit the vertical canals. The second aim of the present paper is to review possible nystagmus patterns in benign paroxysmal positional vertigo (BPPV) by creating a comprehensive framework for peripheral positional vertigo. Beside paroxysmal variants, also more subtle, persistent nystagmus types have to be integrated into this framework; therefore the use of the term ‘peripheral positional vertigo and dizziness’ (PPVD) is suggested. In four healthy individuals the first phase of the PAN I was studied minimum 60 min after alcohol ingestion. As anticipated, positioning from sitting into head hanging prone position elicited persistent purely upbeat nystagmus, and then the positioning back from this position evoked a purely downbeat nystagmus with similar dynamics. These results help to understand the different types of PPVD. It is possible to elicit purely vertical upbeat and downbeat nystagmus by symmetrical positioning in head hanging prone, head hanging supine and sitting positions after alcohol ingestion (PAN 1). [ABSTRACT FROM AUTHOR]