Classification of various manifestations of benign positional paroxysmal nystagmus, due to canalolithiasis or to cupulolithiasis, as a reaction to movements and to the site of detritus, is now possible due to the integration of theoretical knowledge (relationships between the semicircular canals and/or ampullae and the vestibulo-ocular pathways) with the forms of nystagmus induced when the head is placed in various positions. A comparison is made of results in patients examined in three Departments, during the past 3 years, and data presented in the literature. Findings are presented in a database which enables the clinician to compare the standard diagnostic manoeuvres (Dix-Hallpike, Pagnini-McClure, Rose) with results obtained by placing the head in alternative positions. This approach offers all the information needed to identify the site of onset and hence to formulate a correct diagnosis, thus directly indicating the most appropriate liberating or repositioning manoeuvre or--in the case of a suspected central lesion--to suggest further tests. Moreover, it is suggested that this table could become a useful tool for teaching purposes.