Diagnostic testing for endolymphatic hydrops.

The development of a sensitive and specific diagnostic test for endolymphatic hydrops has eluded investigators for over 30 years. The absence of such a test has hampered basic and clinical research into Meniere's disease and related entities. Presently used tests are limited in their applicability because of their low sensitivity and specificity and a poor understanding of the underlying physiologic principles. Despite this, it is generally agreed that some of these studies have merit in selected situations. This article reviews the present state of diagnostic testing for endolymphatic hydrops. The use of nonspecific studies, such as basic audiometry and tests for recruitment, and "specific" studies, such as electrocochleography and dehydration testing, are critically reviewed.