Differential caloric stimulations in vestibular diagnosis.

Abstract

IT IS a little over a half a century since vestibular function testing became applicable in the clinic. Depending solely upon the duration of the provoked vestibular nystagmus, the clinician was satisfied to establish the presence or absence of function or, in pronounced pathology, to identify major asymmetries between right and left. Improvement first came through refined techniques like cold and hot caloric stimulations or cupolometry, and shortly afterwards, by measuring and analyzing parameters of nystagmus intensity. Counting the nystagmus frequency in time units has been proposed (Torok, 1948)1as a reliable expression of the intensity of the elicited vestibulo-ocular reflex, as has the measurement of the velocity of the slow phase of the nystagmus (Henriksson, 1956).2Nystagmography was mandatory to execute critically such measurements. It was offered to the clinician as a means of discriminating between normal and abnormal test results, ie, healthy and diseased vestibular function.