The Normal Limits of CP and DP in the Caloric Test

Abstract

The purpose of this study was to determine the normal limits of canal paresis (CP) and directional preponderance (DP) in the bithermal caloric test. Data were collected from two groups. Group I consisted of 23 young normal subjects. Group II consisted of 89 patients selected from a total of 405 patients referred, because of attacks of vertigo, for pure tone audiometory and vestibular testing to determine the nature of vestibular and/or cochlear disturbances. The maximum eye speeds of the slow phase of all four irrigations were calculated from Jongkees' formula. The normal range corresponded to the mean±2 standard deviations in each group. The results showed that the normal limits of CP and of DP should be set at ±25% and ±19% respectively, in group I, and ±33% and ±33%, respectively, in group II.