Sources of error in interpretation of caloric tests.

Abstract

Caloric testing plays a prominent role in evaluating the vestibular system. A unilateral reduced vestibular response (RVR) is a common abnormality and is consistent with peripheral vestibular pathology. An erroneous interpretation of RVR may be made due to the following circumstances: laboratory technique, the influence of directional preponderance (DP) on monothermal tests (MT), unilateral hyperactivity, or pseudocaloric (PC) nystagmus. These errors in interpretation may be avoided by (1) repeating any single irrigation that is significantly different from the other three, to rule out laboratory technical error; (2) performing bithermal (BT) testing exists, to eliminate the effects of directional preponderance; (3) observing that a right/left (R/L) difference is not due to unilateral hyperactivity, by noting absolute slow phase (SP) velocity; and (4) by demonstrating bidirectional sensitivity of the cupula before concluding that residual caloric function exists instead of no function.