Clinical importance of the minimal caloric test

Abstract

Introduction: The classic Fitzgerald-Hallpike caloric test (CCT) is usually utilized for evaluation of vestibular pathology. With this test, however, superior vestibular nerve function is assessed through stimulation of the lateral semicircular canal only. The minimal caloric test (MCT) allows for evaluation of both superior and inferior vestibular nerve function, through horizontal and posterior semicircular canals stimulation, respectively. The actual impact of MCT on the clinical evaluation of patients presenting with vestibular symptoms is unknown. Purpose: To quantify the diagnostic usefulness of MCT in patients with vestibular symptoms. Material and Method: Transversal diagnostic study. Sensitivity and specificity of MCT were obtained by comparing the lateral semicircular canal response in both MCT and the conventional caloric test. We assessed the number of cases in which the vestibular nerve function information obtained with MCT was relevant for vestibular diagnostic. Results: 44 patients were studied. The sensitivity and specificity of MCT to detect pathologic conditions via lateral semicircular canal stimulation were 93% (CI 95%: 84%-100% and 80%-100%, respectively). In 16% (n =7) of the cases, MCT detected inferior vestibular nerve involvement with normal CCT. Conclusions: MCT is a complementary test, which can be useful for evaluation of patients with vestibular symptoms, given its high sensitivity and specificity to detect superior vestibular nerve pathology through lateral semicircular canal stimulation. In addition, it provides information on the inferior vestibular nerve status, through posterior semicircular canal stimulation. The latter is not provided by conventional CCT.