The Caloric Test and the Video Head-Impulse Test in Patients with Vertigo

Abstract

OBJECTIVE:The caloric test and the video head-impulse test are diagnostic tools that examine the function of the horizontal semicircular canal. There are major differences between the two tests. These are stimulus characteristics, methodology, and function examined. MATERIALS and METHODS:This is a prospective work in 123 patients with different types of vestibular disease seen because of dizziness in which both procedures were performed the same day. First, the spontaneous nystagmus and head-shake nystagmus were measured. The video head-impulse test was carried out, and finally, the caloric test was performed with water at two different temperatures. Both ears were irrigated alternately. Main outcome measures were the canal paresis in the caloric test and gain of vestibulo-ocular reflex, gain asymmetry, and refixation saccades in the vHIT. RESULTS:The caloric test and the vHIT results were fully coincident in 60 patients (48.7%), and the results for both were normal in 36 patients. Discrepancies were found in 3 patients regarding the deficient side, and in 14 patients, an added contralateral (according to the caloric test) abnormal result was obtained. In 46 patients, one of the tests was normal while the other was not, but both were in accordance with the diseased side. The correlation coefficient for canal paresis and gain asymmetry was 0.67, and the agreement was low: κ=0.252. CONCLUSION:The assessment of horizontal semicircular canal function with the vHIT needs to take into consideration not only the gain in VOR but also the existence of refixation saccades. The information from both methods is redundant in some cases but complementary in most, and the existence of discrepancies is very low.

Comparison of two VHIT software programs in diagnostics of semicircular canals

“…These results were also important in the context of interpreting VHIT results that were not previously clear cut or unambiguous. Many authors have reported cases where patients with abnormalities found using sinusoidal tests gave normal VHIT results [5][6][7].…”

Video head-impulse test (vHIT) in dizzy children with normal caloric responses

“…The test is objective and reliable that can assess vertical and horizontal semicircular canals [8]. The subjective bed side HIT has some drawbacks in which there is no quantitative estimation of the extent of VOR gain and it is a purely subjective estimation of the clinician.…”

“…This may be because the disease is in another part of the inner ear (as in the case of patients with BPPV) or because it does not strike in the inner ear (as in some cases of chronic subjective dizziness) and it could be cases with vestibular migraine, cervicogenic vertigo, sacular disorders and systemic causes [8].…”

“…A relative parameter was created and defined as gain asymmetry (Gs) from the gain value obtained for rightward head-impulses (Gr) and leftward head-impulses (Gl). A normal result is defined by gain >0.6 without saccades; this value is taken from the most restricted obtained after evaluation of patients with vestibular neuritis and after neurectomy [8]. Abnormal results were of two types: normal gain with refixation saccades and low gain (<0.6) either with or without saccades.…”

Usefulness of Ultrasound-Computer-Craniocorpography in Unilateral Ménière’s Disease

“…For establishing a necessary topodiagnostic procedure, we are using a neurotological history scheme, audiometry, computer-based electronystagmography with caloric and optokinetic tests, and VHIT [2] along with evaluating speech audiometry and evoked responses. Based on the literature, VEMP (either cervical or ocular) did not show any use in MD [3].…”