Three-Component Analysis of Caloric Nystagmus in Humans

Clinical significance of vertical component of caloric response including its second phase in vertiginous patients

“…Where does the vertical component originate from? It is reported that all three semicircular canals are inhibited during cold calorization in a supine position [2,3]. Suzuki et al [13] and Cohen et al [14] proved in an animal experiment that the vertical nystagmus toward the upper eyelid is generated by the inhibition of the anterior canal or excitation of the posterior canal.…”

“…Patients with suspected central vestibular disorders underwent brain MRI or CT examination, which revealed no abnormality except for aging change such as small lacunar infarctions. (3) No spontaneous nystagmus in total darkness with eyes open and with eyes closed. (4) No positioning nystagmus examined by Stenger's maneuver.…”

“…Since then, the caloric test has been very useful as a method to check the function of each labyrinth separately. Although the caloric response is caused by all three semicircular canals [2,3], the vertical component of the caloric response was rarely discussed due to the difficulty of its accurate measurement in electronystagmography (ENG). Likewise, interest in the caloric test was restricted to the first phase, because normally the caloric second phase did not appear when the subject remained in their original testing position [4].…”

Is horizontal semicircular canal ocular reflex influenced by otolith organs input?

“…Several researchers consider that the origins of vertical and torsional components are the posterior and superior semicircular canals [1,2]. However, it has been clear that neither posterior nor superior canal receives a caloric effect, on the basis of the fact that elicited nystagmus stops in the sitting position [3,4].…”

Image analysis of quick phase eye movements in nystagmus with high-speed video system

“…Unlike ENG, the analysis of nystagmus by means of image processing can measure three components of nystagmus (horizontal, vertical and torsional) and is of great help in the diagnosis of vertigo. Three-component analysis of nystagmus including the torsional component using normal VOG is useful for diagnosing vertigo such as benign paroxysmal positional vertigo (BPPV) (FETTER et al, 1995;YAGI et al, 1992;1997). A normal video system with 30flames/s, which is used in clinical situations, can precisely record the slow phase of nystagmus but cannot detect quick phase eye movement accurately (JUHOLA et al, 1985).…”