Significance of Caloric Test in Reversed Position.
- Author:
Sung Wan BYUN
1
;
Soon Kwan HONG
;
Chun Dong KIM
;
Hye Jin YOON
;
Sang Il PARK
;
Hyun Jeong HONG
;
Ju Ae CHANG
;
Sung Hye KIM
Author Information
1. Department of Otolaryngology, College of Medicine, Ewha Womans University, Seoul, Korea. byunsw@chollian.net
- Publication Type:Original Article
- Keywords:
Barany's thermal convection theory;
Caloric nystagmus;
Caloric test
- MeSH:
Caloric Tests*;
Convection;
Ear;
Gravitation;
Nystagmus, Physiologic;
Semicircular Canals
- From:Korean Journal of Otolaryngology - Head and Neck Surgery
1998;41(10):1264-1268
- CountryRepublic of Korea
- Language:Korean
-
Abstract:
BACKGROUND AND OBJECTIVES: Caloric nystagmus has been known since a century ago, and the thermal convection theory proposed by Barany has been widely accepted. Gravity plays an important role in thermal convection. In 1984, caloric nystagmus was reported in weightless space environments and although the response was weak, the nystagmus was found to occur in the same direction as the earth. This implies that factors other than thermal convection might participate in the caloric nystagmus. MATERIALS AND METHODS: Using 50 normal ears as subjects, this study compared the responses of conventional caloric test and reversed caloric test, which places the plane of the lateral semicircular canal upside down. RESULTS: The direction of the nystagmus was reversed, and the maximal slow phase velocity was decreased compared to that of the normal caloric test. CONCLUSION: The reversed direction of the nystagmus observed in this study basically supports the theory by Barany, however, the differences that are noted implicate that other factors with a certain direction maybe involved.
