title: Vertical component of the caloric response, including a caloric second phase provoked by positional change: a preliminary report.
abstract: We measured the horizontal and vertical components of caloric nystagmus in 120 ears of 60 vertiginous patients who had moderate to vigorous caloric first-phase response in both ears, no spontaneous nystagmus, and no severe disorders in the central nervous system. We provoked a caloric first phase in the supine position with 5 ml of water at 20 degrees C for 15 seconds. We provoked a caloric second phase by changing the position of a patient from supine to sitting after the end of the first phase. The horizontal component of the caloric second phase was recorded in 108 of 120 ears (90%). The vertical component was recorded in 57 of 120 ears (48%) during the caloric first phase and in 51 of 120 ears (43%) during the caloric second phase. We suspected that the vertical component of the caloric first phase was mainly due to the inhibition of the anterior semicircular canal.
authors.affiliation: Department of Otolaryngology, Tokyo Women's Medical University, Medical Center East, Tokyo, Japan. yaot@dnh.twmu.ac.jp
authors.forename: Sachiko
authors.initials: S
authors.lastname: Aoki
authors.forename: Yasuko
authors.initials: Y
authors.lastname: Arai
authors.forename: Natsumi
authors.initials: N
authors.lastname: Ide
authors.forename: Eisaku
authors.initials: E
authors.lastname: Sugiura
authors.forename: Keisuke
authors.initials: K
authors.lastname: Miyajima
mesh_terms: D000328:Adult; D000368:Aged; D002150:Caloric Tests; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D009760:Nystagmus, Physiologic; D011187:Posture; D012665:Semicircular Canals / Q000503:physiopathology; D014717:Vertigo / Q000175:diagnosis / Q000503:physiopathology*