2.1 Subjects
The following subjects participated in these experiments.
Normal volunteers under 65 years of age (control group)
N= 50, age: 21- 42 years, average age: 29 years, standard deviation (SD): 5 years, and age distribution: second decade: 20, third decade: 22, fourth decade: 8. The definition of normal volunteers was that they had no vertigo or past history of neurological disease.
Bilateral no response to the Caloric test (bilateral group)
N= 20, age: 18- 75 years, average age: 51 years, SD: 17 years, and age distribution: first decade: 3, third decade: 4, fourth decade: 3, fifth decade: 4, sixth decade: 3, seventh decade: 3. The details of the underlying diseases in the 20 patients are as follows: idiopathic: 8, meningitis: 5, neurofibromatosis type 2 (NF2): 4, auditory nerve disease6: 2 and syphilitic labyrinthitis: 1. The Caloric test used irrigated cold water (4℃, 2 ml) for 20 seconds.