Abstract
In patients with vertigo, complaints vary from a strong sensation of rotation to a vague feeling of unsteadiness. We investigated the relationship between vertiginous sensation and maximal slow phase velocity (SPV) of nystagmus during alternate bithermal caloric test in normal volunteers. We also studied age-related changes in the test results.
The subjects consisted of 44 normal volunteers (10 males and 34 females), ranging from 17 to 78 (mean 43.9) years of age. Water stimuli of 40 ml at two different temperatures (30 and 44°C) were alternately given for 20 sec to the bilateral ears. Overall, 176 stimuli were administered.
Results. Vertigo, dizziness and absence of abnormal feelings were noted in 79.8, 13.7 and 6.5% of all ear stimuli, respectively. Mean SPVs in subjects with these findings were 23.4, 15.8 and 16.7 °/sec, respectively. It was speculated that the sensation of rotation was accompanied by SPV above about 20°/sec. There were no significant differences of SPV between in subjects with dizziness and subjects without abnormal feelings. To study changes in vertiginous sensation and SPV with age, the subjects were divided into 5 groups with 10 year intervals. The mean SPVs accompanying vertiginous sensation were 25.4°/sec in the group <30 years, 20.5°/sec in the group ≥30 and <40 years, 24.6°/sec in the group ≥ 40 and < 50 years, 21.8°/sec in the group ≥50 and <60 years, and 24.8°/sec in the group ≥60 years. Since there were no significant differences among these groups, SPV accompanying vertiginous sensation did not correlate with age.
