Influence of hyperlipidemia and smoking on age-related changes in caloric response and pure-tone hearing.

To examine the influence of hyperlipidemia and smoking on age-related changes in caloric response and pure-tone hearing, a caloric test and pure-tone audiometry were performed in 14 healthy volunteers and in 78 tinnitus patients without subjective hearing loss. The patients were from 24 to 84 years of age, and were divided into 4 groups: the no-risk group (N group), the smoking alone group (S group), the hyperlipidemia alone group (L group), and the smoking plus hyperlipidemia group (S-L group). Slow phase eye velocity of the caloric nystagmus (SPEV) and average hearing level at high frequencies were compared between the N groups and the other groups. There was a significant difference in SPEV only between the N and S-L groups, but not in the hearing level. This suggests that age-related changes in the caloric response be promoted by atherosclerosis, unlike presbycusis.