Wet air as an alternative to traditional water irrigation during caloric vestibular testing

To evaluate whether caloric vestibular testing by wet air (WAI) is better than by dry air (DAI) in comparison to the gold standard using water (WAT).

Prospective study, comparison with reference standard.

Fifty volunteers with normal ear and balance function were enrolled in a prospective study. After side-specific warm and cold DAI, WAI, and WAT experimental nystagmuses were recorded using video-oculography. Peak slow nystagmus phase velocity (SPV) data at test culmination and the subjective tolerance of the methods were analyzed by visual analog scale.

The three methods differed significantly with respect to warm versus cold stimulation and stimulus side, with one exception. In the case of cold stimulation on the left side, SPV values did not differ between DAI and WAI. The intraclass correlation coefficients (ICCs) of WAT versus WAI were indicative of a medium to high agreement with the SPV data for all four individual irrigations. The ICCs of the WAT/DAI comparison were usually smaller. Generally, smaller individual differences were shown in Bland-Altman plots comparing WAI and WAT than plots comparing DAI and WAT. WAI had better subjective tolerability than WAT.

WAI is an alternative caloric test method for anxious subjects oversensitive to WAT and probably for patients with suspected pathological ear canal and tympanic membrane findings.