Balancing the Caloric-Induced Nystagmus Velocity with Cold Air and Water

A useful alternative to the traditional water caloric is to use an air stimulus. However, the caloric test has not been standardized and a range of parameters are being used in different audiology clinics. The aim of this study was to determine cold air parameters that resulted in a similar slow-component eye velocity to that for water irrigation. Twelve normal subjects underwent caloric testing using air temperatures in the range 18-33 degrees C. The duration and air-flow rate were held constant at 60 s and 5 l/min. A water irrigation at 30 degrees C for 30 s and delivering 150 ml resulted in a mean slow-component eye velocity of 17 degrees/s. An equal response was obtained with an air temperature of 21.0 degrees C. Further work is required to find equivalent air and water responses for other combinations of parameters.