Reliabilities of air and water caloric responses.

Air is a safer and more convenient caloric-irrigating medium than water, but many otologists are reluctant to use it because they suspect that it yields less reliable nystagmus responses. To compare reliabilities of air and water caloric responses, we subjected eight normal persons to 12 irrigations each of 50 degrees C air, 44 degrees C water, 24 degrees C air, and 30 degrees C water. Standard caloric-testing conditions were used, and nystagmus responses were recorded by the method of electronystagmography. We found that the reliabilities of air and water caloric responses were not significantly different. A single observation permitted estimation of response strength within approximalely +/- 5 degrees/sec (95% confidence level), regardless of whether air or water was used as the irrigating medium.