[Air caloric test: as useful as the water caloric test (author's transl)].
Twenty normal probands were examined by us with air (60 sec, 121/min, 45 degrees/29 degrees C) and 25 with water (30 sec, 30 cm3, 44 degrees/30 degrees C) caloric test. Additionally we evaluated the influence of flow rate and tip position on the temperature near the tympanic membrane during the irrigation, using a polyacryl copy of the external auditory canal. A high flow rate and a reproducible tip position very near to the tympanic membrane during the irrigation appeared to be essential to achieve reliable results in air caloric test. Measurements of the actual temperatur should be done therefore at the irrigation tip delivery in every caloric test with air. Lower heat capacity of air, air jamming near the tympanic membrane and heat losses through the meatus wall are the main reasons of more distinct temperature drops and a higher variability in air caloric test, than in the common caloric test with water. Therefore, the air caloric test as a reliable instrument should be reserved for those cases, were water is contradicted.