Intervals for Successive Caloric Irrigations

Abstract

In order to evaluate the precise intervals for successive caloric irrigations of the bilateral ears, a total of 72 normal ears (36 persons) and eight ears with central perforated tympanic membrane were examined using a caloric stimulus with 20 ml water at 20 degrees centigrade for 20 s. Nystagmus was examined using infrared CCD Frenzel spectacles, and the parameters were recorded on an electro nystagumograph. For normal ears temperature changes of the ear canal following irrigation were examined using an infrared tympanic thermometor and changes in the promontory of the perforated ear were examined by microthermistor via the perforatin. For normal ears nystagmus on ENG ceased after 288 s (mean+2 s.d.), and using CCD spectacles it ceased after 336 s. For perforated ears ENG stopped after 258 s. Thus, the waiting time for successive caloric irrigations of the bilateral ears was 5.6 minutes. In addition, since it took 15 minutes for the temperatures of the normal ear canal to return to the original temperature, the waiting time for the same ear was 15 minutes.