The screening value of monothermal caloric tests.

A valid screening caloric test should decrease examination time, increase patient comfort and maintain a high degree of sensitivity in predicting bithermal (BT) caloric results. This prospective study of 362 consecutive electronystagmograms (ENG) compared right/left (R/L) difference results obtained using monothermal (MT) warm and cold irrigations alone with that of the (combined) BT tests. Comparing MT warm and cold irrigations, false negative (normal MT but abnormal BT test) results were obtained in 14% and 25% of irrigations, while false positive (abnormal MT but normal BT test) information was obtained in 22% and 15% of irrigations, respectively. False negative MT tests preclude detection of the abnormal BT test, while false positive tests require unnecessary completion of the BT caloric irrigations. This lack of diagnostic sensitivity limits the usefulness of the MT irrigation as a screening test.