簡易温度刺激検査の再検討 Ａｉｒ ｃａｌｏｒｉｃ刺激装置を用いて

Abstract

The simple cold caloric test (20°C, 5 ml water irrigation for 10 sec. and stimulation for 20 sec.) is an established method of investigating right and left vestibular function separately. In addition, this test should decrease examination time and patient's discomfort.The caloric response in this test is considered to be normal when the maximal slow phase eye velocity (MSV) is not less than 20°/sec.. We have used the simple caloric test as one of the routine vestibular function tests.As stimulation, air irrigation (15°C, 61/min., 60 sec.) is used instead of water irrigation.We have experienced that the MSV in both ears equally showed less than 20°/sec., or a large difference although each ear revealed normal caloric response.Therefore, we reexamined the simple cold caloric test for 24 normal volunteers. The purpose of the study was to investigate in normal subjects whether the MSV of both ears was equal or a normal caloric response was obtained. The results were follows, 1) MSV not less than 20°/sec. was demonstrated in 83% of normal volunteers. 2) The MSV in these subjects ranged from 9°/sec. (minimum) to 50°/sec. (maximum). 3) There was good correlation between the right and left MSV (mean±2SD). It is concluded that, in the response to simple cold caloric test, there are individual differences but not very much difference between the right and left ear of the same individual.