In 1970, Torok studied the obtained between the response to two different heat stimulation intensities at the same temperature. A decrease in response to the strong stimulus(i.e., a diminished ratio) was called 'vestibluar decruitment', and it was regarded as a topodiagnostic indicator of central vestibular lesion. In order to evaluate the reliability of vestibular decruitment defined by Torok's technique, the authors analyzed 11 normal individuals and 13 patients with definite pathology of central nervous system by monothermal caloric test. The results obtained were as follows ; 1) In the control group, normal ratio(1.2 to 3.5) was seen in 8 cases(72.7%) ; decruitment (<1.2) in 3 cases(27.3%) ; recruitment(>3.5)in 0 cases. 2) In the group with central pathology, normal ratio was seen in 2 cases(15.4%) ; decruitment in 11 cases(84.6%) ; recruitment in 0 cases. 3) The application of Fisher's exact test(two tail) demonstrated that 11 cases(84.6%) of decruitment from the group with central pathology were significantly larger than 3 cases(27.3%) of decruitment from the control group(p=0.01109). 4) Decruitment-type ratios were observed. In the control group, all 3 cases of decruiment were type I decruitment. In the group with central pathology, distribution according to degree of decrutiment was as follows : type I decruitment, 6 cases ; type II decruitment, 5 cases ; type III decruitment, 0 cases. We observed directional correlation between CNS pathology and decruitment. In the group with central pathology, 8 cases were unilateral both CNS pathology and decruitment. Three of these cases showed decruitment ipsilateral to the CNS pathology and were distributed as follows : brainstem lesions, 2 cases ; cerebellar lesion, 1 case. Five remainders of these cases showed decruitment contralateral to the CNS pathology and were distributed as follows : basal ganglia lesions, 3 cases ; thalamic lesions, 2 cases. All cases of CNS pathology contralateral to the decruitment were located above brainstem.