前庭血管系反射と起立性循環調節

Abstract

There is little definitive evidence of the clinical significance of the vestibular-cardiovascular reflex in humans, despite the fact that the vestibular system is known to contribute to cardiovascular control in animals. Our first finding in this paper was that about 10% of 1479 dizzy patients in our hospital met the criteria for orthostatic hypotension (OH) set by the American Autonomic Society (2011). Second, a positive rate of the criteria for the OH was significantly higher in patients with abnormal subjective visual vertical (SVV) than patients with normal SVV, however abnormality of canal function did not affect the positive rate of the OH. Third, we classified 248 dizzy patients aged<65 into three groups based on their vestibular evoked myogenic potential (VEMP) responses; absent VEMP, asymmetry VEMP and normal VEMP. In order to investigate the effect of the otolith disorder, which was estimated by the VEMP, on the orthostatic blood pressure responses, the subjects' systolic blood pressure (SBP), diastolic blood pressure (DBP) and heart rate were monitored during the orthostatic test after standing up. The male patients in the absent VEMP group presented a significant drop in their DBP at 1 min. after standing up (p<0.05) without any change in SBP. In the entire group of participants, a total of 19.6% of the patients in the absent VEMP group fulfilled the criteria for orthostatic hypotension (OH), which was significantly larger than the 8.6% of patients in the normal VEMP group and the 7.2% in the asymmetry VEMP group (P<0.05). Our results suggest that vestibular disorders due to the dysfunction of otolith organs provoke OH.