Some patients have different vertiginous symptoms such as faintness, rotatory sensation or swaying sensation when rising to the standing position. These symptoms, hereafter referred to as orthostatic vertigo (OV), are believed to occur due to hypoperfusion of the brain with the orthostatic decrease in blood pressure (BP). However, it is unclear whether the orthostatic decrease in blood pressure is directly involved in the onset of OV. Therefore, we studied the influence of the orthostatic change in BP on OV. All 780 subjects in the present study had orthostatic changes in their BP examined, including 239 cases with OV and 541 cases without OV. Orthostatic hypotension (OH) was defined as a systolic BP decrease of more than 20 mmHg when standing. In subjects with a BP of 140 mmHg and over before standing, the orthostatic decrease in BP was more than 20 mmHg in cases with OV, significantly different from those without OV. In the case of a BP over 160 mmHg, subjects with OV showed a severe OH greater than 30 mmHg. In contrast, when the BP was under 140 mmHg, OH was not detected even in those subjects with OV. Under 110 mmHg BP, there was no difference of orthostatic decrease in blood pressure between in cases with OV and those without OV. These results suggest that it is necessary to consider the BP before standing when assessing the incidence of OV due to OH.
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