We analyzed data collected from 134 patients (37 males and 97 females) with dizziness and/or vertigo who were confirmed to have orthostatic dysregulation (OD) based on a questionnaire survey between December 1990 and November 1994. The patients ranged in age from 10 to 80 years with a mean age of 42.5 years for males and 44.6 years for females. Patients with OD consulted our clinic more frequently in summer than in the other seasons. Orthostatic dizziness was the most common manifestation among

more »

... the major symptoms of OD and was noted in 116 of 134 patients (86.6%). Fatigue was the most frequent complaint among the minor symptoms of OD and was noted in 97 of 134 patients (72.4%). OD was noted in 47 patients (35.1%) with dizziness or vertigo of unknown origin, in 22 (16.4%) of those with Meniere's disease, in 18 (13.4%) with dizziness or vertigo from central disorder, in 14 (10.4%) with hypotension, and 33 (24.6%) of those with other disorders. As for the positive rate on Schellong test, patients with OD and control subjects, showed 49.2% and 27.8%, respectively, and this difference was significant. These results suggest that autonomic imbalance suspected from the OD questionnaire and the Schellong test results probably affects the occurrence of vertigo and/or dizziness.