Analysis of Autonomic Function Tests in Patients with Orthostatic Dizziness / 대한이비인후과학회지

ABSTRACT

BACKGROUND AND OBJECTIVES: Orthostatic dizziness (OD) is defined as dizziness provoked by standing up from a supine or sitting position. It can be caused by the abnormality of autonomic nerve function system as well as vestibular system. We studied the autonomic nerve function in patients with OD. SUBJECTS AND METHOD: The authors reviewed the medical records of 50 OD patients who showed normal findings of vestibular function test and brain magnetic resonance imaging. Of the 50 patients, 34 patients were enrolled in this study. We performed a standardized autonomic function test to 34 OD patients. RESULTS: The result of autonomic nerve function test revealed abnormal findings in 26 (76%) of the 34 patients. Tests performed were for the following sympathetic failure, including abnormal decrease in blood pressure during tilt table test, Valsalva maneuver, sympathetic skin response and heart rate response to deep breathing. CONCLUSION: Autonomic dysfunction is frequently found in patients with OD after excluding other causes with extensive investigations. Sympathetic failure or hyperactivity may be postulated as one of the possible causes of OD. Autonomic function test could be useful in understanding the mechanism of OD and treatment of OD in patients.