Autonomic dysfunction in chronic persistent dizziness

• We studied autonomic function in chronic persistent dizziness without other causes.
• We performed standardized autonomic function tests with Finometer devices.
• Sympathetic hyperactivity or failure was found in nearly 70% of the patients.
• Sympathetic dysfunction may be assumed as a cause of chronic persistent dizziness.

ObjectiveTo investigate the autonomic dysfunction in patients with chronic persistent dizziness using standardized autonomic function tests.MethodsWe prospectively recruited 18 patients with chronic persistent dizziness after excluding other causes with extensive investigations. A standardized battery of autonomic tests including the head up tilt (HUT) test, Valsalva maneuver (VM), and heart rate (HR) response to deep breathing was performed.ResultsApproximately eighty percent of the patients showed at least one abnormality in autonomic tests. Two patterns of autonomic abnormality were identified: sympathetic failure, including abnormal decrease in blood pressure (BP) during HUT test or abnormal sympathetic indices related with the BP recovery during late phase II and phase IV during VM, and sympathetic hyperactivity, including abnormal increase in HR response during HUT test or an exaggerated phase IV response manifesting increased β-adrenergic tone during VM.ConclusionsAutonomic dysfunction is frequently found in patients with chronic persistent dizziness after excluding other causes with extensive investigations. Sympathetic failure or hyperactivity may be postulated as one of the possible causes of chronic persistent dizziness. Clinicians should be aware of the possibility of autonomic dysfunction in patients with chronic dizziness, even if the dizziness is not orthostatic but persistent.