Symptoms of cerebral hypoperfusion or autonomic overaction which develop while the subject is standing, but are relieved on recumbency. Types of this include NEUROCARDIOGENIC syncope; postural orthostatic tachycardia syndrome; and neurogenic ORTHOSTATIC hypotension. (From Noseworthy, JH., Neurological therapeutics Principles and Practice, 2007, p2575-2576)