High prevalence of neurovascular instability in neurodegenerative dementias.

Orthostatic hypotension and carotid sinus hypersensitivity were assessed in patients meeting clinical criteria for dementia with Lewy bodies (DLB; n=30) and AD (n=35). Cardioinhibitory carotid sinus hypersensitivity (CI) was the most common sign (AD patients, 28%; DLB patients, 41%). Preliminary data from a secondary analysis excluding patients with hypertension or EKG evidence of ischemia suggested that CI may be significantly more common in DLB. Larger studies are needed to evaluate the implications for treatment and to explore the underlying mechanisms.