Background: Patients with autonomic failure may experience postural dizziness, syncope, and falls. Identifying symptomatic dysautonomia in dementia is of importance to ensure appropriate management and reduce risk of falls.
Objective: The aim of this prospective study is to identify cardiovascular autonomic dysfunction in patients suffering from behavioral variant of frontotemporal dementia (bvFTD), compared to Alzheimer's disease (AD).
Methods: Patients were prospectively recruited from 2009 until 2013. Clinical autonomic function tests were carried out in an Autonomic Unit according to Ewing's cardiovascular battery. Parasympathetic tests included resting heart rate variability, deep breathing, and Valsalva. Sympathetic function tests compromised blood pressure regulation on valsalva, cutaneous cold stimulation, and 70° head up tilt including of plasma noradrenaline.
Results: 26 patients (17 female) with bvFTD and 18 patients (10 female) with AD were examined. Mean age of bvFTD was 69 ± 11 years, AD 74 ± 9 years. History taking was often not conclusive and did not correlate with autonomic signs. In 42% bvFTD patients and 44% AD patients, autonomic dysfunction was demonstrated. Manifest orthostatic hypotension (OH) was present in 19% of bvFTD and 33% AD patients. Frequency of autonomic dysfunction and orthostatic hypotension did not differ between bvFTD and AD, but were significantly higher than in healthy controls. Autonomic dysfunction was associated with an increased risk of falling (assessed with Tinetti Score).
Conclusion: This is the first prospective study to elucidate autonomic dysfunction in bvFTD patients. There is a considerable higher frequency of cardiovascular dysfunction and OH in bvFTD. History taking may be not conclusive thus cannot exclude cardiovascular dysautonomia.
Keywords: Alzheimer's disease; autonomic dysfunction; autonomic nervous system; dementia; frontotemporal dementia.