title: Reduced sympathetic response to head-up tilt in subjects with mild cognitive impairment or mild Alzheimer's dementia.
abstract: BACKGROUND
  Hemodynamic control was compared in patients with mild cognitive impairment (MCI) or mild Alzheimer's dementia (AD) as well as in healthy elderly subjects.
  
  
  METHODS
  Noninvasive, continuous hemodynamic recordings were obtained from 14 patients and 48 controls during supine rest (tilt of 30 and 70°). Cardiac output, end-diastolic volume, total peripheral resistance, heart rate variability (HRV), systolic blood pressure variability (SBPV), and baroreceptor sensitivity were calculated.
  
  
  RESULTS
  At 70° tilt, the HRV indices differed significantly, with higher high-frequency (HF) variability as well as lower low-frequency (LF) variability and LF/HF ratios in the patients. The patients had significantly lower SBPV in the LF range at 30° tilt.
  
  
  CONCLUSIONS
  The results indicate a poorer sympathetic response to orthostatic stress in MCI and mild AD. © 2015 S. Karger AG, Basel.
authors: Department of Geriatric Medicine, Oslo University Hospital, Bergen ; Institute of Clinical Medicine, University of Oslo, Bergen.
authors: Marte Rognstad
authors: MR
authors: Mellingsæter
authors: Department of Geriatric Medicine, Oslo University Hospital, Bergen ; Institute of Clinical Medicine, University of Oslo, Bergen.
authors: Torgeir Bruun
authors: TB
authors: Wyller
authors: Diakonhjemmet Hospital, Oslo, Bergen ; Department of Clinical Science, University of Bergen, Bergen.
authors: Anette Hylen
authors: AH
authors: Ranhoff
authors: Department of Geriatric Medicine, Oslo University Hospital, Bergen ; Institute of Clinical Medicine, University of Oslo, Bergen.
authors: Nenad
authors: N
authors: Bogdanovic
authors: Institute of Clinical Medicine, University of Oslo, Bergen ; Department of Pediatrics, Akershus University Hospital, Lørenskog, Norway.
authors: Vegard Bruun
authors: VB
authors: Wyller
keywords: Alzheimer's dementia; Autonomic function; Head-up tilt; Mild cognitive impairment