title: Physical activity monitoring in patients with peripheral arterial disease: validation of an activity monitor.
abstract: OBJECTIVE
  The daily life physical activity (PA) of patients with peripheral arterial disease (PAD) may be severely hampered by intermittent claudication (IC). From a therapeutic, as well as research, point of view, it may be more relevant to determine improvement in PA as an outcome measure in IC. The aim of this study was to validate daily activities using a novel type of tri-axial accelerometer (Dynaport MoveMonitor) in patients with IC.
  
  
  METHODS
  Patients with IC were studied during a hospital visit. Standard activities (locomotion, lying, sitting, standing, shuffling, number of steps and "not worn" detection) were video recorded and compared with activities scored by the MoveMonitor. Inter-rater reliability (expressed in intraclass correlation coefficients [ICC]), sensitivity, specificity, and positive predictive values (PPV) were calculated for each activity.
  
  
  RESULTS
  Twenty-eight hours of video observation were analysed (n = 21). Our video annotation method (the gold standard method) appeared to be accurate for most postures (ICC > 0.97), except for shuffling (ICC = 0.38). The MoveMonitor showed a high sensitivity (>86%), specificity (>91%), and PPV (>88%) for locomotion, lying, sitting, and "not worn" detection. Moderate accuracy was found for standing (46%), while shuffling appeared to be undetectable (18%). A strong correlation was found between video recordings and the MoveMonitor with regard to the calculation of the "number of steps" (ICC = 0.90).
  
  
  CONCLUSIONS
  The MoveMonitor provides accurate information on a diverse set of postures, daily activities, and number of steps in IC patients. However, the detection of low amplitude movements, such as shuffling and "sitting to standing" transfers, is a matter of concern. This tool is useful in assessing the role of PA as a novel, clinically relevant outcome parameter in IC.
authors.affiliation: Catharina Hospital, Department of Vascular Surgery, P.O. Box 1350, 5602 ZA Eindhoven, The Netherlands; Caphri Research School, Maastricht University, P.O. Box 606, 6200 MD Maastricht, The Netherlands.
authors.forename: H J P
authors.initials: HJ
authors.lastname: Fokkenrood
authors.affiliation: Catharina Hospital, Department of Vascular Surgery, P.O. Box 1350, 5602 ZA Eindhoven, The Netherlands.
authors.forename: N
authors.initials: N
authors.lastname: Verhofstad
authors.affiliation: Catharina Hospital, Department of Vascular Surgery, P.O. Box 1350, 5602 ZA Eindhoven, The Netherlands.
authors.forename: M M L
authors.initials: MM
authors.lastname: van den Houten
authors.affiliation: Catharina Hospital, Department of Vascular Surgery, P.O. Box 1350, 5602 ZA Eindhoven, The Netherlands; Caphri Research School, Maastricht University, P.O. Box 606, 6200 MD Maastricht, The Netherlands.
authors.forename: G J
authors.initials: GJ
authors.lastname: Lauret
authors.affiliation: MUMC+, Department of Vascular Surgery, P.O. Box 5800, 6202 AZ Maastricht, The Netherlands; Klinikum Aachen, Department of Vascular Surgery, Pauwelsstraße 30, 52074 Aachen, Germany.
authors.forename: C
authors.initials: C
authors.lastname: Wittens
authors.affiliation: Maxima Medical Center, Department of Vascular Surgery, P.O. Box 7777, 5500 MB Veldhoven, The Netherlands; Carim Research School, Maastricht University, P.O. Box 606, 6200 MD Maastricht, The Netherlands.
authors.forename: M R M
authors.initials: MR
authors.lastname: Scheltinga
authors.affiliation: Catharina Hospital, Department of Vascular Surgery, P.O. Box 1350, 5602 ZA Eindhoven, The Netherlands; Caphri Research School, Maastricht University, P.O. Box 606, 6200 MD Maastricht, The Netherlands. Electronic address: joep.teijink@catharinaziekenhuis.nl.
authors.forename: J A W
authors.initials: JA
authors.lastname: Teijink
mesh_terms: D056044:Actigraphy / Q000295:instrumentation*; D000368:Aged; D004867:Equipment Design; D017079:Exercise Tolerance; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D009043:Motor Activity; D058729:Peripheral Arterial Disease / Q000175:diagnosis* / Q000503:physiopathology; D011237:Predictive Value of Tests; D015203:Reproducibility of Results; D014741:Video Recording; D016138:Walking
keywords: Activity monitor; Ambulatory activities; Intermittent claudication; Physical activity