title: Usability of a gravity- and tilt-compensated sensor with data logging function to measure posturing compliance in patients after macular hole surgery: a pilot study.
abstract: BACKGROUND
  To investigate the use of a small gravity- and tilt-compensated, head-fixed sensor with data-logging function to measure compliance and head posture of patients after macular hole surgery based on the recommendation of a face-down position. Main outcome measures were the median inclination, the times with correct or incorrect head position and the acceptance/annoyance of a data-logging device.
  
  
  METHODS
  A small battery-driven electronic sensor device with gravity and tilt compensations was placed within a plastic box and fixed on a patient's head with a headband. Face-down position data were logged every half second for 24 h after macular hole surgery and were stored on a memory card.
  
  
  RESULTS
  Thirteen patients were involved (seven females, six males, median age, 68 years, range, 50-75 years), two cases with early dropout. Ten of 11 datasets could be evaluated showing a complete data record file. The average percentage for face-down >45° was 18% within 24 h and 17% in the daytime. The median inclination was -6.7° (min: -89.7° max: 90°). The sensor system was well tolerated and disturbance was rated low by all ten patients.
  
  
  CONCLUSIONS
  While the patients' face-down posture considerably varied over time in extent and continuity, the assessment might lead to optimizing the patients' compliance with the optimal position. Results showed an excellent acceptance of the motion sensor.
authors.affiliation: Centre for Ophthalmology, University Eye-Hospital, Eberhard Karls University of Tuebingen, Schleichstr. 12, 72076, Tuebingen, Germany, martin.leitritz@med.uni-tuebingen.de.
authors.forename: Martin Alexander
authors.initials: MA
authors.lastname: Leitritz
authors.forename: Focke
authors.initials: F
authors.lastname: Ziemssen
authors.forename: Bogomil
authors.initials: B
authors.lastname: Voykov
authors.forename: Karl Ulrich
authors.initials: KU
authors.lastname: Bartz-Schmidt
mesh_terms: D000368:Aged; D015374:Biosensing Techniques / Q000295:instrumentation*; D003626:Data Display; D058450:Endotamponade; D005260:Female; D005466:Fluorocarbons; D006112:Gravitation; D018475:Head-Down Tilt; D006801:Humans; D008297:Male; D008875:Middle Aged; D010349:Patient Compliance / Q000706:statistics & numerical data*; D010865:Pilot Projects; D016684:Prone Position; D012167:Retinal Perforations / Q000601:surgery*; D014821:Vitrectomy
chemical_list: D005466:Fluorocarbons; C048381:perfluoroethane