title: Feasibility of cardiopulmonary exercise testing and training using a robotics-assisted tilt table in dependent-ambulatory stroke patients.
abstract: BACKGROUND
  We evaluated the feasibility of an augmented robotics-assisted tilt table (RATT) for incremental cardiopulmonary exercise testing (CPET) and exercise training in dependent-ambulatory stroke patients.
  
  
  METHODS
  Stroke patients (Functional Ambulation Category ≤ 3) underwent familiarization, an incremental exercise test (IET) and a constant load test (CLT) on separate days. A RATT equipped with force sensors in the thigh cuffs, a work rate estimation algorithm and real-time visual feedback to guide the exercise work rate was used. Feasibility assessment considered technical feasibility, patient tolerability, and cardiopulmonary responsiveness.
  
  
  RESULTS
  Eight patients (4 female) aged 58.3 ± 9.2 years (mean ± SD) were recruited and all completed the study. For IETs, peak oxygen uptake (V'O2peak), peak heart rate (HRpeak) and peak work rate (WRpeak) were 11.9 ± 4.0 ml/kg/min (45 % of predicted V'O2max), 117 ± 32 beats/min (72 % of predicted HRmax) and 22.5 ± 13.0 W, respectively. Peak ratings of perceived exertion (RPE) were on the range "hard" to "very hard". All 8 patients reached their limit of functional capacity in terms of either their cardiopulmonary or neuromuscular performance. A ventilatory threshold (VT) was identified in 7 patients and a respiratory compensation point (RCP) in 6 patients: mean V'O2 at VT and RCP was 8.9 and 10.7 ml/kg/min, respectively, which represent 75 % (VT) and 85 % (RCP) of mean V'O2peak. Incremental CPET provided sufficient information to satisfy the responsiveness criteria and identification of key outcomes in all 8 patients. For CLTs, mean steady-state V'O2 was 6.9 ml/kg/min (49 % of V'O2 reserve), mean HR was 90 beats/min (56 % of HRmax), RPEs were > 2, and all patients maintained the active work rate for 10 min: these values meet recommended intensity levels for bouts of training.
  
  
  CONCLUSIONS
  The augmented RATT is deemed feasible for incremental cardiopulmonary exercise testing and exercise training in dependent-ambulatory stroke patients: the approach was found to be technically implementable, acceptable to the patients, and it showed substantial cardiopulmonary responsiveness. This work has clinical implications for patients with severe disability who otherwise are not able to be tested.
authors.affiliation: Institute for Rehabilitation and Performance Technology, Division of Mechanical Engineering, Department of Engineering and Information Technology, Bern University of Applied Sciences, Burgdorf, Switzerland. jittima.saengsuwan@bfh.ch.|ARTORG Center for Biomedical Engineering Research, Gerontechnology and Rehabilitation Research Group, University of Bern, Bern, Switzerland. jittima.saengsuwan@bfh.ch.|Research Department, Reha Rheinfelden, Rheinfelden, Switzerland. jittima.saengsuwan@bfh.ch.|Department of Physical Medicine and Rehabilitation, Faculty of Medicine, Khon Kaen University, Khon Kaen, Thailand. jittima.saengsuwan@bfh.ch.
authors.forename: Jittima
authors.initials: J
authors.lastname: Saengsuwan
authors.affiliation: Research Department, Reha Rheinfelden, Rheinfelden, Switzerland. cel.huber@bluewin.ch.
authors.forename: Celine
authors.initials: C
authors.lastname: Huber
authors.affiliation: Research Department, Reha Rheinfelden, Rheinfelden, Switzerland. joni.schreiber@hotmail.com.
authors.forename: Jonathan
authors.initials: J
authors.lastname: Schreiber
authors.affiliation: Institute for Rehabilitation and Performance Technology, Division of Mechanical Engineering, Department of Engineering and Information Technology, Bern University of Applied Sciences, Burgdorf, Switzerland. C.Schuster@reha-rhf.ch.|Research Department, Reha Rheinfelden, Rheinfelden, Switzerland. C.Schuster@reha-rhf.ch.
authors.forename: Corina
authors.initials: C
authors.lastname: Schuster-Amft
authors.affiliation: ARTORG Center for Biomedical Engineering Research, Gerontechnology and Rehabilitation Research Group, University of Bern, Bern, Switzerland. tobias.nef@artorg.unibe.ch.
authors.forename: Tobias
authors.initials: T
authors.lastname: Nef
authors.affiliation: Institute for Rehabilitation and Performance Technology, Division of Mechanical Engineering, Department of Engineering and Information Technology, Bern University of Applied Sciences, Burgdorf, Switzerland. Kenneth.hunt@bfh.ch.|Research Department, Reha Rheinfelden, Rheinfelden, Switzerland. Kenneth.hunt@bfh.ch.
authors.forename: Kenneth J
authors.initials: KJ
authors.lastname: Hunt
mesh_terms: D015444:Exercise / Q000502:physiology; D005080:Exercise Test / Q000295:instrumentation* / Q000379:methods; D005240:Feasibility Studies; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D012129:Respiratory Function Tests / Q000295:instrumentation* / Q000379:methods; D012371:Robotics / Q000295:instrumentation* / Q000379:methods; D000071939:Stroke Rehabilitation