title: High Cable Forces Deteriorate Pinch Force Control in Voluntary-Closing Body-Powered Prostheses.
abstract: BACKGROUND
  It is generally asserted that reliable and intuitive control of upper-limb prostheses requires adequate feedback of prosthetic finger positions and pinch forces applied to objects. Body-powered prostheses (BPPs) provide the user with direct proprioceptive feedback. Currently available BPPs often require high cable operation forces, which complicates control of the forces at the terminal device. The aim of this study is to quantify the influence of high cable forces on object manipulation with voluntary-closing prostheses.
  
  
  METHODS
  Able-bodied male subjects were fitted with a bypass-prosthesis with low and high cable force settings for the prehensor. Subjects were requested to grasp and transfer a collapsible object as fast as they could without dropping or breaking it. The object had a low and a high breaking force setting.
  
  
  RESULTS
  Subjects conducted significantly more successful manipulations with the low cable force setting, both for the low (33% more) and high (50%) object's breaking force. The time to complete the task was not different between settings during successful manipulation trials.
  
  
  CONCLUSIONS
  High cable forces lead to reduced pinch force control during object manipulation. This implies that low cable operation forces should be a key design requirement for voluntary-closing BPPs.
authors.affiliation: Delft Institute of Prosthetics and Orthotics, Department of Biomechanical Engineering, Delft University of Technology, Delft, The Netherlands.
authors.forename: Mona
authors.identifier: http://orcid.org/0000-0003-3264-9413
authors.initials: M
authors.lastname: Hichert
authors.affiliation: Delft Haptics Lab, Department of Biomechanical Engineering, Delft University of Technology, Delft, The Netherlands.
authors.forename: David A
authors.initials: DA
authors.lastname: Abbink
authors.affiliation: Institute of Biomedical Engineering University of New Brunswick, Fredericton, Canada.|Department of Engineering Science, University of Greenwich, Chatham Maritime, United Kingdom.
authors.forename: Peter J
authors.initials: PJ
authors.lastname: Kyberd
authors.affiliation: Delft Institute of Prosthetics and Orthotics, Department of Biomechanical Engineering, Delft University of Technology, Delft, The Netherlands.
authors.forename: Dick H
authors.initials: DH
authors.lastname: Plettenburg
mesh_terms: D000328:Adult; D001186:Artificial Limbs; D018737:Hand Strength / Q000502:physiology; D006801:Humans; D008297:Male; D011474:Prosthesis Design