title: Carpal tunnel syndrome impairs sustained precision pinch performance.
abstract: OBJECTIVE
  The purpose of this study was to investigate effects of carpal tunnel syndrome (CTS) on digit force control during a sustained precision pinch.
  
  
  METHODS
  Eleven CTS individuals and 11 age- and gender-matched healthy volunteers participated in the study. The subjects were instructed to isometrically pinch an instrumented apparatus for 60s with a stable force output. Visual feedback of force output was provided for the first 30s but removed for the remaining 30s. Pinch forces were examined for accuracy, variability, and inter-digit correlation.
  
  
  RESULTS
  CTS led to a decrease in force accuracy and an increase in amount of force variability, particularly without visual feedback (p<0.001). However, CTS did not affect the structure of force variability or force correlation between digits (p>0.05). The force of the thumb was less accurate and more variable than that of the index finger for both the CTS and healthy groups (p<0.001).
  
  
  CONCLUSIONS
  Sensorimotor deficits associated with CTS lead to inaccurate and unstable digit forces during sustained precision pinch.
  
  
  CONCLUSIONS
  This study shed light on basic and pathophysiological mechanisms of fine motor control and aids in development of new strategies for diagnosis and evaluation of CTS.
authors.affiliation: Hand Research Laboratory, Departments of Biomedical Engineering, Orthopaedic Surgery, and Physical Medicine and Rehabilitation, Cleveland Clinic, Cleveland, OH, USA. Electronic address: ke.li.phd@gmail.com.
authors.forename: Ke
authors.initials: K
authors.lastname: Li
authors.affiliation: Hand Research Laboratory, Departments of Biomedical Engineering, Orthopaedic Surgery, and Physical Medicine and Rehabilitation, Cleveland Clinic, Cleveland, OH, USA. Electronic address: evansp2@ccf.org.
authors.forename: Peter J
authors.initials: PJ
authors.lastname: Evans
authors.affiliation: Hand Research Laboratory, Departments of Biomedical Engineering, Orthopaedic Surgery, and Physical Medicine and Rehabilitation, Cleveland Clinic, Cleveland, OH, USA. Electronic address: seitzw@ccf.org.
authors.forename: William H
authors.initials: WH
authors.lastname: Seitz
authors.affiliation: Hand Research Laboratory, Departments of Biomedical Engineering, Orthopaedic Surgery, and Physical Medicine and Rehabilitation, Cleveland Clinic, Cleveland, OH, USA. Electronic address: liz4@ccf.org.
authors.forename: Zong-Ming
authors.initials: ZM
authors.lastname: Li
mesh_terms: D000328:Adult; D002349:Carpal Tunnel Syndrome / Q000175:diagnosis / Q000503:physiopathology*; D056228:Feedback, Sensory / Q000502:physiology; D005260:Female; D005385:Fingers / Q000503:physiopathology*; D006801:Humans; D008297:Male; D008875:Middle Aged; D052581:Pinch Strength / Q000502:physiology; D011597:Psychomotor Performance / Q000502:physiology; D013933:Thumb / Q000503:physiopathology*
keywords: Carpal tunnel syndrome; Force accuracy; Force coordination; Force variability; Precision pinch