title: Forearm electromyographic changes with the use of a haptic force-feedback computer mouse.
abstract: OBJECTIVE
  To examine changes in biomechanical and motor control associated with a force-feedback computer mouse.
  
  
  BACKGROUND
  Haptic computer mice can improve the movement times for point-and-click tasks; however, changes in upper extremity biomechanics and motor control are unknown.
  
  
  METHODS
  Eighteen people (ages 22-37 years) performed a point-and-click task 80 times using a force-feedback computer mouse across three different conditions: (a) no force feedback, emulating a conventional mouse; (b) a single attractive force field at the desired target that pulls the mouse to the center of the target; and (c) an attractive force field at the desired target as well as others between the two possible targets, distracting the user from the intended target. Cursor kinematics, wrist posture, and electromyographic (EMG) forearm muscle activity were recorded.
  
  
  RESULTS
  The point-and-click movements were 30% faster with the addition of a single force field and 3% faster with the addition of multiple force fields. The Fitts' law index of performance metrics improved from 2.9 bits/response to 4.1 bits/response for multiple attractive fields and to 6.0 bits/response for a single force field. For the distracting force fields, the cursor maximum velocities were over 50% faster. EMG amplitude values were largest for the distracting force fields. These data suggest that the operator uses increased muscle activity to accelerate the mouse through the distracting force fields.
  
  
  CONCLUSIONS
  When implementing attractive haptic force fields, one needs to consider how to reduce these observed effects of potential distracting force fields.
  
  
  CONCLUSIONS
  Applications include human-computer interface design for pointing devices extensively used for the graphical user interface.
authors.affiliation: Harvard School of Public Health, 665 Huntington Ave., Boston, MA 02115, USA. jax@hsph.harvard.edu
authors.forename: Jack T
authors.initials: JT
authors.lastname: Dennerlein
authors.forename: Maria-Helena J
authors.initials: MH
authors.lastname: DiMarino
mesh_terms: D000328:Adult; D004576:Electromyography; D005246:Feedback; D005260:Female; D005542:Forearm / Q000294:innervation*; D006801:Humans; D008297:Male; D008404:Massachusetts; D014110:Touch; D014584:User-Computer Interface