Changes in the relationship between movement velocity and movement distance in primary focal hand dystonia

J Mot Behav. 2008 Jul;40(4):301-13. doi: 10.3200/JMBR.40.4.301-314.

Abstract

The authors examined the relationship between movement velocity and distance and the associated muscle activation patterns in 18 individuals with focal hand dystonia (FHD) compared with a control group of 18 individuals with no known neuromuscular condition. Participants performed targeted voluntary wrist and elbow flexion movements as fast as possible across 5 movement distances. Individuals with FHD were slower than controls across all distances, and this difference was accentuated for longer movements. Muscle activation patterns were triphasic in the majority of individuals with FHD, and muscle activation scaled with distance in a similar manner to controls. Cocontraction did not explain movement slowing in individuals with dystonia, but there was a trend toward underactivation of the 1st agonist burst in the dystonic group. The authors concluded that slowness is a consistent feature of voluntary movement in FHD and is present even in the absence of dystonic posturing. Underactivation of the 1st agonist burst appears to be the most likely reason to explain slowing.

Publication types

  • Randomized Controlled Trial
  • Research Support, N.I.H., Extramural

MeSH terms

  • Action Potentials / physiology
  • Adult
  • Biomechanical Phenomena
  • Dystonic Disorders / diagnosis
  • Dystonic Disorders / physiopathology*
  • Elbow Joint / innervation
  • Elbow Joint / physiology
  • Electromyography
  • Female
  • Hand / innervation
  • Humans
  • Male
  • Middle Aged
  • Movement / physiology*
  • Muscle Contraction / physiology*
  • Muscle Weakness / diagnosis
  • Muscle Weakness / physiopathology*
  • Psychomotor Performance / physiology
  • Wrist Joint / innervation
  • Wrist Joint / physiology