title: Enhanced left-finger deftness following dominant upper- and lower-limb amputation.
abstract: BACKGROUND
  After amputation, the sensorimotor cortex reorganizes, and these alterations might influence motor functions of the remaining extremities.
  
  
  OBJECTIVE
  The authors examined how amputation of the dominant or nondominant upper or lower extremity alters deftness in the intact limbs.
  
  
  METHODS
  The participants were 32 unilateral upper- or lower-extremity amputees and 6 controls. Upper-extremity deftness was tested by coin rotation (finger deftness) and pegboard (arm, hand, and finger deftness) tasks.
  
  
  RESULTS
  Following right-upper- or right-lower-extremity amputation, the left hand's finger movements were defter than the left-hand fingers of controls. In contrast, with left-upper- or left-lower-extremity amputation, the right hand's finger performance was the same as that of the controls.
  
  
  CONCLUSIONS
  Although this improvement might be related to increased use (practice), the finding that right-lower-extremity amputation also improved the left hand's finger deftness suggests an alternative mechanism. Perhaps in right-handed persons the left motor cortex inhibits the right side of the body more than the right motor cortex inhibits the left side, and the physiological changes induced by right-sided amputation reduced this inhibition.
authors.affiliation: Department of Neurology, Uniformed Services University of Health Sciences, Bethesda, MD 20814-4799, USA.
authors.forename: Kelley M
authors.initials: KM
authors.lastname: Swanberg
authors.forename: Abigail M
authors.initials: AM
authors.lastname: Clark
authors.forename: Julia E
authors.initials: JE
authors.lastname: Kline
authors.forename: Ilana R
authors.initials: IR
authors.lastname: Yurkiewicz
authors.forename: Brenda L
authors.initials: BL
authors.lastname: Chan
authors.forename: Paul F
authors.initials: PF
authors.lastname: Pasquina
authors.forename: Kenneth M
authors.initials: KM
authors.lastname: Heilman
authors.forename: Jack W
authors.initials: JW
authors.lastname: Tsao
mesh_terms: D000328:Adult; D000671:Amputation, Surgical; D000704:Analysis of Variance; D005385:Fingers / Q000502:physiology*; D007839:Functional Laterality / Q000502:physiology; D006225:Hand / Q000502:physiology; D006801:Humans; D035002:Lower Extremity / Q000502:physiology*; D008297:Male; D009048:Motor Skills / Q000502:physiology*; D013003:Somatosensory Cortex / Q000502:physiology; D034941:Upper Extremity / Q000502:physiology