Functional motor compensation in amyotrophic lateral sclerosis

J Neurol. 2005 Aug;252(8):944-52. doi: 10.1007/s00415-005-0787-y. Epub 2005 Mar 6.


The present study investigated the fMRI correlates of functional compensation/neural reorganization of the motor system in patients with amyotrophic lateral sclerosis (ALS). The hypothesis was that ALS patients would recruit additional brain regions compared with controls in a motor task and that activity in these regions would vary as a function of task difficulty. Patients and controls executed a motor task with two sequences (a simple and a more difficult one) of consecutive button presses. Patients and controls both activated brain regions known to be involved in motor execution and control. Activity in ipsilateral motor areas as well as difficulty-related activity in the left cerebellum could only be observed in patients. The behavioral data indicated that the motor task was much more difficult for patients than for controls. At nearly equal difficulty the observed patterns of hemodynamic activity in controls were very similar to those observed in ALS. The findings suggest that functional compensation in ALS relies on existing resources and mechanisms that are not primarily developed as a consequence of the lesion.

Publication types

  • Comparative Study

MeSH terms

  • Adult
  • Aged
  • Amyotrophic Lateral Sclerosis / physiopathology*
  • Analysis of Variance
  • Brain Mapping
  • Case-Control Studies
  • Female
  • Functional Laterality / physiology
  • Humans
  • Image Processing, Computer-Assisted / methods
  • Magnetic Resonance Imaging / methods
  • Male
  • Middle Aged
  • Motor Activity / physiology*
  • Motor Cortex / blood supply
  • Motor Cortex / physiopathology*
  • Oxygen / blood
  • Psychomotor Performance / physiology*
  • Reaction Time / physiology


  • Oxygen