On the relative contribution of the paretic leg to the control of posture after stroke

Neurorehabil Neural Repair. 2009 Mar-Apr;23(3):267-74. doi: 10.1177/1545968308323928. Epub 2008 Dec 12.

Abstract

Background: Reduced postural steadiness and asymmetry of weight bearing are characteristic for posture after stroke.

Objective: To examine the relative contribution of each leg to postural control in a cohort of 33 stroke patients at 5 stages during 3 months of inpatient rehabilitation, while taking clinical scores of sensory and motor impairments of the paretic leg into account.

Methods: Participants were instructed to stand as symmetrically as possible under both sensory and cognitive manipulations, while a dual-plate force platform was used to assess the contribution of each leg to postural control, quantified by the amplitude, velocity, and regularity of recorded center-of-pressure trajectories. A greater contribution of the nonparetic leg was expected, particularly in patients with ankle clonus, disturbed sensibility, and lack of selective muscle control on the paretic side.

Results: With follow-up assessments, weight-bearing asymmetry and postural steadiness improved. Patients strongly relied on visual information. When attention was distracted by having the patients perform an arithmetic task, weight-bearing asymmetry increased, suggesting that symmetric weight bearing was attention demanding. Patients with severe motor impairments of the paretic leg showed greater static (weight-bearing) and dynamic (lateralized control) asymmetries than patients with limited motor impairments, whereas postural steadiness did not differ between these subgroups. Disturbed sensation did not affect weight-bearing asymmetry, postural steadiness, or lateralized control.

Conclusion: Patients with severe motor impairments of the paretic leg employ an effective compensatory strategy consisting of asymmetric weight bearing and lateralized control.

MeSH terms

  • Adaptation, Physiological / physiology
  • Aged
  • Disability Evaluation
  • Female
  • Functional Laterality / physiology
  • Gait Disorders, Neurologic / etiology
  • Gait Disorders, Neurologic / physiopathology*
  • Humans
  • Leg / physiopathology*
  • Male
  • Middle Aged
  • Movement / physiology*
  • Muscle Contraction / physiology
  • Muscle, Skeletal / innervation
  • Muscle, Skeletal / physiopathology
  • Paresis / etiology
  • Paresis / physiopathology*
  • Posture / physiology*
  • Psychomotor Performance / physiology
  • Stroke / physiopathology*
  • Weight-Bearing / physiology