Contribution of each lower limb to upright standing in stroke patients.
OBJECTIVE
To analyze the postural behavior of standing stroke patients: (1) To differentiate between postural impairment attributable to the neurological condition (deficits attributable to the cerebral lesion) and postural impairment attributable to new mechanical constraints caused by body weight asymmetry; (2) To assess the involvement of each limb in the postural impairment; (3) To better understand which clinical deficits underlie the postural impairment.


METHODS
The posturographic characteristics of each limb in 41 stroke patients (first hemispheric stroke: 16 left, 25 right cerebral lesions) required to stand in their preferred posture were compared to those in 40 matched healthy individuals required to stand asymmetrically.


RESULTS
Compared to normal individuals in a similar asymmetrical posture, stroke patients were more unstable. The weight bearing asymmetry and the lateral postural instability were mainly related to spatial neglect. The paretic limb was unable to bring into play a normal longitudinal pattern of the center of pressure, which reflects an impaired stabilization control. Overall postural instability occurred when the strong limb was unable to compensate for the postural impairment of the paretic limb.


CONCLUSIONS
The weight bearing asymmetry of standing stroke patients is not the primary cause of their postural imbalance, which is rather the consequence of impaired control of postural stabilization involving both limbs. Weight bearing asymmetry may not be the principle target of rehabilitation programs aiming at restoring standing balance after stroke. Instead it is suggested that more account should be taken of the compensatory role of the strong limb.
Genthon
Nicolas
N
Service de Rééducation Neurologique, INSERM U887, Centre de Médecine Physique & Réadaptation et CIT - CHU, 23, rue Gaffarel; BP 77908 F - 21079 Dijon cedex, France.
Rougier
Patrice
P
Gissot
Anne-Sophie
AS
Froger
Jérôme
J
Pélissier
Jacques
J
Pérennou
Dominic
D
D000368:Aged; D001696:Biomechanical Phenomena; D005246:Feedback / Q000502:physiology; D005260:Female; D007839:Functional Laterality / Q000502:physiology; D020233:Gait Disorders, Neurologic / Q000209:etiology / Q000503:physiopathology*; D006801:Humans; D007866:Leg / Q000294:innervation / Q000503:physiopathology*; D008297:Male; D008875:Middle Aged; D009068:Movement / Q000502:physiology; D018482:Muscle, Skeletal / Q000294:innervation / Q000503:physiopathology; D010291:Paresis / Q000209:etiology / Q000503:physiopathology*; D010468:Perceptual Disorders / Q000209:etiology / Q000503:physiopathology; D004856:Postural Balance / Q000502:physiology*; D011312:Pressure; D011434:Proprioception / Q000502:physiology; D020127:Recovery of Function / Q000502:physiology; D012016:Reference Values; D020886:Somatosensory Disorders / Q000209:etiology / Q000503:physiopathology; D020521:Stroke / Q000150:complications / Q000503:physiopathology*; D013647:Task Performance and Analysis; D014796:Visual Perception / Q000502:physiology; D016474:Weight-Bearing / Q000502:physiology