Article

During standing, forces and moments exerted at the feet serve to
maintain stability in the face of constant centre-of-mass movement. These actions
are temporally synchronized in healthy individuals.
Stroke is typically a
unilateral injury resulting in increased sensori-motor impairment in the
contra-lesional compared with the ipsi-lesional lower-limb, which could lead to
reduced between-limb synchronization for control of standing balance. The purpose
of this study is to investigate between-limb synchronization of standing balance
control in individuals with stroke; a potentially important index of control of
upright stability. METHODS: Twenty healthy controls and 33 individuals with
unilateral stroke were assessed. Stability was assessed during a 30-second quiet
standing trial by measuring data from two force plates (one per foot).
Limb-specific centre of pressure was calculated. Between-limb synchronization was
defined as the coefficient of the correlation between the left and right foot for
both the antero-posterior and medio-lateral centre of pressure time series.
Synchronization, weight-bearing symmetry, and root mean square of the total
centre of pressure excursion were compared between controls and stroke
participants. FINDINGS: Stroke participants swayed more, were more asymmetric,
and had less between-limb synchronization than healthy controls. Among
individuals with stroke, reduced between-limb synchronization was related to
increased postural sway in the medio-lateral direction and increased
weight-bearing asymmetry. INTERPRETATION: Individuals with stroke have reduced
temporal synchronization of centre of pressure fluctuations under the feet when
controlling quiet standing. The clinical significance of reduced synchronization
remains to be determined, although it appears linked to increased medio-lateral
sway and weight-bearing asymmetry.
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Langue : ANGLAIS