Recovery of Quiet Standing Balance and Lower Limb Motor Impairment Early Poststroke: How Are They Related?

Background: Recovery of quiet standing balance early poststroke has been poorly investigated using repeated measurements.

Objective: To investigate (1) the time course of steady-state balance in terms of postural stability and inter-limb symmetry, and (2) longitudinal associations with lower limb motor recovery in the first 3 months poststroke.

Methods: Forty-eight hemiparetic subjects (age: 58.9 ± 16.1 years) were evaluated at weeks 3, 5, 8, and 12 poststroke. Motor impairments concerned the Fugl-Meyer assessment (FM-LE) and Motricity Index total score (MI-LE) or ankle item separately (MI-ankle). Postural stability during quiet 2-legged stance was calculated as the net center-of-pressure area (COP) and direction-dependent velocities (COP and COP). Dynamic control asymmetry (DCA) and weight-bearing asymmetry (WBA) estimated inter-limb symmetries in balance control and loading. Linear mixed models determined (1) time-dependent change and (2) the - and -subject associations between motor impairments and postural stability or inter-limb symmetry.

Results: Time-dependent improvements were significant for FM-LE, MI-LE, MI-ankle, COP, COP, and COP, and tended to plateau by week 8. DCA and WBA did not exhibit significant change. -subject analyses yielded significant regression coefficients for FM-LE, MI-LE, and MI-ankle scores with COP, COP, and COP up until week 8, and with WBA until week 12. -subject regression coefficients of motor recovery with change in COP, COP, COP, DCA, or WBA were generally non-significant.

Conclusions: Postural stability improved significantly in the first 8 weeks poststroke, independent of lower limb motor recovery at the most affected side subjects. Our findings suggest that subjects preferred to compensate with their less affected side, making metrics reflecting inter-limb asymmetries in balance invariant for change early poststroke.: Clinicaltrials.gov. unique identifier NCT03728036.