Affiliations: Department of Rehabilitation Medicine, VU University
Medical Centre Amsterdam, The Netherlands | Department of Rehabilitation Medicine, Rudolf Magnus
Institute of Neuroscience, UMC Utrecht, The Netherlands | Research Bureau, Isala klinieken, Zwolle, The
Netherlands
Note: [] Corresponding author: G. Kwakkel, PhD, Senior researcher, Rudolf
Magnus Institute, Department of Rehabilitation, University Medical Centre, PO
Box 85060, Utrecht, The Netherlands. E-mail: g.kwakkel@vumc.nl
Abstract: Purpose: A number of longitudinal studies show that about one third
of all patients regain dexterity following a stroke. However, the determinants
of improvement of upper limb function are largely unknown. The aim of the
present study was to investigate the longitudinal relationship of functional
change in the upper paretic limb and change in time-dependent covariates in
order to develop a multivariable regression model to predict improvement in dexterity. Methods: Based on 18 repeated measurements over time during
the first post-stroke year, 101 stroke patients with first-ever ischemic middle
cerebral artery strokes were investigated. Baseline characteristics as well as
longitudinal information from Action Research Arm Test (ARAT), Fugl-Meyer arm
and hand score (FM-arm and FM-hand), Motricity Index arm and leg score (MI-arm
and MI-leg), letter cancellation task (LCT), Fugl-Meyer balance score
(FM-balance) and progress of time were obtained prospectively. Outcome
constituted of change scores on the ARAT over first year post stroke. Adjoining
measurements of time-dependent variables were used to calculate time-dependent
changes producing change scores. Results: In total 1570 of the 1717
change scores were available for longitudinal regression analysis. The
regression model shows that FM-hand change scores was the most important
relative factor in predicting improvement on ARAT (standardized β=0.357;
p< 0.001) followed by change scores on FM-arm (β = 0.007;
p< 0.001), whereas progress of time was significantly negatively
associated with improvement on ARAT (β = −0.001; p< 0.001). Conclusions: Functional improvement of the upper paretic limb is mainly
determined by improvement of the paretic hand, followed by synergistic
independent movement of the paretic arm. Progress of time itself is an
independent covariate that is negatively associated with upper limb function
suggesting that most pronounced improvements occur earlier after stroke.
