Prediction of motor recovery using initial impairment and fMRI 48 h poststroke.
ABSTRACT There is substantial interpatient variation in recovery from upper limb impairment after stroke in patients with severe initial impairment. Defining recovery as a change in the upper limb Fugl-Meyer score (ΔFM), we predicted ΔFM with its conditional expectation (i.e., posterior mean) given upper limb Fugl-Meyer initial impairment (FM(ii)) and a putative functional magnetic resonance imaging (fMRI) recovery measure. Patients with first time, ischemic stroke were imaged at 2.5 ± 2.2 days poststroke with 1.5-T fMRI during a hand closure task alternating with rest (fundamental frequency = 0.025 Hz, scan duration = 172 s). Confirming a previous finding, we observed that the prediction of ΔFM by FM(ii) alone is good in patients with nonsevere initial hemiparesis but is not good in patients with severe initial hemiparesis (96% and 16% of the total sum of squares of ΔFM explained, respectively). In patients with severe initial hemiparesis, prediction of ΔFM by the combination of FM(ii) and the putative fMRI recovery measure nonsignificantly increased predictive explanation from 16% to 47% of the total sum of squares of ΔFM explained. The implications of this preliminary negative result are discussed.
Full-textDOI: · Available from: Leeor Alon, Jun 02, 2015
SourceAvailable from: Tanja Nijboer[Show abstract] [Hide abstract]
ABSTRACT: The aim of the current study was to investigate the longitudinal relationship between improvements of synergism and strength of the upper paretic limb and severity of visuo-spatial neglect during the first 52 weeks post-stroke. The longitudinal association between severity of VSN and motor impairment using Fugl Meyer motor score and Motricity Index of the arm was measured in an intensive repeated measurement design including 18 measurement sessions for each subject. Neglect was assessed using the letter cancellation test applied in a prospective cohort of 101 ischemic, first-ever, hemispheric stroke patients. All time-dependent measures were taken weekly, starting within 14 days post-stroke. From week 10 to 20 biweekly measurements are obtained. The longitudinal relationship of (bi)weekly time on improvement of motor functions and severity of neglect was investigated using random coefficient analysis and trend analyses. Fifty-one of the 101 stroke patients showed neglect at stroke onset. Less improvement of synergism and strength of the upper paretic limb was associated with more severe neglect. This association was most pronounced in the first 10 weeks post-stroke. The seemingly suppressive effect of neglect on upper-limb motor recovery appears to take place mainly during spontaneous neurological recovery of first 10 weeks post-stroke. This finding suggests that damage to large-scale white matter tracts of especially the perceptual-attention networks suppress recovery of other networks at distance in the brain suggesting a common underlying mechanism.PLoS ONE 06/2014; 9(6):e100584. DOI:10.1371/journal.pone.0100584 · 3.53 Impact Factor
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ABSTRACT: Muscle synergies describe common patterns of co- or reciprocal activation that occur during movement. After stroke, these synergies change, often in stereotypical ways. The mechanism underlying this change reflects damage to key motor pathways as a result of the stroke lesion, and the subsequent reorganization along the neuroaxis, which may be further detrimental or restorative to motor function. The time course of abnormal synergy formation seems to lag spontaneous recovery that occurs in the initial weeks after stroke. In healthy individuals, motor cortical activity, descending via the corticospinal tract (CST) is the predominant driver of voluntary behavior. When the CST is damaged after stroke, other descending pathways may be up-regulated to compensate. The contribution of these pathways may emerge as new synergies take shape at the chronic stage after stroke, as a result of plasticity along the neuroaxis. The location of the stroke lesion and properties of the secondary descending pathways and their regulation are then critical for shaping the synergies in the remaining motor behavior. A consideration of the integrity of remaining descending motor pathways may aid in the design of new rehabilitation therapies.Frontiers in Human Neuroscience 02/2015; 9:82. DOI:10.3389/fnhum.2015.00082 · 2.90 Impact Factor
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ABSTRACT: Purpose of review This review presents recent developments in the prediction of motor recovery after stroke; explores whether rehabilitation interventions delivered during the spontaneous recovery process can improve outcomes; and identifies the first trials to focus on the rate rather than extent of motor recovery (Supplementary Digital Content 1). Recent findings Two recent studies have attempted to accelerate the rate of motor recovery during the first few weeks after stroke, with neuromodulation techniques designed to facilitate excitability of the ipsilesional motor cortex. One trial using transcranial direct current stimulation was negative, and the other trial using bilateral priming was positive. These contrasting results may be explained by important differences in trial design. This new focus on modifying rate, rather than extent, of motor recovery is in line with accumulating evidence that the motor recovery plateau is largely determined by the extent of damage to descending motor pathways, which is currently untreatable. Summary Interventions that facilitate neural plasticity and reorganization may accelerate recovery of motor function during the spontaneous recovery period, without affecting final outcome. This may represent a useful new approach for future trials conducted during rehabilitation at the subacute stage of stroke.Current Opinion in Neurology 12/2014; 27(6):624-30. DOI:10.1097/WCO.0000000000000153 · 5.73 Impact Factor