Proportional recovery after stroke depends on corticomotor integrity

Byblow, Winston D.; Stinear, Cathy M.; Barber, P. Alan; Petoe, Matthew A.; Ackerley, Suzanne J.

doi:10.1002/ana.24472

Cited by 326 publications

(466 citation statements)

References 49 publications

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“…Our findings agree with earlier studies on the modulation of CSE after stroke [3,31]. The rMTs of the UH corresponded well with those reported in the healthy population [28] and agree with earlier reports in stroke patients, which demonstrate that in general the CSE of the contralesional corticospinal tract is within normal limits in the acute and chronic stages [2,30].…”

Section: Discussionsupporting

confidence: 93%

“…The changes in CSE tend to be observed on the affected hemisphere (AH), while the CSE on the contralesional unaffected hemisphere (UH) is often less altered [3,4,30]. This interhemispheric asymmetry has been reported to be greatest in the acute stage, after which it begins to recover [3,30]. Recovery from stroke is based at least partly on the reorganization of the surviving parts of the brain and rebuilding of functional networks [23,26].…”

Section: Introductionmentioning

confidence: 99%

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Longitudinal study on modulated corticospinal excitability throughout recovery in supratentorial stroke

Julkunen

Könönen

Määttä

et al. 2016

Neuroscience Letters

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Longitudinal study on modulated corticospinal excitability throughout recovery in supratentorial stroke, Neuroscience Letters http://dx.doi.org/10. 1016/j.neulet.2016.02.014 This is a PDF file of an unedited manuscript that has been accepted for publication. As a service to our customers we are providing this early version of the manuscript. The manuscript will undergo copyediting, typesetting, and review of the resulting proof before it is published in its final form. Please note that during the production process errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain. AbstractCorticospinal excitability (CSE) is modulated by stroke-induced lesions affecting the brain. This modulation is known to be dependent on the timing of the evaluation, and strongest abnormalities are often found in the acute stage. Our study aimed to characterize changes in CSE asymmetry between the affected and the unaffected hemisphere (AH and UH) during the first month after stroke onset and at 6 month follow-up. Neuronavigated transcranial magnetic stimulation (nTMS) was used to assess the CSE of the abductor pollicis brevis (APB) muscle of the hand and tibialis anterior (TA) muscle of the leg in 16 patients over 5 time-points. AH excitability recovered significantly during 6 months, whereas interhemispheric asymmetry remained significant up to 1 month post-stroke in the APB muscle. Greater initial CSE was associated with good motor function at 6 months. The motor cortical excitatory recovery initiated within week of the stroke and was most prominent within 1 month after stroke onset. Lesion size correlated with CSE of the UH at 10 days, while overall severity of the symptoms correlated inversely with CSE of the AH. This study demonstrates the quick improvement in the CSE via estimation of interhemispheric asymmetry; however, the recovery in the asymmetry continues to normalize even after reaching the threshold for normal values in CSE.

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Section: Discussionsupporting

confidence: 93%

Section: Introductionmentioning

confidence: 99%

Longitudinal study on modulated corticospinal excitability throughout recovery in supratentorial stroke

Julkunen

Könönen

Määttä

et al. 2016

Neuroscience Letters

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“…This is in agreement with a recent study 6 and extends previous algorithms for prediction of the severity of impairment at the chronic stage 7 to prediction of improvement gains. Patients with mild degeneration observed in the CST will recover about 70% of impaired upper limb function, while expected recovery in patients with severe CST degeneration drops to approximately ,30%.…”

supporting

confidence: 92%

Predicting motor improvement after stroke with clinical assessment and diffusion tensor imaging

et al. 2016

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Reliable predictors of motor improvement in individual patients after stroke are scarce. Acute determination of upper limb Fugl-Meyer assessment (FMA) appears to have predictive value.1,2 This approach predicts that patients will improve approximately 70% of the difference between the maximum upper extremity FMA score and the score first tested for a given individual (recoverytypical). However, a significant subset of patients improves much less than predicted (recovery-atypical). Alternative models using other techniques like diffusion tensor imaging (DTI) 3,4 also fail to predict recovery in some patients. Here, we show that a combination of FMA and DTI obtained in the first weeks after stroke accurately discriminate between recovery-typical and recovery-atypical patients. In addition, we identify an alternative set of model parameters required for predictions in the recovery-atypical subgroup.We examined 25 patients (mean age 61 years, 11 female) with first ischemic stroke. Patients had a mean NIH Stroke Scale score of 11 (table e-1 on the Neurology ® Web site at Neurology.org). FMA 5 and DTI (appendix e-1) were obtained 2 weeks and 3 months after stroke onset. The FMA was performed by a trained occupational therapist blinded to the DTI results. Corticospinal tract (CST) asymmetry was calculated from the mean fractional anisotropy (FA) of the CST 3 :As with previous observations, 3,4 patients with greater CST asymmetry at 2 weeks had proportionally more severe motor deficits, both 2 weeks and 3 months after stroke onset (Spearman r , 20.8, p , 0.0001, figure 1, A and B). However, CST asymmetry was not significantly related to FMA improvement from 2 weeks to 3 months ( figure 1C). These findings were also confirmed when FA ispilesional /FA contralesional ratios were used as predictors rather than CST asymmetry.As expected, a majority of patients followed the FMA-based model predictions ( figure 1D; filled symbols), while a subgroup of patients exhibited recovery-atypical profiles ( figure 1D; unfilled circles). In order to further characterize the 2 patient subgroups, we computed the model residuals as the difference between the predicted FMA improvement and the observed FMA improvement. The residuals clearly differentiate recovery-typical ( figure 1E; filled bars) from recoveryatypical patients (unfilled bars). All recovery-atypical Ethan R. Buch, PhD Sviatlana Rizk, PhD Pierre Nicolo, MS Leonardo G. Cohen, MD Armin Schnider, MD Adrian G. Guggisberg, MD Figure 1 Fugl-Meyer assessment (FMA) and diffusion tensor imaging (DTI) predictors of motor improvementCorticospinal tract (CST) asymmetry at 2 weeks correlated with the severity of motor deficits at (A) 2 weeks and (B) 3 months after stroke, but not with (C) the change between these 2 time points. (D) The model DFMA 5 0.7*(66-FMA intial ), represented by a continuous line, predicted future FMA improvement in most patients (filled symbols), but there was a significant recovery-atypical subset (n 5 9; unfilled circles). (E) Recovery-atypical patients were def...

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“…9 In line with this concept, Byblow et al 10 recently demonstrated that CST integrity as assessed by the presence of motor-evoked potentials (MEPs) was a better predictor of the ability to recover compared with initial clinical impairment, thus improving the 70% rule. Furthermore, they also demonstrated the added value of fractional anisotropy (FA) measurements in the CST toward improving prediction of motor function recovery in combination with MEPs.…”

Section: April 2016mentioning

confidence: 96%

Early Fiber Number Ratio Is a Surrogate of Corticospinal Tract Integrity and Predicts Motor Recovery After Stroke

Bigourdan

Munsch

Coupé

et al. 2016

Stroke

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≈70% of their initial motor impairment, 4,5 which, therefore, already conveys strong predictive information. Nevertheless, this 70% rule fails in patients with initial severe deficit, 4,5 and the variability in medium to long-term outcome is not adequately explained by initial clinical severity alone for those patients. The interindividual variability in the relation between initial impairment and subsequent recovery hampers accurate individualized prognosis. 6 Although infarct volume could be helpful to improve prognostication, 7 its power as an independent predictor of clinical outcome is still debated. 8Background and Purpose-The contribution of imaging metrics to predict poststroke motor recovery needs to be clarified.We tested the added value of early diffusion tensor imaging (DTI) of the corticospinal tract toward predicting long-term motor recovery. Methods-One hundred seventeen patients were prospectively assessed at 24 to 72 hours and 1 year after ischemic stroke with diffusion tensor imaging and motor scores (Fugl-Meyer). The initial fiber number ratio (iFNr) and final fiber number ratio were computed as the number of streamlines along the affected corticospinal tract normalized to the unaffected side and were compared with each other. The prediction of motor recovery (ΔFugl-Meyer) was first modeled using initial Fugl-Meyer and iFNr. Multivariate ordinal logistic regression models were also used to study the association of iFNr, initial Fugl-Meyer, age, and stroke volume with Fugl-Meyer at 1 year. Results-The iFNr correlated with the final fiber number ratio at 1 year (r=0.70; P<0.0001). The initial Fugl-Meyer strongly predicted motor recovery (≈73% of initial impairment) for all patients except those with initial severe stroke (FuglMeyer<50). For these severe patients (n=26), initial Fugl-Meyer was not correlated with motor recovery (R 2 =0.13; p=ns), whereas iFNr showed strong correlation (R 2 =0.56; P<0.0001). In multivariate analysis, the iFNr was an independent predictor of motor outcome (β=2.601; 95% confidence interval=0.304-5.110; P=0.031), improving prediction compared with using only initial Fugl-Meyer, age, and stroke volume (P=0.026). Conclusions-Early measurement of FNr at 24 to 72 hours poststroke is a surrogate marker of corticospinal tract integrity and provides independent prediction of motor outcome at 1 year especially for patients with severe initial impairment.

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Proportional recovery after stroke depends on corticomotor integrity

Cited by 326 publications

References 49 publications

Longitudinal study on modulated corticospinal excitability throughout recovery in supratentorial stroke

Longitudinal study on modulated corticospinal excitability throughout recovery in supratentorial stroke

Predicting motor improvement after stroke with clinical assessment and diffusion tensor imaging

Early Fiber Number Ratio Is a Surrogate of Corticospinal Tract Integrity and Predicts Motor Recovery After Stroke

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