We don't need these predictions of failure to recover, we need protocols that will deliver recovery.
Contralesional Motor Cortex Activation Depends on Ipsilesional Corticospinal Tract Integrity in Well-Recovered Subcortical Stroke Patients
Neurorehabilitation andNeural RepairXX(X) 1 –10© The Author(s) 2011 Reprints and permission: http://www.sagepub.com/journalsPermissions.navDOI: 10.1177/1545968311427706http://nnr.sagepub.com
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10.1177/1545968311427706LozeetalNeurorehabilitation and NeuralRepair© TheAuthor(s)2010eprints and permission:http://www.sagepub.com/journalsPermissions.nav
Martin Lotze, MD 1,
Willy Beutling 1,
Moritz Loibl 1,
Martin Domin 1,
Thomas Platz,MD 2,
Ulf Schminke, MD 1,
and Winston D. Byblow, PhD 3
1 University of Greifswald, Greifswald, Germany
2 BDH-Klinik Greifswald, Greifswald, Germany
3 University of Auckland, Auckland, New Zealand
Corresponding Author:
Martin Lotze, Functional Imaging Unit, Center for Diagnostic Radiologyand Neuroradiology, University of Greifswald, Friedrich-Löffler-Straße23a, D-17487 Greifswald, GermanyEmail: martin.lotze@uni-greifswald.de
The relationship between structural and functional integrity of descending motor pathways can predict the potential(Potential is NOT WHAT SURVIVORS WANT, they want actual. WHEN THE FUCK WILL YOU GET THERE!) for motor recovery after stroke. The authors examine the relationship between brain imaging biomarkers within contralesional and ipsilesional hemispheres and hand function in well-recovered patients after subcortical stroke at the level of the internal capsule.
Objective.
Measures of functional activation and integrity of the ipsilesional corticospinal tract might predict paretic hand function.
Methods.
A total of 14 patients in the chronic stable phase of motor recovery after subcortical stroke and 24 healthy age-matched individuals participated in the study. Functional MRI was used to examine BOLD contrast during passive wrist flexion–extension and paced or maximum-velocity active fist clenching. Functional integrity of the corticospinal pathway was assessed by transcranial magnetic stimulation to obtain motor-evoked potentials(MEPs) in the first dorsal interosseus muscle of the paretic and nonparetic hands. Fractional anisotropy and the proportion of traces between hemispheres in the posterior limb of both internal capsules were quantified using diffusion weighted MRI.
Results.
Patients with smaller MEPs had a weaker paretic hand and more primary motor cortex activation in theiraffected hemisphere.
Asymmetry between white matter tracts of either hemisphere was associated with reduced precision grip strength and increased BOLD activation within the contralesional dorsal premotor cortex for demanding hand tasks.
Conclusion.
There may be beneficial reorganization in contralesional secondary motor areas with increasing damage to the corticospinal tract after subcortical stroke. Associations between clinical, functional, and structural integrity measures in chronic stroke may lead to a better understanding of motor recovery processes.
1 University of Greifswald, Greifswald, Germany
2 BDH-Klinik Greifswald, Greifswald, Germany
3 University of Auckland, Auckland, New Zealand
Corresponding Author:
Martin Lotze, Functional Imaging Unit, Center for Diagnostic Radiologyand Neuroradiology, University of Greifswald, Friedrich-Löffler-Straße23a, D-17487 Greifswald, GermanyEmail: martin.lotze@uni-greifswald.de
Abstract
Background.The relationship between structural and functional integrity of descending motor pathways can predict the potential(Potential is NOT WHAT SURVIVORS WANT, they want actual. WHEN THE FUCK WILL YOU GET THERE!) for motor recovery after stroke. The authors examine the relationship between brain imaging biomarkers within contralesional and ipsilesional hemispheres and hand function in well-recovered patients after subcortical stroke at the level of the internal capsule.
Objective.
Measures of functional activation and integrity of the ipsilesional corticospinal tract might predict paretic hand function.
Methods.
A total of 14 patients in the chronic stable phase of motor recovery after subcortical stroke and 24 healthy age-matched individuals participated in the study. Functional MRI was used to examine BOLD contrast during passive wrist flexion–extension and paced or maximum-velocity active fist clenching. Functional integrity of the corticospinal pathway was assessed by transcranial magnetic stimulation to obtain motor-evoked potentials(MEPs) in the first dorsal interosseus muscle of the paretic and nonparetic hands. Fractional anisotropy and the proportion of traces between hemispheres in the posterior limb of both internal capsules were quantified using diffusion weighted MRI.
Results.
Patients with smaller MEPs had a weaker paretic hand and more primary motor cortex activation in theiraffected hemisphere.
Asymmetry between white matter tracts of either hemisphere was associated with reduced precision grip strength and increased BOLD activation within the contralesional dorsal premotor cortex for demanding hand tasks.
Conclusion.
There may be beneficial reorganization in contralesional secondary motor areas with increasing damage to the corticospinal tract after subcortical stroke. Associations between clinical, functional, and structural integrity measures in chronic stroke may lead to a better understanding of motor recovery processes.
Introduction
About 75% of those who experience stroke have lingering upper-limb impairment.1Based on clinical presentation alone, it is difficult to gauge which patients will recover upper-limb function several months later.2
This study examines the relationship between neuroimaging parameters and upper-limb function months after stroke in well-recovered patients.Experimentally, structural and functional cerebral parameters may indicate motor function at the chronic phase after stroke. With respect to functional magnetic resonance imaging (fMRI), increased activation in motor areas of both the damaged hemisphere (DAM-H) and the hemisphere contra-lateral to the affected one (CON-H) have been reported.3
Greater chronic motor impairment is associated with an increase of fMRI activation in motor areas of both hemispheres during simple, repetitive hand movements.4
In contrast, good motor-recovery is related to a near normal DAM-H fMRI activation associated with movement execution of the affected hand.5
The importance of CON-H activation is not completely understood but may be indicative of good outcomes for some patients.6,7
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