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Kim DH, Kang CS, Kyeong S. Robot-assisted gait training promotes brain reorganization after stroke: A randomized controlled pilot study. NeuroRehabilitation 2020; 46:483-489. [DOI: 10.3233/nre-203054] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Affiliation(s)
- Dae Hyun Kim
- Department of Physical Medicine and Rehabilitation, Veterans Health Service Medical Center, Seoul, South Korea
| | - Chang Soon Kang
- Department of Physical Medicine and Rehabilitation, Veterans Health Service Medical Center, Seoul, South Korea
| | - Sohyun Kyeong
- Department of Physical Medicine and Rehabilitation, Veterans Health Service Medical Center, Seoul, South Korea
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2
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Weller P, Wittsack HJ, Siebler M, Hömberg V, Seitz RJ. Motor Recovery as Assessed with Isometric Finger Movements and Perfusion Magnetic Resonance Imaging after Acute Ischemic Stroke. Neurorehabil Neural Repair 2016; 20:390-7. [PMID: 16885425 DOI: 10.1177/1545968305285037] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Objective. Recovery from hemiparetic stroke is variable. An important goal for clinicians and clinical researchers is to identify predictors of recovery. The initial phase after acute ischemic stroke is considered to be of major importance for neurological outcome. The authors sought to determine in patients with acute ischemic stroke whether early motor recovery, as measured by repetitive isometric index-thumb oppositions, is correlated with ischemic lesion volume. Methods. Thirty-six acute hemiparetic stroke patients with residual hand function were investigated. The European Stroke Scale (ESS) score was determined on admission and at discharge. Performance of repetitive index finger-thumb pinch movements was measured daily during the 1st 8 days after stroke onset. Brain ischemia volume was determined digitally in time-to-peak magnetic resonance images of per-fusion. Results. The recovery of patients with ( P = 0.002) and without ( P < 0.001) thrombolysis as assessed with the ESS was paralleled by an increase in isometric grip force and movement rate ( P < 0.05). Recovery was predicted by the area of moderately impaired perfusion indicated by the per-fusion mismatch volume ( r = 0.578, P < 0.001). Conclusions. In acute stroke, recovery of hand function is predicted by the volume of salvageable ischemic tissue, as determined by the perfusion mismatch.
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Affiliation(s)
- Patrick Weller
- Department of Neurology, University Hospital Düsseldorf, Düsseldorf, Germany
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Rath J, Wurnig M, Fischmeister F, Klinger N, Höllinger I, Geißler A, Aichhorn M, Foki T, Kronbichler M, Nickel J, Siedentopf C, Staffen W, Verius M, Golaszewski S, Koppelstaetter F, Auff E, Felber S, Seitz RJ, Beisteiner R. Between- and within-site variability of fMRI localizations. Hum Brain Mapp 2016; 37:2151-60. [PMID: 26955899 DOI: 10.1002/hbm.23162] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2015] [Revised: 12/12/2015] [Accepted: 02/17/2016] [Indexed: 11/11/2022] Open
Abstract
This study provides first data about the spatial variability of fMRI sensorimotor localizations when investigating the same subjects at different fMRI sites. Results are comparable to a previous patient study. We found a median between-site variability of about 6 mm independent of task (motor or sensory) and experimental standardization (high or low). An intraclass correlation coefficient analysis using data quality measures indicated a major influence of the fMRI site on variability. In accordance with this, within-site localization variability was considerably lower (about 3 mm). We conclude that the fMRI site is a considerable confound for localization of brain activity. However, when performed by experienced clinical fMRI experts, brain pathology does not seem to have a relevant impact on the reliability of fMRI localizations. Hum Brain Mapp 37:2151-2160, 2016. © 2016 Wiley Periodicals, Inc.
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Affiliation(s)
- Jakob Rath
- Department of Neurology and MR Center of Excellence, Medical University of Vienna, Austria
| | - Moritz Wurnig
- Department of Neurology and MR Center of Excellence, Medical University of Vienna, Austria
| | - Florian Fischmeister
- Department of Neurology and MR Center of Excellence, Medical University of Vienna, Austria
| | - Nicolaus Klinger
- Department of Neurology and MR Center of Excellence, Medical University of Vienna, Austria
| | - Ilse Höllinger
- Department of Neurology and MR Center of Excellence, Medical University of Vienna, Austria
| | - Alexander Geißler
- Department of Neurology and MR Center of Excellence, Medical University of Vienna, Austria
| | - Markus Aichhorn
- Centre for Cognitive Neuroscience, University of Salzburg, Salzburg, Austria
| | - Thomas Foki
- Department of Neurology and MR Center of Excellence, Medical University of Vienna, Austria
| | - Martin Kronbichler
- Centre for Cognitive Neuroscience, University of Salzburg, Salzburg, Austria.,Neuroscience Institute, Christian-Doppler-Clinic, Paracelsus Medical University, Salzburg, Austria
| | - Janpeter Nickel
- Department of Neurology, University Hospital Düsseldorf, Germany
| | | | - Wolfgang Staffen
- Department of Neurology, Christian-Doppler-Clinic, Paracelsus Medical University, Salzburg, Austria
| | - Michael Verius
- Department of Radiology, Medical University of Innsbruck, Austria
| | - Stefan Golaszewski
- Department of Neurology, Christian-Doppler-Clinic, Paracelsus Medical University, Salzburg, Austria
| | | | - Eduard Auff
- Department of Neurology, Medical University of Vienna, Austria
| | - Stephan Felber
- Institute for Diagnostic Radiology, Stiftungsklinikum Mittelrhein, Koblenz, Germany
| | - Rüdiger J Seitz
- Department of Neurology, University Hospital Düsseldorf, Germany.,Centre of Neurology and Neuropsychiatry, Heinrich-Heine-University Düsseldorf, LVR-Klinikum Düsseldorf, Germany
| | - Roland Beisteiner
- Department of Neurology and MR Center of Excellence, Medical University of Vienna, Austria
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Carrera E, Jones PS, Morris RS, Alawneh J, Hong YT, Aigbirhio FI, Fryer TD, Carpenter TA, Warburton EA, Baron JC. Is neural activation within the rescued penumbra impeded by selective neuronal loss? Brain 2013; 136:1816-29. [DOI: 10.1093/brain/awt112] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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Salinet ASM, Haunton VJ, Panerai RB, Robinson TG. A systematic review of cerebral hemodynamic responses to neural activation following stroke. J Neurol 2013; 260:2715-21. [DOI: 10.1007/s00415-013-6836-z] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2012] [Accepted: 01/04/2013] [Indexed: 10/27/2022]
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Manganotti P, Storti SF, Formaggio E, Acler M, Zoccatelli G, Pizzini FB, Alessandrini F, Bertoldo A, Toffolo GM, Bovi P, Beltramello A, Moretto G, Fiaschi A. Effect of median-nerve electrical stimulation on BOLD activity in acute ischemic stroke patients. Clin Neurophysiol 2011; 123:142-53. [PMID: 21741301 DOI: 10.1016/j.clinph.2011.05.028] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2011] [Revised: 05/09/2011] [Accepted: 05/13/2011] [Indexed: 11/19/2022]
Abstract
OBJECTIVE To investigate blood oxygenation level-dependent (BOLD) activation during somatosensory electrical stimulation of the median nerve in acute stroke patients and to determine its correlation with ischemic damage and clinical recovery over time. METHODS Fourteen acute stroke patients underwent functional magnetic resonance imaging (fMRI) during contralesional median-nerve electrical stimulation 12-48 h after stroke. Findings were then validated by diffusion tensor imaging (DTI) and motor evoked potential by transcranial magnetic stimulation (TMS). RESULTS Poor clinical recovery at three months was noted in four patients with no activation in the early days after stroke, whereas good clinical recovery was observed in eight patients with a normal activation pattern in the primary sensory motor area in the acute phase. In two patients BOLD activation correlated weakly with clinical recovery. Findings from TMS and DTI partially correlated with clinical recovery and functional scores. CONCLUSIONS Clinically relevant insights into the "functional reserve" of stroke patients gained with peripheral nerve stimulation during fMRI may carry prognostic value already in the acute period of a cerebrovascular accident. SIGNIFICANCE BOLD activation maps could provide insights into the functional organization of the residual systems and could contribute to medical decision making in neurological and rehabilitative treatment.
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Affiliation(s)
- P Manganotti
- Department of Neurological, Neuropsychological, Morphological and Movement Sciences, Section of Clinical Neurology, University of Verona, Verona, Italy
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7
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Seitz RJ, Donnan GA. Role of neuroimaging in promoting long-term recovery from ischemic stroke. J Magn Reson Imaging 2010; 32:756-72. [PMID: 20882606 DOI: 10.1002/jmri.22315] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Affiliation(s)
- Rüdiger J Seitz
- Department of Neurology, University Hospital Düsseldorf, and Biomedical Research Centre, Heinrich-Heine-University Düsseldorf, Germany.
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Nomi JS, Scherfeld D, Friederichs S, Schäfer R, Franz M, Wittsack HJ, Azari NP, Missimer J, Seitz RJ. On the neural networks of empathy: A principal component analysis of an fMRI study. BEHAVIORAL AND BRAIN FUNCTIONS : BBF 2008; 4:41. [PMID: 18798977 PMCID: PMC2564949 DOI: 10.1186/1744-9081-4-41] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/07/2008] [Accepted: 09/17/2008] [Indexed: 11/29/2022]
Abstract
BACKGROUND Human emotional expressions serve an important communicatory role allowing the rapid transmission of valence information among individuals. We aimed at exploring the neural networks mediating the recognition of and empathy with human facial expressions of emotion. METHODS A principal component analysis was applied to event-related functional magnetic imaging (fMRI) data of 14 right-handed healthy volunteers (29 +/- 6 years). During scanning, subjects viewed happy, sad and neutral face expressions in the following conditions: emotion recognition, empathizing with emotion, and a control condition of simple object detection. Functionally relevant principal components (PCs) were identified by planned comparisons at an alpha level of p < 0.001. RESULTS Four PCs revealed significant differences in variance patterns of the conditions, thereby revealing distinct neural networks: mediating facial identification (PC 1), identification of an expressed emotion (PC 2), attention to an expressed emotion (PC 12), and sense of an emotional state (PC 27). CONCLUSION Our findings further the notion that the appraisal of human facial expressions involves multiple neural circuits that process highly differentiated cognitive aspects of emotion.
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Affiliation(s)
- Jason S Nomi
- Department of Neurology, University Hospital Düsseldorf, Moorenstrasse 5, 40225, Düsseldorf, Germany
- Department of Psychology, University of Hawaii at Hilo, College of Arts and Sciences, 200 W. Kawili Street, Hilo, Hawaii 96720-4091, USA
| | - Dag Scherfeld
- Department of Neurology, University Hospital Düsseldorf, Moorenstrasse 5, 40225, Düsseldorf, Germany
| | - Skara Friederichs
- Department of Neurology, University Hospital Düsseldorf, Moorenstrasse 5, 40225, Düsseldorf, Germany
| | - Ralf Schäfer
- Clinical Institute of Psychosomatic Medicine and Psychotherapy, University Hospital Düsseldorf, Moorenstrasse 5, 40225 Düsseldorf, Germany
| | - Matthias Franz
- Clinical Institute of Psychosomatic Medicine and Psychotherapy, University Hospital Düsseldorf, Moorenstrasse 5, 40225 Düsseldorf, Germany
| | - Hans-Jörg Wittsack
- Institute of Diagnostic Radiology, University Hospital Düsseldorf, Moorenstrasse 5, 40225 Düsseldorf, Germany
| | - Nina P Azari
- Department of Psychology, University of Hawaii at Hilo, College of Arts and Sciences, 200 W. Kawili Street, Hilo, Hawaii 96720-4091, USA
| | | | - Rüdiger J Seitz
- Department of Neurology, University Hospital Düsseldorf, Moorenstrasse 5, 40225, Düsseldorf, Germany
- Biomedical Research Centre, Heinrich-Heine-University Düsseldorf, Moorenstrasse 5, 40225 Düsseldorf, Germany
- Brain Imaging Centre West, 52407 Jülich, Germany
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Cramer SC. Repairing the human brain after stroke: I. Mechanisms of spontaneous recovery. Ann Neurol 2008; 63:272-87. [PMID: 18383072 DOI: 10.1002/ana.21393] [Citation(s) in RCA: 538] [Impact Index Per Article: 33.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Stroke remains a leading cause of adult disability. Some degree of spontaneous behavioral recovery is usually seen in the weeks after stroke onset. Variability in recovery is substantial across human patients. Some principles have emerged; for example, recovery occurs slowest in those destined to have less successful outcomes. Animal studies have extended these observations, providing insight into a broad range of underlying molecular and physiological events. Brain mapping studies in human patients have provided observations at the systems level that often parallel findings in animals. In general, the best outcomes are associated with the greatest return toward the normal state of brain functional organization. Reorganization of surviving central nervous system elements supports behavioral recovery, for example, through changes in interhemispheric lateralization, activity of association cortices linked to injured zones, and organization of cortical representational maps. A number of factors influence events supporting stroke recovery, such as demographics, behavioral experience, and perhaps genetics. Such measures gain importance when viewed as covariates in therapeutic trials of restorative agents that target stroke recovery.
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Affiliation(s)
- Steven C Cramer
- Departments of Neurology and Anatomy & Neurobiology, University of California, Irvine, Irvine, CA 92868-4280, USA.
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Seitz R, Schäfer R, Scherfeld D, Friederichs S, Popp K, Wittsack HJ, Azari N, Franz M. Valuating other people’s emotional face expression: a combined functional magnetic resonance imaging and electroencephalography study. Neuroscience 2008; 152:713-22. [DOI: 10.1016/j.neuroscience.2007.10.066] [Citation(s) in RCA: 66] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2007] [Revised: 10/11/2007] [Accepted: 01/16/2008] [Indexed: 12/30/2022]
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Nickel J, Jörgens S, Bussfeld P, Seitz RJ. Asymptomatic motor cortex displacement due to a giant arachnoid cyst. Neurocase 2007; 13:328-33. [PMID: 18781430 DOI: 10.1080/13554790701849910] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
Abstract
Cerebral lesions are held to induce plastic changes of the brain. Less well established, however, is how much space-occupying brain lesions may only displace functional representations. In a 66-year-old man we show, by means of functional magnetic resonance imaging and transcranial magnetic stimulation, a profound displacement of the motor cortex due to a large asymptomatic arachnoid cyst. Thus, the chronically compressed brain is capable of sustaining normal brain function without utilizing the potential of cortical plasticity.
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Affiliation(s)
- J Nickel
- Department of Neurology, University Hospital Düsseldorf, Düsseldorf, Germany.
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Jörgens S, Kleiser R, Indefrey P, Seitz RJ. Handedness and functional MRI-activation patterns in sentence processing. Neuroreport 2007; 18:1339-43. [PMID: 17762709 DOI: 10.1097/wnr.0b013e32825a67db] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
We investigate differences of cerebral activation in 12 right-handed and left-handed participants, respectively, using a sentence-processing task. Functional MRI shows activation of left-frontal and inferior-parietal speech areas (BA 44, BA9, BA 40) in both groups, but a stronger bilateral activation in left-handers. Direct group comparison reveals a stronger activation in right-frontal cortex (BA 47, BA 6) and left cerebellum in left-handers. Laterality indices for the inferior-frontal cortex are less asymmetric in left-handers and are not related to the degree of handedness. Thus, our results show that sentence-processing induced enhanced activation involving a bilateral network in left-handed participants.
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Affiliation(s)
- Silke Jörgens
- Department of Neurology, Heinrich-Heine-University Düsseldorf, Germany.
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Seitz RJ, Buetefisch CM. Recovery from ischemic stroke: a translational research perspective for neurology. FUTURE NEUROLOGY 2006. [DOI: 10.2217/14796708.1.5.571] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Ischemic stroke is the most frequent neurological disease, characterized by an age-related incidence and chronic disability in the majority of patients. A great challenge in acute stroke is to predict the degree to which a patient will eventually recover. Magnetic resonance imaging has revealed that treatment-induced reperfusion limits the extent of ischemic brain damage, thereby enabling rapid and profound recovery. Nevertheless, patients may retain deficits in motor, sensory or cognitive functions due to the residual lesion. Functional neuroimaging and transcranial magnetic stimulation have shown that recovery is associated with abnormal activation in the perilesional vicinity and in brain areas remote from the lesion. This is likely related to altered functional properties or morphological changes in both cerebral hemispheres. Recent neurorehabilitative strategies, including forced use, mental imagery and peripheral nerve or cortex stimulation, aim at modulating these functional networks. Accordingly, translational research has provided new vistas on the neurobiological mechanisms of recovery and opened future avenues for science-based pharmacological and neurophysiological training strategies in stroke.
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Affiliation(s)
- Rüdiger J Seitz
- Department of Neurology, Biomedical Research Centre, Hienrich-Heine-University Düsseldorf, Brain Imaging Centre West, Research Centre Jülich, University Hospital Düsseldorf, Moorenstrasse 5 40225 Düsseldorf, Germany
| | - Cathrin M Buetefisch
- Department of Neurology, Robert C Byrd Health Science Center, , 1 Medical Center Drive, West Virginia University PO Box 9180, Morgantown, WV 26505, USA
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Bütefisch CM, Kleiser R, Seitz RJ. Post-lesional cerebral reorganisation: evidence from functional neuroimaging and transcranial magnetic stimulation. ACTA ACUST UNITED AC 2006; 99:437-54. [PMID: 16723211 DOI: 10.1016/j.jphysparis.2006.03.001] [Citation(s) in RCA: 64] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
Reorganisation of cerebral representations has been hypothesised to underlie the recovery from ischaemic brain infarction. The mechanisms can be investigated non-invasively in the human brain using functional neuroimaging and transcranial magnetic stimulation (TMS). Functional neuroimaging showed that reorganisation is a dynamic process beginning after stroke manifestation. In the acute stage, the mismatch between a large perfusion deficit and a smaller area with impaired water diffusion signifies the brain tissue that potentially enables recovery subsequent to early reperfusion as in thrombolysis. Single-pulse TMS showed that the integrity of the cortico-spinal tract system was critical for motor recovery within the first four weeks, irrespective of a concomitant affection of the somatosensory system. Follow-up studies over several months revealed that ischaemia results in atrophy of brain tissue adjacent to and of brain areas remote from the infarct lesion. In patients with hemiparetic stroke activation of premotor cortical areas in both cerebral hemispheres was found to underlie recovery of finger movements with the affected hand. Paired-pulse TMS showed regression of perilesional inhibition as well as intracortical disinhibition of the motor cortex contralateral to the infarction as mechanisms related to recovery. Training strategies can employ post-lesional brain plasticity resulting in enhanced perilesional activations and modulation of large-scale bihemispheric circuits.
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Siekierka-Kleiser EM, Kleiser R, Wohlschläger AM, Freund HJ, Seitz RJ. Quantitative Assessment of Recovery from Motor Hemineglect in Acute Stroke Patients. Cerebrovasc Dis 2006; 21:307-14. [PMID: 16490939 DOI: 10.1159/000091535] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2005] [Accepted: 10/24/2005] [Indexed: 11/19/2022] Open
Abstract
BACKGROUND AND PURPOSE Motor hemineglect is characterized by an underutilization of one side of the body. It is a higher-order motor disorder that resembles hemiplegia although being substantially different from it due to a preserved motor output system. Its role for poststroke recovery is still unclear. METHODS We studied 52 patients presenting with acute hemiparetic stroke over the first 7 days after symptom onset. Nineteen patients had unilateral motor hemineglect. Impairment was clinically assessed with the European Stroke Scale and a multifactorial motor score. It was further assessed quantitatively, as overall arm activity was measured continuously by Actiwatches. Lesion volumes were measured morphometrically within 24 h on perfusion- and diffusion-weighted magnetic resonance images and on average on day 9 by T2-weighted magnetic resonance imaging. RESULTS Patients with motor hemineglect were characterized by significantly reduced initial arm activity in comparison to patients without motor hemineglect. This was paralleled by larger brain lesions in the patients with motor hemineglect. Patients with motor neglect either recovered virtually completely (5 cases; 2/5 left hemisphere; 3/5 treated with recombinant tissue plasminogen activator, rt-PA) within 7 days or did not improve at all (14 cases; 3/14 left hemisphere; 3/14 rt-PA treated). CONCLUSION Our data reveal a high incidence of motor hemineglect in patients with acute stroke. They further show that these patients are more severely compromised than those without motor hemineglect. A rapid and near complete recovery was observed in about one fourth of the motor hemineglect patients and may be related to involvement of the left hemisphere or to therapy with thrombolysis.
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Affiliation(s)
- E M Siekierka-Kleiser
- Department of Neurology, University Hospital Dusseldorf, Heinrich Heine University Dusseldorf, Germany
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Rijntjes M. Mechanisms of recovery in stroke patients with hemiparesis or aphasia: new insights, old questions and the meaning of therapies. Curr Opin Neurol 2006; 19:76-83. [PMID: 16415681 DOI: 10.1097/01.wco.0000203886.28068.38] [Citation(s) in RCA: 76] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
PURPOSE OF REVIEW The mechanisms responsible for recovery after stroke in patients with hemiparesis or aphasia are under intense study, since knowledge of these mechanisms is a prerequisite for choosing which therapy a patient receives and when to apply it. RECENT FINDINGS Most of the recent insights are obtained with longitudinal studies using functional imaging and direct cortical stimulation during the process of recovery. They reveal that reorganization is a highly dynamic process, involving the establishment of new communications in the remaining system and showing similarities to learning processes in healthy individuals. Lesion localization is a major determinant for recovery and the pattern of reorganization. Neurobiological hypotheses lead to clinical studies, which in turn are now used to confirm or reject these hypotheses. SUMMARY Although our understanding of the mechanisms responsible for recovery is increasing, the application of this knowledge in daily praxis is still limited. A better understanding of the underlying mechanisms, however, can lead to appropriate therapies for individual patients.
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Affiliation(s)
- Michel Rijntjes
- Department of Neurology, University Clinic Freiburg, Freiburg, Germany.
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Cramer SC, Shah R, Juranek J, Crafton KR, Le V. Activity in the Peri-Infarct Rim in Relation to Recovery From Stroke. Stroke 2006; 37:111-5. [PMID: 16306462 DOI: 10.1161/01.str.0000195135.70379.1f] [Citation(s) in RCA: 57] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Background and Purpose—
In the rim of tissue surrounding a cortical infarct, animal studies have described an increase in a number of growth-related processes that likely contribute to behavioral recovery. The current study hypothesized that in patients with good outcome after stroke, brain activation in peri-infarct tissue would be greater than normal.
Methods—
In 15 patients with good recovery chronically after ischemic cortical stroke, activation within peri-infarct brain tissue was directly compared with activation within the same brain tissue of 13 control subjects.
Results—
Although most patients did show activation within peri-infarct tissues, their activation compared with controls was reduced rather than increased. Evaluation of the T2*-weighted images underlying functional MRI mapping disclosed a significant gradient of increased T2* signal in peri-infarct tissues, likely attributable to tissue changes such as gliosis.
Conclusions—
Among well-recovered stroke patients, cortical activation is present in the area surrounding a cortical infarct but is smaller than normal. A baseline derangement of the T2*-weighted signal underlying functional MRI (fMRI) is also present in this area, which might influence interpretation of fMRI findings. The relationship between increased tissue T2* signal and fMRI activation is not known and requires further study.
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Affiliation(s)
- Steven C Cramer
- Department of Neurology, University of Washington, Seattle, USA.
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