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Nolte CH, Albach FN, Heuschmann PU, Brunecker P, Villringer K, Endres M, Fiebach JB. Silent New DWI Lesions within the First Week after Stroke. Cerebrovasc Dis 2012; 33:248-54. [DOI: 10.1159/000334665] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2011] [Accepted: 10/21/2011] [Indexed: 11/19/2022] Open
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77
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Xu C, Schmidt WUH, Villringer K, Brunecker P, Kiselev V, Gall P, Fiebach JB. Vessel size imaging reveals pathological changes of microvessel density and size in acute ischemia. J Cereb Blood Flow Metab 2011; 31:1687-95. [PMID: 21468091 PMCID: PMC3170945 DOI: 10.1038/jcbfm.2011.38] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
The aim of this study was to test the feasibility of vessel size imaging with precise evaluation of apparent diffusion coefficient and cerebral blood volume and to apply this novel technique in acute stroke patients within a pilot group to observe the microvascular responses in acute ischemic tissue. Microvessel density-related quantity Q and mean vessel size index (VSI) were assessed in 9 healthy volunteers and 13 acute stroke patients with vessel occlusion within 6 hours after symptom onset. Our results in healthy volunteers matched with general anatomical observations. Given the limitation of a small patient cohort, the median VSI in the ischemic area was higher than that in the mirrored region in the contralateral hemisphere (P<0.05). Decreased Q was observed in the ischemic region in 2 patients, whereas no obvious changes of Q were found in the remaining 11 patients. In a patient without recanalization, the VSI hyperintensity in the subcortical area matched well with the final infarct. These data reveal that different observations of microvascular response in the acute ischemic tissue seem to emerge and vessel size imaging may provide useful information for the definition of ischemic penumbra and have an impact on future therapeutic approaches.
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78
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Haeusler KG, Koch L, Ueberreiter J, Coban N, Safak E, Kunze C, Villringer K, Endres M, Schultheiss HP, Fiebach JB, Schirdewan A. Safety and reliability of the insertable Reveal XT recorder in patients undergoing 3 Tesla brain magnetic resonance imaging. Heart Rhythm 2011; 8:373-6. [PMID: 21070885 DOI: 10.1016/j.hrthm.2010.11.008] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/28/2010] [Accepted: 11/02/2010] [Indexed: 10/18/2022]
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79
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Fiebach JB, Hopt A, Vucic T, Brunecker P, Nolte CH, Doege C, Villringer K, Jungehulsing GJ, Kunze C, Wegener S, Villringer A. Inverse mismatch and lesion growth in small subcortical ischaemic stroke. Eur Radiol 2010; 20:2983-9. [PMID: 20571802 DOI: 10.1007/s00330-010-1858-8] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2010] [Revised: 04/30/2010] [Accepted: 05/19/2010] [Indexed: 11/24/2022]
Abstract
OBJECTIVE Infarction typically develops within the borders of an initial hypoperfused tissue. We prospectively investigated whether in small subcortical stroke patients infarct growth can occur beyond the margins of the affected vascular territories. METHODS In 19 consecutive patients, stroke MRI was performed within 14 h after ictus, and at days 2 and 6 (± 1). Size of diffusion and perfusion disturbances were determined. Infarct volume measured on T2-weighted images on day 6 was considered as imaging endpoint. RESULTS At the initial examination, the mean diffusion lesion [apparent diffusion coefficient (ADC) lesion size, 1.82 ± 1.2 ml] was larger (p = 0.0002) than the perfusion lesion [mean transit time (MTT) lesion size, 0.72 ± 0.69 ml]. Such an "inverse mismatch" (ADC lesion > MTT lesion) was present in 14/19 patients at baseline and in all patients on day 2. Final lesion volume at day 6 was 3.2 ± 1.6 ml which was larger than the initial perfusion deficit (p = 0.02). CONCLUSION In small subcortical ischaemic stroke "inverse mismatch" is frequent and infarction develops beyond the initial perfusion disturbance. This indicates that cytotoxic processes probably triggered by the infarct core are a dominant mechanism for lesion growth. Areas with normal perfusion but which are threatened by cytotoxic damage developing over several days seem prime targets for neuroprotective therapy.
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Hohmann J, Schaaf T, Villringer K, Kunz H, Tolxdorff T, Wolf KJ. Verbesserter Workflow zur Produktion von eLearning-Inhalten unter Verwendung offener interoperabler, internationaler Standards und Standard-Office-Applikationen. ROFO-FORTSCHR RONTG 2005. [DOI: 10.1055/s-2005-868378] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
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81
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Wolf KJ, Villringer K, Mitznegg P. Radiology and General Practice. ROFO-FORTSCHR RONTG 2004; 176:15-7. [PMID: 14712401 DOI: 10.1055/s-2004-814674] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
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82
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Grüsser SM, Mühlnickel W, Schaefer M, Villringer K, Christmann C, Koeppe C, Flor H. Remote activation of referred phantom sensation and cortical reorganization in human upper extremity amputees. Exp Brain Res 2004; 154:97-102. [PMID: 14557916 DOI: 10.1007/s00221-003-1649-4] [Citation(s) in RCA: 57] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2002] [Accepted: 07/03/2003] [Indexed: 11/25/2022]
Abstract
Phantom limb sensation, whether painful or not, frequently occurs after peripheral nerve lesions. It can be elicited by stimulating body parts adjacent to the amputation site (referred to as phantom sensation) and it is often similar in quality to the stimulation at the remote site. The present study induced referred phantom sensations in two upper limb amputees. Neuroelectric source imaging (ESI) as well as functional magnetic resonance imaging (fMRI) was used to assess reorganization in primary somatosensory cortex (SI). Whereas recent studies found mislocalization of sensation related to stimulation mainly in regions adjacent and ipsilateral to the amputation site, we report here the elicitation of phantom sensation in the arm by stimulation in the lower body part both ipsi- and contralateral to the amputation in two arm amputees. The fMRI evaluation of one patient showed no shift in the location of the foot whereas ESI revealed major reorganization of the mouth region in primary somatosensory cortex in both patients. These data suggest that cortical structures other than SI might be contributing to the phenomenon of referred sensation. Candidate structures are the thalamus, secondary somatosensory cortex, posterior parietal cortex and prefrontal cortex.
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83
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Deuchert M, Ruben J, Schwiemann J, Meyer R, Thees S, Krause T, Blankenburg F, Villringer K, Kurth R, Curio G, Villringer A. Event-related fMRI of the somatosensory system using electrical finger stimulation. Neuroreport 2002; 13:365-9. [PMID: 11930139 DOI: 10.1097/00001756-200203040-00023] [Citation(s) in RCA: 51] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
Cortical signal intensity changes due to brief (1 s) innocuous electrical stimuli applied to the second and fifth finger of the right hand were measured by means of fMRI at 1.5 T. The activation pattern in this event-related fMRI approach closely resembled that obtained in recent block-design studies. Activations were found in contralateral primary (SI) and bilaterally in secondary (SII) somato-sensory cortex as well as in posterior parietal cortex, insula, and supplementary motor area (SMA). In SI, the somatotopic organization of the hand area is demonstrated, more clearly to be seen in area 3b than in area 1 and 2. In conclusion, the feasibility to employ event-related somatosensory stimulation paradigms in fMRI studies is demonstrated.
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84
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Meyer R, Blankenburg F, Ruben J, Schwiemann J, Thees S, Kurth R, Curio G, Villringer K, Villringer A. Mirror-representation of the right hand in human primary sensory cortex — An fMRI study. Neuroimage 2001. [DOI: 10.1016/s1053-8119(01)92540-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022] Open
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85
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Kurth R, Villringer K, Kombos T, Süss O, Brock M, Villringer A, Wolf KJ. Correlation of preoperative fMRI of the primary motor cortex and intraoperative monopolar electrostimulation during neuronavigated-surgery of intracerebral tumours. Neuroimage 2001. [DOI: 10.1016/s1053-8119(01)92524-8] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022] Open
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86
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Grüsser SM, Winter C, Mühlnickel W, Denke C, Karl A, Villringer K, Flor H. The relationship of perceptual phenomena and cortical reorganization in upper extremity amputees. Neuroscience 2001; 102:263-72. [PMID: 11166112 DOI: 10.1016/s0306-4522(00)00491-7] [Citation(s) in RCA: 112] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
In this study 16 unilateral upper extremity amputees participated in a comprehensive psychophysiological examination that included the assessment of painful and non-painful phantom and stump sensations, thermal and electric perception as well as two-point discrimination thresholds, the detailed analysis of referred sensation and the measurement of reorganizational changes in primary somatosensory cortex using neuroelectric source imaging. Reorganization of the primary somatosensory cortex was associated with increased habitual phantom limb pain, telescoping, non-painful stump sensations and painful referred sensation induced by painful stimulation. It was unrelated to non-painful phantom sensations, non-painful referred sensation elicited by painful or non-painful stimulation, painful referred sensation elicited by non-painful stimulation, perception thresholds and stump pain. These data substantiate the hypothesis that painful and non-painful phantom phenomena are mediated by different neural substrates.
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Ruben J, Schwiemann J, Deuchert M, Meyer R, Krause T, Curio G, Villringer K, Kurth R, Villringer A. Somatotopic organization of human secondary somatosensory cortex. Cereb Cortex 2001; 11:463-73. [PMID: 11313298 DOI: 10.1093/cercor/11.5.463] [Citation(s) in RCA: 198] [Impact Index Per Article: 8.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
This fMRI study investigated the human somatosensory system, especially the secondary somatosensory cortex (SII), with respect to its potential somatotopic organization. Eight subjects received electrical stimulation on their right second finger, fifth finger and hallux. Within SII, the typical finding for both fingers was a representation site within the contralateral parietal operculum roughly halfway between the lip of the lateral sulcus and its fundus, whereas the representation site of the hallux was found more medially to this position at the fundus of the lateral sulcus, near the posterior pole of the insula. Somatotopy in SII seems to be less fine-grained than in primary somatosensory cortex (SI), as, in contrast to SI, no separate representations of the two fingers in SII were observed. A similar somatotopic representation pattern between fingers and the hallux was also observed within ipsilateral SII, indicating somatotopy of contra- as well as ipsilateral SII using unilateral stimulation. Further areas exhibiting activation were found in the superior and inferior parietal lobule, in the supplementary and cingulate motor area, and in the insula.
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Krause T, Kurth R, Ruben J, Schwiemann J, Villringer K, Deuchert M, Moosmann M, Brandt S, Wolf K, Curio G, Villringer A. Representational overlap of adjacent fingers in multiple areas of human primary somatosensory cortex depends on electrical stimulus intensity: an fMRI study. Brain Res 2001; 899:36-46. [PMID: 11311865 DOI: 10.1016/s0006-8993(01)02147-3] [Citation(s) in RCA: 53] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Functional magnetic resonance imaging (fMRI) was used to examine the influence of non-painful electrical stimulus intensity on the BOLD response in human primary somatosensory cortex (SI). In ten healthy subjects, index and middle finger of the right hand were stimulated separately at two different stimulus intensities. The activated volume of single finger representations as well as the volume of representational overlap of the two activations increased following an increase in stimulus intensity. This effect was seen in two different subdivisions of SI, one in the depth of the central sulcus, presumably corresponding to Brodmann area (BA) 3b, and one on the crown of the postcentral gyrus, presumably corresponding to BA 1/2. Relative overlap (ratio of overlap volume to volume of individual finger representation) was larger in BA 1/2 than in BA 3b. Additionally, in both areas relative overlap increased significantly from low to high stimulus intensity. Relative overlap did not change when different correlation thresholds were employed arguing against an unspecific 'spillover effect'. Analysis of signal intensity time courses indicated that the response difference to high versus low stimulus strength was not present during the initial seconds of stimulation, during which both led to a similar signal intensity increase. Only during the following maintenance level of the response did the response to high stimulus intensity reach a significantly higher plateau level than the one due to low intensity stimulation, an effect which was present in both areas, BA 3b and BA 1/2, respectively.
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89
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Villringer K, Wolf KJ. [Importance of the functional magnetic resonance (fMR)in the radiological diagnosis]. ROFO-FORTSCHR RONTG 2001; 173:165-7. [PMID: 11293853 DOI: 10.1055/s-2001-11592] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/16/2022]
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90
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Platz T, Kim IH, Pintschovius H, Winter T, Kieselbach A, Villringer K, Kurth R, Mauritz KH. Multimodal EEG analysis in man suggests impairment-specific changes in movement-related electric brain activity after stroke. Brain 2000; 123 Pt 12:2475-90. [PMID: 11099449 DOI: 10.1093/brain/123.12.2475] [Citation(s) in RCA: 60] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
Abstract
Movement-related slow cortical potentials and event-related desynchronization of alpha (alpha-ERD) and beta (beta-ERD) activity after self-paced voluntary triangular finger movements were studied in 13 ischaemic supratentorial stroke patients and 10 age-matched control subjects during movement preparation and actual performance. The stroke patients suffered from central arm paresis (n = 8), somatosensory deficits (n = 3) or ideomotor apraxia (n = 2). The multimodal EEG analysis suggested impairment-specific changes in the movement-related electrical activity of the brain. The readiness potential of paretic subjects was centred more anteriorly and laterally; during movement, they showed increased beta-ERD at left lateral frontal recording sites. Patients with somatosensory deficits showed reduced alpha-ERD and beta-ERD during both movement preparation and actual performance. Patients with ideomotor apraxia showed more lateralized frontal movement-related slow cortical potentials during both movement preparation and performance, and reduced left parietal beta-ERD during movement preparation. We conclude that (i) disturbed motor efference is associated with an increased need for excitatory drive of pyramidal cells in motor and premotor areas or an attempt to drive movements through projections from these areas to brainstem motor systems during movement preparation; (ii) an undisturbed somatosensory afference might contribute to the release of relevant cortical areas from their 'idling' state when movements are prepared and performed; and (iii) apraxic patients have a relative lack of activity of the mesial frontal motor system and the left parietal cortex, which is believed to be part of a network subserving ideomotor praxis.
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91
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Kurth R, Villringer K, Curio G, Wolf KJ, Krause T, Repenthin J, Schwiemann J, Deuchert M, Villringer A. fMRI shows multiple somatotopic digit representations in human primary somatosensory cortex. Neuroreport 2000; 11:1487-91. [PMID: 10841363] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/16/2023]
Abstract
Using electrical finger nerve stimulation in normal human subjects, fMRI detected separate representations for all 5 fingers in the primary somatosensory cortex. Responses were located in the posterior wall of the deep central sulcus (most likely corresponding to Brodmann Area (BA) 3b), and the anterior (BA 1) or posterior crown of the postcentral gyrus (BA 2) with rare activations in BA 3a and 4. In BA 3b we found a regular somatotopic mediolateral digit arrangement for fingers 5 to 1 with a mean Euclidean distance of 16 mm between fingers 1 and 5. In contrast BA 1/2 showed a greater number of adjacent activation foci with significantly more overlap and partly even reversed ordering of neighbouring fingers.
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92
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Krause T, Kurth R, Villringer K, Ruben J, Schwiemann J, Deuchert M, Curio G, Villringer A. Electrical stimulus intensity influences representational overlap of adjacent fingers in multiple areas of human primary somatosensory cortex. Neuroimage 2000. [DOI: 10.1016/s1053-8119(00)91828-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022] Open
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93
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Deuchert M, Ruben J, Meyer R, Schwiemann J, Thees S, Krause T, Curio G, Villringer K, Kurth R, Villringer A. Event-related fMRI of the somatosensory system. Neuroimage 2000. [DOI: 10.1016/s1053-8119(00)91831-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
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94
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Schwiemann J, Ruben J, Deuchert M, Meyer R, Krause T, Curio G, Villringer K, Kurth R, Villringer A. Multiple somatotopic maps in human somatosensory cortices: An fMRI study. Neuroimage 2000. [DOI: 10.1016/s1053-8119(00)91817-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022] Open
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95
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Kunkel A, Kopp B, Müller G, Villringer K, Villringer A, Taub E, Flor H. Constraint-induced movement therapy for motor recovery in chronic stroke patients. Arch Phys Med Rehabil 1999; 80:624-8. [PMID: 10378486 DOI: 10.1016/s0003-9993(99)90163-6] [Citation(s) in RCA: 202] [Impact Index Per Article: 8.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
OBJECTIVE Assessment of the effectiveness of constraint-induced (CI) movement therapy and quantitative evaluation of the effects of CI therapy. DESIGN Intervention study; case series; pretreatment to posttreatment measures and follow-up 3 months after intervention. SETTING An outpatient department. PATIENTS Five chronic stroke patients with moderate motor deficit; convenience sample. INTERVENTIONS CI therapy consisting of restraint of the unaffected upper extremity in a sling for 14 days combined with 6 hours of training per weekday of the affected upper extremity. MAIN OUTCOME MEASURES Actual Amount of Use Test (AAUT), Motor Activity Log (MAL), Wolf Motor Function Test (WMFT), and Arm Motor Ability Test (AMAT) RESULTS: There was a substantial improvement in the performance times of the laboratory tests (AMAT, WMFT, p < or = .039) and in the quality of movement (AMAT, WMFT, p < or = .049; MAL, p = .049), particularly in the use of the extremity in "real world" environments (AAUT, p = .020), supported by results of quantitative evaluation. The effect sizes were large and comparable to those found in previous studies of CI therapy. CONCLUSIONS CI therapy is an efficacious treatment for chronic stroke patients, especially in terms of real world outcome.
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Kopp B, Kunkel A, Mühlnickel W, Villringer K, Taub E, Flor H. Plasticity in the motor system related to therapy-induced improvement of movement after stroke. Neuroreport 1999; 10:807-10. [PMID: 10208552 DOI: 10.1097/00001756-199903170-00026] [Citation(s) in RCA: 138] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
Abstract
Neuroplasticity might play a beneficial role in the recovery of function after stroke but empirical evidence for this is lacking thus far. Constraint-induced (CI) therapy was used to increase the use of a paretic upper extremity in four hemiparetic stroke patients. Dipole modeling of steady-state movement-related cortical potentials was applied before and after training and 3 months later. The source locations associated with affected hand movement were unusual at follow-up because activation of the ipsilateral hemisphere was found in the absence of mirror movements of the unaffected hand. This long-term change may be considered as an initial demonstration of large-scale neuroplasticity associated with increased use of the paretic limb after application of CI therapy.
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97
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Kepenthin J, Villringer K, Kurth R, Curio G, Schwiemann J, Wolf KJ, Villringer A. Frequency dependence of fMRI signal intensity changes during somatosensory stimulation of single linger. Neuroimage 1998. [DOI: 10.1016/s1053-8119(18)31228-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
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98
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Villringer K, Kurth R, Repenthin J, Stoll T, Curio G, Schwiemann J, Wolf KJ, Villringer A. FMRI Mapping of Digital and Facial Sites in Human Brodmann Area 3b. Neuroimage 1998. [DOI: 10.1016/s1053-8119(18)31236-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/28/2022] Open
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99
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Ruben J, Wenzel R, Obrig H, Villringer K, Bernarding J, Hirth C, Heekeren H, Dirnagl U, Villringer A. Haemoglobin oxygenation changes during visual stimulation in the occipital cortex. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 1998; 428:181-7. [PMID: 9500046 DOI: 10.1007/978-1-4615-5399-1_26] [Citation(s) in RCA: 20] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
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100
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Kurth R, Villringer K, Mackert BM, Schwiemann J, Braun J, Curio G, Villringer A, Wolf KJ. fMRI assessment of somatotopy in human Brodmann area 3b by electrical finger stimulation. Neuroreport 1998; 9:207-12. [PMID: 9507956 DOI: 10.1097/00001756-199801260-00006] [Citation(s) in RCA: 105] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
Functional magnetic resonance imaging (fMRI) is capable of detecting focal brain activation induced by electrical stimulation of single fingers in human subjects. In eight subjects somatotopic arrangement of the second and fifth finger was found in Brodmann area 3b of the primary somatosensory cortex. In four subjects the representation area of the second finger was located lateral and inferior to the fifth finger; in one subject the somatotopy was reversed. In three subjects representation areas of the two fingers in Brodmann area 3b were found overlapping. Additional activated areas were found on the crown of ipsilateral and contralateral postcentral gyrus (Brodmann areas 1 and 2) and posterior parietal cortex.
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