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Motor Organization in Schizencephaly: Outcomes of Transcranial Magnetic Stimulation and Diffusion Tensor Imaging of Motor Tract Projections Correlate with the Different Domains of Hand Function. BIOMED RESEARCH INTERNATIONAL 2021; 2021:9956609. [PMID: 34527746 PMCID: PMC8437638 DOI: 10.1155/2021/9956609] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/22/2021] [Revised: 07/12/2021] [Accepted: 08/14/2021] [Indexed: 12/30/2022]
Abstract
Objective Schizencephaly is a rare congenital malformation that causes motor impairment. To determine the treatment strategy, each domain of the motor functions should be appropriately evaluated. We correlated a color map of diffusion tensor imaging (DTI) and transcranial magnetic stimulation (TMS) with the hand function test (HFT) to identify the type of hand function that each test (DTI and TMS) reflects. Further, we attempted to demonstrate the motor neuron organization in schizencephaly. Method This retrospective study was conducted on 12 patients with schizencephaly. TMS was conducted in the first dorsal interosseous (FDI), biceps (BB), and deltoid muscles of the upper extremity, and contralateral MEP (cMEP) and ipsilateral MEP (iMEP) were recorded. The HFT included the grip strength, box and block (B&B), and 9-hole peg test. The schizencephalic cleft was confirmed using magnetic resonance imaging, and the corticospinal tract (CST) was identified using the color map of DTI. The symmetry indices for the peduncle and CST at pons level were calculated as the ratios of the cross-sectional area of the less-affected side and that of the more-affected side. Result In the more-affected hemisphere TMS, no iMEP was obtained. In the less-affected hemisphere TMS, the iMEP response was detected in 9 patients and cMEP in all patients, which was similar to the pattern observed in unilateral lesion. Paretic hand grip strength was strongly correlated with the presence of iMEP (p = 0.044). The symmetry index of the color map of DTI was significantly correlated with the B&B (p = 0.008, R 2 = 0.416), whereas the symmetry index of the peduncle was not correlated with all HFTs. Conclusion In patients with schizencephaly, the iMEP response rate is correlated with the hand function related to strength, while the symmetricity of the CST by the color map of DTI is correlated with the hand function associated with dexterity. Additionally, we suggest the possible motor organization pattern of schizencephaly following interhemispheric competition.
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Ono Y, Hirosawa T, Hasegawa C, Ikeda T, Kudo K, Naito N, Yoshimura Y, Kikuchi M. Influence of oxytocin administration on somatosensory evoked magnetic fields induced by median nerve stimulation during hand action observation in healthy male volunteers. PLoS One 2021; 16:e0249167. [PMID: 33788881 PMCID: PMC8011787 DOI: 10.1371/journal.pone.0249167] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2020] [Accepted: 03/12/2021] [Indexed: 01/04/2023] Open
Abstract
Watching another person’s hand movement modulates somatosensory evoked magnetic fields (SEFs). Assuming that the mirror neuron system may have a role in this phenomenon, oxytocin should enhance these effects. This single-blinded, placebo-controlled, crossover study therefore used magnetoencephalography (MEG) to investigate SEFs following electrical stimulation of the right median nerve in 20 healthy male participants during hand movement observation, which were initially presented as static images followed by moving images. The participants were randomly assigned to receive either oxytocin or saline during the first trial, with the treatment being reversed during a second trial. Log-transformed ratios of the N20 and N30 amplitudes were calculated and compared between moving and static images observations. Phase locking (calculated using intertrial phase coherence) of brain oscillations was also analyzed to evaluate alpha, beta and gamma rhythm changes after oxytocin administration. Log N30 ratios showed no significant changes after placebo administration but showed a decreasing tendency (albeit not significant) after placebo administration, which may suggest mirror neuron system involvement. In contrast, log N20 ratios were increased after placebo administration, but showed no significant change after oxytocin administration. Interestingly, the gamma band activity around N20 increased after placebo administration, suggesting that oxytocin exerted an analgesic effect on median nerve stimulation, and inhibited the gamma band increase. Oxytocin might therefore modulate not only the mirror neuron system, but also the sensory processing associated with median nerve stimulation.
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Affiliation(s)
- Yasuki Ono
- Department of Neuropsychiatry, Graduate School of Medicine, Hirosaki University, Hirosaki, Japan
- Department of Psychiatry and Neurobiology, Graduate School of Medical Science, Kanazawa University, Kanazawa, Japan
- * E-mail:
| | - Tetsu Hirosawa
- Department of Psychiatry and Neurobiology, Graduate School of Medical Science, Kanazawa University, Kanazawa, Japan
| | - Chiaki Hasegawa
- Research Center for Child Mental Development, Kanazawa University, Kanazawa, Japan
| | - Takashi Ikeda
- Research Center for Child Mental Development, Kanazawa University, Kanazawa, Japan
| | | | - Nobushige Naito
- Department of Psychiatry and Neurobiology, Graduate School of Medical Science, Kanazawa University, Kanazawa, Japan
| | - Yuko Yoshimura
- Research Center for Child Mental Development, Kanazawa University, Kanazawa, Japan
| | - Mitsuru Kikuchi
- Department of Psychiatry and Neurobiology, Graduate School of Medical Science, Kanazawa University, Kanazawa, Japan
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3
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de Tommaso M, Betti V, Bocci T, Bolognini N, Di Russo F, Fattapposta F, Ferri R, Invitto S, Koch G, Miniussi C, Piccione F, Ragazzoni A, Sartucci F, Rossi S, Valeriani M. Pearl and pitfalls in brain functional analysis by event-related potentials: a narrative review by the Italian Psychophysiology and Cognitive Neuroscience Society on methodological limits and clinical reliability-part II. Neurol Sci 2020; 41:3503-3515. [PMID: 32683566 DOI: 10.1007/s10072-020-04527-x] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2019] [Accepted: 06/21/2020] [Indexed: 12/13/2022]
Abstract
This review focuses on new and/or less standardized event-related potentials methods, in order to improve their knowledge for future clinical applications. The olfactory event-related potentials (OERPs) assess the olfactory functions in time domain, with potential utility in anosmia and degenerative diseases. The transcranial magnetic stimulation-electroencephalography (TMS-EEG) could support the investigation of the intracerebral connections with very high temporal discrimination. Its application in the diagnosis of disorders of consciousness has achieved recent confirmation. Magnetoencephalography (MEG) and event-related fields (ERF) could improve spatial accuracy of scalp signals, with potential large application in pre-surgical study of epileptic patients. Although these techniques have methodological limits, such as high inter- and intraindividual variability and high costs, their diffusion among researchers and clinicians is hopeful, pending their standardization.
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Affiliation(s)
- Marina de Tommaso
- Applied Neurophysiology and Pain Unit-AnpLab-University of Bari Aldo Moro, Bari, Italy
| | - Viviana Betti
- Department of Psychology, Sapienza University of Rome, Rome, Italy.,Fondazione Santa Lucia, Istituto Di Ricovero e Cura a Carattere Scientifico, Rome, Italy
| | - Tommaso Bocci
- Dipartimento di Scienze della Salute, University of Milano, Milan, Italy
| | - Nadia Bolognini
- Department of Psychology & NeuroMi, University of Milano Bicocca, Milan, Italy.,Laboratory of Neuropsychology, IRCCS Istituto Auxologico, Milan, Italy
| | - Francesco Di Russo
- Dept. of Movement, Human and Health Sciences, University of Rome "Foro Italico", Rome, Italy
| | | | | | - Sara Invitto
- INSPIRE - Laboratory of Cognitive and Psychophysiological Olfactory Processes, University of Salento, Lecce, Italy
| | - Giacomo Koch
- Fondazione Santa Lucia, Istituto Di Ricovero e Cura a Carattere Scientifico, Rome, Italy.,Neuroscience Department, Policlinico Tor Vergata, Rome, Italy
| | - Carlo Miniussi
- Center for Mind/Brain Sciences - CIMeC, University of Trento, Rovereto, Italy.,Cognitive Neuroscience Section, IRCCS Istituto Centro San Giovanni di Dio Fatebenefratelli, Brescia, Italy
| | - Francesco Piccione
- Brain Imaging and Neural Dynamics Research Group, IRCCS San Camillo Hospital, Venice, Italy
| | - Aldo Ragazzoni
- Unit of Neurology and Clinical Neurophysiology, Fondazione PAS, Scandicci, Florence, Italy
| | - Ferdinando Sartucci
- Section of Neurophysiopathology, Department of Clinical and Experimental Medicine, University of Pisa, Pisa, Italy.,CNR Institute of Neuroscience, Pisa, Italy
| | - Simone Rossi
- Department of Medicine, Surgery and Neuroscience Siena Brain Investigation and Neuromodulation LAb (SI-BIN Lab), University of Siena, Siena, Italy
| | - Massimiliano Valeriani
- Neurology Unit, Bambino Gesù Hospital, Rome, Italy. .,Center for Sensory-Motor Interaction, Aalborg University, Aalborg, Denmark.
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Baik SW, Kim GW, Ko MH, Seo JH, Won YH, Park SH. An Unusual, Intermediate-Sized Lesion Affecting Motor Organization in a Patient With Schizencephaly: A Case Report. Front Hum Neurosci 2020; 14:258. [PMID: 32765236 PMCID: PMC7381274 DOI: 10.3389/fnhum.2020.00258] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2020] [Accepted: 06/11/2020] [Indexed: 11/13/2022] Open
Abstract
Schizencephalies are abnormal clefts of the cerebral hemispheres that result from abnormal late neuronal migration and cortical organization. In the present study, we report a different type of unusual motor organization in a patient with a schizencephalic cleft in the right hemisphere and polymicrogyria in the opposite hemisphere. Despite similar brain pathology affecting the sensorimotor cortex, motor organization differed from previously known bilateral congenital brain lesions. We conducted a transcranial magnetic stimulation (TMS) and diffusion tensor image (DTI) study to confirm the motor organization. In this case, ipsilateral corticospinal projections to the paretic hands were observed during TMS of the less affected hemisphere, along with polymicrogyria, similar to the previous study. However, a crossed corticospinal tract to the paretic hand from the more severely affected hemisphere was observed in this case-a pattern of motor organization that has yet to be reported in this patient population. Our findings indicate that motor organization after early brain injury may be affected by the interhemispheric competition of the corticospinal system and bilateral brain lesions, thereby resulting in unilateral hemiparesis.
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Affiliation(s)
- Sung-Woon Baik
- Department of Physical Medicine and Rehabilitation, Chonbuk National University Hospital, Jeonju, South Korea
| | - Gi-Wook Kim
- Department of Physical Medicine and Rehabilitation, Chonbuk National University Hospital, Jeonju, South Korea.,Research Institue of Clinical Medicine of Chonbuk National University-Biomedical Research Institue of Chonbuk National University Hospital, Jeonju, South Korea.,Translational Research & Clinical Trial Center for Medical Device, Chonbuk National University Hospital, Jeonju, South Korea
| | - Myoung-Hwan Ko
- Department of Physical Medicine and Rehabilitation, Chonbuk National University Hospital, Jeonju, South Korea.,Research Institue of Clinical Medicine of Chonbuk National University-Biomedical Research Institue of Chonbuk National University Hospital, Jeonju, South Korea.,Translational Research & Clinical Trial Center for Medical Device, Chonbuk National University Hospital, Jeonju, South Korea
| | - Jeoung-Hwan Seo
- Department of Physical Medicine and Rehabilitation, Chonbuk National University Hospital, Jeonju, South Korea.,Research Institue of Clinical Medicine of Chonbuk National University-Biomedical Research Institue of Chonbuk National University Hospital, Jeonju, South Korea
| | - Yu-Hui Won
- Department of Physical Medicine and Rehabilitation, Chonbuk National University Hospital, Jeonju, South Korea.,Research Institue of Clinical Medicine of Chonbuk National University-Biomedical Research Institue of Chonbuk National University Hospital, Jeonju, South Korea
| | - Sung-Hee Park
- Department of Physical Medicine and Rehabilitation, Chonbuk National University Hospital, Jeonju, South Korea.,Research Institue of Clinical Medicine of Chonbuk National University-Biomedical Research Institue of Chonbuk National University Hospital, Jeonju, South Korea
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5
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Bulubas L, Sardesh N, Traut T, Findlay A, Mizuiri D, Honma SM, Krieg SM, Berger MS, Nagarajan SS, Tarapore PE. Motor Cortical Network Plasticity in Patients With Recurrent Brain Tumors. Front Hum Neurosci 2020; 14:118. [PMID: 32317952 PMCID: PMC7146050 DOI: 10.3389/fnhum.2020.00118] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2019] [Accepted: 03/16/2020] [Indexed: 12/15/2022] Open
Abstract
Objective: The adult brain’s potential for plastic reorganization is an important mechanism for the preservation and restoration of function in patients with primary glial neoplasm. Patients with recurrent brain tumors requiring multiple interventions over time present an opportunity to examine brain reorganization. Magnetoencephalography (MEG) is a noninvasive imaging modality that can be used for motor cortical network mapping which, when performed at regular intervals, offers insight into this process of reorganization. Utilizing MEG-based motor mapping, we sought to characterize the reorganization of motor cortical networks over time in a cohort of 78 patients with recurrent glioma. Methods: MEG-based motor cortical maps were obtained by measuring event-related desynchronization (ERD) in ß-band frequency during unilateral index finger flexion. Each patient presented at our Department at least on two occasions for tumor resection due to tumor recurrence, and MEG-based motor mapping was performed as part of preoperative assessment before each surgical resection. Whole-brain activation patterns from first to second MEG scan (obtained before first and second surgery) were compared. Additionally, we calculated distances of activation peaks, which represent the location of the primary motor cortex (MC), to determine the magnitude of movement in motor eloquent areas between the first and second MEG scan. We also explored which demographic, anatomic, and pathological factors influence these shifts. Results: The whole-brain activation motor maps showed a subtle movement of the primary MC from first to second timepoint, as was confirmed by the determination of motor activation peaks. The shift of ipsilesional MC was directly correlated with a frontal-parietal tumor location (p < 0.001), presence of motor deficits (p = 0.021), and with a longer period between MEG scans (p = 0.048). Also, a disengagement of wide areas in the contralesional (ipsilateral to finger movement) hemisphere at the second time point was observed. Conclusions: MEG imaging is a sensitive method for depicting the plasticity of the motor cortical network. Although the location of the primary MC undergoes only subtle changes, appreciable shifts can occur in the setting of a stronger and longer impairment of the tumor on the MC. The ipsilateral hemisphere may serve as a reservoir for functional recovery.
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Affiliation(s)
- Lucia Bulubas
- Biomagnetic Imaging Lab, Department of Radiology and Biomedical Imaging, University of California San Francisco (UCSF), San Francisco, CA, United States.,Department of Neurological Surgery, University of California San Francisco (UCSF), San Francisco, CA, United States.,Department of Neurosurgery and TUM-Neuroimaging Center, Klinikum Rechts der Isar, Technische Universität (TU), Munich, Germany.,Department of Psychiatry and Psychotherapy, University Hospital, Ludwig-Maximilians Universität (LMU), Munich, Germany.,International Max Planck Research School for Translational Psychiatry (IMPRS-TP), Munich, Germany
| | - Nina Sardesh
- Biomagnetic Imaging Lab, Department of Radiology and Biomedical Imaging, University of California San Francisco (UCSF), San Francisco, CA, United States.,Department of Neurological Surgery, University of California San Francisco (UCSF), San Francisco, CA, United States
| | - Tavish Traut
- Biomagnetic Imaging Lab, Department of Radiology and Biomedical Imaging, University of California San Francisco (UCSF), San Francisco, CA, United States.,Department of Neurological Surgery, University of California San Francisco (UCSF), San Francisco, CA, United States
| | - Anne Findlay
- Biomagnetic Imaging Lab, Department of Radiology and Biomedical Imaging, University of California San Francisco (UCSF), San Francisco, CA, United States.,Department of Neurological Surgery, University of California San Francisco (UCSF), San Francisco, CA, United States
| | - Danielle Mizuiri
- Biomagnetic Imaging Lab, Department of Radiology and Biomedical Imaging, University of California San Francisco (UCSF), San Francisco, CA, United States.,Department of Neurological Surgery, University of California San Francisco (UCSF), San Francisco, CA, United States
| | - Susanne M Honma
- Biomagnetic Imaging Lab, Department of Radiology and Biomedical Imaging, University of California San Francisco (UCSF), San Francisco, CA, United States.,Department of Neurological Surgery, University of California San Francisco (UCSF), San Francisco, CA, United States
| | - Sandro M Krieg
- Department of Neurosurgery and TUM-Neuroimaging Center, Klinikum Rechts der Isar, Technische Universität (TU), Munich, Germany
| | - Mitchel S Berger
- Biomagnetic Imaging Lab, Department of Radiology and Biomedical Imaging, University of California San Francisco (UCSF), San Francisco, CA, United States.,Department of Neurological Surgery, University of California San Francisco (UCSF), San Francisco, CA, United States
| | - Srikantan S Nagarajan
- Biomagnetic Imaging Lab, Department of Radiology and Biomedical Imaging, University of California San Francisco (UCSF), San Francisco, CA, United States.,Department of Neurological Surgery, University of California San Francisco (UCSF), San Francisco, CA, United States
| | - Phiroz E Tarapore
- Biomagnetic Imaging Lab, Department of Radiology and Biomedical Imaging, University of California San Francisco (UCSF), San Francisco, CA, United States.,Department of Neurological Surgery, University of California San Francisco (UCSF), San Francisco, CA, United States
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Acute Phase Neuronal Activity for the Prognosis of Stroke Recovery. Neural Plast 2019; 2019:1971875. [PMID: 31611914 PMCID: PMC6755296 DOI: 10.1155/2019/1971875] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2019] [Revised: 05/17/2019] [Accepted: 06/24/2019] [Indexed: 11/17/2022] Open
Abstract
Strokes causing similar lesions and clinical states can be followed by diverse regains of neurological functions, indicating that the clinical recovery can depend on individual modulating factors. A promising line to disclose these factors, to finally open new therapeutic strategies, is to search for individual indices of recovery prognosis. Here, we pursued on strengthening the value of acute phase electrophysiological biomarkers for poststroke functional recovery in a wide group of patients. We enrolled 120 patients affected by a monohemispheric stroke within the middle cerebral artery territory (70 left and 50 right damages) and collected the NIH stroke scale (NIHSS) score in the acute phase (T0, median 4 days) and chronic follow-up (T1, median 6 months). At T0, we executed electrophysiological noninvasive assessment (19-channel electroencephalography (EEG) or 28 channels per side magnetoencephalography (MEG)) of brain activity at rest by means of band powers in the contra- and ipsilesional hemispheres (CLH, ILH) or the homologous area symmetry (HArS). Low-band (2-6 Hz) HArS entered the regression model for predicting the stabilized clinical state (p < 0.001), with bilateral impairment correlated with a poor outcome. Present data strengthen the fact that low-band impairment of homologous ipsi- and contralesional hemispheric regions in the acute stroke indicate a negative prognosis of clinical recovery.
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7
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Gopaul U, Carey L, Callister R, Nilsson M, van Vliet P. Combined somatosensory and motor training to improve upper limb function following stroke: a systematic scoping review. PHYSICAL THERAPY REVIEWS 2019. [DOI: 10.1080/10833196.2018.1553668] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Affiliation(s)
- Urvashy Gopaul
- School of Health Sciences, University of Newcastle, Newcastle, NSW, Australia
- Hunter Medical Research Institute, Newcastle, NSW, Australia
| | - Leeanne Carey
- School of Allied Health, La Trobe University, Melbourne, VIC, Australia
- Neurorehabilitation and Recovery, Stroke Division, The Florey Institute of Neuroscience and Mental Health, Melbourne, VIC, Australia
| | - Robin Callister
- Hunter Medical Research Institute, Newcastle, NSW, Australia
- School of Biomedical Sciences and Pharmacy, University of Newcastle, Newcastle, NSW, Australia
| | - Michael Nilsson
- Hunter Medical Research Institute, Newcastle, NSW, Australia
| | - Paulette van Vliet
- Hunter Medical Research Institute, Newcastle, NSW, Australia
- School of Humanities and Social Sciences, University of Newcastle, Newcastle, NSW, Australia
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Gopaul U, van Vliet P, Callister R, Nilsson M, Carey L. COMbined Physical and somatoSEnsory training after stroke: Development and description of a novel intervention to improve upper limb function. PHYSIOTHERAPY RESEARCH INTERNATIONAL 2018; 24:e1748. [PMID: 30230136 DOI: 10.1002/pri.1748] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2018] [Revised: 05/17/2018] [Accepted: 08/15/2018] [Indexed: 01/21/2023]
Abstract
BACKGROUND AND PURPOSE After stroke, reach-to-grasp goal-directed movements are disrupted as a result of both residual motor and somatosensory impairments. This report describes the rationale and development of a new upper limb stroke rehabilitation intervention known as COMPoSE: "COMbined Physical and somatoSEnsory training," designed to improve somatosensory and motor deficits in the upper limb after stroke. A standardized training matrix has been developed to facilitate intervention delivery. METHODS The COMPoSE intervention was developed through the following stages: (a) Definition and operationalization of somatosensory and motor variables used in training sensation and movement after stroke; (b) development of methods to give feedback to enhance skill acquisition; and (c) Combination of somatosensory and motor variables, and feedback, into a standardized training matrix. The reporting of the COMPoSE intervention adheres to the recommendations of the Template for Intervention Description and Replication checklist to facilitate replication of the intervention in the future. RESULTS The essential features of COMPoSE include combined somatosensory-motor training variables (grasp pressure, distance, object size, crushability, surface texture, and friction), feedback, and calibration using a haptic device providing measures of grasp pressure, use of anticipation trials, and high-dose repetitive task practice. Ten treatment sessions are delivered over 3 weeks, using a standardized matrix for treatment delivery. CONCLUSION COMPoSE is a new intervention that combines somatosensory and movement training, delivered synchronously, within the same intervention, and within the same task.
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Affiliation(s)
- Urvashy Gopaul
- School of Physiotherapy, University of Newcastle, Callaghan, New South Wales, Australia.,Stroke and Brain Injury, Hunter Medical Research Institute, New Lambton Heights, New South Wales, Australia
| | - Paulette van Vliet
- School of Humanities and Social Sciences, University of Newcastle, Callaghan, New South Wales, Australia.,Stroke and Brain Injury, Hunter Medical Research Institute, New Lambton Heights, New South Wales, Australia
| | - Robin Callister
- School of Biomedical Sciences and Pharmacy, University of Newcastle, Callaghan, New South Wales, Australia.,Stroke and Brain Injury, Hunter Medical Research Institute, New Lambton Heights, New South Wales, Australia
| | - Michael Nilsson
- Stroke and Brain Injury, Hunter Medical Research Institute, New Lambton Heights, New South Wales, Australia
| | - Leeanne Carey
- School of Allied Health, La Trobe University, Melbourne, Victoria, Australia.,Neurorehabilitation and Recovery, Stroke Division, The Florey Institute of Neuroscience and Mental Health, Heidelberg, Victoria, Australia
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A systematic review investigating the relationship of electroencephalography and magnetoencephalography measurements with sensorimotor upper limb impairments after stroke. J Neurosci Methods 2018; 311:318-330. [PMID: 30118725 DOI: 10.1016/j.jneumeth.2018.08.009] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2018] [Revised: 07/17/2018] [Accepted: 08/09/2018] [Indexed: 02/03/2023]
Abstract
BACKGROUND Predicting sensorimotor upper limb outcome receives continued attention in stroke. Neurophysiological measures by electroencephalography (EEG) and magnetoencephalography (MEG) could increase the accuracy of predicting sensorimotor upper limb recovery. NEW METHOD The aim of this systematic review was to summarize the current evidence for EEG/MEG-based measures to index neural activity after stroke and the relationship between abnormal neural activity and sensorimotor upper limb impairment. Relevant papers from databases EMBASE, CINHAL, MEDLINE and pubMED were identified. Methodological quality of selected studies was assessed with the Modified Downs and Black form. Data collected was reported descriptively. RESULTS Seventeen papers were included; 13 used EEG and 4 used MEG applications. Findings showed that: (a) the presence of somatosensory evoked potentials in the acute stage are related to better outcome of upper limb motor impairment from 10 weeks to 6 months post-stroke; (b) an interhemispheric imbalance of cortical oscillatory signals associated with upper limb impairment; and (c) predictive models including beta oscillatory cortical signal factors with corticospinal integrity and clinical measures could enhance upper limb motor prognosis. COMPARING WITH EXISTING METHOD The combination of neurological biomarkers with clinical measures results in higher statistical power than using neurological biomarkers alone when predicting motor recovery in stroke. CONCLUSIONS Alterations in neural activity by means of EEG and MEG are demonstrated from the early post-stroke stage onwards, and related to sensorimotor upper limb impairment. Future work exploring cortical oscillatory signals in the acute stage could provide further insight about prediction of upper limb sensorimotor recovery.
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10
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Disentangling Somatosensory Evoked Potentials of the Fingers: Limitations and Clinical Potential. Brain Topogr 2018; 31:498-512. [PMID: 29353446 PMCID: PMC5889784 DOI: 10.1007/s10548-017-0617-4] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/03/2017] [Accepted: 12/30/2017] [Indexed: 12/21/2022]
Abstract
In searching for clinical biomarkers of the somatosensory function, we studied reproducibility of somatosensory potentials (SEP) evoked by finger stimulation in healthy subjects. SEPs induced by electrical stimulation and especially after median nerve stimulation is a method widely used in the literature. It is unclear, however, if the EEG recordings after finger stimulation are reproducible within the same subject. We tested in five healthy subjects the consistency and reproducibility of responses through bootstrapping as well as test–retest recordings. We further evaluated the possibility to discriminate activity of different fingers both at electrode and at source level. The lack of consistency and reproducibility suggest responses to finger stimulation to be unreliable, even with reasonably high signal-to-noise ratio and adequate number of trials. At sources level, somatotopic arrangement of the fingers representation was only found in one of the subjects. Although finding distinct locations of the different fingers activation was possible, our protocol did not allow for non-overlapping dipole representations of the fingers. We conclude that despite its theoretical advantages, we cannot recommend the use of somatosensory potentials evoked by finger stimulation to extract clinical biomarkers.
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12
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Macháčková K, Vyskotová J, Opavský J. Recovery of somatosensory and motor functions of the paretic upper limb in patients after stroke: Comparison of two therapeutic approaches. ACTA GYMNICA 2016. [DOI: 10.5507/ag.2015.026] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022] Open
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13
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Simonetta-Moreau M. Non-invasive brain stimulation (NIBS) and motor recovery after stroke. Ann Phys Rehabil Med 2014; 57:530-542. [DOI: 10.1016/j.rehab.2014.08.003] [Citation(s) in RCA: 53] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2014] [Accepted: 08/06/2014] [Indexed: 12/24/2022]
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14
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Somatotopic finger mapping using MEG: toward an optimal stimulation paradigm. Clin Neurophysiol 2013; 124:1659-70. [PMID: 23518470 DOI: 10.1016/j.clinph.2013.01.027] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2012] [Revised: 12/19/2012] [Accepted: 01/15/2013] [Indexed: 11/21/2022]
Abstract
OBJECTIVE In non-invasive somatotopic mapping based on neuromagnetic source analysis, the recording time can be shortened and accuracy improved by applying simultaneously vibrotactile stimuli at different frequencies to multiple body sites and recording multiple steady-state responses. This study compared the reliability of sensory evoked responses, source localization performance, and reproducibility of digit maps for three different stimulation paradigms. METHODS Vibrotactile stimuli were applied to the fingertip and neuromagnetic steady-state responses were recorded. Index and middle fingers were stimulated either sequentially in separate blocks, simultaneously at different frequencies, or in alternating temporal order within a block. RESULTS Response amplitudes were largest and source localization was most accurate between 21 and 23 Hz. Separation of adjacent digits was significant for all paradigms in all participants. Suppressive interactions occurred between simultaneously applied stimuli. However, when frequently alternating between stimulus sites, the higher stimulus novelty resulted in increased amplitudes and superior localization performance. CONCLUSIONS When receptive fields are strongly overlapping, the alternating stimulation is preferable over recording multiple steady state responses. SIGNIFICANCE The new paradigm improved the measurement of the distance of somatotopic finger representation in human primary somatosensory cortex, which is an important metric for neuroplastic reorganization after learning and rehabilitation training.
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15
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Recovery mechanisms of somatosensory function in stroke patients: implications of brain imaging studies. Neurosci Bull 2013; 29:366-72. [PMID: 23471867 DOI: 10.1007/s12264-013-1315-1] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2012] [Accepted: 08/20/2012] [Indexed: 10/27/2022] Open
Abstract
Somatosensory dysfunction is associated with a high incidence of functional impairment and safety in patients with stroke. With developments in brain mapping techniques, many studies have addressed the recovery of various functions in such patients. However, relatively little is known about the mechanisms of recovery of somatosensory function. Based on the previous human studies, a review of 11 relevant studies on the mechanisms underlying the recovery of somatosensory function in stroke patients was conducted based on the following topics: (1) recovery of an injured somatosensory pathway, (2) peri-lesional reorganization, (3) contribution of the unaffected somatosensory cortex, (4) contribution of the secondary somatosensory cortex, and (5) mechanisms of recovery in patients with thalamic lesions. We believe that further studies in this field using combinations of diffusion tensor imaging, functional neuroimaging, and magnetoencephalography are needed. In addition, the clinical significance, critical period, and facilitatory strategies for each recovery mechanism should be clarified.
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Jang SH, Lee MY. Correlation between somatosensory function and cortical activation induced by touch stimulation in patients with intracerebral hemorrhage. Int J Neurosci 2013; 123:248-52. [PMID: 23227782 DOI: 10.3109/00207454.2012.755968] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
OBJECTIVES The correlation between somatosensory function and cortical activation induced by touch stimulation in patients with intracerebral hemorrhage (ICH) was investigated by functional magnetic resonance imaging (fMRI). METHODS Thirty-two chronic ICH patients with somatosensory deficits in tactile sensation were enrolled. For fMRI, touch stimulation was applied on the dorsum of the affected hand (contralateral to the ICH), using a rubber brush at a frequency of 1 Hz. Regions of interests (ROIs) were set at the primary sensory-motor cortex [SM1: Brodmann's area (BA) 1, 2, 3, 4], the posterior parietal cortex (PPC: BA 5, 7) and the secondary somatosensory cortex (S2: BA 43) in both hemispheres. The tactile sensation subscale of the Nottingham Sensory Assessment (NSA) was used to determine somatosensory function. RESULTS Significant correlations were found between NSA scores and voxel counts in the contralateral (ipsilesional) SM1 (r = 0.642; p < 0.05), the contralateral PPC (r = 0.507; p < 0.05) and the ipsilateral (contralesional) SM1 (r = 0.466; p < 0.05). However, no correlation was found between NSA scores and the contralateral S2 (r = 0.323; p > 0.05), the ipsilateral PPC (r = 0.252; p > 0.05) or the ipsilateral S2 (r = 0.280; p > 0.05). CONCLUSIONS It was found that somatosensory functions were positively correlated with degrees of blood oxygenation level dependent signal change of the following ROIs: the contralateral SM1, the contralateral PPC and the ipsilateral SM1. Opposingly, the S2 showed no correlation on either side of the brain.
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Affiliation(s)
- Sung Ho Jang
- Department of Physical Medicine and Rehabilitation, College of Medicine, Yeungnam University, Taegu, Republic of Korea
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Effect of afferent input on motor cortex excitability during stroke recovery. Clin Neurophysiol 2012; 123:2429-36. [PMID: 22721651 DOI: 10.1016/j.clinph.2012.05.017] [Citation(s) in RCA: 47] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2012] [Revised: 05/21/2012] [Accepted: 05/23/2012] [Indexed: 11/20/2022]
Abstract
OBJECTIVE Afferent input is proposed to mediate its effect on motor functions by modulating the excitability of the motor cortex. We aimed to clarify - in a longitudinal study - how afferent input affects motor cortex excitability after stroke and how it is associated with recovery of hand function. METHODS The motor cortex excitability was studied by measuring the reactivity of the motor cortex beta rhythm to somatosensory stimulation. We recorded the amplitude of the suppression and subsequent rebound of the beta oscillations during tactile finger stimulation with MEG in 23 first-ever stroke patients within one week and at 1 and 3 months after stroke, with concomitant evaluation of hand function. RESULTS The strength of the beta rhythm rebound, suggested to reflect decreased motor cortex excitability, was weak in the affected hemisphere after stroke and it was subsequently increased during recovery. The rebound strength correlated with hand function tests in all recordings. CONCLUSION Motor cortex excitability is modulated by afferent input after stroke. The motor cortex excitability is increased in the AH acutely after stroke and decreases in parallel with recovery of hand function. SIGNIFICANCE The results implicate the importance of parallel recovery of both sensory and motor systems in functional recovery after stroke.
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Castellanos NP, Bajo R, Cuesta P, Villacorta-Atienza JA, Paúl N, Garcia-Prieto J, Del-Pozo F, Maestú F. Alteration and reorganization of functional networks: a new perspective in brain injury study. Front Hum Neurosci 2011; 5:90. [PMID: 21960965 PMCID: PMC3177176 DOI: 10.3389/fnhum.2011.00090] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2010] [Accepted: 08/11/2011] [Indexed: 11/29/2022] Open
Abstract
Plasticity is the mechanism underlying the brain’s potential capability to compensate injury. Recently several studies have shown how functional connections among the brain areas are severely altered by brain injury and plasticity leading to a reorganization of the networks. This new approach studies the impact of brain injury by means of alteration of functional interactions. The concept of functional connectivity refers to the statistical interdependencies between physiological time series simultaneously recorded in various areas of the brain and it could be an essential tool for brain functional studies, being its deviation from healthy reference an indicator for damage. In this article, we review studies investigating functional connectivity changes after brain injury and subsequent recovery, providing an accessible introduction to common mathematical methods to infer functional connectivity, exploring their capabilities, future perspectives, and clinical uses in brain injury studies.
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Affiliation(s)
- Nazareth P Castellanos
- Laboratory of Cognitive and Computational Neuroscience, Centre for Biomedical Technology, Universidad Politécnica de Madrid Madrid, Spain
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Maldonado IL, Moritz-Gasser S, de Champfleur NM, Bertram L, Moulinié G, Duffau H. Surgery for gliomas involving the left inferior parietal lobule: new insights into the functional anatomy provided by stimulation mapping in awake patients. J Neurosurg 2011; 115:770-9. [PMID: 21699481 DOI: 10.3171/2011.5.jns112] [Citation(s) in RCA: 90] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
OBJECT Surgery in the left dominant inferior parietal lobule (IPL) is challenging because of a high density of somatosensory and language structures, both in the cortex and white matter. In the present study, on the basis of the results provided by direct cerebral stimulation in awake patients, the authors revisit the anatomofunctional aspects of surgery within the left IPL. METHODS Fourteen consecutive patients underwent awake craniotomy for a glioma involving the left IPL. Intraoperative motor, sensory, and language mapping was performed before and during the tumor removal, at both the cortical and subcortical levels, to optimize the extent of resection, which was determined based on functional boundaries. Anatomofunctional correlations were performed by combining the results of intraoperative mapping and those provided by pre- and postoperative MR imaging. RESULTS At the cortical level, the primary somatosensory area (retrocentral gyrus) limited the resection anteriorly in all cases, at least partially. Less frequently, speech arrest or articulatory problems were observed within the parietal operculum (4 cases). The lateral limit was determined by language sites that were variably distributed. Anomia was the most frequent response (9 cases) at the posterior third of the superior (and/or middle) temporal gyrus. Posteriorly, less reproducible reorganized language sites were seldom observed in the posterior portion of the angular gyrus (2 cases). At the subcortical level, in addition to somatosensory responses due to stimulation of the thalamocortical pathways, articulatory disturbances were induced by stimulation of white matter in the anterior and lateral part of the surgical cavity (11 cases). This tract anatomically corresponds to the horizontal portion of the lateral segment of the superior longitudinal fascicle (SLF III). Deeper and superiorly, phonemic paraphasia was the main language disturbance (12 cases), elicited by stimulation of the posterosuperior portion of the arcuate fascicle. All these eloquent structures were surgically preserved. Despite slight cognitive disorders (working memory, writing, or calculation) in 6 cases, no patient retained a severe or a moderate postoperative deficit (except one with right hemianopia [mean follow-up 41.8 months]). Resection was total or near total in 9 patients and partial in 3 cases. CONCLUSIONS To the authors' knowledge, this is the first series dedicated to the surgery of gliomas involving the left IPL. Interestingly, a certain degree of interindividual variability was observed in the distribution of the cortical maps, especially for language. Therefore, it is suggested that no rigid pattern of resection can be considered within the left IPL, and that surgery in this region should be performed in awake patients to adapt the tumor removal to individual functional limits. Nonetheless, several landmarks have been regularly identified, especially at the subcortical levels (SLF III and arcuate fascicle); a better knowledge of these functional tracts could be helpful to optimize functional outcomes.
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Affiliation(s)
- Igor Lima Maldonado
- Department of Neurosurgery, Hôpital Gui de Chauliac, Montpellier University Hospital, Montpellier, France
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Roiha K, Kirveskari E, Kaste M, Mustanoja S, Mäkelä JP, Salonen O, Tatlisumak T, Forss N. Reorganization of the primary somatosensory cortex during stroke recovery. Clin Neurophysiol 2011; 122:339-45. [DOI: 10.1016/j.clinph.2010.06.032] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2010] [Revised: 06/02/2010] [Accepted: 06/21/2010] [Indexed: 10/19/2022]
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Houzé B, Perchet C, Magnin M, Garcia-Larrea L. Cortical representation of the human hand assessed by two levels of high-resolution EEG recordings. Hum Brain Mapp 2011; 32:1894-904. [PMID: 21246666 DOI: 10.1002/hbm.21155] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2009] [Revised: 08/05/2010] [Accepted: 08/05/2010] [Indexed: 11/09/2022] Open
Abstract
Increasing interest in cortical plasticity has prompted the growing use of somatosensory evoked potentials (SEPs) to estimate changes in the cortical representation of body regions. Here, we tested the effect of different sites of hand stimulation and of the density of spatial sampling in the quality of estimation of somatosensory sources. Sources of two SEP components from the primary somatosensory cortex (N20/P20 and P45) were estimated using two levels of spatial sampling (64- vs. 128-channel) and stimulation of four distal sites in the upper limbs, including single digits (first vs. fifth) and distal nerves with comparable cortical projection (superficial branch of the radial nerve and distal ulnar nerve). The most robust separation of somatosensory sources was achieved by comparing the cortical representations of the first digit and the distal ulnar nerve territories on the N20/P20 component of SEPs. Although both the 64- and the 128-electrode montages correctly discriminated these two areas, only the 128-electrode montage was able to significantly separate sources in the other cases, notably when using first versus fifth digit stimulation. Trustworthy distinction of cortical representations was not obtainable when using the P45 component, probably because of greater activation volume, radial orientation of sources in areas 1-2 and increased variability with attention and vigilance. Assessment of tangential SEP components to stimulation of first digit versus ulnar nerve appears the best option to assess plastic somatosensory changes, especially when using relatively low-electrode sampling.
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Affiliation(s)
- Bérengère Houzé
- Central Integration of Pain, INSERM U879/University Claude Bernard Lyon 1, France.
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Stępień M, Conradi J, Waterstraat G, Hohlefeld FU, Curio G, Nikulin VV. Event-related desynchronization of sensorimotor EEG rhythms in hemiparetic patients with acute stroke. Neurosci Lett 2010; 488:17-21. [PMID: 21056625 DOI: 10.1016/j.neulet.2010.10.072] [Citation(s) in RCA: 48] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2010] [Revised: 10/21/2010] [Accepted: 10/29/2010] [Indexed: 10/18/2022]
Abstract
Previous neuroimaging studies based on neurovascular coupling have shown that stroke affects both, strength and spatial extent of brain activation during upper limb movements. Here, we investigated the sub-second amplitude dynamics of a direct neuronal measure, i.e., event-related desynchronization (ERD) of EEG oscillations during finger movements, in patients with acute cortical and subcortical stroke. Acute cortical strokes were found to decrease the ERD of alpha oscillations for the affected pericentral sensorimotor areas compared to a control group. Within the cortical stroke group, the affected hemisphere showed a smaller alpha-ERD compared to the unaffected hemisphere when each was contralateral to the acting hand. Furthermore, when cortical stroke patients moved their paretic hand, the ipsilateral (i.e., contralesional) alpha-ERD was stronger than the contralateral (ipsilesional) ERD. Interestingly, the alpha-ERD amplitude in a hemisphere with a cortical stroke was relatively well preserved for non-paretic hand movements compared to alpha-ERD amplitude for paretic hand movements. This finding provides a new perspective for assessing the rehabilitative potential, which could be utilized through training of the still responsive cortical network, e.g., via enforced use of the paretic hand.
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Affiliation(s)
- Magdalena Stępień
- Neurophysics Group, Department of Neurology, Charité University Medicine Berlin, Germany
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From maps to form to space: touch and the body schema. Neuropsychologia 2009; 48:645-54. [PMID: 19699214 DOI: 10.1016/j.neuropsychologia.2009.08.017] [Citation(s) in RCA: 118] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2009] [Revised: 07/14/2009] [Accepted: 08/16/2009] [Indexed: 11/24/2022]
Abstract
Evidence from patients has shown that primary somatosensory representations are plastic, dynamically changing in response to central or peripheral alterations, as well as experience. Furthermore, recent research has also demonstrated that altering body posture results in changes in the perceived sensation and localization of tactile stimuli. Using evidence from behavioral studies with brain-damaged and healthy subjects, as well as functional imaging, we propose that the traditional concept of the body schema should be divided into three components. First are primary somatosensory representations, which are representations of the skin surface that are typically somatotopically organized, and have been shown to change dynamically due to peripheral (usage, amputation, deafferentation) or central (lesion) modifications. Second, we argue for a mapping from a primary somatosensory representation to a secondary representation of body size and shape (body form representation). Finally, we review evidence for a third set of representations that encodes limb position and is used to represent the location of tactile stimuli relative to the subject using external, non-somatotopic reference frames (postural representations).
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Sullivan JE, Hedman LD. Sensory dysfunction following stroke: incidence, significance, examination, and intervention. Top Stroke Rehabil 2008; 15:200-17. [PMID: 18647725 DOI: 10.1310/tsr1503-200] [Citation(s) in RCA: 108] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
Recent studies have provided evidence of the widespread incidence of sensory dysfunction following stroke. The importance of these findings lies in the association between sensory loss poststroke and poorer outcomes in motor capacity, functional abilities, length of inpatient stay, and quality of life. Since literature suggests that clinicians can use information about clients' sensory status to predict rehabilitation outcomes and select appropriate interventions, the accuracy of somatosensory assessment is extremely clinically relevant. However, many of the clinical tests that are commonly used to examine sensation have not been found to be valid or reliable. Emerging evidence supports the efficacy of several interventions that target the sensory systems. This article reviews the incidence, significance, examination, and interventions for sensory dysfunction following stroke and summarizes the important characteristics of interventions directed at somatosensation.
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Affiliation(s)
- Jane E Sullivan
- Department of Physical Therapy & Human Movement Sciences, Feinberg School of Medicine Northwestern University, Chicago, IL, USA
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Masiero S, Carraro E. Upper limb movements and cerebral plasticity in post-stroke rehabilitation. Aging Clin Exp Res 2008; 20:103-8. [PMID: 18431076 DOI: 10.1007/bf03324755] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Rehabilitative interventions for the plegic/paretic upper limb of stroke survivors are more effective if they are early, intensive, and provide multisensory stimulation. Various rehabilitative approaches have been proposed to date, but little has been published on clinical efficacy. The mechanism underlying recovery of neurological injury after stroke is still incompletely understood, but more than one process is probably involved and cerebral plasticity undoubtedly plays a key role. The goal of this review was to identify which movements and type of therapeutic arm exercises may influence cerebral plasticity in plegic/paretic stroke survivors. Evidence suggests that plasticity is stimulated more by the arm's movement trajectory than by its final position in space. Rehabilitation should be based on simple, repetitive, unidirectional or, better still, complex and multidirectional movements in all spatial planes, such as circular or spiral movements. It should also incorporate a feedback system, since this seems to bring about earlier and better motor and functional outcomes.
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Affiliation(s)
- Stefano Masiero
- Rehabilitation Unit, Department of Rehabilitation Medicine, University of Padua, 35128 Padua, Italy.
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Stoeckel MC, Pollok B, Schnitzler A, Seitz RJ. Studying the human somatosensory hand area: A new way to compare fMRI and MEG. J Neurosci Methods 2007; 164:280-91. [PMID: 17597225 DOI: 10.1016/j.jneumeth.2007.05.016] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2006] [Revised: 04/03/2007] [Accepted: 05/13/2007] [Indexed: 10/23/2022]
Abstract
Valid localization is a prerequisite to study plasticity of the somatosensory cortex in humans. We compared the localizations of left and right thumb and little finger in the primary somatosensory cortex obtained with fMRI and MEG. Representations were investigated in 11 healthy right-handed subjects using echoplanar fMRI and 122-channel MEG together with electric finger stimulation. Activation observed with fMRI was based on an increase in the BOLD signal. Most of the activation clusters (71.1%) were located on the lateral surface of the postcentral gyrus. Representations of thumb and little finger were 17mm apart on average and consistently showed a somatotopic arrangement with the thumb representation inferior, lateral, and anterior to the representation of the little finger. Activation observed with MEG was modelled by equivalent current dipoles. Dipole localization was compatible with an assumed origin of activation within the posterior wall of the central sulcus. The Euclidian distance between corresponding dipoles was 11.5mm on average with deviations from the expected spatial arrangement of 35, 30, and 20% in the x-, y- und z-direction, respectively. Our study demonstrates how relative localization of somatosensory activations can serve as an indicator for localization validity when comparing different methods or studying somatosensory plasticity.
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Affiliation(s)
- Maria Cornelia Stoeckel
- Department of Neurology, University Hospital Düsseldorf, Moorenstr. 5, 40225 Düsseldorf, Germany.
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Tecchio F, Pasqualetti P, Zappasodi F, Tombini M, Lupoi D, Vernieri F, Rossini PM. Outcome prediction in acute monohemispheric stroke via magnetoencephalography. J Neurol 2007; 254:296-305. [PMID: 17345051 DOI: 10.1007/s00415-006-0355-0] [Citation(s) in RCA: 44] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2006] [Accepted: 07/25/2006] [Indexed: 12/21/2022]
Abstract
BACKGROUND Following an ischemic stroke a highly variable clinical outcome is commonly evident despite similar onset symptoms as well as lesion characteristics. The aim of this study was to identify indexes providing early prediction of functional recovery, in addition to clinical severity and lesion dimension at onset of stroke. METHODS In 32 patients, magnetoencephalographic (MEG) parameters collected in the acute phase (<10 days from symptoms onset, T0) from affected (AH) and unaffected (UH) hemispheres at rest and evoked by sensory stimuli were evaluated in association with the clinical outcome in a stabilized phase (T1, median 7.8 months) classified with three levels: worsening, partial and full recovery. RESULTS Multiple multinomial logistic regression indicated AH gamma and UH delta band powers able to prognosticate clinical outcome at T1. After inclusion in this analysis, lesion volume had the strongest predictive ability, and UH delta band power remained as a predictive factor with a measurable cut-off, maximizing both sensitivity and specificity of the prediction: a patient with UH delta below cut-off would recover to some extent; a patient with UH delta above cut-off would have a probability of about 70% to worsen. CONCLUSIONS MEG UH delta and AH gamma band powers were found to provide useful information about long-term outcome prognosis. Only the increase of delta band activity in the unaffected hemisphere contains information about the outcome in addition to the lesion volume.
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Affiliation(s)
- Franca Tecchio
- Istituto di Scienze e Tecnologie della Cognizione (ISTC), CNR, Rome, Italy.
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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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Tzvetanov P, Rousseff RT. Predictive value of median-SSEP in early phase of stroke: a comparison in supratentorial infarction and hemorrhage. Clin Neurol Neurosurg 2006; 107:475-81. [PMID: 16202820 DOI: 10.1016/j.clineuro.2004.12.008] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2004] [Revised: 12/05/2004] [Accepted: 12/14/2004] [Indexed: 11/18/2022]
Abstract
OBJECTIVE To compare the prognostic value of median somatosensory evoked potentials (M-SSEP) changes in the early phase of supratentorial infarction and hemorrhage. MATERIAL AND METHODS This study includes 130 patients (mean age 62+/-11.4 years, 43 women, large middle cerebral artery territory infarction in 36 patients, restricted/lacunar in 55, massive supratentorial hemorrhage in 10, small/medium size hemorrhage in 31). M-SSEP were recorded early (0-7 days in ischemia, 0-21 days in hemorrhage) and patients stratified into groups with absent, abnormal, normal response. Clinical state was determined by the Medical Research Council (MRC) scale, Barthel Index and Rankin score and followed for at least 6 months. RESULTS Moderate prognostic correlation was established between N20-P25 amplitudes (r=0.34, p<0.05) and N20-P25 amplitude ratio (r=0.45, p<0.01) and Barthel Index at 6 months in patients with ischemic stroke. Moderate relationship (r=-0.34, p<0.05) exists also between N20-P25 ratio and Rankin score at 6 months in patients with small/medium size hemorrhage. In large infarctions and small/medium size cerebral hemorrhages correlations with all clinical indices of outcome are weak. In massive hemorrhage, only a weak correlation (r=-0.19, p<0.05) between amplitude ratio and Rankin score was found. The combination of initial MRC and N20-P25 amplitude ratio has 10% (in hemorrhage) to 15% (in infarction) greater prognostic value (p<0.05) than initial alone. CONCLUSIONS M-SSEP have independent predictive value regarding functional recovery in ischemic stroke and small/medium size cerebral hemorrhage. Combined assessment of initial MRC and M-SSEP substantially improves prognosis in acute stroke.
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Affiliation(s)
- Plamen Tzvetanov
- Stroke Unit, Medical University of Pleven, Department of Neurology, Georgi Kochev str. 8A, Pleven 5800, Bulgaria.
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Tecchio F, Zappasodi F, Pasqualetti P, Rossini PM. Neural connectivity in hand sensorimotor brain areas: an evaluation by evoked field morphology. Hum Brain Mapp 2005; 24:99-108. [PMID: 15468154 PMCID: PMC6871686 DOI: 10.1002/hbm.20073] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
The connectivity pattern of the neural network devoted to sensory processing depends on the timing of relay recruitment from receptors to cortical areas. The aim of the present work was to uncover and quantify the way the cortical relay recruitment is reflected in the shape of the brain-evoked responses. We recorded the magnetic somatosensory evoked fields (SEF) generated in 36 volunteers by separate bilateral electrical stimulation of median nerve, thumb, and little fingers. After defining an index that quantifies the shape similarity of two SEF traces, we studied the morphologic characteristics of the recorded SEFs within the 20-ms time window that followed the impulse arrival at the primary sensory cortex. Based on our similarity criterion, the shape of the SEFs obtained stimulating the median nerve was observed to be more similar to the one obtained from the thumb (same median nerve innervation) than to the one obtained from the little finger (ulnar nerve innervation). In addition, SEF shapes associated with different brain regions were more similar within an individual than between subjects. Because the SEF morphologic characteristics turned out to be quite diverse among subjects, we defined similarity levels that allowed us to identify three main classes of SEF shapes in normalcy. We show evidence that the morphology of the evoked response describes the anatomo-functional connectivity pattern in the primary sensory areas. Our findings suggest the possible existence of a thalamo-cortico-thalamic responsiveness loop related to the different classes.
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Affiliation(s)
- Franca Tecchio
- Istituto di Scienze e Tecnologie della Cognizione-Consiglio Nationale della Ricerche, 00186 Roma, Italy.
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Tzvetanov P, Rousseff RT, Atanassova P. Prognostic value of median and tibial somatosensory evoked potentials in acute stroke. Neurosci Lett 2005; 380:99-104. [PMID: 15854759 DOI: 10.1016/j.neulet.2005.01.023] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2004] [Revised: 12/27/2004] [Accepted: 01/09/2005] [Indexed: 11/20/2022]
Abstract
The predictive values of early somatosensory evoked potentials (SSEPs) for the functional outcome after stroke are investigated. Ninety-four stroke patients (mean age: 61.2, S.D.: 11.8) with CT confirmed diagnoses of middle cerebral artery (MCA) infarction in 71 and supratentorial intracerebral hemorrhage in 23. Median and tibial SSEPs were recorded within 3 days of onset. SSEP parameters were compared to motor (MRC) and functional ability (Barthel index) followed up at 1, 3, 6 and 12 months. Upper limb MRC remains the strongest single predictor of functional outcome, determining 54.3% of Barthel index value at 12 months. The highest predictive value among SSEP parameters has N20-P25 amplitude ratio-34.5%. Combined application of upper limb MRC and N20-P25 amplitude ratio provided significantly stronger prognostic information-66%. Combined assessment of SSEP parameters and muscle power in acute stroke considerably improves prediction of functional outcome.
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Affiliation(s)
- Plamen Tzvetanov
- Stroke Unit, Department of Neurology, Medical University of Pleven, Georgi Kochev str. 8A, Pleven 5800, Bulgaria.
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Stoeckel MC, Jörgens S, Witte OW, Seitz RJ. Reduced somatosensory hand representation in thalidomide-induced dysmelia as revealed by fMRI. Eur J Neurosci 2005; 21:556-62. [PMID: 15673455 DOI: 10.1111/j.1460-9568.2005.03866.x] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
The concept of cerebral plasticity suggests that the hand representation in somatosensory cortex is abnormal in congenital malformation disorders. To investigate this issue we studied 11 subjects with different degrees of upper extremity dysmelia due to thalidomide embryopathy in comparison to 10 control subjects. In the affected subjects fingers are typically missing in radio-ulnar order beginning with the thumb. Haemodynamic responses to electrical stimulation of the radial-most and ulnar-most fingers were measured in each subject using functional magnetic resonance tomography. The size of the hand area in the primary somatosensory cortex was estimated by calculating the Euclidian distance between corresponding activation peaks on the lateral postcentral gyrus. The cortical somatosensory hand representation was found to be significantly smaller in dysmelic subjects as compared with the control subjects (P <0.001). The shrinkage of the hand area was not proportional to the number of missing fingers. Furthermore, the cortical representation of the ulnar fingers in the dysmelic subjects was shifted towards the cortical thumb representation of the control group. We suggest that the unproportional reduction of the hand area together with the observed shift may reflect use-dependent rather than malformation-induced reorganization of the somatosensory hand area.
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Affiliation(s)
- M Cornelia Stoeckel
- Department of Neurology, University Hospital Düsseldorf, Moorenstr. 5, 40225 Düsseldorf, Germany.
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Popovic DB, Popovic MB, Sinkjaer T, Stefanovic A, Schwirtlich L. Therapy of paretic arm in hemiplegic subjects augmented with a neural prosthesis: a cross-over study. Can J Physiol Pharmacol 2005; 82:749-56. [PMID: 15523532 DOI: 10.1139/y04-057] [Citation(s) in RCA: 90] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
There are indications that both intensive exercise and electrical stimulation have a beneficial effect on arm function in post-stroke hemiplegic patients. We recommend the use of Functional Electrical Therapy (FET), which combines electrical stimulation of the paretic arm and intensive voluntary movement of the arm to exercise daily functions. FET was applied 30 min daily for 3 weeks. Forty-one acute hemiplegics volunteered in the 18-months single blinded cross-over study (CoS). Nineteen patients (Group A) participated in FET during their acute hemiplegia, and 22 patients (Group B) participated in FET during their chronic phase of hemiplegia. Group B patients were controls during FET in acute hemiplegia, and Group A patients were controls during the FET in chronic hemiplegia. Thirty-two patients completed the study. The outcomes of the Upper Extremity Function Test (UEFT) were used to assess the ability of patients to functionally use objects, as were the Drawing Test (DT) (used to assess the coordination of the arm), the Modified Ashworth Scale, the range of movement, and the questionnaire estimating the patients' satisfaction with the usage of the paretic arm. Patients who participated in the FET during the acute phase of hemiplegia (Group A) reached functionality of the paretic arm, on average, in less than 6 weeks, and maintained this near-normal use of the arm and hand throughout the follow-up. The gains in all outcome scores were significantly larger in Group A after FET and at all follow-ups compared with the scores before the treatment. The gains in patients who participated in the FET in the chronic phase of hemiplegia (Group B) were measurable, yet not significant. The speed of recovery was larger during the period of the FET compared with the follow-up period. The gains in Group A were significantly larger compared with the gains in Group B. The FET greatly promotes the recovery of the paretic arm if applied during the acute phase of post-stroke hemiplegia.
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Affiliation(s)
- Dejan B Popovic
- Center for Sensory-Motor Interaction, Aalborg University, Fredrik Bajersvej 7-D3, DK-9220 Aalborg Øst, Denmark.
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Stoeckel MC, Pollok B, Witte OW, Seitz RJ, Schnitzler A. Shrinkage of Somatosensory Hand Area in Subjects With Upper Extremity Dysmelia Revealed by Magnetoencephalography. J Neurophysiol 2005; 93:813-8. [PMID: 15469960 DOI: 10.1152/jn.00749.2004] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
The effect of peripheral lesions on cerebral somatosensory representations is well studied for experimentally induced amputations and deafferentations acquired later in life. However, few studies have investigated the brain's capacity for plastic changes in congenital malformations. We studied somatosensory-evoked fields to electrical stimulation of the bordering fingers in 10 subjects with upper extremity dysmelia in comparison with 10 control subjects using a 122-channel whole-head magnetometer. The number of developed fingers varied between two and four in the affected subjects. We localized finger representations in the primary somatosensory cortex and calculated Euclidian distances to estimate the size of the somatosensory hand area. Euclidian distances were significantly smaller in dysmelic subjects (5.7 mm) than in control subjects (11.6 mm) and were related to the number of the developed fingers on the contralateral hand. In contrast, individual finger representations were not found to be reduced. We suggest that the shrinkage of the somatosensory hand area might be related to the congenital nature of the malformation, to the smaller anatomical hand size in the affected subjects, and/or to use-dependent effects due to impaired hand function.
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Oliviero A, Tecchio F, Zappasodi F, Pasqualetti P, Salustri C, Lupoi D, Ercolani M, Romani GL, Rossini PM. Brain sensorimotor hand area functionality in acute stroke: insights from magnetoencephalography. Neuroimage 2005; 23:542-50. [PMID: 15488403 DOI: 10.1016/j.neuroimage.2004.06.040] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2003] [Revised: 03/05/2004] [Accepted: 06/22/2004] [Indexed: 11/16/2022] Open
Abstract
An understanding of the functional readjustments that the brain undergoes during the early days after a stroke would give us a major insight into how and how much neurons are capable to react to an insult. Thirty-two patients affected by an acute monohemispheric ischemic stroke were enrolled in the study. Magnetoencephalography was used to record the somatosensory-evoked fields (SEF) generated in response to median nerve stimulation. Latency, strength, and position of the related early cortical components (M20 and M30) were studied both separately within each hemisphere, and in terms of interhemispheric differences. Interhemispheric cross-correlations among SEF waveshapes in the two hemispheres were also investigated. Overall, except for some source displacement possibly induced by the perilesional edema, results did not demonstrate any unusual neural recruitment. The severity of the clinical picture was found related to the sources' strengths (both as absolute values and as interhemispheric differences), to excessive interhemispheric differences in SEF waveshapes and in the M30 latencies. Signs of an enhanced excitability were present in the affected hemisphere (AH) following a cortical lesion, usually in combination with preserved hand functionality. An enhanced excitability of the unaffected hemisphere (UH) was paired with larger lesions with cortical involvement; signs compatible with an abnormal transcallosal transmission and intracortical function of inhibitory GABAergic interneurons in the AH were found subtending UH enhancement. Spared responsiveness from Brodmann's area (BA) 2 and posterior parietal areas despite an altered response from BA 3b was found in six patients, combined to high hand functionality. Present results in acute phase increase the knowledge of the mechanisms governing brain adaptation/reaction capabilities, for future efforts to establish therapeutic and rehabilitative procedures.
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Affiliation(s)
- Antonio Oliviero
- AFaR, Ospedale Fatebenefratelli, Dipartimento di Neuroscienze, Isola Tiberina, Rome, Italy
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Kim YH, Jang SH, Byun WM, Han BS, Lee KH, Ahn SH. Ipsilateral motor pathway confirmed by combined brain mapping of a patient with hemiparetic stroke: A case report11No commercial party having a direct financial interest in the results of the research supporting this article has or will confer a benefit on the author(s) or on any organization with which the author(s) is/are associated. Arch Phys Med Rehabil 2004; 85:1351-3. [PMID: 15295764 DOI: 10.1016/j.apmr.2003.08.102] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
This study investigated the motor control pathway using both functional magnetic resonance imaging (fMRI) and transcranial magnetic stimulation (TMS) in a patient with left hemiparesis with an infarction on the posterior limb of the right internal capsule. fMRI was performed using the blood oxygen level-dependent technique at 1.5 T with a standard head coil. The motor activation task consisted of hand grasp-release movements in 1-Hz cycles. TMS was performed using a butterfly coil; the intersection of the wings (center of the coil) was applied tangentially to the scalp 1.0 cm apart. Stimulation was performed at 100% of maximal output. Motor evoked potentials (MEPs) from both abductor pollicis brevis (APB) muscles were obtained simultaneously. fMRI showed that the unaffected (left) primary sensorimotor cortex (SM1) was activated by movements of the unaffected (right) hand. Conversely, the bilateral SM1 were activated by movements of the affected (left) hand. Brain mapping using TMS showed that ipsilateral MEPs were obtained at the affected (left) APB muscle when the unaffected (left) motor cortex was stimulated. We concluded that the ipsilateral motor pathway from the unaffected motor cortex to the affected hand was present in this patient.
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Affiliation(s)
- Yun-Hee Kim
- Department of Physical Medicine & Rehabilitation, School of Medicine Sungkyunkwan University, Samsung Medical Center, Taegu, South Korea
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Kim YH, Jang SH, Han BS, Kwon YH, You SH, Byun WM, Park JW, Yoo WK. Ipsilateral motor pathway confirmed by diffusion tensor tractography in a patient with schizencephaly. Neuroreport 2004; 15:1899-902. [PMID: 15305133 DOI: 10.1097/00001756-200408260-00013] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
We evaluated the hand motor function of a right hemiparetic patient with schizencephaly using a combination of fMRI, transcranial magnetic stimulation, and diffusion tensor tractography (DTT). Only the unaffected (right) primary sensori-motor cortex was found to be activated during either affected (right) or unaffected hand movements. Evoked motor potentials with similar characteristics were obtained from both abductor pollicis brevis muscles simultaneously when stimulating the unaffected motor cortex. Moreover, a tract presumed to be a corticospinal tract was observed in the unaffected hemisphere by DTT, however, no tract was observed in the affected hemisphere. Our results indicate that the ipsilateral corticospinal tract extended from the unaffected (right) motor cortex to both hands. This finding may reflect functional reorganization of motor function in a patient with congenital brain disorder.
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Affiliation(s)
- Yun-Hee Kim
- Department of Physical Medicine and Rehabilitation, Sungkyunkwan University School of Medicine, Samsung Medical Center, 50 Ilwon-dong, Kangnam-ku, Seoul, 135-710, Republic of Korea
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Rossini PM, Dal Forno G. Integrated technology for evaluation of brain function and neural plasticity. Phys Med Rehabil Clin N Am 2004; 15:263-306. [PMID: 15029909 DOI: 10.1016/s1047-9651(03)00124-4] [Citation(s) in RCA: 92] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
The study of neural plasticity has expanded rapidly in the past decades and has shown the remarkable ability of the developing, adult, and aging brain to be shaped by environmental inputs in health and after a lesion. Robust experimental evidence supports the hypothesis that neuronal aggregates adjacent to a lesion in the sensorimotor brain areas can take over progressively the function previously played by the damaged neurons. It definitely is accepted that such a reorganization modifies sensibly the interhemispheric differences in somatotopic organization of the sensorimotor cortices. This reorganization largely subtends clinical recovery of motor performances and sensorimotor integration after a stroke. Brain functional imaging studies show that recovery from hemiplegic strokes is associated with a marked reorganization of the activation patterns of specific brain structures. To regain hand motor control, the recovery process tends over time to bring the bilateral motor network activation toward a more normal intensity/extent, while overrecruiting simultaneously new areas, perhaps to sustain this process. Considerable intersubject variability exists in activation/hyperactivation pattern changes over time. Some patients display late-appearing dorsolateral prefrontal cortex activation, suggesting the development of "executive" strategies to compensate for the lost function. The AH in stroke often undergoes a significant "remodeling" of sensory and motor hand somatotopy outside the "normal" areas, or enlargement of the hand representation. The UH also undergoes reorganization, although to a lesser degree. Although absolute values of the investigated parameters fluctuate across subjects, secondary to individual anatomic variability, variation is minimal with regards to interhemispheric differences, due to the fact that individual morphometric characters are mirrored in the two hemispheres. Excessive interhemispheric asymmetry of the sensorimotor hand areas seems to be the parameter with highest sensitivity in describing brain reorganization after a monohemispheric lesion, and mapping motor and somatosensory cortical areas through focal TMS, fMRI, PET, EEG, and MEG is useful in studying hand representation and interhemispheric asymmetries in normal and pathologic conditions. TMS and MEG allow the detection of sensorimotor areas reshaping, as a result of either neuronal reorganization or recovery of the previously damaged neural network. These techniques have the advantage of high temporal resolution but also have limitations. TMS provides only bidimensional scalp maps, whereas MEG, even if giving three-dimensional mapping of generator sources, does so by means of inverse procedures that rely on the choice of a mathematical model of the head and the sources. These techniques do not test movement execution and sensorimotor integration as used in everyday life. fMRI and PET may provide the ideal means to integrate the findings obtained with the other two techniques. This multitechnology combined approach is at present the best way to test the presence and amount of plasticity phenomena underlying partial or total recovery of several functions, sensorimotor above all. Dynamic patterns of recovery are emerging progressively from the relevant literature. Enhanced recruitment of the affected cortex, be it spared perilesional tissue, as in the case of cortical stroke, or intact but deafferented cortex, as in subcortical strokes, seems to be the rule, a mechanism especially important in early postinsult stages. The transfer over time of preferential activation toward contralesional cortices, as observed in some cases, seems, however, to reflect a less efficient type of plastic reorganization, with some aspects of maladaptive plasticity. Reinforcing the use of the affected side can cause activation to increase again in the affected side with a corresponding enhancement of clinical function. Activation of the UH MI may represent recruitment of direct (uncrossed) corticospinal tracts and relate more to mirror movements, but it more likely reflects activity redistribution within preexisting bilateral, large-scale motor networks. Finally, activation of areas not normally engaged in the dysfunctional tasks, such as the dorsolateral prefrontal cortex or the superior parietal cortex in motor paralysis, might reflect the implication of compensatory cognitive strategies. An integrated approach with technologies able to investigate functional brain imaging is of considerable value in providing information on the excitability, extension, localization, and functional hierarchy of cortical brain areas. Deepening knowledge of the mechanisms regulating the long-term recovery (even if partial), observed for most neurologic sequelae after neural damage, might prompt newer and more efficacious therapeutic and rehabilitative strategies for neurologic diseases.
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Affiliation(s)
- Paolo M Rossini
- Department of Clinical Neuroscience, Hospital Fatebenefratelli, Isola Tiberina 39, 00186-Rome, Italy
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39
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Waberski TD, Gobbelé R, Kawohl W, Cordes C, Buchner H. Immediate cortical reorganization after local anesthetic block of the thumb: source localization of somatosensory evoked potentials in human subjects. Neurosci Lett 2003; 347:151-4. [PMID: 12875908 DOI: 10.1016/s0304-3940(03)00650-5] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
Psychophysical observations after anesthesia of the thumb raise the question whether the functional border between the thumb and the index is functionally distinct. We present a source localization study using equivalent current dipole modeling of somatosensory evoked potentials (SEPs) following mechanical air-puff stimulation of the first, second and third digits before and during anesthesia of the thumb. Source reconstruction was based on 96-channel SEP recordings. During anesthesia of the thumb the distance between the cortical representation of the thumb and the second and third digits immediately decreased. This indicates a shift of the cortical representation of the second and third digits towards the deafferented area of the anesthetized thumb. Thus, the present results did not confirm the hypothesis of a functional border of the cortical representation between thumb and index finger in this particular task.
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Affiliation(s)
- T D Waberski
- Department of Neurology, University Hospital Aachen, Pauwelsstrasse 30, D-52057, Aachen, Germany.
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40
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Abstract
Recovery of function after a stroke is attributable to several factors, including events in the first few days (eg, reabsorption of perilesional oedema, tissue reperfusion). However, consistent reorganisation and recovery after a stroke takes weeks or months. In the early stages, recovery from stroke can vary greatly among patients with identical clinical symptoms. Neuroimaging techniques that enable us to assess baseline and task-related functions, and neurophysiological techniques that measure brain function in "real time", can be used to study the recovery of brain lesions after a stroke. In this review, we discuss important neuroimaging and neurophysiological studies of post-stroke brain reorganisation.
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Gallien P, Aghulon C, Durufle A, Petrilli S, de Crouy AC, Carsin M, Toulouse P. Magnetoencephalography in stroke: a 1-year follow-up study. Eur J Neurol 2003; 10:373-82. [PMID: 12823488 DOI: 10.1046/j.1468-1331.2003.00593.x] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Recovery after stroke is closely linked to cerebral plasticity. Magnetoencephalography (MEG) is a non-invasive technique, which allows location of cerebral cells activities. In the present work, a cohort of patients has been studied with MEG. Twelve patients with a recent ischemic or hemorragic stroke were included as soon as possible after onset of stroke. Neurologic assessment, including standard neurologic examination, functional independence measure (FIM) and Orgogozo's scale was performed for 1 year in addition to a study of the somatosensory evoked field (SEF) using a 37-channel Biomagnetometer system. No response could be recorded in five patients at the first SEF exploration. In three cases, no response was ever recorded during the study. All these patients had a bad recovery. The location of the SEF sources was always in the normal non-infarcted cortex of the postcentral gyrus. Sensory recovery seemed to be linked to the reorganization of the persistent functional cortex, which was a limiting factor for recovery. These observations confirm the experimental results obtained in animal models. After stroke it can be assumed that in the case of incomplete lesion, an intensive sensory peripheral stimulation could maximize the use of residual sensory function and then contribute to improve the sensory deficit. In case of total sensory loss other techniques have to be used, such as visual monitoring of hand activity in order to improve hand function.
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Affiliation(s)
- P Gallien
- Department of Physical Medicine, Centre Hospitalier et Universitaire de Rennes, Hôpital Pontchaillou, Rennes Cedex, France.
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De Gennaro L, Ferrara M, Bertini M, Pauri F, Cristiani R, Curcio G, Romei V, Fratello F, Rossini PM. Reproducibility of callosal effects of transcranial magnetic stimulation (TMS) with interhemispheric paired pulses. Neurosci Res 2003; 46:219-27. [PMID: 12767485 DOI: 10.1016/s0168-0102(03)00060-9] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Abstract
Transcranial magnetic stimulation (TMS) of the motor cortex of one hemisphere (conditioning stimulus (CS)) inhibits EMG responses evoked in distal hand muscles by a later magnetic stimulus given at an appropriate interval, over the opposite hemisphere (test stimulus (TS)). This effect is commonly attributed to an inhibition produced at cortical level via a transcallosal route. The present study assessed the reproducibility of the transcallosal inhibition effects in different sessions in healthy subjects. Within- and between-subject variability, relating to interhemispheric differences was also evaluated. A magnetic CS on one hemisphere effectively inhibited EMG responses of the abductor digiti minimi stimulated by a TS delivered over the opposite hemisphere in a range of intervals centered at 12 ms. Even though group effects were reproduced in separate sessions, the high between- and within-subject variability yielded low test-retest correlations. This differentiation forces the definition of reproducibility (or repeatability), as the replication of the same mean curves of EMG reduction, and of reliability, as the between- or within-subject correlations between values of specific EMG measures.
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Affiliation(s)
- Luigi De Gennaro
- Dipartimento di Psicologia-Sezione di Neuroscienze, Università degli Studi di Roma La Sapienza, Via dei Marsi, 78, Italy.
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Zappoli R. Permanent or transitory effects on neurocognitive components of the CNV complex induced by brain dysfunctions, lesions and ablations in humans. Int J Psychophysiol 2003; 48:189-220. [PMID: 12763574 DOI: 10.1016/s0167-8760(03)00054-0] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
Since the mid-1960s, essentially using electrophysiological methods, our research group has examined the effects of different brain diseases in humans, both on first- and second-order conditioned responses and on some types of neurocognitive potentials of the CNV complex. This didactic lecture will focus on our various attempts to identify and understand the neuroanatomical and neurophysiological substrates involved in cognitive information processing followed by the conception and execution of sensory-motor and behavioural responses evoked by significant acoustic stimuli, in both pathological situations and normal control subjects. Great interest was, e.g. aroused in the early 1970s by the rare, fortunately unrepeatable, opportunity of examining the CNV patterns in various psychiatric patients treated with psychosurgical Freeman-Watts bilateral prefrontal 'radical' lobotomy, also with repeated recordings (The Responsive Brain (1976) 158; Multidisciplinary Perspectives in Event-Related Brain-Potentials Research (1978) 376) or bimedial bifrontal cingulotomy (Multidisciplinary Perspectives in Event-Related Brain Potential Research (1978) 383). In the same period, investigations into CNV activity recorded in patients submitted to complete callosotomy ('split brain': Attention and Performance, vol. IV (1972) 221; Electroenceph. Clin. Neurophysiol. Suppl. 33 (1973) 161) were also begun and were continued into the 1980s, also with regard to other types of ERP (Brain 111 (1988) 553; J. Cog. Neurosci. 2 (1990) 258). All these data furnished unique information about the sub-second dynamics of unilateral or bihemispheric cortico-cortical and cortico-subcortical interconnections in humans. In recent years, with a classic method of analysis based on sequential scalp-topographic bidimensional neuroelectric mapping and 21/19 electrodes connected to three different references, and binaural/monaural clicks as warning signals (S1), we have repeatedly examined the CNV activity of 11 selected patients submitted to complete ablation of the damaged cortical areas, with uni- or bilateral lesions restricted to the prefrontal or associative parieto-temporal areas. We have always used the standard CNV paradigm (S1-S2 motor-response) which evokes a complex of neurocognitive potentials, including the P300 from S1, which are well-known, since they are certainly among the most studied ERPs in the various ages and races of normal subjects, psychiatric patients and subjects with different brain diseases. The most important results have been, (1) In normal subjects the MRI and the latency differences of CNV component measurements along the bidirectional pathways functionally interconnecting ipsilateral distant associative cortical areas (e.g. the arcuate-superior longitudinal complex bundle) were accounted for by the transcortical conduction time, which varies in our scalp recordings from 1 cm/0.74 to 1.28 ms ( approximately 9.8 m/s). (2) Constantly, no true auditory S1-elicited N1a, b, c, P2, N2, P300 components or CNV slow waves (O- and E-wave) were recordable over the whole of the ablated cortical areas, but only clearly identifiable volume-conducted EP/ERPs generated in other hemispheric structures. (3) The post-S1 ERP/CNV complexes on the intact hemisphere were found to be within the normal limits. (4) Effects of severe disruption on the S1 ERP/CNV complexes evocable on the site and on remote ipsilateral apparently normal anatomo-functionally interconnected brain regions were observed in 5 patients, 4 of whom had extensive frontocortical ablations. In two of the latter the distant disruptive action on the CNV components over the neuroradiologically normal ipsilateral two-way connected post-rolandic sensory and association areas was seen to be partially reversible, showing aspects of a probable slowly evolving diaschisis-like effect. Similar deactivation of some ERP components was observed in reverse on the ipsilateral dorsolateral frontocortical region in the fifth patient with a large parieto-temporal cortex ablation. These data require confirmahese data require confirmation, and when this phenomenon is observable, it must be appropriately monitored with different methods of functional neuroimaging. This will serve not only for medical and neuropsychophysiological diagnosis purposes, but also particularly for a correct and really useful planning of neuro-rehabilitation activities in selected cases.
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Affiliation(s)
- Roberto Zappoli
- Department of Neurological and Psychiatric Sciences, University of Florence, Viale G.B. Morgagni 85, 50134, Florence, Italy.
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Baciu M, Le Bas JF, Segebarth C, Benabid AL. Presurgical fMRI evaluation of cerebral reorganization and motor deficit in patients with tumors and vascular malformations. Eur J Radiol 2003; 46:139-46. [PMID: 12714230 DOI: 10.1016/s0720-048x(02)00083-9] [Citation(s) in RCA: 49] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
Abstract
The aim of this fMRI study was to evaluate the motor reorganization (cerebral plasticity) and the risk of motor deficit in patients presenting with tumors and vascular malformations, within the framework of their pre-surgical planning. Functional MR imaging data was obtained from 17 patients. Ten patients (seven with tumors and three with vascular malformations) presented with motor reorganization. The results of the present study suggest that the evaluation of the cerebral reorganization is an essential step in predicting the risk of motor deficit in patients having surgical indication for treatment. Furthermore, the cerebral reorganization constitutes an important factor for surgical decision.
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Affiliation(s)
- M Baciu
- Laboratoire de Psychologie Expérimentale, UMR CNRS 5105, Université Pierre Mendès-France, 151 Rue des Universités, Domaine Universitaire, 38400 Saint Martin d'Hères, Grenoble BP47, France.
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45
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Tzvetanov P, Rousseff RT, Milanov I. Lower limb SSEP changes in stroke-predictive values regarding functional recovery. Clin Neurol Neurosurg 2003; 105:121-7. [PMID: 12691805 DOI: 10.1016/s0303-8467(02)00132-4] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
OBJECTIVE To assess the predictive value of lower limbs somatosensory evoked potentials (SSEPs) in the acute phase of stroke. MATERIALS AND METHODS 94 stroke patients (mean age: 61.2; S.D.: 11.8; 43 women) were included. Computed tomography confirmed diagnosis was cortical middle cerebral artery (MCA) infarction in 35, subcortical MCA in 11, and mixed in 25. By size, infarctions were large (29), limited (33), and lacunar (9). Thalamic haemorrhage was found in eight patients, putaminal in seven, small capsular in two, massive in two and lobar in four patients. All patients presented with hemiparesis (54) or hemiplegia (40), pure in five and combined with hemihypesthesia in 89. Tibial nerve SSEPs were recorded early in the course of the disease (up to third day). SSEP parameters (presence/absence of SSEP, absolute P40 latency, amplitude and amplitude ratio-affected/healthy side of P40-N50) were evaluated and compared with motor ability using the Medical Research Council (MRC) scale, and daily living activities using Barthel index (ADLB) followed for 3 months after stroke. Disability was assessed after the Rankin scale. RESULTS The absolute amplitude of P40 has moderately strong correlation with Barthel index (r=0.63) and nearly moderate (r=-0.46) with Rankin scale at 3 months. P40 ratio exhibits weaker correlations with clinical outcome parameters. The combination of SSEP abnormalities and MRC has stronger predictive value than MRC alone (P<0.0001 vs P<0.03). CONCLUSIONS Tibial SSEP investigation early in stroke, independently or combined with muscle power assessment, significantly increases prognostic capability.
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Affiliation(s)
- Pl Tzvetanov
- Stroke Unit, Department of Neurology, Medical University of Pleven, Georgi Kochev str. 8A, Pleven 5800, Bulgaria.
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Verrotti A, Pizzella V, Trotta D, Madonna L, Chiarelli F, Romani GL. Magnetoencephalography in pediatric neurology and in epileptic syndromes. Pediatr Neurol 2003; 28:253-61. [PMID: 12849877 DOI: 10.1016/s0887-8994(03)00017-1] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
In recent years, great advances in the knowledge of neuromagnetism have permitted the application of Superconducting Quantum Interference Devices to the pathophysiologic study of the human brain. In particular, in pediatric neurology, the integration of biomagnetism with magnetic resonance imaging and other techniques for medical imaging have allowed for precise neuromagnetic measurements of the human brain. The more frequently used technique is magnetoencephalography. Recent data have illustrated the usefulness of magnetoencephalography in mapping activity of sensory and motor areas and in studying the spatiotemporal pattern of brain activation specific to somatosensory function. Moreover, magnetoencephalography is an important tool to localize epileptic activity; magnetic source imaging superimposes magnetoencephalographic localizations on the magnetic resonance imaging and yields improved spatial resolution as compared with surface electroencephalography. The role of magnetoencephalography in evaluating patients with epilepsy continues to evolve; in fact, it seems to be very useful in the localization of the epileptogenic zone in patients with partial epilepsy. This application of magnetoencephalography is essential in the selection of epileptic children candidates to surgical treatment of seizures.
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Kanno A, Nakasato N, Hatanaka K, Yoshimoto T. Ipsilateral area 3b responses to median nerve somatosensory stimulation. Neuroimage 2003; 18:169-77. [PMID: 12507453 DOI: 10.1006/nimg.2002.1283] [Citation(s) in RCA: 46] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Magnetoencephalography investigation of the somatosensory evoked fields for median nerve stimulation detected ipsilateral area 3b responses in 18 hemispheres of 14 (1 normal subject and 13 patients with brain diseases) among 482 consecutive subjects. The major three peaks in the ipsilateral response were named iP50m, iN75m, and iP100m, based on the current orientation in the posterior, anterior, and posterior directions and the latency of 52.7 +/- 6.2, 74.1 +/- 9.4, and 100.2 +/- 15.8 ms (mean +/- standard deviation), respectively. The moment of the iP50m dipole (9.4 +/- 5.7 nAm) was significantly smaller than that of the N20m dipole of the contralateral response (cN20m, 27.5 +/- 10.5 nAm, P < 0.0001). Dipoles of iP50m and cN20m were similarly localized on the posterior bank of the central sulcus. iP50m in the present study had the same current orientation as and peak latency similar to that of the first ipsilateral primary somatosensory response to lip stimulation in our previous report. Therefore, the somatosensory afferent pathway from the hand may reach directly to the ipsilateral area 3b at least in part of the human population.
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Affiliation(s)
- Akitake Kanno
- Ryogo Center, Kohnan Hospital, 4-20-1 Nagamachi-minami, Taihaku-ku, Sendai, Japan
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Sterr A, Freivogel S, Schmalohr D. Neurobehavioral aspects of recovery: assessment of the learned nonuse phenomenon in hemiparetic adolescents. Arch Phys Med Rehabil 2002; 83:1726-31. [PMID: 12474177 DOI: 10.1053/apmr.2002.35660] [Citation(s) in RCA: 72] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
OBJECTIVE To test the learned nonuse assumption of constraint-induced movement therapy (CIMT), through behavioral assessment, that residual movement abilities are not used to their fullest extent in persons with chronic hemiparesis. DESIGN Repeated-measures cohort design. SETTING Rehabilitation clinic in southwest Germany. PARTICIPANTS Twenty-one persons with upper-limb hemiparesis after brain injury and 21 age-matched healthy controls. Participants were hospitalized when tested. INTERVENTIONS Not applicable. MAIN OUTCOME MEASURES Spontaneous affected hand use for the items of the Motor Activity Log and the Actual Amount of Use Test were compared with the subjects' actual ability to perform these items with the affected hand. RESULTS A significant difference between the residual movement capability and the spontaneous use was found in both tests. Most movements could be performed with moderate to good movement quality with the affected hand, but were still performed with the unaffected "good" hand in the spontaneous-use condition. This effect was equally strong in right- and left-side affected persons. CONCLUSION Hemiparetic persons do not use their residual movement capabilities to the fullest extent. According to the learned nonuse model, this behavior reflects a learned suppression of affected arm movements, which may be overcome by CIMT.
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Affiliation(s)
- Annette Sterr
- Department of Psychology, University of Liverpool, UK.
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Tecchio F, Padua L, Aprile I, Rossini PM. Carpal tunnel syndrome modifies sensory hand cortical somatotopy: a MEG study. Hum Brain Mapp 2002; 17:28-36. [PMID: 12203686 PMCID: PMC6871819 DOI: 10.1002/hbm.10049] [Citation(s) in RCA: 121] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022] Open
Abstract
The adult somatosensory system has shown reorganizational abilities at cortical and subcortical levels after peripheral nerve lesions. In the present study the effects of carpal tunnel syndrome (CTS) are investigated as reflected on the somatotopy of the primary cortical hand representation. Position and intensity of cortical sources activated by the separate electrical stimulation of median nerve and Digits 1, 3, and 5 of both affected and non-affected hands are evaluated by magnetoencephalographic (MEG) technique. Correlation of MEG results with patient-, physician- and neurophysiological-oriented evaluations of CTS was carried out. Patients showed changes in cortical hand somatotopy in strict relationship to self-referred assessment of symptoms and hand disability in daily activities, including: 1) a more extended representation of the affected hand when paresthesias prevailed; and 2) a more restricted representation due to lateral shift of the little finger was observed when pain symptoms dominated the clinical picture. Contralateral to the side of CTS, the cortical sources activated by Digit 5-stimulation appeared significantly enhanced with respect to contralateral ones from non-affected hand. When comparing the amplitude of peripheral sensory nerve action potentials of median and ulnar nerves to that of cortical responses (i.e., ECD strengths of M20 and M30 components after stimulation of Digits 3 and 5), a significant selective amplification of M30 with respect to M20 and sensory nerve action potential (SNAP) appeared during Digit 3 stimulation compared to that observed for Digit 5. This has been interpreted as a central magnification mechanism in brain responsiveness, possibly revealing a safety factor enabling sensory perception despite the small peripheral signal due to nerve trunk dysfunction. Hum.
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Jang SH, Byun WM, Ahn SH, Chang Y, Han BS. The authors reply. Arch Phys Med Rehabil 2002. [DOI: 10.1016/s0003-9993(02)70027-0] [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]
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