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1.
J Stroke Cerebrovasc Dis ; 26(8): 1787-1792, 2017 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-28476507

RESUMO

BACKGROUND: Todd's paralysis (TP) is a well-known postictal paresis in which patients present with transient weakness in their limb(s) after seizures. Although recognized as a stroke mimic in clinical practice, the pathophysiological mechanism and clinical features of TP remain unknown. Furthermore, its diagnosis can be erroneous in neurological emergency practice. We aimed to illustrate the clinical features and identify factors associated with TP. METHODS: This single-center, retrospective observational study included consecutive adult patients who presented with convulsive seizure and were referred to an urban tertiary care emergency department between August 2010 and April 2016. The diagnosis of TP was set as the primary outcome measure. Clinical and laboratory variables were evaluated. RESULTS: Of 1381 eligible convulsive seizures in 1187 patients, TP was observed in 89 seizures (6.4%) in 75 patients. Patients with TP were significantly older, more likely to have convulsive status epilepticus, and had a longer duration of convulsion than patients without TP. TP was found in 19.7% (39 of 198) of convulsive seizures with remote etiologies including those due to old stroke. These etiologies were identified as independent significant risk factors for TP compared with seizures with cryptogenic etiology. The positive likelihood ratio of TP seizures was 11.2 for remote seizure etiologies. CONCLUSIONS: Our results indicated that the diagnosis of TP highly suggests premorbid or comorbid structural lesions in the central nervous system, including old stroke. This consideration in seizure etiology may help in reducing the risk of misdiagnosis of acute stroke in emergency settings and further antiepileptic treatment.


Assuntos
Paralisia/epidemiologia , Convulsões/epidemiologia , Acidente Vascular Cerebral/epidemiologia , Adulto , Idoso , Feminino , Humanos , Incidência , Japão/epidemiologia , Masculino , Pessoa de Meia-Idade , Paralisia/diagnóstico , Paralisia/fisiopatologia , Estudos Retrospectivos , Medição de Risco , Fatores de Risco , Convulsões/diagnóstico , Convulsões/fisiopatologia , Acidente Vascular Cerebral/diagnóstico , Acidente Vascular Cerebral/fisiopatologia , Centros de Atenção Terciária , Fatores de Tempo
2.
J Stroke Cerebrovasc Dis ; 24(12): 2754-8, 2015 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-26460245

RESUMO

BACKGROUND: The accuracy of the Alberta Stroke Program Early CT Score (ASPECTS) as a prognostic indicator in the treatment of cerebral infarction with thrombolysis remains controversial. We hypothesized that ASPECTS can more accurately predict treatment outcomes by excluding isolated cortical swelling (ICS) from ASPECTS and retrospectively tested patients treated with thrombolysis. METHODS: This retrospective cohort study included 106 patients treated with intravenous thrombolysis for cerebral infarction in our hospital. We included only patients with middle cerebral artery infarction. For the modification of ASPECTS, we removed each ICS from the ASPECTS system. We compared the correlation coefficients between the ASPECTS and modified ASPECTS with regard to treatment outcome, and performed a multivariate logistic regression analysis to evaluate the association between modified ASPECTS and outcomes. The primary outcome was a modified Rankin Scale score equal to or less than 2 on discharge and the secondary outcomes included an improvement of National Institutes of Health Stroke Scale (NIHSS) score of 4 or greater within 24 hours. RESULTS: Seventy-two patients were included in this study. The correlation coefficient of modified ASPECTS was significantly higher than that of ASPECTS in the primary outcome (r = .249 versus r = .363, P < .001) and in the improvement of NIHSS score (r = .303 versus r = .443, P < .001). Multivariate analysis revealed that a modified ASPECTS greater than 7 was significantly associated with the primary outcome (odds ratio [OR] = 1.334, 95% confidence interval [CI] = 1.071-1.661, P = .012) and the improvement of the NIHSS score (OR = 1.555, 95% CI = 1.208-2.003, P = .001). CONCLUSIONS: The present study reveals that ASPECTS may be more strongly associated with outcome by excluding ICS.


Assuntos
Isquemia Encefálica/tratamento farmacológico , Córtex Cerebral/diagnóstico por imagem , Fibrinolíticos/uso terapêutico , Acidente Vascular Cerebral/tratamento farmacológico , Terapia Trombolítica , Ativador de Plasminogênio Tecidual/uso terapêutico , Idoso , Idoso de 80 Anos ou mais , Alberta , Isquemia Encefálica/diagnóstico por imagem , Angiografia Cerebral , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Prognóstico , Estudos Retrospectivos , Acidente Vascular Cerebral/diagnóstico por imagem , Resultado do Tratamento
3.
J Neurophysiol ; 109(6): 1626-37, 2013 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-23274310

RESUMO

Using near-infrared spectroscopy (NIRS) and multichannel probes, we studied hemoglobin (Hb) concentration changes when single-pulse transcranial magnetic stimulation (TMS) was applied over the left hemisphere primary motor cortex (M1). Seventeen measurement probes were centered over left M1. Subjects were studied in both active and relaxed conditions, with TMS intensity set at 100%, 120%, and 140% of the active motor threshold. The magnetic coils were placed so as to induce anteromedially directed currents in the brain. Hb concentration changes were more prominent at channels over M1 and posterior to it. Importantly, Hb concentration changes at M1 after TMS differed depending on whether the target muscle was in an active or relaxed condition. In the relaxed condition, Hb concentration increased up to 3-6 s after TMS, peaking at ∼6 s, and returned to the baseline. In the active condition, a smaller increase in Hb concentrations continued up to 3-6 s after TMS (early activation), followed by a decrease in Hb concentration from 9 to 12 s after TMS (delayed deactivation). Hb concentration changes in the active condition at higher stimulus intensities were more pronounced at locations posterior to M1 than at M1. We conclude that early activation occurs when M1 is activated transsynaptically. The relatively late deactivation may result from the prolonged inhibition of the cerebral cortex after activation. The posterior-dominant activation at higher intensities in the active condition may result from an additional activation of the sensory cortex due to afferent inputs from muscle contraction evoked by the TMS.


Assuntos
Hemoglobinas/análise , Córtex Motor/química , Estimulação Magnética Transcraniana , Adulto , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Espectroscopia de Luz Próxima ao Infravermelho
4.
J Neurosci ; 31(43): 15376-83, 2011 Oct 26.
Artigo em Inglês | MEDLINE | ID: mdl-22031883

RESUMO

The supplementary motor area (SMA-proper) plays a key role in the preparation and execution of voluntary movements. Anatomically, SMA-proper is densely reciprocally connected to primary motor cortex (M1), but neuronal coordination within the SMA-M1 network and its modification by external perturbation are not well understood. Here we modulated the SMA-M1 network using MR-navigated multicoil associative transcranial magnetic stimulation in healthy subjects. Changes in corticospinal excitability were assessed by recording motor evoked potential (MEP) amplitude bilaterally in a hand muscle. We found timing-dependent bidirectional Hebbian-like MEP changes during and for at least 30 min after paired associative SMA-M1 stimulation. MEP amplitude increased if SMA stimulation preceded M1 stimulation by 6 ms, but decreased if SMA stimulation lagged M1 stimulation by 15 ms. This associative plasticity in the SMA-M1 network was highly topographically specific because paired associative stimulation of pre-SMA and M1 did not result in any significant MEP change. Furthermore, associative plasticity in the SMA-M1 network was strongly state-dependent because it required priming by near-simultaneous M1 stimulation to occur. We conclude that timing-dependent bidirectional associative plasticity is demonstrated for the first time at the systems level of a human corticocortical neuronal network. The properties of this form of plasticity are fully compatible with spike-timing-dependent plasticity as defined at the cellular level. The necessity of priming may reflect the strong interhemispheric connectivity of the SMA-M1 network. Findings are relevant for better understanding reorganization and potentially therapeutic modification of neuronal coordination in the SMA-M1 network after cerebral lesions such as stroke.


Assuntos
Potencial Evocado Motor/fisiologia , Córtex Motor/fisiologia , Plasticidade Neuronal/fisiologia , Adulto , Análise de Variância , Biofísica , Eletromiografia/métodos , Feminino , Lateralidade Funcional , Humanos , Masculino , Tempo de Reação/fisiologia , Fatores de Tempo , Estimulação Magnética Transcraniana , Adulto Jovem
5.
Hum Brain Mapp ; 33(4): 824-39, 2012 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-21425396

RESUMO

The dorsal premotor cortex (PMd) is thought to play a significant role in movement preparation cued by sensory information rather than in self-initiated movements. The evidence in humans for this contention is still circumstantial. Here we explored the effects of modulation of PMd by excitability decreasing 1 Hz repetitive transcranial magnetic stimulation (rTMS) versus excitability increasing 5 Hz rTMS on two forms of movement related cortical potentials: contingent negative variation (CNV) versus Bereitschaftspotential (BP) reflecting externally cued versus self-triggered movement preparation. Ten healthy right-handed subjects performed visually cued or self-triggered simple sequential finger movements with their right hand. CNV and BP were recorded by 25 EEG electrodes covering the fronto-centro-parietal cortex and divided into an early (1500-500 ms before a go-signal or movement onset) and a late potential (500-0 ms). MRI-navigated 1 Hz rTMS of the left PMd resulted in significant increase of the late CNV over the left central region predominantly contralateral to the prepared right hand movement, while 5 Hz rTMS had no effect on CNV. In contrast, 1 and 5 Hz rTMS did not modify BP. Control experiments of 1 Hz rTMS of the supplementary motor area (SMA) and of low-intensity 1 Hz rTMS of the left primary motor cortex did not change CNV, but 1 Hz SMA-rTMS increased late BP. This double dissociation of effects of PMd-rTMS versus SMA-rTMS on CNV versus BP provides direct evidence that the left PMd in humans is more involved in preparatory processes of externally cued rather than self-initiated movements, contrasting with an opposite role of the SMA.


Assuntos
Mapeamento Encefálico , Córtex Cerebral/fisiologia , Sinais (Psicologia) , Lateralidade Funcional/fisiologia , Movimento/fisiologia , Adulto , Variação Contingente Negativa/fisiologia , Eletroencefalografia , Potencial Evocado Motor/fisiologia , Feminino , Humanos , Masculino , Processamento de Sinais Assistido por Computador , Estimulação Magnética Transcraniana , Adulto Jovem
6.
Exp Brain Res ; 220(1): 79-87, 2012 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-22623093

RESUMO

The supplementary motor area (SMA) is important for preparation and execution of voluntary movements and densely anatomically connected with the hand area of primary motor cortex (M1). However, little is known about the effective connectivity between SMA and ipsilateral M1 (SMA â†’ M1). Here, we used paired-coil transcranial magnetic stimulation (pcTMS) to study the SMA â†’ M1 effective connectivity in healthy human subjects. In Experiment 1, we tested the effects of different induced current directions in the SMA and M1, and different intensities of conditioning SMA stimulation. Coil placement over the SMA-proper was verified by MRI-navigation. We found a SMA â†’ M1 facilitatory effect on motor evoked potential (MEP) amplitude that occurred very specifically only with an induced conditioning current directed from the midline towards the targeted SMA, an induced test current in M1 directed antero-medially and sufficient intensity of conditioning SMA stimulation. In Experiment 2, we selected these effective parameters to explore the effects of SMA â†’ M1 on the active MEP amplitude, cortical silent period (CSP) duration, and using a triple-pulse protocol, on short-interval intracortical inhibition (SICI) and intracortical facilitation (ICF). None of these measures was affected by conditioning SMA stimulation. Our findings demonstrate that pcTMS identifies predominantly facilitatory connections from SMA-proper to the hand area of the ipsilateral M1. The successful activation of this connection depends on effective SMA-proper stimulation, is state dependent and likely mediated via excitatory interneurons in M1.


Assuntos
Potencial Evocado Motor/fisiologia , Córtex Motor/fisiologia , Vias Neurais/fisiologia , Estimulação Magnética Transcraniana , Adulto , Análise de Variância , Fenômenos Biofísicos/fisiologia , Eletromiografia , Feminino , Humanos , Masculino , Córtex Motor/anatomia & histologia , Inibição Neural/fisiologia , Tempo de Reação , Fatores de Tempo , Adulto Jovem
7.
Neurocase ; 18(4): 330-5, 2012.
Artigo em Inglês | MEDLINE | ID: mdl-22117108

RESUMO

Ambient echolalia is a rare condition with few reported cases. We report the case of a 20-year-old man with a germinoma around the bilateral ventriculus lateralis who exhibited ambient echolalia. Clinical features included instinctive grasp reaction and compulsive manipulation of tools in his right hand. Speech or mental deterioration has been cited as a cause of ambient echolalia, but neither dementia nor aphasia was present. We propose that ambient echolalia in our case could be interpreted as a disinhibition of pre-existing essentially intact motor subroutines due to damage of the medial frontal lobe.


Assuntos
Neoplasias Encefálicas/complicações , Ecolalia/etiologia , Ecolalia/psicologia , Germinoma/complicações , Neoplasias Encefálicas/psicologia , Neoplasias Encefálicas/terapia , Terapia Combinada , Lobo Frontal/patologia , Germinoma/psicologia , Germinoma/terapia , Humanos , Imageamento por Ressonância Magnética , Masculino , Testes Neuropsicológicos , Procedimentos Neurocirúrgicos , Adulto Jovem
9.
Intern Med ; 61(4): 513-516, 2022 Feb 15.
Artigo em Inglês | MEDLINE | ID: mdl-34393160

RESUMO

A 79-year-old woman with type 2 diabetes receiving insulin was rushed to our hospital due to severe hypoglycemia. Glucose was administered, and the consciousness disturbance was promptly improved. A few hours later, conjugate deviation of the eyes to the right and left hemiplegia occurred at a normal glucose level. Cerebral magnetic resonance imaging (MRI) showed hyperintensities of the right posterior limb of the internal capsule and the medial thalamus on diffusion-weighted imaging sequences. However, the changes observed using MRI disappeared completely on the third day, and her symptoms subsequently improved. This may have been a case of glucose reperfusion injury.


Assuntos
Diabetes Mellitus Tipo 2 , Hipoglicemia , Traumatismo por Reperfusão , Idoso , Diabetes Mellitus Tipo 2/complicações , Feminino , Glucose , Hemiplegia/etiologia , Humanos , Hipoglicemia/etiologia , Imageamento por Ressonância Magnética/métodos
10.
Clin Neurol Neurosurg ; 212: 107036, 2022 01.
Artigo em Inglês | MEDLINE | ID: mdl-34861467

RESUMO

OBJECTIVE: Along with cerebrospinal fluid (CSF) analysis, enhancement on contrast-enhanced MRI is useful to diagnose meningitis. However, the conditions for its appearance have not been clarified. This study aimed to investigate the association between CSF parameters and enhancement on contrast-enhanced head or spinal MRI in patients with bacterial meningitis (BM) or tuberculous meningitis (TM). METHODS: A total of 12 patients with BM and 23 patients with TM who underwent both CSF analysis and contrast-enhanced MRI were included. The correlation between CSF analysis and MRI findings has been examined using receiver operating characteristic (ROC) analysis. RESULTS: Contrast enhancement was found in 7 and 10 patients with BM and TM, respectively. Both CSF analysis and MRI were useful to distinct between BM and TM, and the enhancement implied the severity of them. In patients with BM, higher CSF protein and lower CSF glucose were associated with enhancement on MRI, while not only CSF protein and glucose but also leukocyte and lymphocyte counts were associated with it in TM. CSF adenosine deaminase (ADA) did not show discriminant ability of the MRI findings. CONCLUSIONS: CSF analysis is associated with enhancement on contrast-enhanced MRI both in BM and TM. Our findings indicate the importance of CSF analysis in assessing the need to perform contrast-enhanced MRI, which may be useful in diagnosis, distinction, and estimation of prognosis in those patients.


Assuntos
Líquido Cefalorraquidiano , Imageamento por Ressonância Magnética , Meningites Bacterianas/líquido cefalorraquidiano , Meningites Bacterianas/diagnóstico , Adolescente , Adulto , Idoso , Idoso de 80 Anos ou mais , Líquido Cefalorraquidiano/imunologia , Líquido Cefalorraquidiano/metabolismo , Feminino , Humanos , Masculino , Meningites Bacterianas/diagnóstico por imagem , Pessoa de Meia-Idade , Estudos Retrospectivos , Tuberculose Meníngea/líquido cefalorraquidiano , Tuberculose Meníngea/diagnóstico por imagem , Adulto Jovem
11.
Glob Health Med ; 4(5): 282-284, 2022 Oct 31.
Artigo em Inglês | MEDLINE | ID: mdl-36381573

RESUMO

Studies have reported that COVID-19 is associated not only with pneumonia but also with cerebrovascular disease. Consequently, medical personnel involved in treating stroke in the emergency medicine setting have been placed in a situation that requires them to provide treatment while always remaining mindful of the possibility of COVID-19. Here, we describe the current state of stroke treatment during the COVID-19 pandemic. Four patients with stroke and concomitant COVID-19 were treated at our facility. We treated 3 patients with cerebral infarction and 1 patient with cerebral venous sinus thrombosis. All 3 patients with cerebral infarction had a poor outcome. This was attributed in part to the poor general condition of the patients due to concomitant COVID-19, as well as to the severity of the major artery occlusion and cerebral infarction. One patient with cerebral venous sinus thrombosis had a good outcome. Anticoagulant therapy was administered at our hospital and resulted in a stable clinical course. Our hospital has worked to establish an examination and treatment system that enables mechanical thrombectomy to be performed even during the COVID-19 pandemic. We devised a protocol showing the steps to be taken from initial treatment to admission to the cerebral angiography room. Our hospital was able to continue accepting requests for emergency admission thanks to the examination and treatment system we established. Up-to-date information should continue to be collected to create examination and treatment systems.

12.
Neuromuscul Disord ; 32(1): 25-32, 2022 01.
Artigo em Inglês | MEDLINE | ID: mdl-34916121

RESUMO

Autoantibodies against 3­hydroxy-3-methylglutaryl-CoA reductase (HMGCR) and the signal recognition particle (SRP) are representative antibodies causing immune-mediated necrotizing myopathies (IMNM), called as anti-HMGCR and anti-SRP myopathies, respectively. Here, we analyzed the differences in routine blood test results between 56 anti-HMGCR and 77 anti-SRP myopathy patients. A higher alanine transaminase (ALT) level and a lower aspartate transaminase (AST)/ALT ratio were observed in anti-HMGCR myopathy patients [ALT, 265.7 ±â€¯213.3 U/L (mean ± standard deviation); AST/ALT ratio, 0.88 ±â€¯0.32] than in anti-SRP-myopathy patients (ALT, 179.3 ±â€¯111.2 U/L, p < 0.05; AST/ALT ratio, 1.28 ±â€¯0.40, p < 0.01). In the active phase, anti-HMGCR myopathy often showed ALT predominance, whereas anti-SRP myopathy often showed AST predominance. In addition, there were differences in erythrocyte sedimentation rate (ESR), total cholesterol (TChol) level, and high-density lipoprotein (HDL) level between anti-HMGCR and anti-SRP myopathies (ESR: HMGCR, 24.4 ±â€¯20.8 mm/1 h; SRP, 35.7 ±â€¯26.7 mm/1 h, p = 0.0334; TChol: HMGCR, 226.7 ±â€¯36.6 mg/dL; SRP, 207.6 ±â€¯40.8 mg/dL, p = 0.0163; HDL: HMGCR, 58.4 ±â€¯13.9 mg/dL; SRP, 46.2 ±â€¯17.3 mg/dL, p < 0.01). Additional studies on the differences in routine blood test results may further reveal the pathomechanisms of IMNM.


Assuntos
Alanina Transaminase/sangue , Hidroximetilglutaril-CoA Redutases/sangue , Doenças Musculares/sangue , Adulto , Idoso , Autoanticorpos/sangue , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Adulto Jovem
13.
Intern Med ; 61(22): 3439-3444, 2022 Nov 15.
Artigo em Inglês | MEDLINE | ID: mdl-36070957

RESUMO

We herein report a case of cerebral infarct in a patient with coronavirus disease 2019 (COVID-19) infection who died of aspiration pneumonia. The postmortem examination of the brain revealed embolic infarct with negative findings on quantitative reverse transcription polymerase chain reaction (qRT-PCR) as well as immunohistochemistry to detect severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). The systemic examination only revealed low copy numbers of SARS-CoV-2 in the bronchus. This is the first and so far only autopsy case of COVID-19 infection with pathologic and virologic findings of the postmortem brain in Japan.


Assuntos
COVID-19 , Humanos , COVID-19/complicações , SARS-CoV-2 , Autopsia , Teste para COVID-19 , Infarto Cerebral/complicações
14.
J Clin Neurosci ; 75: 128-133, 2020 May.
Artigo em Inglês | MEDLINE | ID: mdl-32178991

RESUMO

To date, hospital length of stay (LOS) determinants for convulsive status epilepticus's (CSE) acute-phase treatment have not been sufficiently investigated, as opposed to those for status epilepticus's (SE) outcome predictors, such as status epilepticus severity score (STESS). Here, we aimed at assessing the significance of STESS in the LOS in patients with CSE. We retrospectively reviewed consecutive adult patients with CSE who were transported to the emergency department of our urban tertiary care hospital in Tokyo, Japan. The study period was from August 2010 to September 2015. The primary endpoint was the LOS of patients with CSE who were directly discharged after acute-phase treatment, and survival analysis for LOS until discharge was conducted. As a result, among 132 eligible patients with CSE admitted to our hospital, 96 (72.7%) were directly discharged with a median LOS of 10 days (IQR: 4-19 days). CSE patients with severe seizures, represented by higher STESS (≥3), had a significantly longer LOS after adjustments with multiple covariates (p = 0.016, in restricted mean survival time analysis). Additionally, prediction for the binomial longer/shorter LOS achieved better performance when STESS was incorporated into the prediction model. Our findings indicate that STESS can also be used as a rough predictor of longer LOS at index admission of patients with CSE.


Assuntos
Tempo de Internação , Índice de Gravidade de Doença , Estado Epiléptico/diagnóstico , Adulto , Serviço Hospitalar de Emergência , Feminino , Humanos , Japão , Masculino , Pessoa de Meia-Idade , Alta do Paciente , Prognóstico , Estudos Retrospectivos , Convulsões , Estado Epiléptico/mortalidade , Análise de Sobrevida
15.
Mult Scler Relat Disord ; 38: 101500, 2020 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-31733424

RESUMO

Anti-myelin oligodendrocyte glycoprotein antibodies (MOG-ab) have been detected in various disorders of the central nervous system including acute disseminated encephalomyelitis (ADEM), neuromyelitis optica spectrum disorders (NMOSD), optic neuritis, myelitis, and cortical encephalitis. We report an atypical case of MOG-ab-associated encephalomyelitis with part of the clinical manifestations resembling limbic encephalitis. Multifocal, hyperintense, bilateral lesions predominantly affecting the white matter on brain magnetic resonance imaging and marked response to steroid therapy were compatible with a MOG-ab-associated disease. This case illustrates that MOG-ab-associated disease should be considered in encephalomyelitis involving the bilateral limbic system.


Assuntos
Encefalomielite Aguda Disseminada/diagnóstico , Encefalite Límbica/diagnóstico , Glicoproteína Mielina-Oligodendrócito/imunologia , Adulto , Autoanticorpos , Diagnóstico Diferencial , Encefalomielite Aguda Disseminada/imunologia , Humanos , Encefalite Límbica/imunologia , Masculino
16.
Hum Brain Mapp ; 30(11): 3645-56, 2009 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-19384889

RESUMO

Paired associative transcranial magnetic stimulation (PAS) has been shown to induce long-term potentiation (LTP)-like or long-term depression (LTD)-like change in excitability of human primary motor cortex (M1), as probed by motor evoked potential (MEP) amplitude. In contrast, little is known about PAS effects on volitional motor cortical activity. In 10 healthy subjects, movement related cortical potentials (MRCP) were recorded to index volitional motor cortical activity during preparation of simple thumb abduction (prime mover: abductor pollicis brevis, APB) or wrist extension movements (prime mover: extensor carpi radialis, ECR). PAS(LTP) increased, PAS(LTD) decreased, and PAS(control) did not change MEP(APB), while MEP(ECR), not targeted by PAS, remained unchanged in all PAS conditions. PAS(LTP) decreased MRCP negativity during the late Bereitschaftspotential (-500 to 0 ms before movement onset), only in the APB task, and predominantly over central scalp electrodes contralateral to the thumb movements. This effect correlated negatively with the PAS(LTP) induced increase in MEP(APB). PAS(LTD) and PAS(control) did not affect MRCP amplitude. Findings indicate a specific interference of PAS with preparatory volitional motor cortical activity, suggestive of a net result caused by increased M1 excitability and disrupted effective connectivity between premotor areas and M1.


Assuntos
Variação Contingente Negativa/fisiologia , Potencial Evocado Motor/fisiologia , Córtex Motor/fisiologia , Movimento/fisiologia , Estimulação Magnética Transcraniana , Adulto , Análise de Variância , Mapeamento Encefálico , Estimulação Elétrica/métodos , Eletroencefalografia/métodos , Eletromiografia/métodos , Feminino , Dedos/inervação , Humanos , Masculino , Músculo Esquelético , Tempo de Reação , Punho/inervação , Adulto Jovem
17.
J Neurol ; 255(8): 1236-43, 2008 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-18563467

RESUMO

Bilateral symptoms and signs of Parkinson's disease (PD) are often improved by unilateral subthalamic nucleus deep brain stimulation (STN-DBS). However, the mechanism for such bilateral effects is unknown. This study was intended to examine effects of unilateral STN-DBS using positron emission computed tomography (PET) and to elucidate mechanisms for bilateral improvement achieved by unilateral stimulation.We conducted (18)F-fluorodeoxyglucose ((18)FDG) and (18)F-fluorodopa ((18)F-DOPA ) PET scans in PD patients whose bilateral limb symptoms and axial symptoms were improved by unilateral DBS. Two scans were performed in each PET study: when DBS was on and off. We compared those images using statistic parametric mapping (SPM) 99.The significant clinical improvement obtained by unilateral DBS was shown as improvements in bilateral motor limb, axial, and gait subscores of the Unified PD Rating Scale (UPDRS). Moreover, (18)FDG PET revealed significant metabolic increases in the ipsilateral ventrolateral thalamic areas and metabolic decrease at the contralateral globus pallidus interna (GPi). In contrast, (18)F-DOPA PET showed no significant differences between DBS on and off.Ipsilateral thalamic activation might induce ipsilateral motor cortical activation, which explains the improvement of contralateral limb symptoms. Furthermore, deactivation of the contralateral GPi might disinhibit the thalamus and contralateral motor cortex, which explains reduction of ipsilateral limb symptoms. These results suggest the mechanisms for bilateral improvement achieved by unilateral DBS.


Assuntos
Estimulação Encefálica Profunda/métodos , Lateralidade Funcional/fisiologia , Doença de Parkinson/terapia , Tomografia por Emissão de Pósitrons , Núcleo Subtalâmico/fisiopatologia , Adulto , Idoso , Encéfalo/diagnóstico por imagem , Encéfalo/patologia , Mapeamento Encefálico , Feminino , Radioisótopos de Flúor/metabolismo , Humanos , Masculino , Pessoa de Meia-Idade , Doença de Parkinson/diagnóstico por imagem , Índice de Gravidade de Doença
18.
Clin Neurophysiol ; 119(10): 2291-7, 2008 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-18723394

RESUMO

OBJECTIVE: Short-interval intracortical inhibition (SICI) is a widely used paired-pulse transcranial magnetic stimulation (TMS) measure to assess inhibition in human motor cortex. However, facilitatory processes may contaminate SICI under certain conditions. Here, we specifically address the contribution of short-interval intracortical facilitation (SICF). METHODS: A SICF interstimulus interval (ISI) curve was obtained in nine healthy subjects according to an established paired-pulse TMS protocol [Ziemann U, Tergau F, Wassermann EM, Wischer S, Hildebrandt J, Paulus W. Demonstration of facilitatory I-wave interaction in the human motor cortex by paired transcranial magnetic stimulation. J Physiol (Lond) 1998a;511:181-190]. The individual ISI leading to SICF peak1, trough1, peak2, trough2 and peak3 was selected for the subsequent measurement of SICI intensity curves (SICI(peak1), SICI(trough1), SICI(peak2), SICI(trough2), SICI(peak3)) using intensity variation of the first stimulus (S1) from 50% to 120% of active motor threshold (AMT) in the first dorsal interosseous muscle. RESULTS: SICI(peak1) (mean ISI, 1.54ms) and SICI(trough1) (mean ISI, 1.97ms) showed a sigmoid SICI increase with S1 intensity. SICI(trough1) reached the strongest SICI and was therefore chosen for comparison with the other SICI curves. SICI(peak2) (mean ISI, 2.61ms) was U-shaped with a similar increase at low S1 intensities, but a decrease when S1 intensity exceeded 90% AMT. Correlation analyses suggested that this decrease was caused by SICF. SICI(trough2) (mean ISI, 3.50ms) and SICI(peak3) (mean ISI, 4.26ms) showed considerably less inhibition than SICI(trough1) over the whole range of S1 intensities. CONCLUSIONS: Findings show that commonly accepted protocols of testing SICI (ISI of 2-3ms, S1 intensity approximately 95% AMT) bear the risk of measuring net inhibition contaminated by SICF. SIGNIFICANCE: SICF may contribute to apparently reduced SICI in patients with neurological or psychiatric disorders.


Assuntos
Potencial Evocado Motor/fisiologia , Córtex Motor/fisiologia , Inibição Neural/fisiologia , Adulto , Análise de Variância , Limiar Diferencial/fisiologia , Limiar Diferencial/efeitos da radiação , Relação Dose-Resposta à Radiação , Estimulação Elétrica/métodos , Eletromiografia/métodos , Feminino , Humanos , Masculino , Inibição Neural/efeitos da radiação , Tempo de Reação/efeitos da radiação , Análise de Regressão , Fatores de Tempo , Estimulação Magnética Transcraniana/métodos
19.
Exp Brain Res ; 185(2): 279-86, 2008 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-17940759

RESUMO

The aim of the present paper is to study effects of short and long duration transcranial direct current stimulation (tDCS) on the human motor cortex. In eight normal volunteers, motor evoked potentials (MEPs) induced by transcranial magnetic stimulation (TMS) were recorded from the right first dorsal interosseous muscle, and tDCS was given with electrodes over the left primary motor cortex (M1) and the contralateral orbit. We performed two experiments: one for short duration tDCS (100 ms, 1, 3 or 5 mA) and the other for long duration tDCS (10 min, 1 mA). The stimulus onset asynchrony (SOA) between the onset of tDCS and TMS were 1-7 and 10-120 ms for the former experiment. In the latter experiment, TMS was given 0-20 min after the end of 10 min tDCS. We evaluated the effect of tDCS on the motor cortex by comparing MEPs conditioned by tDCS with control MEPs. Cathodal short duration tDCS significantly reduced the size of responses to motor cortical stimulation at SOAs of 1-7 ms when the intensity was equal to or greater than 3 mA. Anodal short duration tDCS significantly increased MEPs when the intensity was 3 mA, but the enhancement did not occur when using 5 mA conditioning stimulus. Moreover, both anodal and cathodal short duration tDCS decreased responses to TMS significantly at SOAs of 20-50 ms and enhanced them at an SOA of 90 ms. Long duration cathodal tDCS decreased MEPs at 0 and 5 min after the offset of tDCS and anodal long duration tDCS increased them at 1 and 15 min. We conclude that the effect at SOAs less than 10 ms is mainly caused by acute changes in resting membrane potential induced by tDCS. The effect at SOAs of 20-100 ms is considered to be a nonspecific effect of a startle-like response produced by activation of skin sensation at the scalp. The effect provoked by long duration tDCS may be short-term potentiation or depression like effects.


Assuntos
Potencial Evocado Motor/fisiologia , Mãos/fisiologia , Córtex Motor/fisiologia , Estimulação Magnética Transcraniana/métodos , Adulto , Estimulação Elétrica/métodos , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Fatores de Tempo
20.
Rinsho Shinkeigaku ; 48(5): 343-6, 2008 May.
Artigo em Japonês | MEDLINE | ID: mdl-18540382

RESUMO

We reported two patients with unilateral lateral medullary infarction involving severe, long-term respiratory failure. The first patient is an 86-year-old man presenting with gait disturbance, hoarseness and dysphagia. A right lateral medullary infarction was revealed by brain MRI. On the fifth hospitalized day, acute respiratory failure occurred. His condition failed to recover, and he was still attached to a ventilator 10 months after the onset. The second patient is an 83-year-old woman mainly presenting with dysphagia. A tiny infarction in the right lateral medulla was revealed by brain MRI. On the third day after the onset, acute respiratory failure occurred, which was not changed even at 8 months later. Although the symptoms and the lesion in the medulla were quite different between two patients, dysphagia and respiratory failure occurred in both patients. Therefore, it is postulated that the lesion that causes dyspnea may be approximate to the lesion that causes dysphagia. Many previously reported cases presenting respiratory failure seemed to suffer swallowing difficulty as well. We conclude that elderly patients suffering from unilateral lateral medullary infarction with dysphagia can present respiratory failure a few days after the onset, demonstrating the need to observe them under intensive attention.


Assuntos
Infarto Cerebral/complicações , Bulbo/irrigação sanguínea , Insuficiência Respiratória/etiologia , Idoso de 80 Anos ou mais , Infarto Cerebral/diagnóstico , Transtornos de Deglutição/etiologia , Feminino , Humanos , Imageamento por Ressonância Magnética , Masculino , Respiração Artificial , Insuficiência Respiratória/terapia , Traqueotomia
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