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Kober SE, Schweiger D, Reichert JL, Neuper C, Wood G. Upper Alpha Based Neurofeedback Training in Chronic Stroke: Brain Plasticity Processes and Cognitive Effects. Appl Psychophysiol Biofeedback 2017; 42:69-83. [PMID: 28197747 PMCID: PMC5344963 DOI: 10.1007/s10484-017-9353-5] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/03/2022]
Abstract
In the present study, we investigated the effects of upper alpha based neurofeedback (NF) training on electrical brain activity and cognitive functions in stroke survivors. Therefore, two single chronic stroke patients with memory deficits (subject A with a bilateral subarachnoid hemorrhage; subject B with an ischemic stroke in the left arteria cerebri media) and a healthy elderly control group (N = 24) received up to ten NF training sessions. To evaluate NF training effects, all participants performed multichannel electroencephalogram (EEG) resting measurements and a neuropsychological test battery assessing different cognitive functions before and after NF training. Stroke patients showed improvements in memory functions after successful NF training compared to the pre-assessment. Subject B had a pathological delta (0.5-4 Hz) and upper alpha (10-12 Hz) power maximum over the unaffected hemisphere before NF training. After NF training, he showed a more bilateral and "normalized" topographical distribution of these EEG frequencies. Healthy participants as well as subject A did not show any abnormalities in EEG topography before the start of NF training. Consequently, no changes in the topographical distribution of EEG activity were observed in these participants when comparing the pre- and post-assessment. Hence, our results show that upper alpha based NF training had on the one hand positive effects on memory functions, and on the other hand led to cortical "normalization" in a stroke patient with pathological brain activation patterns, which underlines the potential usefulness of NF as neurological rehabilitation tool.
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Affiliation(s)
- Silvia Erika Kober
- Department of Psychology, University of Graz, Universitaetsplatz 2/III, 8010 Graz, Austria
- BioTechMed-Graz, Mozartgasse 12/II, Graz, 8010 Austria
| | - Daniela Schweiger
- Department of Psychology, University of Graz, Universitaetsplatz 2/III, 8010 Graz, Austria
| | | | - Christa Neuper
- Department of Psychology, University of Graz, Universitaetsplatz 2/III, 8010 Graz, Austria
- BioTechMed-Graz, Mozartgasse 12/II, Graz, 8010 Austria
- Institute of Neural Engineering, Laboratory of Brain-Computer Interfaces, Graz University of Technology, Stremayrgasse 16, Graz, 8010 Austria
| | - Guilherme Wood
- Department of Psychology, University of Graz, Universitaetsplatz 2/III, 8010 Graz, Austria
- BioTechMed-Graz, Mozartgasse 12/II, Graz, 8010 Austria
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102
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Naros G, Gharabaghi A. Physiological and behavioral effects of β-tACS on brain self-regulation in chronic stroke. Brain Stimul 2017; 10:251-259. [DOI: 10.1016/j.brs.2016.11.003] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2016] [Revised: 10/04/2016] [Accepted: 11/07/2016] [Indexed: 12/21/2022] Open
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103
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Brain Symmetry Index in Healthy and Stroke Patients for Assessment and Prognosis. Stroke Res Treat 2017; 2017:8276136. [PMID: 28251015 PMCID: PMC5304313 DOI: 10.1155/2017/8276136] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2016] [Revised: 11/22/2016] [Accepted: 01/10/2017] [Indexed: 01/08/2023] Open
Abstract
Objective. Quantitative neurophysiological signal parameters are of value in predicting motor recovery after stroke. The novel role of EEG-derived brain symmetry index for motor function prognostication in the subacute phase after stroke is explored. Methods. Ten male stroke patients and ten matched healthy controls were recruited. Motor function was first assessed clinically using the MRC score, its derivative Motricity Index, and the Fugl–Meyer assessment score. EEG was subsequently recorded first with subjects at rest and then during hand grasping motions, triggered by visual cues. Brain symmetry index (BSI) was used to identify the differences in EEG-quantified interhemispheric cortical power asymmetry observable in healthy versus cortical and subcortical stroke patients. Subsequently, any correlation between BSI and motor function was explored. Results. BSI was found to be significantly higher in stroke subjects compared to healthy controls (p = 0.023). The difference in BSI was more pronounced in the cortical stroke subgroup (p = 0.016). BSI showed only a mild general decrease on repeated monthly recording. Notably, a statistically significant correlation was observed between early BSI and Fugl–Meyer score later in recovery (p < 0.050). Conclusions. Brain symmetry index is increased in the subacute poststroke phase and correlates with motor function 1-2 months after stroke.
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104
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Continuous EEG Monitoring for Early Detection of Delayed Cerebral Ischemia in Subarachnoid Hemorrhage: A Pilot Study. Neurocrit Care 2017; 24:207-16. [PMID: 26432793 DOI: 10.1007/s12028-015-0205-y] [Citation(s) in RCA: 54] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
Abstract
INTRODUCTION Early identification of delayed cerebral ischemia (DCI) in patients with aneurysmal subarachnoid hemorrhage (aSAH) is a major challenge. The aim of this study was to investigate whether quantitative EEG (qEEG) features can detect DCI prior to clinical or radiographic findings. METHODS A prospective cohort study was performed in aSAH patients in whom continuous EEG (cEEG) was recorded. We studied 12 qEEG features. We compared the time point at which qEEG changed with the time point that clinical deterioration occurred or new ischemia was noted on CT scan. RESULTS Twenty aSAH patients were included of whom 11 developed DCI. The alpha/delta ratio (ADR) was the most promising feature that showed a significant difference in change over time in the DCI group (median -62% with IQR -87 to -39%) compared to the control group (median +27% with IQR -32 to +104%, p = 0.013). Based on the ROC curve, a threshold was chosen for a combined measure of ADR and alpha variability (AUC: 91.7, 95% CI 74.2-100). The median time that elapsed between change of qEEG and clinical DCI diagnosis was seven hours (IQR -11-25). Delay between qEEG and CT scan changes was 44 h (median, IQR 14-117). CONCLUSION In this study, ADR and alpha variability could detect DCI development before ischemic changes on CT scan was apparent and before clinical deterioration was noted. Implementation of cEEG in aSAH patients can probably improve early detection of DCI.
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105
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Simis M, Doruk D, Imamura M, Anghinah R, Morales-Quezada L, Fregni F, Battistella LR. Neurophysiologic predictors of motor function in stroke. Restor Neurol Neurosci 2016; 34:45-54. [PMID: 26518670 DOI: 10.3233/rnn-150550] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023]
Abstract
PURPOSE Understanding the neural mechanisms of stroke recovery is of paramount importance for neurorehabilitation. METHODS For this purpose, we analyzed several TMS and EEG variables and their association with motor recovery. Thirty-five subjects with chronic stroke were recruited. The neurophysiological examination included assessments by transcranial magnetic stimulation (TMS), intra- and inter-hemispheric EEG coherence in different frequency bands (e.g. alpha (8-13 Hz)) as determined by quantitative electroencephalography (qEEG). Motor function was measured by Fugl-Meyer (FM). Multiple univariate and multivariate linear regression analyses were performed to identify the predictors for FM. RESULTS Multivariate analyses, showed a significant interaction effect of motor threshold (MT) in the lesioned hemisphere and beta coherence in the unlesioned hemisphere. This interaction suggests that higher beta activity in the unlesioned hemisphere strengthens the negative association between MT and FM scores. CONCLUSIONS Our results suggest that MT in the lesioned hemisphere is the strongest predictors of motor recovery after stroke. Moreover, cortical activity in the unlesioned hemisphere measured by qEEG provides additional information, specifying the association between MT and FM scores. Therefore, complementary application of EEG and TMS can help constitute a better model of the lesioned and the unlesioned hemispheres that supports the importance of bihemispheric activity in recovery.
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Affiliation(s)
- Marcel Simis
- Physical and Rehabilitation Medicine Institute of the University of Sao Paulo Medical School General Hospital, Brazil.,Laboratory of Neuromodulation, Spaulding Rehabilitation Hospital and Massachusetts General Hospital, Harvard Medical School, Boston, USA
| | - Deniz Doruk
- Laboratory of Neuromodulation, Spaulding Rehabilitation Hospital and Massachusetts General Hospital, Harvard Medical School, Boston, USA
| | - Marta Imamura
- Physical and Rehabilitation Medicine Institute of the University of Sao Paulo Medical School General Hospital, Brazil
| | - Renato Anghinah
- Physical and Rehabilitation Medicine Institute of the University of Sao Paulo Medical School General Hospital, Brazil
| | - Leon Morales-Quezada
- Laboratory of Neuromodulation, Spaulding Rehabilitation Hospital and Massachusetts General Hospital, Harvard Medical School, Boston, USA
| | - Felipe Fregni
- Physical and Rehabilitation Medicine Institute of the University of Sao Paulo Medical School General Hospital, Brazil.,Laboratory of Neuromodulation, Spaulding Rehabilitation Hospital and Massachusetts General Hospital, Harvard Medical School, Boston, USA
| | - Linamara Rizzo Battistella
- Physical and Rehabilitation Medicine Institute of the University of Sao Paulo Medical School General Hospital, Brazil
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106
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Caliandro P, Vecchio F, Miraglia F, Reale G, Della Marca G, La Torre G, Lacidogna G, Iacovelli C, Padua L, Bramanti P, Rossini PM. Small-World Characteristics of Cortical Connectivity Changes in Acute Stroke. Neurorehabil Neural Repair 2016; 31:81-94. [PMID: 27511048 DOI: 10.1177/1545968316662525] [Citation(s) in RCA: 70] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Background After cerebral ischemia, disruption and subsequent reorganization of functional connections occur both locally and remote to the lesion. Recently, complexity of brain connectivity has been described using graph theory, a mathematical approach that depicts important properties of complex systems by quantifying topologies of network representations. Functional and dynamic changes of brain connectivity can be reliably analyzed via electroencephalography (EEG) recordings even when they are not yet reflected in structural changes of connections. Objective We tested whether and how ischemic stroke in the acute stage may determine changes in small-worldness of cortical networks as measured by cortical sources of EEG. Methods Graph characteristics of EEG of 30 consecutive stroke patients in acute stage (no more than 5 days after the event) were examined. Connectivity analysis was performed using eLORETA in both hemispheres. Results Network rearrangements were mainly detected in delta, theta, and alpha bands when patients were compared with healthy subjects. In delta and alpha bands similar findings were observed in both hemispheres regardless of the side of ischemic lesion: bilaterally decreased small-worldness in the delta band and bilaterally increased small-worldness in the alpha2 band. In the theta band, bilaterally decreased small-worldness was observed only in patients with stroke in the left hemisphere. Conclusions After an acute stroke, brain cortex rearranges its network connections diffusely, in a frequency-dependent modality probably in order to face the new anatomical and functional frame.
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Affiliation(s)
- Pietro Caliandro
- Catholic University, Rome, Italy .,Fondazione Don Carlo Gnocchi Onlus, Milan, Italy
| | | | | | | | | | | | | | - Chiara Iacovelli
- Catholic University, Rome, Italy.,Fondazione Don Carlo Gnocchi Onlus, Milan, Italy
| | - Luca Padua
- Catholic University, Rome, Italy.,Fondazione Don Carlo Gnocchi Onlus, Milan, Italy
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107
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Electroencephalographic markers of robot-aided therapy in stroke patients for the evaluation of upper limb rehabilitation. Int J Rehabil Res 2016; 38:294-305. [PMID: 26317486 DOI: 10.1097/mrr.0000000000000125] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
Stroke is the leading cause of permanent disability in developed countries; its effects may include sensory, motor, and cognitive impairment as well as a reduced ability to perform self-care and participate in social and community activities. A number of studies have shown that the use of robotic systems in upper limb motor rehabilitation programs provides safe and intensive treatment to patients with motor impairments because of a neurological injury. Furthermore, robot-aided therapy was shown to be well accepted and tolerated by all patients; however, it is not known whether a specific robot-aided rehabilitation can induce beneficial cortical plasticity in stroke patients. Here, we present a procedure to study neural underpinning of robot-aided upper limb rehabilitation in stroke patients. Neurophysiological recordings use the following: (a) 10-20 system electroencephalographic (EEG) electrode montage; (b) bipolar vertical and horizontal electrooculographies; and (c) bipolar electromyography from the operating upper limb. Behavior monitoring includes the following: (a) clinical data and (b) kinematic and dynamic of the operant upper limb movements. Experimental conditions include the following: (a) resting state eyes closed and eyes open, and (b) robotic rehabilitation task (maximum 80 s each block to reach 4-min EEG data; interblock pause of 1 min). The data collection is performed before and after a program of 30 daily rehabilitation sessions. EEG markers include the following: (a) EEG power density in the eyes-closed condition; (b) reactivity of EEG power density to eyes opening; and (c) reactivity of EEG power density to robotic rehabilitation task. The above procedure was tested on a subacute patient (29 poststroke days) and on a chronic patient (21 poststroke months). After the rehabilitation program, we observed (a) improved clinical condition; (b) improved performance during the robotic task; (c) reduced delta rhythms (1-4 Hz) and increased alpha rhythms (8-12 Hz) during the resting state eyes-closed condition; (d) increased alpha desynchronization to eyes opening; and (e) decreased alpha desynchronization during the robotic rehabilitation task. We conclude that the present procedure is suitable for evaluation of the neural underpinning of robot-aided upper limb rehabilitation.
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108
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Abnormal EEG Complexity and Functional Connectivity of Brain in Patients with Acute Thalamic Ischemic Stroke. COMPUTATIONAL AND MATHEMATICAL METHODS IN MEDICINE 2016; 2016:2582478. [PMID: 27403202 PMCID: PMC4923597 DOI: 10.1155/2016/2582478] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 01/23/2016] [Revised: 03/26/2016] [Accepted: 04/10/2016] [Indexed: 11/28/2022]
Abstract
Ischemic thalamus stroke has become a serious cardiovascular and cerebral disease in recent years. To date the existing researches mostly concentrated on the power spectral density (PSD) in several frequency bands. In this paper, we investigated the nonlinear features of EEG and brain functional connectivity in patients with acute thalamic ischemic stroke and healthy subjects. Electroencephalography (EEG) in resting condition with eyes closed was recorded for 12 stroke patients and 11 healthy subjects as control group. Lempel-Ziv complexity (LZC), Sample Entropy (SampEn), and brain network using partial directed coherence (PDC) were calculated for feature extraction. Results showed that patients had increased mean LZC and SampEn than the controls, which implied the stroke group has higher EEG complexity. For the brain network, the stroke group displayed a trend of weaker cortical connectivity, which suggests a functional impairment of information transmission in cortical connections in stroke patients. These findings suggest that nonlinear analysis and brain network could provide essential information for better understanding the brain dysfunction in the stroke and assisting monitoring or prognostication of stroke evolution.
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109
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Wu J, Srinivasan R, Burke Quinlan E, Solodkin A, Small SL, Cramer SC. Utility of EEG measures of brain function in patients with acute stroke. J Neurophysiol 2016; 115:2399-405. [PMID: 26936984 DOI: 10.1152/jn.00978.2015] [Citation(s) in RCA: 71] [Impact Index Per Article: 8.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2015] [Accepted: 02/24/2016] [Indexed: 01/23/2023] Open
Abstract
EEG has been used to study acute stroke for decades; however, because of several limitations EEG-based measures rarely inform clinical decision-making in this setting. Recent advances in EEG hardware, recording electrodes, and EEG software could overcome these limitations. The present study examined how well dense-array (256 electrodes) EEG, acquired with a saline-lead net and analyzed with whole brain partial least squares (PLS) modeling, captured extent of acute stroke behavioral deficits and varied in relation to acute brain injury. In 24 patients admitted for acute ischemic stroke, 3 min of resting-state EEG was acquired at bedside, including in the ER and ICU. Traditional quantitative EEG measures (power in a specific lead, in any frequency band) showed a modest association with behavioral deficits [NIH Stroke Scale (NIHSS) score] in bivariate models. However, PLS models of delta or beta power across whole brain correlated strongly with NIHSS score (R(2) = 0.85-0.90) and remained robust when further analyzed with cross-validation models (R(2) = 0.72-0.73). Larger infarct volume was associated with higher delta power, bilaterally; the contralesional findings were not attributable to mass effect, indicating that EEG captures significant information about acute stroke effects not available from MRI. We conclude that 1) dense-array EEG data are feasible as a bedside measure of brain function in patients with acute stroke; 2) high-dimension EEG data are strongly correlated with acute stroke behavioral deficits and are superior to traditional single-lead metrics in this regard; and 3) EEG captures significant information about acute stroke injury not available from structural brain imaging.
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Affiliation(s)
- Jennifer Wu
- Department of Anatomy and Neurobiology, University of California, Irvine, California
| | - Ramesh Srinivasan
- Department of Cognitive Sciences, University of California, Irvine, California; and
| | - Erin Burke Quinlan
- Department of Anatomy and Neurobiology, University of California, Irvine, California; Department of Neurology, University of California, Irvine, California
| | - Ana Solodkin
- Department of Anatomy and Neurobiology, University of California, Irvine, California; Department of Neurology, University of California, Irvine, California
| | - Steven L Small
- Department of Neurology, University of California, Irvine, California
| | - Steven C Cramer
- Department of Anatomy and Neurobiology, University of California, Irvine, California; Department of Neurology, University of California, Irvine, California
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110
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Repeatability of functional anisotropy in navigated transcranial magnetic stimulation--coil-orientation versus response. Neuroreport 2016; 26:515-21. [PMID: 26011386 DOI: 10.1097/wnr.0000000000000380] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
Transcranial magnetic stimulation (TMS) can be used for evaluating the function of motor pathways. According to the principles of electromagnetism and electrophysiology, TMS activates those neurons that are suitably oriented with respect to the TMS-induced electric field. We hypothesized that TMS could potentially be able to evaluate the neuronal structure, although until now, this putative application has not been exploited. We have developed a TMS-based method to evaluate the function and structure of the motor cortex concurrently in a quantitative manner. This method produced a measure, the anisotropy index (AI), which is based on the motor-evoked potentials induced at different coil orientations. The AI was demonstrated to exhibit an association with both motor cortex excitability and neuronal structure. In the present study, we evaluated the repeatability (intrasession and intersession) of AI in three consecutive measurements. In addition, we studied the repeatability of the optimal coil angle in inducing motor-evoked potentials. Two of the measurements were conducted on the same stimulation target and the third on a remapped target. The coefficient of repeatability of the AI was 0.022 for intrasession and 0.040 for intersession assessments. For the optimal stimulation angle, the coefficients of repeatability were 3.7° and 5.1°, respectively. Both the AI and the optimal stimulation angle demonstrated good repeatability (Cronbach's α>0.760). In conclusion, the results indicate that the AI can provide a reliable estimation of local functional anisotropy changes under conditions affecting the cortex, such as during stroke or focal dysplasia.
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111
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Carrick FR, Oggero E, Pagnacco G, Wright CHG, Machado C, Estrada G, Pando A, Cossio JC, Beltrán C. Eye-Movement Training Results in Changes in qEEG and NIH Stroke Scale in Subjects Suffering from Acute Middle Cerebral Artery Ischemic Stroke: A Randomized Control Trial. Front Neurol 2016; 7:3. [PMID: 26834698 PMCID: PMC4722822 DOI: 10.3389/fneur.2016.00003] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2015] [Accepted: 01/08/2016] [Indexed: 11/25/2022] Open
Abstract
Context Eye-movement training (EMT) can induce altered brain activation and change the functionality of saccades with changes of the brain in general. Objective To determine if EMT would result in changes in quantitative electroencephalogram (qEEG) and NIH Stroke Scale (NIHSS) in patients suffering from acute middle cerebral artery (MCA) infarction. Our hypothesis is that there would be positive changes in qEEG and NIHSS after EMT in patients suffering from acute MCA ischemic stroke. Design Double-blind randomized controlled trial. Setting and participants Thirty-four subjects with acute MCA ischemic stroke treated at university affiliated hospital intensive care unit. Interventions Subjects were randomized into a “control” group treated only with aspirin (125 mg/day) and a “treatment” group treated with aspirin (125 mg/day) and a subject-specific EMT. Main outcome measures Delta–alpha ratio, power ratio index, and the brain symmetry index calculated by qEEG and NIHSS. Results There was strong statistical and substantive significant improvement in all outcome measures for the group of stroke patients undergoing EMT. Such improvement was not observed for the “control” group, and there were no adverse effects. Conclusion The addition of EMT to a MCA ischemic stroke treatment paradigm has demonstrated statistically significant changes in outcome measures and is a low cost, safe, and effective complement to standard treatment.
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Affiliation(s)
- Frederick Robert Carrick
- Neurology, Carrick Institute, Cape Canaveral, FL, USA; Global Clinical Scholars Research Training Program (GCSRT), Harvard Medical School, Boston, MA, USA; Institute of Neurology and Neurosurgery, Havana, Cuba; Bedfordshire Centre for Mental Health Research, University of Cambridge, Cambridge, UK
| | - Elena Oggero
- Neurology, Carrick Institute, Cape Canaveral, FL, USA; Electrical and Computer Engineering, University of Wyoming, Laramie, WY, USA
| | - Guido Pagnacco
- Neurology, Carrick Institute, Cape Canaveral, FL, USA; Electrical and Computer Engineering, University of Wyoming, Laramie, WY, USA
| | - Cameron H G Wright
- Neurology, Carrick Institute, Cape Canaveral, FL, USA; Electrical and Computer Engineering, University of Wyoming, Laramie, WY, USA
| | - Calixto Machado
- Neurology, Carrick Institute, Cape Canaveral, FL, USA; Institute of Neurology and Neurosurgery, Havana, Cuba
| | - Genco Estrada
- Institute of Neurology and Neurosurgery , Havana , Cuba
| | | | - Juan C Cossio
- Institute of Neurology and Neurosurgery , Havana , Cuba
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112
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Abstract
To determine the optimal use and indications of electroencephalography (EEG) in critical care management of acute brain injury (ABI). An electronic literature search was conducted for articles in English describing electrophysiological monitoring in ABI from January 1990 to August 2013. A total of 165 studies were included. EEG is a useful monitor for seizure and ischemia detection. There is a well-described role for EEG in convulsive status epilepticus and cardiac arrest (CA). Data suggest EEG should be considered in all patients with ABI and unexplained and persistent altered consciousness and in comatose intensive care unit (ICU) patients without an acute primary brain condition who have an unexplained impairment of mental status. There remain uncertainties about certain technical details, e.g., the minimum duration of EEG studies, the montage, and electrodes. Data obtained from both EEG and EP studies may help estimate prognosis in ABI patients, particularly following CA and traumatic brain injury. Data supporting these recommendations is sparse, and high quality studies are needed. EEG is used to monitor and detect seizures and ischemia in ICU patients and indications for EEG are clear for certain disease states, however, uncertainty remains on other applications.
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113
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Auriat AM, Neva JL, Peters S, Ferris JK, Boyd LA. A Review of Transcranial Magnetic Stimulation and Multimodal Neuroimaging to Characterize Post-Stroke Neuroplasticity. Front Neurol 2015; 6:226. [PMID: 26579069 PMCID: PMC4625082 DOI: 10.3389/fneur.2015.00226] [Citation(s) in RCA: 82] [Impact Index Per Article: 9.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2015] [Accepted: 10/12/2015] [Indexed: 01/09/2023] Open
Abstract
Following stroke, the brain undergoes various stages of recovery where the central nervous system can reorganize neural circuitry (neuroplasticity) both spontaneously and with the aid of behavioral rehabilitation and non-invasive brain stimulation. Multiple neuroimaging techniques can characterize common structural and functional stroke-related deficits, and importantly, help predict recovery of function. Diffusion tensor imaging (DTI) typically reveals increased overall diffusivity throughout the brain following stroke, and is capable of indexing the extent of white matter damage. Magnetic resonance spectroscopy (MRS) provides an index of metabolic changes in surviving neural tissue after stroke, serving as a marker of brain function. The neural correlates of altered brain activity after stroke have been demonstrated by abnormal activation of sensorimotor cortices during task performance, and at rest, using functional magnetic resonance imaging (fMRI). Electroencephalography (EEG) has been used to characterize motor dysfunction in terms of increased cortical amplitude in the sensorimotor regions when performing upper limb movement, indicating abnormally increased cognitive effort and planning in individuals with stroke. Transcranial magnetic stimulation (TMS) work reveals changes in ipsilesional and contralesional cortical excitability in the sensorimotor cortices. The severity of motor deficits indexed using TMS has been linked to the magnitude of activity imbalance between the sensorimotor cortices. In this paper, we will provide a narrative review of data from studies utilizing DTI, MRS, fMRI, EEG, and brain stimulation techniques focusing on TMS and its combination with uni- and multimodal neuroimaging methods to assess recovery after stroke. Approaches that delineate the best measures with which to predict or positively alter outcomes will be highlighted.
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Affiliation(s)
- Angela M Auriat
- Department of Physical Therapy, Faculty of Medicine, University of British Columbia , Vancouver, BC , Canada
| | - Jason L Neva
- Department of Physical Therapy, Faculty of Medicine, University of British Columbia , Vancouver, BC , Canada
| | - Sue Peters
- Department of Physical Therapy, Faculty of Medicine, University of British Columbia , Vancouver, BC , Canada
| | - Jennifer K Ferris
- Graduate Program in Neuroscience, Faculty of Medicine, University of British Columbia , Vancouver, BC , Canada
| | - Lara A Boyd
- Department of Physical Therapy, Faculty of Medicine, University of British Columbia , Vancouver, BC , Canada ; Graduate Program in Neuroscience, Faculty of Medicine, University of British Columbia , Vancouver, BC , Canada
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114
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Rabiller G, He JW, Nishijima Y, Wong A, Liu J. Perturbation of Brain Oscillations after Ischemic Stroke: A Potential Biomarker for Post-Stroke Function and Therapy. Int J Mol Sci 2015; 16:25605-40. [PMID: 26516838 PMCID: PMC4632818 DOI: 10.3390/ijms161025605] [Citation(s) in RCA: 71] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2015] [Revised: 10/06/2015] [Accepted: 10/15/2015] [Indexed: 01/08/2023] Open
Abstract
Brain waves resonate from the generators of electrical current and propagate across brain regions with oscillation frequencies ranging from 0.05 to 500 Hz. The commonly observed oscillatory waves recorded by an electroencephalogram (EEG) in normal adult humans can be grouped into five main categories according to the frequency and amplitude, namely δ (1-4 Hz, 20-200 μV), θ (4-8 Hz, 10 μV), α (8-12 Hz, 20-200 μV), β (12-30 Hz, 5-10 μV), and γ (30-80 Hz, low amplitude). Emerging evidence from experimental and human studies suggests that groups of function and behavior seem to be specifically associated with the presence of each oscillation band, although the complex relationship between oscillation frequency and function, as well as the interaction between brain oscillations, are far from clear. Changes of brain oscillation patterns have long been implicated in the diseases of the central nervous system including ischemic stroke, in which the reduction of cerebral blood flow as well as the progression of tissue damage have direct spatiotemporal effects on the power of several oscillatory bands and their interactions. This review summarizes the current knowledge in behavior and function associated with each brain oscillation, and also in the specific changes in brain electrical activities that correspond to the molecular events and functional alterations observed after experimental and human stroke. We provide the basis of the generations of brain oscillations and potential cellular and molecular mechanisms underlying stroke-induced perturbation. We will also discuss the implications of using brain oscillation patterns as biomarkers for the prediction of stroke outcome and therapeutic efficacy.
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Affiliation(s)
- Gratianne Rabiller
- Department of Neurological Surgery, University of California at San Francisco and Department of Veterans Affairs Medical Center, 1700 Owens Street, San Francisco, CA 94158, USA.
- UCSF and SFVAMC, San Francisco, CA 94158, USA.
- Univ. de Bordeaux, Institut des Maladies Neurodégénératives, UMR 5293, Bordeaux 33000, France.
- CNRS, Institut des Maladies Neurodégénératives, UMR 5293, Bordeaux 33000, France.
| | - Ji-Wei He
- Department of Neurological Surgery, University of California at San Francisco and Department of Veterans Affairs Medical Center, 1700 Owens Street, San Francisco, CA 94158, USA.
- UCSF and SFVAMC, San Francisco, CA 94158, USA.
| | - Yasuo Nishijima
- Department of Neurological Surgery, University of California at San Francisco and Department of Veterans Affairs Medical Center, 1700 Owens Street, San Francisco, CA 94158, USA.
- UCSF and SFVAMC, San Francisco, CA 94158, USA.
- Department of Neurosurgery, Tohoku University Graduate School of Medicine 1-1 Seiryo-machi, Aoba-ku, Sendai 980-8574, Japan.
| | - Aaron Wong
- Department of Neurological Surgery, University of California at San Francisco and Department of Veterans Affairs Medical Center, 1700 Owens Street, San Francisco, CA 94158, USA.
- UCSF and SFVAMC, San Francisco, CA 94158, USA.
- Rice University, 6100 Main St, Houston, TX 77005, USA.
| | - Jialing Liu
- Department of Neurological Surgery, University of California at San Francisco and Department of Veterans Affairs Medical Center, 1700 Owens Street, San Francisco, CA 94158, USA.
- UCSF and SFVAMC, San Francisco, CA 94158, USA.
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Finnigan S, Wong A, Read S. Defining abnormal slow EEG activity in acute ischaemic stroke: Delta/alpha ratio as an optimal QEEG index. Clin Neurophysiol 2015; 127:1452-1459. [PMID: 26251106 DOI: 10.1016/j.clinph.2015.07.014] [Citation(s) in RCA: 103] [Impact Index Per Article: 11.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2015] [Revised: 06/24/2015] [Accepted: 07/15/2015] [Indexed: 10/23/2022]
Abstract
OBJECTIVE Quantitative electroencephalographic (QEEG) indices sensitive to abnormal slow (relative to faster) activity power seem uniquely informative for clinical management of ischaemic stroke (IS), including around acute reperfusion therapies. However these have not been compared between IS and control samples. The primary objective was to identify the QEEG slowing index and threshold value which can most accurately discriminate between IS patients and controls. METHODS The samples comprised 28 controls (mean age: 70.4; range: 56-84) and 18 patients (mean age: 69.3; range: 51-86). Seven indices were analysed: relative bandpower (delta, theta, alpha, beta), delta/alpha power ratio (DAR), (delta+theta)/(alpha+beta) ratio (DTABR) and QSLOWING. The accuracies of each index for classifying participants (IS or control) were analysed using receiver operating characteristic (ROC) techniques. RESULTS All indices differed significantly between the samples (p<.001). DAR alone exhibited optimal classifier accuracy, with a threshold of 3.7 demonstrating 100% sensitivity and 100% specificity for discriminating between radiologically-confirmed, acute IS or control. DTABR and relative delta were the next most accurate classifiers. CONCLUSIONS DAR of 3.7 demonstrated maximal accuracy for classifying all 46 participants as acute IS or control. SIGNIFICANCE DAR assessment may inform clinical management of IS and perhaps other neurocritical patients.
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Affiliation(s)
- Simon Finnigan
- UQ Centre for Clinical Research, University of Queensland, Brisbane, Australia; Centre for Allied Health Research, Royal Brisbane and Women's Hospital, Metro North Hospital and Health Service, Queensland, Australia.
| | - Andrew Wong
- School of Medicine, University of Queensland, Brisbane, Australia; Acute Stroke Unit, Neurology Department, Royal Brisbane and Women's Hospital, Metro North Hospital and Health Service, Queensland, Australia
| | - Stephen Read
- School of Medicine, University of Queensland, Brisbane, Australia; Acute Stroke Unit, Neurology Department, Royal Brisbane and Women's Hospital, Metro North Hospital and Health Service, Queensland, Australia
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Wang D, Yee BJ, Wong KK, Kim JW, Dijk DJ, Duffin J, Grunstein RR. Comparing the effect of hypercapnia and hypoxia on the electroencephalogram during wakefulness. Clin Neurophysiol 2015; 126:103-9. [DOI: 10.1016/j.clinph.2014.04.012] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2013] [Revised: 04/07/2014] [Accepted: 04/12/2014] [Indexed: 01/01/2023]
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Schleiger E, Sheikh N, Rowland T, Wong A, Read S, Finnigan S. Frontal EEG delta/alpha ratio and screening for post-stroke cognitive deficits: The power of four electrodes. Int J Psychophysiol 2014; 94:19-24. [DOI: 10.1016/j.ijpsycho.2014.06.012] [Citation(s) in RCA: 58] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2014] [Revised: 05/13/2014] [Accepted: 06/17/2014] [Indexed: 11/26/2022]
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Gavvala J, Abend N, LaRoche S, Hahn C, Herman ST, Claassen J, Macken M, Schuele S, Gerard E. Continuous EEG monitoring: a survey of neurophysiologists and neurointensivists. Epilepsia 2014; 55:1864-71. [PMID: 25266728 DOI: 10.1111/epi.12809] [Citation(s) in RCA: 91] [Impact Index Per Article: 9.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 08/21/2014] [Indexed: 01/12/2023]
Abstract
OBJECTIVE Continuous EEG monitoring (cEEG) of critically ill adults is being used with increasing frequency, and practice guidelines on indications for cEEG monitoring have recently been published. However, data describing the current practice of cEEG in critically ill adults is limited. We aimed to describe the current practice of cEEG monitoring in adults in the United States. METHODS A survey assessing cEEG indications and procedures was sent to one intensivist and one neurophysiologist responsible for intensive care unit (ICU) cEEG at 151 institutions in the United States. At some institutions only one physician could be identified. RESULTS One hundred thirty-seven physicians from 97 institutions completed the survey. Continuous EEG is utilized by nearly all respondents to detect nonconvulsive seizures (NCS) in patients with altered mental status following clinical seizures, intra cerebral hemorrhage (ICH), traumatic brain injury, and cardiac arrest, as well as to characterize abnormal movements suspected to be seizures. The majority of physicians monitor comatose patients for 24-48 h. In an ideal situation with unlimited resources, 18% of respondents would increase cEEG duration. Eighty-six percent of institutions have an on-call EEG technologist available 24/7 for new patient hookups, but only 26% have technologists available 24/7 in-house. There is substantial variability in who reviews EEG and how frequently it is reviewed as well as use of quantitative EEG. SIGNIFICANCE Although there is general agreement regarding the indications for ICU cEEG, there is substantial interinstitutional variability in how the procedure is performed.
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Affiliation(s)
- Jay Gavvala
- Department of Neurology, Feinberg School of Medicine, Northwestern University, Chicago, Illinois, U.S.A
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Abstract
The brain is a self-organizing system which displays self-similarities at different spatial and temporal scales. Thus, the complexity of its dynamics, associated to efficient processing and functional advantages, is expected to be captured by a measure of its scale-free (fractal) properties. Under the hypothesis that the fractal dimension (FD) of the electroencephalographic signal (EEG) is optimally sensitive to the neuronal dysfunction secondary to a brain lesion, we tested the FD's ability in assessing two key processes in acute stroke: the clinical impairment and the recovery prognosis. Resting EEG was collected in 36 patients 4-10 days after a unilateral ischemic stroke in the middle cerebral artery territory and 19 healthy controls. National Health Institute Stroke Scale (NIHss) was collected at T0 and 6 months later. Highuchi FD, its inter-hemispheric asymmetry (FDasy) and spectral band powers were calculated for EEG signals. FD was smaller in patients than in controls (1.447±0.092 vs 1.525±0.105) and its reduction was paired to a worse acute clinical status. FD decrease was associated to alpha increase and beta decrease of oscillatory activity power. Larger FDasy in acute phase was paired to a worse clinical recovery at six months. FD in our patients captured the loss of complexity reflecting the global system dysfunction resulting from the structural damage. This decrease seems to reveal the intimate nature of structure-function unity, where the regional neural multi-scale self-similar activity is impaired by the anatomical lesion. This picture is coherent with neuronal activity complexity decrease paired to a reduced repertoire of functional abilities. FDasy result highlights the functional relevance of the balance between homologous brain structures' activities in stroke recovery.
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Zappasodi F, Olejarczyk E, Marzetti L, Assenza G, Pizzella V, Tecchio F. Fractal dimension of EEG activity senses neuronal impairment in acute stroke. PLoS One 2014; 9:e100199. [PMID: 24967904 PMCID: PMC4072666 DOI: 10.1371/journal.pone.0100199] [Citation(s) in RCA: 87] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2014] [Accepted: 05/23/2014] [Indexed: 01/15/2023] Open
Abstract
The brain is a self-organizing system which displays self-similarities at different spatial and temporal scales. Thus, the complexity of its dynamics, associated to efficient processing and functional advantages, is expected to be captured by a measure of its scale-free (fractal) properties. Under the hypothesis that the fractal dimension (FD) of the electroencephalographic signal (EEG) is optimally sensitive to the neuronal dysfunction secondary to a brain lesion, we tested the FD's ability in assessing two key processes in acute stroke: the clinical impairment and the recovery prognosis. Resting EEG was collected in 36 patients 4-10 days after a unilateral ischemic stroke in the middle cerebral artery territory and 19 healthy controls. National Health Institute Stroke Scale (NIHss) was collected at T0 and 6 months later. Highuchi FD, its inter-hemispheric asymmetry (FDasy) and spectral band powers were calculated for EEG signals. FD was smaller in patients than in controls (1.447±0.092 vs 1.525±0.105) and its reduction was paired to a worse acute clinical status. FD decrease was associated to alpha increase and beta decrease of oscillatory activity power. Larger FDasy in acute phase was paired to a worse clinical recovery at six months. FD in our patients captured the loss of complexity reflecting the global system dysfunction resulting from the structural damage. This decrease seems to reveal the intimate nature of structure-function unity, where the regional neural multi-scale self-similar activity is impaired by the anatomical lesion. This picture is coherent with neuronal activity complexity decrease paired to a reduced repertoire of functional abilities. FDasy result highlights the functional relevance of the balance between homologous brain structures' activities in stroke recovery.
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Affiliation(s)
- Filippo Zappasodi
- Dept. of Neuroscience, Imaging and Clinical Sciences, ‘G. d’Annunzio’ University, Chieti, Italy
- Institute for Advanced Biomedical Technologies, ‘G. d’Annunzio’ University, Chieti, Italy
| | - Elzbieta Olejarczyk
- Institute for Advanced Biomedical Technologies, ‘G. d’Annunzio’ University, Chieti, Italy
- Nałęcz Institute of Biocybernetics and Biomedical Engineering, Polish Academy of Sciences, Warsaw, Poland
| | - Laura Marzetti
- Dept. of Neuroscience, Imaging and Clinical Sciences, ‘G. d’Annunzio’ University, Chieti, Italy
- Institute for Advanced Biomedical Technologies, ‘G. d’Annunzio’ University, Chieti, Italy
| | - Giovanni Assenza
- Institute of Neurology, Campus Biomedico University of Rome, Rome, Italy
| | - Vittorio Pizzella
- Dept. of Neuroscience, Imaging and Clinical Sciences, ‘G. d’Annunzio’ University, Chieti, Italy
- Institute for Advanced Biomedical Technologies, ‘G. d’Annunzio’ University, Chieti, Italy
| | - Franca Tecchio
- Laboratory of Electrophysiology for Translational neuroScience (LET’S), ISTC, National Research Council (CNR), Fatebenefratelli hospital – Isola Tiberina, Rome, Italy
- Dept. of Imaging, IRCCS San Raffale Pisana, Rome, Italy
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Shibasaki H, Nakamura M, Sugi T, Nishida S, Nagamine T, Ikeda A. Automatic interpretation and writing report of the adult waking electroencephalogram. Clin Neurophysiol 2014; 125:1081-94. [DOI: 10.1016/j.clinph.2013.12.114] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2013] [Revised: 12/03/2013] [Accepted: 12/17/2013] [Indexed: 11/28/2022]
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Wang D, Piper AJ, Yee BJ, Wong KK, Kim JW, D'Rozario A, Rowsell L, Dijk DJ, Grunstein RR. Hypercapnia is a key correlate of EEG activation and daytime sleepiness in hypercapnic sleep disordered breathing patients. J Clin Sleep Med 2014; 10:517-22. [PMID: 24910553 PMCID: PMC4046358 DOI: 10.5664/jcsm.3700] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
BACKGROUND The key determinants of daytime drowsiness in sleep disordered breathing (SDB) are unclear. Hypercapnia has not been examined as a potential contributor due to the lack of reliable measurement during sleep. To overcome this limitation, we studied predominantly hypercapnic SDB patients to investigate the role of hypercapnia on EEG activation and daytime sleepiness. METHODS We measured overnight polysomnography (PSG), arterial blood gases, and Epworth Sleepiness Scale in 55 severe SDB patients with obesity hypoventilation syndrome or overlap syndrome (COPD+ obstructive sleep apnea) before and ∼3 months after positive airway pressure (PAP) treatment. Quantitative EEG analyses were performed, and the Delta/ Alpha ratio was used as an indicator of EEG activation. RESULTS After the PAP treatment, these patients showed a significant decrease in their waking pCO(2), daytime sleepiness, as well as all key breathing/oxygenation parameters during sleep. Overnight Delta/Alpha ratio of EEG was significantly reduced. There is a significant cross-correlation between a reduced wake pCO(2), a faster (more activated) sleep EEG (reduced Delta/Alpha ratio) and reduced daytime sleepiness (all p < 0.05) with PAP treatment. Multiple regression analyses showed the degree of change in hypercapnia to be the only significant predictor for both ESS and Delta/ Alpha ratio. CONCLUSIONS Hypercapnia is a key correlate of EEG activation and daytime sleepiness in hypercapnic SDB patients. The relationship between hypercapnia and sleepiness may be mediated by reduced neuro-electrical brain activity.
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Affiliation(s)
- David Wang
- Department of Respiratory and Sleep Medicine, Royal Prince Alfred Hospital, Sydney, Australia (work performed)
- Woolcock Institute of Medical Research, University of Sydney, Sydney, Australia
| | - Amanda J. Piper
- Department of Respiratory and Sleep Medicine, Royal Prince Alfred Hospital, Sydney, Australia (work performed)
- Woolcock Institute of Medical Research, University of Sydney, Sydney, Australia
| | - Brendon J. Yee
- Department of Respiratory and Sleep Medicine, Royal Prince Alfred Hospital, Sydney, Australia (work performed)
- Woolcock Institute of Medical Research, University of Sydney, Sydney, Australia
- Centre for Integrated Research and Understanding of Sleep (CIRUS), University of Sydney, Sydney, Australia
| | - Keith K. Wong
- Department of Respiratory and Sleep Medicine, Royal Prince Alfred Hospital, Sydney, Australia (work performed)
- Woolcock Institute of Medical Research, University of Sydney, Sydney, Australia
- Centre for Integrated Research and Understanding of Sleep (CIRUS), University of Sydney, Sydney, Australia
| | - Jong-Won Kim
- Centre for Integrated Research and Understanding of Sleep (CIRUS), University of Sydney, Sydney, Australia
- School of Physics, University of Sydney, Sydney, Australia
| | - Angela D'Rozario
- Woolcock Institute of Medical Research, University of Sydney, Sydney, Australia
- Centre for Integrated Research and Understanding of Sleep (CIRUS), University of Sydney, Sydney, Australia
| | - Luke Rowsell
- Woolcock Institute of Medical Research, University of Sydney, Sydney, Australia
| | - Derk-Jan Dijk
- Surrey Sleep Research Centre, University of Surrey, UK
| | - Ronald R. Grunstein
- Department of Respiratory and Sleep Medicine, Royal Prince Alfred Hospital, Sydney, Australia (work performed)
- Woolcock Institute of Medical Research, University of Sydney, Sydney, Australia
- Centre for Integrated Research and Understanding of Sleep (CIRUS), University of Sydney, Sydney, Australia
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123
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Quantitative electroencephalography and behavioural correlates of daytime sleepiness in chronic stroke. BIOMED RESEARCH INTERNATIONAL 2014; 2014:794086. [PMID: 24883327 PMCID: PMC4032711 DOI: 10.1155/2014/794086] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/12/2013] [Revised: 03/18/2014] [Accepted: 04/01/2014] [Indexed: 11/17/2022]
Abstract
Sleepiness is common after stroke, but in contrast to its importance for rehabilitation, existing studies focus primarily on the acute state and often use subjective sleepiness measures only. We used quantitative electroencephalography (qEEG) to extract physiological sleepiness, as well as subjective reports, in response to motor-cognitive demand in stroke patients and controls. We hypothesised that (a) slowing of the EEG is chronically sustained after stroke; (b) increased power in lower frequencies and increased sleepiness are associated; and (c) sleepiness is modulated by motor-cognitive demand. QEEGs were recorded in 32 chronic stroke patients and 20 controls using a Karolinska Drowsiness Test protocol administered before and after a motor priming task. Subjective sleepiness was measured using the Karolinska Sleepiness Scale. The findings showed that power density was significantly increased in delta and theta frequency bands over both hemispheres in patients which were not associated with subjective sleepiness ratings. This effect was not observed in controls. The motor priming task induced differential hemispheric effects with greater increase in low-frequency bands and presumably compensatory increases in higher frequency bands. The results indicate sustained slowing in the qEEG in chronic stroke, but in contrast to healthy controls, these changes are not related to perceived sleepiness.
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124
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Tangwiriyasakul C, Mocioiu V, van Putten MJAM, Rutten WLC. Classification of motor imagery performance in acute stroke. J Neural Eng 2014; 11:036001. [PMID: 24737062 DOI: 10.1088/1741-2560/11/3/036001] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
OBJECTIVE Effective motor imagery performance, seen as strong suppression of the sensorimotor rhythm, is the key element in motor imagery therapy. Therefore, optimization of methods to classify whether the subject is performing the imagery task is a prerequisite. An optimal classification method should have high performance accuracy and use a small number of channels. We investigated the additional benefit of the common spatial pattern filtering (CSP) to a linear discriminant analysis (LDA) classifier, for different channel configurations. METHODS Ten hemispheric acute stroke patients and 11 healthy subjects were included. EEGs were recorded using 60 channels. The classifier was trained with a motor execution task. For both healthy controls and patients, analysis of recordings was initially limited to 3 and 11 electrodes recording from the motor cortex area, and later repeated using 45 electrodes. RESULTS No significant improvement on the addition of CSP to LDA was found (in both cases, the area under the receiving operating characteristic (AU-ROC) ≈ 0.70 (acceptable)). We then repeated the LDA+CSP method on recordings of 45 electrodes, since the use of imagery neuronal circuits may well extend beyond the motor area. AU-ROC rose to 0.90, but no virtual 'most responsible' electrode was observed. Finally, in mild-to-moderate stroke patients we could successfully use the EEG data recorded from the healthy hemisphere to train the classifier (AU-ROC ≈ 0.70). SIGNIFICANCE Including only the channels on the unaffected motor cortex is sufficient to train a classifier.
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Affiliation(s)
- Chayanin Tangwiriyasakul
- Neural Engineering, Institute for Biomedical Technology and Technical Medicine, University of Twente, Enschede, The Netherlands. Clinical Neurophysiology, Institute for Biomedical Technology and Technical Medicine, University of Twente, Enschede, The Netherlands
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Tangwiriyasakul C, Verhagen R, Rutten WLC, van Putten MJAM. Temporal evolution of event-related desynchronization in acute stroke: a pilot study. Clin Neurophysiol 2013; 125:1112-20. [PMID: 24290502 DOI: 10.1016/j.clinph.2013.10.047] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2013] [Revised: 10/09/2013] [Accepted: 10/11/2013] [Indexed: 11/19/2022]
Abstract
OBJECTIVE Assessment of event-related desynchronization (ERD) may assist in predicting recovery from stroke and rehabilitation, for instance in BCI applications. Here, we explore the temporal evolution of ERD during stroke recovery. METHODS Ten stroke patients and eleven healthy controls were recruited to participate in a hand movement task while EEG was being recorded. Four measurements were conducted in eight patients within four months. We quantified changes of ERD using a modulation strength measure, S(m), which represents an area and amplitude of ERD. RESULTS 7/8 patients showed good recovery. Absence-or-reduction of ipsilesional modulation was initially found in stroke patients but not in the healthy controls. In the patient group, two evolutions were found in 6/8 patients: a significant increase in ipsilesional S(m); and a decreasing trend in contralesional S(m). In the only non-recovery patient, absence of ipsilesional modulation was observed, while his contralesional S(m) increased with time after stroke. CONCLUSION The two evolutions presumably reflect the reorganization of brain networks and functional recovery after acute stroke. The significant increase of ipsilesional S(m) in patients with a good recovery suggests an important role of this hemisphere during recovery. SIGNIFICANCE Improved understanding of ERD in acute stroke may assist in prognostication and rehabilitation.
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Affiliation(s)
- Chayanin Tangwiriyasakul
- Neural Engineering, Institute for Biomedical Technology and Technical Medicine (MIRA), University of Twente, Enschede, The Netherlands; Clinical Neurophysiology, Institute for Biomedical Technology and Technical Medicine (MIRA), University of Twente, Enschede, The Netherlands.
| | - Rens Verhagen
- Clinical Neurophysiology, Institute for Biomedical Technology and Technical Medicine (MIRA), University of Twente, Enschede, The Netherlands
| | - Wim L C Rutten
- Neural Engineering, Institute for Biomedical Technology and Technical Medicine (MIRA), University of Twente, Enschede, The Netherlands
| | - Michel J A M van Putten
- Clinical Neurophysiology, Institute for Biomedical Technology and Technical Medicine (MIRA), University of Twente, Enschede, The Netherlands; Medisch Spectrum Twente, Enschede, The Netherlands
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Tjepkema-Cloostermans MC, van Meulen FB, Meinsma G, van Putten MJAM. A Cerebral Recovery Index (CRI) for early prognosis in patients after cardiac arrest. CRITICAL CARE : THE OFFICIAL JOURNAL OF THE CRITICAL CARE FORUM 2013; 17:R252. [PMID: 24148747 PMCID: PMC4056571 DOI: 10.1186/cc13078] [Citation(s) in RCA: 61] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/07/2013] [Accepted: 09/26/2013] [Indexed: 11/17/2022]
Abstract
Introduction Electroencephalogram (EEG) monitoring in patients treated with therapeutic hypothermia after cardiac arrest may assist in early outcome prediction. Quantitative EEG (qEEG) analysis can reduce the time needed to review long-term EEG and makes the analysis more objective. In this study, we evaluated the predictive value of qEEG analysis for neurologic outcome in postanoxic patients. Methods In total, 109 patients admitted to the ICU for therapeutic hypothermia after cardiac arrest were included, divided over a training and a test set. Continuous EEG was recorded during the first 5 days or until ICU discharge. Neurologic outcomes were based on the best achieved Cerebral Performance Category (CPC) score within 6 months. Of the training set, 27 of 56 patients (48%) and 26 of 53 patients (49%) of the test set achieved good outcome (CPC 1 to 2). In all patients, a 5 minute epoch was selected each hour, and five qEEG features were extracted. We introduced the Cerebral Recovery Index (CRI), which combines these features into a single number. Results At 24 hours after cardiac arrest, a CRI <0.29 was always associated with poor neurologic outcome, with a sensitivity of 0.55 (95% confidence interval (CI): 0.32 to 0.76) at a specificity of 1.00 (CI, 0.86 to 1.00) in the test set. This results in a positive predictive value (PPV) of 1.00 (CI, 0.73 to 1.00) and a negative predictive value (NPV) of 0.71 (CI, 0.53 to 0.85). At the same time, a CRI >0.69 predicted good outcome, with a sensitivity of 0.25 (CI, 0.10 to 0.14) at a specificity of 1.00 (CI, 0.85 to 1.00) in the test set, and a corresponding NPV of 1.00 (CI, 0.54 to 1.00) and a PPV of 0.55 (CI, 0.38 to 0.70). Conclusions We introduced a combination of qEEG measures expressed in a single number, the CRI, which can assist in prediction of both poor and good outcomes in postanoxic patients, within 24 hours after cardiac arrest.
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Sheikh N, Wong A, Read S, Coulthard A, Finnigan S. QEEG may uniquely inform and expedite decisions regarding intra-arterial clot retrieval in acute stroke. Clin Neurophysiol 2013; 124:1913-4. [PMID: 23602491 DOI: 10.1016/j.clinph.2013.03.008] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2013] [Revised: 03/13/2013] [Accepted: 03/19/2013] [Indexed: 11/28/2022]
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Ferre A, Ribó M, Rodríguez-Luna D, Romero O, Sampol G, Molina C, Álvarez-Sabin J. Strokes and their relationship with sleep and sleep disorders. NEUROLOGÍA (ENGLISH EDITION) 2013. [DOI: 10.1016/j.nrleng.2010.09.004] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
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EEG in ischaemic stroke: Quantitative EEG can uniquely inform (sub-)acute prognoses and clinical management. Clin Neurophysiol 2013; 124:10-9. [DOI: 10.1016/j.clinph.2012.07.003] [Citation(s) in RCA: 167] [Impact Index Per Article: 15.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2012] [Revised: 06/13/2012] [Accepted: 07/03/2012] [Indexed: 11/22/2022]
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130
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Foreman B, Claassen J. Quantitative EEG for the detection of brain ischemia. CRITICAL CARE : THE OFFICIAL JOURNAL OF THE CRITICAL CARE FORUM 2012; 16:216. [PMID: 22429809 PMCID: PMC3681361 DOI: 10.1186/cc11230] [Citation(s) in RCA: 171] [Impact Index Per Article: 14.3] [Reference Citation Analysis] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 12/03/2022]
Affiliation(s)
- Brandon Foreman
- Columbia University College of Physicians & Surgeons, Division of Critical Care Neurology, New York, NY, USA
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Wei CC, Huang SW, Hsu SL, Chen HC, Chen JS, Liang H. Analysis of using the tongue deviation angle as a warning sign of a stroke. Biomed Eng Online 2012; 11:53. [PMID: 22908956 PMCID: PMC3507660 DOI: 10.1186/1475-925x-11-53] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2012] [Accepted: 08/13/2012] [Indexed: 12/03/2022] Open
Abstract
Background The symptom of tongue deviation is observed in a stroke or transient ischemic attack. Nevertheless, there is much room for the interpretation of the tongue deviation test. The crucial factor is the lack of an effective quantification method of tongue deviation. If we can quantify the features of the tongue deviation and scientifically verify the relationship between the deviation angle and a stroke, the information provided by the tongue will be helpful in recognizing a warning of a stroke. Methods In this study, a quantification method of the tongue deviation angle was proposed for the first time to characterize stroke patients. We captured the tongue images of stroke patients (15 males and 10 females, ranging between 55 and 82 years of age); transient ischemic attack (TIA) patients (16 males and 9 females, ranging between 53 and 79 years of age); and normal subjects (14 males and 11 females, ranging between 52 and 80 years of age) to analyze whether the method is effective. In addition, we used the receiver operating characteristic curve (ROC) for the sensitivity analysis, and determined the threshold value of the tongue deviation angle for the warning sign of a stroke. Results The means and standard deviations of the tongue deviation angles of the stroke, TIA, and normal groups were: 6.9 ± 3.1, 4.9 ± 2.1 and 1.4 ± 0.8 degrees, respectively. Analyzed by the unpaired Student’s t-test, the p-value between the stroke group and the TIA group was 0.015 (>0.01), indicating no significant difference in the tongue deviation angle. The p-values between the stroke group and the normal group, as well as between the TIA group and the normal group were both less than 0.01. These results show the significant differences in the tongue deviation angle between the patient groups (stroke and TIA patients) and the normal group. These results also imply that the tongue deviation angle can effectively identify the patient group (stroke and TIA patients) and the normal group. With respect to the visual examination, 40% and 32% of stroke patients, 24% and 16% of TIA patients, and 4% and 0% of normal subjects were found to have tongue deviations when physicians “A” and “B” examined them. The variation showed the essentiality of the quantification method in a clinical setting. In the receiver operating characteristic curve (ROC), the Area Under Curve (AUC, = 0.96) indicates good discrimination. The tongue deviation angle more than the optimum threshold value (= 3.2°) predicts a risk of stroke. Conclusions In summary, we developed an effective quantification method to characterize the tongue deviation angle, and we confirmed the feasibility of recognizing the tongue deviation angle as an early warning sign of an impending stroke.
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Affiliation(s)
- Ching-Chuan Wei
- Department of Information and Communication Engineering, Chaoyang University of Technology, Taichung, Taiwan.
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Quantitative electroencephalography in a swine model of cerebral arterial gas embolism. Clin Neurophysiol 2012; 123:411-7. [DOI: 10.1016/j.clinph.2011.06.028] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2011] [Revised: 05/22/2011] [Accepted: 06/08/2011] [Indexed: 12/21/2022]
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Rosenthal ES. The utility of EEG, SSEP, and other neurophysiologic tools to guide neurocritical care. Neurotherapeutics 2012; 9:24-36. [PMID: 22234455 PMCID: PMC3271154 DOI: 10.1007/s13311-011-0101-x] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023] Open
Abstract
Neuromonitoring is an emerging field that aims to characterize real-time neurophysiology to tailor therapy for acute injuries of the central nervous system. While cardiac telemetry has been used for decades among patients requiring critical care of all kinds, neurophysiology and neurotelemetry has only recently emerged as a routine screening tool in comatose patients. The increasing utilization of electroencephalography in comatose patients is primarily due to the recognition of the common occurrence of nonconvulsive seizures among comatose patients, the development of quantitative measures to detect regional ischemia, and the appreciation of electroencephalography phenotypes that indicate prognosis after cardiac arrest. Other neuromonitoring tools, such as somatosensory evoked potentials have a complementary role, surveying the integrity of the neuroaxis as an indicator of prognosis or illness progression in both acute brain and spinal injuries.
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Affiliation(s)
- Eric S Rosenthal
- Department of Neurology, Division of Neurocritical Care and Emergency Neurology, Massachusetts General Hospital, Boston, MA 02114, USA.
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134
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A Quantitative EEG Method for Detecting Post Clamp Changes During Carotid Endarterectomy. J Clin Monit Comput 2011; 25:295-308. [DOI: 10.1007/s10877-011-9308-y] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2010] [Accepted: 09/19/2011] [Indexed: 11/25/2022]
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135
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Predicting success of vagus nerve stimulation (VNS) from interictal EEG. Seizure 2011; 20:541-5. [DOI: 10.1016/j.seizure.2011.04.002] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2010] [Revised: 03/03/2011] [Accepted: 04/01/2011] [Indexed: 11/18/2022] Open
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Lapitskaya N, Nielsen JF, Fuglsang-Frederiksen A. Robotic gait training in patients with impaired consciousness due to severe traumatic brain injury. Brain Inj 2011; 25:1070-9. [PMID: 21870900 DOI: 10.3109/02699052.2011.607782] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
PRIMARY OBJECTIVE This prospective controlled non-randomized study investigated the effects of robotic gait training on electroencephalographic (EEG) brain activity in patients with impaired consciousness due to severe traumatic brain injury (TBI). METHODS Twelve TBI patients and 14 healthy controls underwent a single training session on a computer-driven gait orthosis (Lokomat®). The sensory pathways were assessed using sensory evoked potentials (SEPs). The global delta-alpha EEG power ratio (DAR) and latency of the P300 component of the event-related potentials was assessed prior to and following a training session. RESULTS Baseline measurements showed impaired SEPs in the majority of patients and significantly larger DAR in patients compared to healthy controls. Robotic gait training resulted in a reduction of the DAR in healthy subjects but not in patients. No changes were observed in P300 latencies after training in either patients or healthy controls. CONCLUSION The study showed that robotic gait training induced measurable changes in the EEG power spectrum in healthy individuals, while no changes were observed in patients with severe TBI. The absence of the EEG changes following training might be an indicator of the severity of brain dysfunction.
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Affiliation(s)
- Natallia Lapitskaya
- Research Department, Hammel Neurorehabilitation and Research Centre, Hammel, Denmark.
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137
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Lämmer AB, Beck A, Grummich B, Förschler A, Krügel T, Kahn T, Schneider D, Illes P, Franke H, Krügel U. The P2 receptor antagonist PPADS supports recovery from experimental stroke in vivo. PLoS One 2011; 6:e19983. [PMID: 21611146 PMCID: PMC3096654 DOI: 10.1371/journal.pone.0019983] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2010] [Accepted: 04/21/2011] [Indexed: 11/18/2022] Open
Abstract
BACKGROUND After ischemia of the CNS, extracellular adenosine 5'-triphosphate (ATP) can reach high concentrations due to cell damage and subsequent increase of membrane permeability. ATP may cause cellular degeneration and death, mediated by P2X and P2Y receptors. METHODOLOGY/PRINCIPAL FINDINGS The effects of inhibition of P2 receptors by pyridoxalphosphate-6-azophenyl-2',4'-disulphonic acid (PPADS) on electrophysiological, functional and morphological alterations in an ischemia model with permanent middle cerebral artery occlusion (MCAO) were investigated up to day 28. Spontaneously hypertensive rats received PPADS or vehicle intracerebroventricularly 15 minutes prior MCAO for up to 7 days. The functional recovery monitored by qEEG was improved by PPADS indicated by an accelerated recovery of ischemia-induced qEEG changes in the delta and alpha frequency bands along with a faster and sustained recovery of motor impairments. Whereas the functional improvements by PPADS were persistent at day 28, the infarct volume measured by magnetic resonance imaging and the amount of TUNEL-positive cells were significantly reduced by PPADS only until day 7. Further, by immunohistochemistry and confocal laser scanning microscopy, we identified both neurons and astrocytes as TUNEL-positive after MCAO. CONCLUSION The persistent beneficial effect of PPADS on the functional parameters without differences in the late (day 28) infarct size and apoptosis suggests that the early inhibition of P2 receptors might be favourable for the maintenance or early reconstruction of neuronal connectivity in the periinfarct area after ischemic incidents.
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Affiliation(s)
- Alexandra B. Lämmer
- Department of Neurology,
Friedrich-Alexander-University of Erlangen-Nuremberg, Erlangen,
Germany
- Department of Neurology, University of
Leipzig, Leipzig, Germany
| | - Alexander Beck
- Department of Neurology,
Friedrich-Alexander-University of Erlangen-Nuremberg, Erlangen,
Germany
| | - Benjamin Grummich
- Rudolf-Boehm-Institute of Pharmacology and
Toxicology, University of Leipzig, Leipzig, Germany
| | - Annette Förschler
- Department of Diagnostic and Interventional
Radiology, University of Leipzig, Leipzig, Germany
| | - Thomas Krügel
- Rudolf-Boehm-Institute of Pharmacology and
Toxicology, University of Leipzig, Leipzig, Germany
| | - Thomas Kahn
- Department of Diagnostic and Interventional
Radiology, University of Leipzig, Leipzig, Germany
| | | | - Peter Illes
- Rudolf-Boehm-Institute of Pharmacology and
Toxicology, University of Leipzig, Leipzig, Germany
| | - Heike Franke
- Rudolf-Boehm-Institute of Pharmacology and
Toxicology, University of Leipzig, Leipzig, Germany
| | - Ute Krügel
- Rudolf-Boehm-Institute of Pharmacology and
Toxicology, University of Leipzig, Leipzig, Germany
- * E-mail:
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138
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Cloostermans MC, de Vos CC, van Putten MJAM. A novel approach for computer assisted EEG monitoring in the adult ICU. Clin Neurophysiol 2011; 122:2100-9. [PMID: 21474372 DOI: 10.1016/j.clinph.2011.02.035] [Citation(s) in RCA: 43] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2010] [Revised: 01/20/2011] [Accepted: 02/17/2011] [Indexed: 11/26/2022]
Abstract
OBJECTIVE The implementation of a computer assisted system for real-time classification of the electroencephalogram (EEG) in critically ill patients. METHODS Eight quantitative features were extracted from the raw EEG and combined into a single classifier. The system was trained with 41 EEG recordings and subsequently evaluated using an additional 20 recordings. Through visual analysis, each recording was assigned to one of the following categories: normal, iso-electric, low voltage, burst suppression, slowing, and EEGs with generalized periodic discharges or seizure activity. RESULTS 36 (88%) recordings from the training set and 17 (85%) recordings from the test set were classified correctly. A user interface was developed to present both trend-curves and a diagnostic output in text form. Implementation in a dedicated EEG monitor allowed real-time analysis in the intensive care unit (ICU) during pilot measurements in four patients. CONCLUSIONS We present the first results from a computer assisted EEG interpretation system, based on a combination of eight quantitative features. Our system provided an initial, reasonably accurate interpretation by non-experts of the most common EEG patterns observed in neurological patients in the adult ICU. SIGNIFICANCE Computer assisted EEG monitoring may improve early detection of seizure activity and ischemia in critically ill patients.
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Affiliation(s)
- Marleen C Cloostermans
- Department of Neurology and Clinical Neurophysiology, Medisch Spectrum Twente, Enschede, The Netherlands.
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Finnigan S, Robertson IH. Resting EEG theta power correlates with cognitive performance in healthy older adults. Psychophysiology 2011; 48:1083-7. [DOI: 10.1111/j.1469-8986.2010.01173.x] [Citation(s) in RCA: 102] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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140
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Impaired neuronal synchrony after focal ischemic stroke in elderly patients. Clin Neurophysiol 2011; 122:21-6. [DOI: 10.1016/j.clinph.2010.06.003] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2009] [Revised: 06/02/2010] [Accepted: 06/04/2010] [Indexed: 11/18/2022]
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Kara I, Nurten A, Aydin M, Özkök E, Özen I, Özerman B, Tuna S, Karamürsel S. Ischemia/reperfusion in rat: antioxidative effects of enoant on EEG, oxidative stress and inflammation. Brain Inj 2010; 25:113-26. [PMID: 21117911 DOI: 10.3109/02699052.2010.531688] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
PRIMARY OBJECTIVE The present study was undertaken to evaluate whether enoant, which is rich in polyphenols, has any effect on electroencephalogram (EEG), oxidative stress and inflammation in ischemia/reperfusion (I/R) injury. METHODS Ischemia was induced by 2-hour occlusion of bilateral common carotid artery. Animals orally received enoant. Group 1 was the ischemic control group. Group 2 was treated with enoant of 1.25 g kg⁻¹ per day for 15 days after I/R. Group 3 received the same concentration of enoant as in group 2 for 15 days before and after I/R. Group 4 was the sham operation group. EEG activities were recorded and the levels of TNF-α, IL-1β and IL-6, TBARS and GSH were measured in the whole brain homogenate. RESULTS There were significant changes in EEG activity in groups treated with enoant either before or after ischemia when compared with their basal EEG values. TNF-α, IL-6 and IL-1β levels were significantly increased after I/R. GSH levels in group 3 treated with enoant in both pre- and post-ischemic periods were significantly increased and TBARS concentration was decreased compared with the ischemic group. CONCLUSION The findings support that both pre-ischemic and post-ischemic administrations of enoant might produce neuroprotective action against cerebral ischemia.
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Affiliation(s)
- Ihsan Kara
- Department of Neuroscience, The Institute of Experimental Medicine, Istanbul University, Istanbul, Turkey
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142
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Ferre A, Ribó M, Rodríguez-Luna D, Romero O, Sampol G, Molina CA, Álvarez-Sabin J. Strokes and their relationship with sleep and sleep disorders. Neurologia 2010; 28:103-18. [PMID: 21163212 DOI: 10.1016/j.nrl.2010.09.016] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2010] [Revised: 08/26/2010] [Accepted: 09/18/2010] [Indexed: 10/18/2022] Open
Abstract
INTRODUCTION In the current population, strokes are one of the most important causes of morbidity and mortality, to which new risk factors are increasingly being attributed. Of late, there is increased interest in the relationship between sleep disorders and strokes as regards risk and prognosis. DEVELOPMENT This article presents the changes in sleep architecture and brain activity in stroke patients, as well as the interaction between stroke and sleep disorders, including those which may also influence the outcome and recovery from strokes. The different treatments discussed in the literature are also reviewed, as correct treatment of such sleep disorders may not only improve quality of life and reduce after-effects, but can also increase life expectancy. CONCLUSIONS Sleep disorders are becoming increasingly associated with stroke. In addition to being a risk factor, they can also interfere in the outcome and recovery of stroke patients. This article aims to present an exhaustive and current review on strokes and their relationship with sleep alterations and sleep disorders.
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Affiliation(s)
- A Ferre
- Servicio de Neurofisiología Clínica, Unidad de Sueño, Hospital Universitario de la Vall d'Hebron, Barcelona, España.
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143
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Sheorajpanday RVA, Nagels G, Weeren AJTM, van Putten MJAM, De Deyn PP. Quantitative EEG in ischemic stroke: correlation with functional status after 6 months. Clin Neurophysiol 2010; 122:874-83. [PMID: 20961806 DOI: 10.1016/j.clinph.2010.07.028] [Citation(s) in RCA: 87] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2010] [Revised: 06/21/2010] [Accepted: 07/14/2010] [Indexed: 11/16/2022]
Abstract
OBJECTIVE Stroke is a major cause of adult-onset disability and dependency. We investigated whether EEG parameters are of prognostic value for functional outcome 6 months after ischemic stroke. METHODS One-hundred and ten patients presenting with acute ischemic stroke and persistent neurological deficits at EEG recording were incrementally included. Clinical characteristics, volume of ischemia and EEG parameters were correlated with functional outcome assessed with the modified Rankin Scale (mRS) score. Predictive values for disability, dependency and death were calculated using receiver operating characteristic (ROC) curves and logistic regression modeling. RESULTS The EEG pairwise derived Brain Symmetry Index (pdBSI) and (delta+theta)/(alpha+beta) ratio (DTABR) were significantly correlated with the modified Rankin Scale (mRS) score at month 6 (Spearman ρ=0.46 and ρ=0.47, respectively, p<0.0005 for both). NIHSS (OR 1.15, 95% CI 1.04-1.27, p=0.005) and pdBSI (OR 4.07, 95% CI 1.32-12.58, p=0.015) were independently associated with disability 6 months after stroke. Dependency was independently indicated by NIHSS (OR 1.22, 95% CI 1.09-1.37, p<0.0005) and DTABR (OR 2.25, 95% CI 1.16-4.37, p=0.016). Six month mortality was independently indicated by age at stroke onset (OR 1.18, 95% CI 1.05-1.32, p=0.007), NIHSS (OR 1.11, 95% CI 1.03-1.21, p=0.009) and DTABR (OR 2.04, 95% CI 1.08-3.85, p=0.028). CONCLUSIONS EEG in the subacute setting of ischemic stroke may be of prognostic value for disability, dependency and death after 6 months. SIGNIFICANCE Early prognostication of functional outcome after stroke is relevant to efficient rehabilitation management to enhance recovery and minimize long-term disability.
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Abstract
INTRODUCTION Continuous EEG provides the unique possibility to monitor neuronal function non-invasively. In our pilot study, we evaluated EEG spectral power during spontaneous drops in cerebral perfusion pressure (CPP) in deeply sedated and mechanically ventilated patients with severe stroke. We aimed to identify parameters that may be used for continuous monitoring even in patients with a burst-suppression baseline EEG pattern. METHODS Twenty ventilated and sedated patients with severe hemorrhagic or ischemic stroke underwent continuous EEG monitoring with synchronous CPP recording. RESULTS EEG monitoring duration was 83.9 hours on average per patient. Spectral power of EEG during drops of CPP was compared with epochs during normal CPP under the same levels of sedation. We found a significant decrease in faster EEG activity (3.5-20.7 Hz) during phases of low CPP (unaffected hemisphere P < 0.01, affected hemisphere P < 0.01, both P < 0.01). CONCLUSION Despite considerable changes in baseline activity due to deep sedation and severe brain injury, we found evidence for disturbed neuronal function during drops in CPP. Thus, continuous EEG monitoring may add clinically relevant information on neuronal function in the setting of multimodality brain monitoring. Further studies are needed to implement real-time data analysis in the ICU setting.
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145
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Zhu C, Guo X, Wu W, Jin Z, Qiu Y, Zhu Y, Tong S. Influence of subcortical ischemic stroke on cortical neural network. ANNUAL INTERNATIONAL CONFERENCE OF THE IEEE ENGINEERING IN MEDICINE AND BIOLOGY SOCIETY. IEEE ENGINEERING IN MEDICINE AND BIOLOGY SOCIETY. ANNUAL INTERNATIONAL CONFERENCE 2010; 2009:6818-21. [PMID: 19964912 DOI: 10.1109/iembs.2009.5334483] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
Stroke has remained as a leading cause of death and neurological disability worldwide in the past decades. Previous structural and functional studies reported little information regarding cortical neural network after stroke. Using the causality measure based on multi-channel electroencephalograph (EEG), i.e. partial directed coherence (PDC) in this paper, we investigated the different network patterns involved in pre-motor and parietal areas (F3, F4, C3, C4, P3 and P4) in three groups of patients who suffered unilateral or bilateral hemispheric stroke in basal ganglia with extension into corona radiate. Compared with the results in the control group, stroke patients showed: 1) more vulnerable long-distance intra- and inter-hemispheric interactions due to the ischemic injury; 2) strengthened short-distance interactions between the central areas in the intact hemisphere with the injured counterpart, which implied a functional compensation after unilateral stroke; 3) more suppression of cortical connections after bilateral hemispheric stroke than those with unilateral stroke. Causal interdependence by PDC analysis provides a new insight of cortical functional network following stroke.
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Affiliation(s)
- Chengyu Zhu
- Department of Biomedical Engineering, Shanghai Jiao Tong University, Shanghai 200240, P.R. China
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146
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Logvinova AV, Litt L, Young WL, Lee CZ. Anesthetic concerns in patients with known cerebrovascular insufficiency. Anesthesiol Clin 2010; 28:1-12. [PMID: 20400036 DOI: 10.1016/j.anclin.2010.01.007] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/29/2023]
Abstract
This review outlines the perioperative anesthesia considerations of patients with vascular diseases of the central nervous system, including occlusive cerebrovascular diseases with ischemic risks and various cerebrovascular malformations with hemorrhagic potential. The discussion emphasizes perioperative management strategies to prevent complications and minimize their effects if they occur. Planning the anesthetic and perioperative management is predicated on understanding the goals of the therapeutic intervention and anticipating potential problems.
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Affiliation(s)
- Anna V Logvinova
- Department of Anesthesia and Perioperative Care, University of California, San Francisco, 1001 Potrero Avenue, San Francisco, CA 94110, USA
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147
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Sheorajpanday RVA, Nagels G, Weeren AJTM, De Surgeloose D, De Deyn PP. Additional value of quantitative EEG in acute anterior circulation syndrome of presumed ischemic origin. Clin Neurophysiol 2010; 121:1719-25. [PMID: 20181521 DOI: 10.1016/j.clinph.2009.10.037] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2009] [Revised: 09/23/2009] [Accepted: 10/12/2009] [Indexed: 11/24/2022]
Abstract
OBJECTIVE The clinical course of acute stroke can be highly variable and for effective management outcome prediction needs to be refined. We investigated whether EEG parameters are of additional diagnostic and prognostic value in the early phase of acute ischemic anterior circulation stroke. METHODS Ninety-four patients presenting with acute anterior circulation syndrome (ACS) of presumed ischemic origin were incrementally included. Clinical characteristics were correlated with volume of ischemia and EEG parameters. Predictive values for definite stroke, early neurological deterioration, spontaneous early neurological improvement and death within 1 week after ACS were calculated using ROC curves and logistic regression modelling. RESULTS In patients with normal or near normal NIHSS score of 0 or 1, the pairwise derived brain symmetry index (pdBSI) was an independent predictor for definite stroke displaying an overall accuracy of 80%. Early neurological deterioration was independently predicted by pdBSI with a correct classification rate of 95%. In ROC analysis, death was predicted by pdBSI with overall accuracy of 97%. Spontaneous neurological improvement was independently predicted by the delta+theta/alpha+beta - ratio with overall accuracy of 75%. Small-vessel stroke was independently predicted by pdBSI with a correct classification rate of 92%. CONCLUSIONS EEG may be of prognostic value for spontaneous neurological improvement, early neurological deterioration and death in the acute setting of acute anterior circulation syndrome of presumed ischemic origin. SIGNIFICANCE These findings may have an impact on stroke care.
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148
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Abstract
PURPOSE OF REVIEW Continuous electroencephalography (cEEG) is being used more frequently in intensive care units to detect epileptic activity and ischemia. This review analyzes clinical applications and limitations of cEEG as a routine neuromonitoring tool. RECENT FINDINGS cEEG is primarily used to detect nonconvulsive seizures, which are frequent and possibly associated with harm. Cerebral ischemia, such as that from vasospasm after subarachnoid hemorrhage, can be detected earlier by EEG and quantitative EEG (qEEG). Highly skilled technicians and subspecialty-trained physicians are needed to generate good quality EEG and to interpret these data. qEEG allows more efficient interpretation of large amounts of EEG and may trigger prespecified alarms. Currently, there is little high-quality data on cEEG to define indications, cost-saving potential, and impact on outcome. A few studies have demonstrated how cEEG can be integrated into multimodality brain monitoring of severely brain-injured patients. SUMMARY cEEG should be considered as an integral part of multimodality monitoring of the injured brain, particularly in patients at risk for nonconvulsive seizure or ischemia. Automated alarms may help establish cEEG monitoring as an integral part of brain monitoring. All neurological ICUs that routinely care for patients with refractory status epilepticus should have the capability to perform cEEG monitoring. Further research determining the impact on outcome and making EEG monitoring more user friendly may help move this technique out of the subspecialized ICU setting into the general ICU environment. In the future, it may be possible to use specific EEG parameters as endpoints for therapeutic interventions.
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149
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Bjørk MH, Stovner LJ, Engstrøm M, Stjern M, Hagen K, Sand T. Interictal quantitative EEG in migraine: a blinded controlled study. J Headache Pain 2009; 10:331-9. [PMID: 19705061 PMCID: PMC3452093 DOI: 10.1007/s10194-009-0140-4] [Citation(s) in RCA: 63] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2009] [Accepted: 07/06/2009] [Indexed: 01/01/2023] Open
Abstract
Abnormal electroencephalography (EEG) in migraineurs has been reported in several studies. However, few have evaluated EEG findings in migraineurs during a time period when neither the last attack nor the next attack may interact with the results. We, therefore, compared interictal EEG in migraineurs and headache-free subjects with a design controlled for interference by pre-ictal changes. Pre-ictal EEG findings in the painful cranial side during the next attack after registration were also investigated. Correlations between clinical variables and EEG are reported as well. Interictal EEGs from 33 migraineurs (6 with and 27 without aura) and 31 controls were compared. Absolute power, asymmetry and relative power were studied for delta, theta and alpha frequency bands in parieto-occipital, temporal and fronto-central areas. EEG variables were correlated to attack frequency, headache duration, attack duration, pain intensity, photo- and phonophobia. Compared with controls, migraineurs had increased relative theta power in all cortical regions and increased delta activity in the painful fronto-central region. Absolute power and asymmetry were similar among groups. In age-adjusted analyses, headache intensity correlated with increased delta activity. In this blinded controlled study, we found globally increased relative theta activity in migraineurs. A slight interictal brain dysfunction is probably present between attacks.
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Affiliation(s)
- Marte Helene Bjørk
- Department of Neuroscience, Norwegian University of Science and Technology (NTNU), MTFS, 7489, Trondheim, Norway.
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150
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Sakamoto S, Tanaka H, Tsuyuguchi N, Terakawa Y, Ohata K, Inoue Y, Miki Y, Hara M, Takahashi Y, Nitta K, Sawa H, Satone A, Ide W, Hashimoto I, Kamada H. Quantitative imaging of spontaneous neuromagnetic activity for assessing cerebral ischemia using sLORETA-qm. Neuroimage 2009; 49:488-97. [PMID: 19632340 DOI: 10.1016/j.neuroimage.2009.07.039] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2009] [Revised: 07/15/2009] [Accepted: 07/20/2009] [Indexed: 10/20/2022] Open
Abstract
To image cerebral neural activity in ischemic areas, we proposed a novel technique to analyze spontaneous neuromagnetic fields based on standardized low-resolution brain electromagnetic tomography modified for a quantifiable method (sLORETA-qm). Using a 160-channel whole-head-type magnetoencephalographic system, cerebral magnetic fields were obtained pre- and postoperatively from 5 patients with unilateral internal carotid artery occlusive disease and 16 age-matched healthy volunteers. For quantitative imaging, voxel-based time-averaged intensities of slow waves in 4 frequency bands (0.3-2 Hz, 2-4 Hz, 4-6 Hz and 6-8 Hz) were obtained by the proposed technique based on sLORETA-qm. Positron emission tomography with (15)O gas inhalation ((15)O-PET) was also performed in these patients to evaluate cerebral blood flow and metabolism. In all 5 patients, slow waves in every frequency band were distributed in the area of cerebrovascular insufficiency, as confirmed by (15)O-PET preoperatively. In 4 patients, slow-wave intensities in theta bands (4-6 Hz, 6-8 Hz) decreased postoperatively along with improvements in cerebral blood flow and metabolism, whereas delta bands (0.3-2 Hz, 2-4 Hz) showed no significant differences between pre- and postoperatively. One patient with deterioration of cerebral infarction after surgery showed marked increases in slow-wave intensities in delta bands (0.3-2 Hz, 2-4 Hz) postoperatively, with distribution close to the infarct region. The proposed quantitative imaging of spontaneous neuromagnetic fields enabled clear visualization and alternations of cerebral neural conditions in the ischemic area. This technique may offer a novel, non-invasive method for identifying cerebral ischemia, although further studies in a larger number of patients are warranted.
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