Arnold J. Wilkins
- Published in print:
- 1995
- Published Online:
- January 2008
- ISBN:
- 9780198521747
- eISBN:
- 9780191706691
- Item type:
- book
- Publisher:
- Oxford University Press
- DOI:
- 10.1093/acprof:oso/9780198521747.001.0001
- Subject:
- Psychology, Cognitive Neuroscience
This book provides the first general neurological theory of visual discomfort. The theory attributes the experience of visual discomfort to the strong physiological excitation that certain visual ...
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This book provides the first general neurological theory of visual discomfort. The theory attributes the experience of visual discomfort to the strong physiological excitation that certain visual stimuli give rise to, and the effects of such excitation when the visual cortex of the brain is hyperexcitable. Cortical hyperexcitability is now thought to occur in migraine as well as in epilepsy and other neurological disorders in which seizures are relatively common, such as autism. The theory explains why visual discomfort is experienced from flicker and from striped patterns; why fluorescent lighting and visual display terminals cause headaches; and why reading can give you tired eyes. The theory is based on the observation that people find certain specific visual patterns uncomfortable to look at, and that these same patterns can induce seizures in patients with photosensitive epilepsy. The spatial and temporal characteristics of the unpleasant visual stimuli are described in detail. The theory is applied to the design of lighting, the design of text, and indeed to design more generally. The use of ophthalmic tints to treat visual stress is introduced, and techniques for its prevention are discussed.Less
This book provides the first general neurological theory of visual discomfort. The theory attributes the experience of visual discomfort to the strong physiological excitation that certain visual stimuli give rise to, and the effects of such excitation when the visual cortex of the brain is hyperexcitable. Cortical hyperexcitability is now thought to occur in migraine as well as in epilepsy and other neurological disorders in which seizures are relatively common, such as autism. The theory explains why visual discomfort is experienced from flicker and from striped patterns; why fluorescent lighting and visual display terminals cause headaches; and why reading can give you tired eyes. The theory is based on the observation that people find certain specific visual patterns uncomfortable to look at, and that these same patterns can induce seizures in patients with photosensitive epilepsy. The spatial and temporal characteristics of the unpleasant visual stimuli are described in detail. The theory is applied to the design of lighting, the design of text, and indeed to design more generally. The use of ophthalmic tints to treat visual stress is introduced, and techniques for its prevention are discussed.
Aimee F. Luat and Harry T. Chugani
- Published in print:
- 2010
- Published Online:
- January 2011
- ISBN:
- 9780195342765
- eISBN:
- 9780199863617
- Item type:
- chapter
- Publisher:
- Oxford University Press
- DOI:
- 10.1093/acprof:oso/9780195342765.003.0010
- Subject:
- Neuroscience, Disorders of the Nervous System
The advent of positron emission tomography (PET) scanning using 2-deoxy-2-[18F] fluoro-D-glucose (FDG) has significantly improved our understanding of the pathomechanisms of different pediatric ...
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The advent of positron emission tomography (PET) scanning using 2-deoxy-2-[18F] fluoro-D-glucose (FDG) has significantly improved our understanding of the pathomechanisms of different pediatric epilepsy syndromes. Furthermore, it has dramatically altered our management approach of certain intractable epilepsy syndromes, such as infantile spasms. Glucose metabolism PET scanning has assumed an important role not only in the identification and localization of epileptogenic cortex, but also in assessing the functional integrity of the entire cerebral hemisphere, thereby providing useful diagnostic and prognostic information, including the suggestion of underlying neurometabolic or neurogenetic disorders which may preclude epilepsy surgery. In certain progressive epilepsy syndromes like Rasmussen encephalitis and Sturge-Weber syndrome, PET scanning also may be used to assess disease progression. In this chapter, we discuss the relevant role of brain glucose metabolism PET in understanding the pathogenesis of pediatric epilepsy syndromes with regard to diagnosis and treatment.Less
The advent of positron emission tomography (PET) scanning using 2-deoxy-2-[18F] fluoro-D-glucose (FDG) has significantly improved our understanding of the pathomechanisms of different pediatric epilepsy syndromes. Furthermore, it has dramatically altered our management approach of certain intractable epilepsy syndromes, such as infantile spasms. Glucose metabolism PET scanning has assumed an important role not only in the identification and localization of epileptogenic cortex, but also in assessing the functional integrity of the entire cerebral hemisphere, thereby providing useful diagnostic and prognostic information, including the suggestion of underlying neurometabolic or neurogenetic disorders which may preclude epilepsy surgery. In certain progressive epilepsy syndromes like Rasmussen encephalitis and Sturge-Weber syndrome, PET scanning also may be used to assess disease progression. In this chapter, we discuss the relevant role of brain glucose metabolism PET in understanding the pathogenesis of pediatric epilepsy syndromes with regard to diagnosis and treatment.
Thomas R. Henry
- Published in print:
- 2010
- Published Online:
- January 2011
- ISBN:
- 9780195342765
- eISBN:
- 9780199863617
- Item type:
- chapter
- Publisher:
- Oxford University Press
- DOI:
- 10.1093/acprof:oso/9780195342765.003.0008
- Subject:
- Neuroscience, Disorders of the Nervous System
Epilepsy poses unique problems and opportunities for cerebral imaging with positron emission tomography (PET). After reviewing PET methods in epilepsy applications, this chapter addresses the ...
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Epilepsy poses unique problems and opportunities for cerebral imaging with positron emission tomography (PET). After reviewing PET methods in epilepsy applications, this chapter addresses the extensive applications of 2-[18F]fluoro-2-deoxyglucose (FDG) mapping of glucose metabolism in temporal lobe epilepsy (TLE). The widespread zone of interictal metabolic dysfunction is highly associated with sites of ictal onset and propagation in TLE. Interictal FDG PET is used in correlation with ictal electrophysiologic and structural magnetic resonance findings for the purposes of: 1) increasing certainty that the ictal onset zone has been accurately determined by noninvasive studies prior to therapeutic temporal lobe ablation, 2) optimizing selection of intracranial electrode placement sites for ictal monitoring, and 3) prognostication for epilepsy surgery with regard to seizure control.Less
Epilepsy poses unique problems and opportunities for cerebral imaging with positron emission tomography (PET). After reviewing PET methods in epilepsy applications, this chapter addresses the extensive applications of 2-[18F]fluoro-2-deoxyglucose (FDG) mapping of glucose metabolism in temporal lobe epilepsy (TLE). The widespread zone of interictal metabolic dysfunction is highly associated with sites of ictal onset and propagation in TLE. Interictal FDG PET is used in correlation with ictal electrophysiologic and structural magnetic resonance findings for the purposes of: 1) increasing certainty that the ictal onset zone has been accurately determined by noninvasive studies prior to therapeutic temporal lobe ablation, 2) optimizing selection of intracranial electrode placement sites for ictal monitoring, and 3) prognostication for epilepsy surgery with regard to seizure control.
R. Edward Hogan, Elson L. So, and Terence J. O’Brien
- Published in print:
- 2010
- Published Online:
- January 2011
- ISBN:
- 9780195342765
- eISBN:
- 9780199863617
- Item type:
- chapter
- Publisher:
- Oxford University Press
- DOI:
- 10.1093/acprof:oso/9780195342765.003.0014
- Subject:
- Neuroscience, Disorders of the Nervous System
There is a long history of the association of cerebral blood flow changes during epileptic seizures. The advent of radiopharmaceutical agents to measure cerebral perfusion during seizures has enabled ...
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There is a long history of the association of cerebral blood flow changes during epileptic seizures. The advent of radiopharmaceutical agents to measure cerebral perfusion during seizures has enabled a clinically feasible way to measure ictal cerebral blood flow changes. Studies show that ictal SPECT findings, especially with the use subtraction ictal SPECT techniques, correlate well with other measures of seizure onset and the epileptogenic zone. Ictal SPECT studies are also helpful in predicting outcome after epilepsy surgery. Applications of parametric mapping using ictal SPECT studies have helped to further define regions of perfusion changes in groups of patients with specific regions of seizure onset. Application of parametric mapping techniques in subjects with temporal lobe epilepsy has yielded interesting common patterns of ictal hyperperfusion and hypoperfusion. These studies help define expected patterns of ictal perfusion changes in TLE, as well as shed light on the associated pathophysiology of aspects of ictal semiology, such as the associated changes in consciousness during temporal lobe epileptic seizures.Less
There is a long history of the association of cerebral blood flow changes during epileptic seizures. The advent of radiopharmaceutical agents to measure cerebral perfusion during seizures has enabled a clinically feasible way to measure ictal cerebral blood flow changes. Studies show that ictal SPECT findings, especially with the use subtraction ictal SPECT techniques, correlate well with other measures of seizure onset and the epileptogenic zone. Ictal SPECT studies are also helpful in predicting outcome after epilepsy surgery. Applications of parametric mapping using ictal SPECT studies have helped to further define regions of perfusion changes in groups of patients with specific regions of seizure onset. Application of parametric mapping techniques in subjects with temporal lobe epilepsy has yielded interesting common patterns of ictal hyperperfusion and hypoperfusion. These studies help define expected patterns of ictal perfusion changes in TLE, as well as shed light on the associated pathophysiology of aspects of ictal semiology, such as the associated changes in consciousness during temporal lobe epileptic seizures.
Roger Traub, MD and Miles Whittington, PhD
- Published in print:
- 2010
- Published Online:
- May 2010
- ISBN:
- 9780195342796
- eISBN:
- 9780199776276
- Item type:
- book
- Publisher:
- Oxford University Press
- DOI:
- 10.1093/acprof:oso/9780195342796.001.0001
- Subject:
- Neuroscience, Molecular and Cellular Systems, Development
This book reviews a number of clinical neuropsychiatric conditions in which brain oscillations play an essential role. It discusses how the intrinsic properties of neurons, and the interactions ...
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This book reviews a number of clinical neuropsychiatric conditions in which brain oscillations play an essential role. It discusses how the intrinsic properties of neurons, and the interactions between neurons – mediated by both chemical synapses and by gap junctions – can lead to oscillations in populations of cells. The discussion is based largely on data derived from in vitro systems (hippocampus, cerebral and cerebellar cortex) and from network modeling. Finally, the book considers how brain oscillations can provide insight into normal brain function as well as pathophysiology.Less
This book reviews a number of clinical neuropsychiatric conditions in which brain oscillations play an essential role. It discusses how the intrinsic properties of neurons, and the interactions between neurons – mediated by both chemical synapses and by gap junctions – can lead to oscillations in populations of cells. The discussion is based largely on data derived from in vitro systems (hippocampus, cerebral and cerebellar cortex) and from network modeling. Finally, the book considers how brain oscillations can provide insight into normal brain function as well as pathophysiology.
Helmut Laufs and Rachel Thornton
- Published in print:
- 2010
- Published Online:
- May 2010
- ISBN:
- 9780195372731
- eISBN:
- 9780199776283
- Item type:
- chapter
- Publisher:
- Oxford University Press
- DOI:
- 10.1093/acprof:oso/9780195372731.003.0018
- Subject:
- Neuroscience, Techniques
This chapter reviews the clinical application of electroencephalography/functional magnetic resonance imaging (EEG-fMRI) to epilepsy at two levels. Initially, it summarizes the body of primary ...
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This chapter reviews the clinical application of electroencephalography/functional magnetic resonance imaging (EEG-fMRI) to epilepsy at two levels. Initially, it summarizes the body of primary EEG/fMRI patient studies in epilepsy, focusing on the most comprehensive and up-to-date literature available. It then addresses the question of what researchers have learned about the potentials and limitations of this technique, which is still relatively new. Although EEG/fMRI has not lived up to some of its initial expectations, it will be seen that new avenues have appeared. The chapter concludes with a discussion of the immediate next steps, and an outlook on the future of the field.Less
This chapter reviews the clinical application of electroencephalography/functional magnetic resonance imaging (EEG-fMRI) to epilepsy at two levels. Initially, it summarizes the body of primary EEG/fMRI patient studies in epilepsy, focusing on the most comprehensive and up-to-date literature available. It then addresses the question of what researchers have learned about the potentials and limitations of this technique, which is still relatively new. Although EEG/fMRI has not lived up to some of its initial expectations, it will be seen that new avenues have appeared. The chapter concludes with a discussion of the immediate next steps, and an outlook on the future of the field.
Pamela J. Thompson
- Published in print:
- 2010
- Published Online:
- September 2010
- ISBN:
- 9780199234110
- eISBN:
- 9780191594250
- Item type:
- chapter
- Publisher:
- Oxford University Press
- DOI:
- 10.1093/acprof:oso/9780199234110.003.31
- Subject:
- Psychology, Neuropsychology, Clinical Psychology
Clinical neuropsychology is able to make a unique contribution to the management of epilepsy. Neuropsychological deficits are hidden and are often overlooked as most attention is focused on seizures ...
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Clinical neuropsychology is able to make a unique contribution to the management of epilepsy. Neuropsychological deficits are hidden and are often overlooked as most attention is focused on seizures and the need for control. Undetected cognitive deficits will have far reaching negative consequences that extend beyond academic concerns. The longer cognitive problems go unrecognized the worse the outcome and the more difficult it can be to redress the effects. A neuropsychological assessment provides a systematic and standardized record of cognitive strengths and weaknesses and can be vital in the management of the epilepsies. This chapter begins with a general description of epilepsy. It then discusses investigations for epilepsy, treatment, neuropsychological deficits, chronic cognitive disturbance, neuropsychological impact of treatment, psychological disorders associated with epilepsy, and neuropsychological assessment and rehabilitation.Less
Clinical neuropsychology is able to make a unique contribution to the management of epilepsy. Neuropsychological deficits are hidden and are often overlooked as most attention is focused on seizures and the need for control. Undetected cognitive deficits will have far reaching negative consequences that extend beyond academic concerns. The longer cognitive problems go unrecognized the worse the outcome and the more difficult it can be to redress the effects. A neuropsychological assessment provides a systematic and standardized record of cognitive strengths and weaknesses and can be vital in the management of the epilepsies. This chapter begins with a general description of epilepsy. It then discusses investigations for epilepsy, treatment, neuropsychological deficits, chronic cognitive disturbance, neuropsychological impact of treatment, psychological disorders associated with epilepsy, and neuropsychological assessment and rehabilitation.
Harry Chugani, MD (ed.)
- Published in print:
- 2010
- Published Online:
- January 2011
- ISBN:
- 9780195342765
- eISBN:
- 9780199863617
- Item type:
- book
- Publisher:
- Oxford University Press
- DOI:
- 10.1093/acprof:oso/9780195342765.001.0001
- Subject:
- Neuroscience, Disorders of the Nervous System
Perhaps the most important achievements in the field of epileptology in the past two decades have been in the neuroimaging and genetic breakthroughs as applied to patients with epilepsy. Indeed, ...
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Perhaps the most important achievements in the field of epileptology in the past two decades have been in the neuroimaging and genetic breakthroughs as applied to patients with epilepsy. Indeed, neuroimaging has become a vital part in the study of epilepsy, affecting broad aspects of the disorder ranging from diagnosis and classification to treatment and prognosis. Neuroimaging in epilepsy encompasses many different approaches that have reached various levels of expertise across epilepsy centers worldwide. This book discusses every imaging modality used to gather information on epilepsy. Each technique is described by world experts and epilespy centers worldwide.Less
Perhaps the most important achievements in the field of epileptology in the past two decades have been in the neuroimaging and genetic breakthroughs as applied to patients with epilepsy. Indeed, neuroimaging has become a vital part in the study of epilepsy, affecting broad aspects of the disorder ranging from diagnosis and classification to treatment and prognosis. Neuroimaging in epilepsy encompasses many different approaches that have reached various levels of expertise across epilepsy centers worldwide. This book discusses every imaging modality used to gather information on epilepsy. Each technique is described by world experts and epilespy centers worldwide.
Harry T. Chugani and Ajay Kumar
- Published in print:
- 2010
- Published Online:
- January 2011
- ISBN:
- 9780195342765
- eISBN:
- 9780199863617
- Item type:
- chapter
- Publisher:
- Oxford University Press
- DOI:
- 10.1093/acprof:oso/9780195342765.003.0001
- Subject:
- Neuroscience, Disorders of the Nervous System
Imaging modalities have evolved over the last century and different modalities, such as plain X-ray, air or contrast ventriculography, pneumo-encephalography, cerebral angiography, CT scan, MRI, ...
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Imaging modalities have evolved over the last century and different modalities, such as plain X-ray, air or contrast ventriculography, pneumo-encephalography, cerebral angiography, CT scan, MRI, SPECT and PET scanning all have significantly contributed to the diagnosis and management of epilepsy. Whereas some of the initial imaging modalities, such as X-ray, ventriculography and conventional nuclear medicine imaging have become almost redundant and obsolete, the advent and evolution of various high-resolution tomographic neuroimaging during the past several decades has had a significant impact on the understanding, classification and treatment of patients with epilepsy. Cerebral imaging became almost routine following the development and widespread availability of CT scanning, which quickly became the standard of care in the evaluation of patients with epilepsy until outperformed by much higher resolution and greater structural details of MRI. This chapter briefly reviews the historical aspects and evolution of neuroimaging in epilepsy.Less
Imaging modalities have evolved over the last century and different modalities, such as plain X-ray, air or contrast ventriculography, pneumo-encephalography, cerebral angiography, CT scan, MRI, SPECT and PET scanning all have significantly contributed to the diagnosis and management of epilepsy. Whereas some of the initial imaging modalities, such as X-ray, ventriculography and conventional nuclear medicine imaging have become almost redundant and obsolete, the advent and evolution of various high-resolution tomographic neuroimaging during the past several decades has had a significant impact on the understanding, classification and treatment of patients with epilepsy. Cerebral imaging became almost routine following the development and widespread availability of CT scanning, which quickly became the standard of care in the evaluation of patients with epilepsy until outperformed by much higher resolution and greater structural details of MRI. This chapter briefly reviews the historical aspects and evolution of neuroimaging in epilepsy.
Vivek Gupta and Richard A. Bronen
- Published in print:
- 2010
- Published Online:
- January 2011
- ISBN:
- 9780195342765
- eISBN:
- 9780199863617
- Item type:
- chapter
- Publisher:
- Oxford University Press
- DOI:
- 10.1093/acprof:oso/9780195342765.003.0002
- Subject:
- Neuroscience, Disorders of the Nervous System
This chapter discusses the role of magnetic resonance imaging (MRI) in evaluation of seizure disorders and surgical management of refractory epilepsy. An overview of MRI principles and techniques in ...
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This chapter discusses the role of magnetic resonance imaging (MRI) in evaluation of seizure disorders and surgical management of refractory epilepsy. An overview of MRI principles and techniques in detection of epileptogenic abnormalities is presented, with a synopsis of hippocampal sclerosis and other epileptogenic conditions not covered in other chapters. Emphasis is directed towards key concepts pertaining to the scope and indications of MRI in seizure disorders, and integration of structural imaging in the clinical protocol for evaluation and surgical management of epilepsy. The chapter also provides an introduction to advanced applications of MR such as magnetic resonance spectroscopy (MRS), diffusion MRI, and postprocessing methods.Less
This chapter discusses the role of magnetic resonance imaging (MRI) in evaluation of seizure disorders and surgical management of refractory epilepsy. An overview of MRI principles and techniques in detection of epileptogenic abnormalities is presented, with a synopsis of hippocampal sclerosis and other epileptogenic conditions not covered in other chapters. Emphasis is directed towards key concepts pertaining to the scope and indications of MRI in seizure disorders, and integration of structural imaging in the clinical protocol for evaluation and surgical management of epilepsy. The chapter also provides an introduction to advanced applications of MR such as magnetic resonance spectroscopy (MRS), diffusion MRI, and postprocessing methods.
Renzo Guerrini and Francesco Zellini
- Published in print:
- 2010
- Published Online:
- January 2011
- ISBN:
- 9780195342765
- eISBN:
- 9780199863617
- Item type:
- chapter
- Publisher:
- Oxford University Press
- DOI:
- 10.1093/acprof:oso/9780195342765.003.0003
- Subject:
- Neuroscience, Disorders of the Nervous System
Abnormal cortical development represents a major cause of epilepsy. Most such abnormalities may now be detected using magnetic resonance imaging (MRI), although some remain undetectable even with the ...
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Abnormal cortical development represents a major cause of epilepsy. Most such abnormalities may now be detected using magnetic resonance imaging (MRI), although some remain undetectable even with the best imaging techniques. The largest malformation groups express different perturbations of developmental stages and carry a variable propensity to epileptogenesis, preservation or reorganization of cortical function and for atypical cortical organization. Some patients have obvious neurological impairment, whereas others show unexpected deficits that are detectable only by screening. Drug-resistant epilepsy is frequent but might be amenable to surgical treatment in some patients. Surgical planning should be based on assessments of structural, and if possible functional imaging, as well as clinical and electrographic features. Most malformations of cortical development are caused by genetic defects and brain imaging has been instrumental to the identification of causative genes. Nowadays many patients with epilepsy due to malformations of cortical development can be offered genetic counseling.Less
Abnormal cortical development represents a major cause of epilepsy. Most such abnormalities may now be detected using magnetic resonance imaging (MRI), although some remain undetectable even with the best imaging techniques. The largest malformation groups express different perturbations of developmental stages and carry a variable propensity to epileptogenesis, preservation or reorganization of cortical function and for atypical cortical organization. Some patients have obvious neurological impairment, whereas others show unexpected deficits that are detectable only by screening. Drug-resistant epilepsy is frequent but might be amenable to surgical treatment in some patients. Surgical planning should be based on assessments of structural, and if possible functional imaging, as well as clinical and electrographic features. Most malformations of cortical development are caused by genetic defects and brain imaging has been instrumental to the identification of causative genes. Nowadays many patients with epilepsy due to malformations of cortical development can be offered genetic counseling.
William Davis Gaillard
- Published in print:
- 2010
- Published Online:
- January 2011
- ISBN:
- 9780195342765
- eISBN:
- 9780199863617
- Item type:
- chapter
- Publisher:
- Oxford University Press
- DOI:
- 10.1093/acprof:oso/9780195342765.003.0005
- Subject:
- Neuroscience, Disorders of the Nervous System
Functional Imaging with MRI using BOLD techniques plays an increasing role in clinical practice. fMRI may be used for interictal source localization but is more commonly used to identify eloquent ...
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Functional Imaging with MRI using BOLD techniques plays an increasing role in clinical practice. fMRI may be used for interictal source localization but is more commonly used to identify eloquent areas to be spared during epilepsy surgery. fMRI is used to identify primary sensory cortex –visual, sensory, and auditory and to identify motor cortex. There are several language paradigms that may be used to identify frontal (“expressive”) and temporal (“receptive”) speech. These methods have excellent agreement with Wada and predict post operative naming outcomes. There are circumstances in which fMRI is not helpful as the BOLD response may be disrupted by several pathological processes. fMRI memory tasks have good agreement with Wada, demonstrate material specificity, show functional capacity to be more important than functional reserve, and may predict outcomes of specific memory tasks.Less
Functional Imaging with MRI using BOLD techniques plays an increasing role in clinical practice. fMRI may be used for interictal source localization but is more commonly used to identify eloquent areas to be spared during epilepsy surgery. fMRI is used to identify primary sensory cortex –visual, sensory, and auditory and to identify motor cortex. There are several language paradigms that may be used to identify frontal (“expressive”) and temporal (“receptive”) speech. These methods have excellent agreement with Wada and predict post operative naming outcomes. There are circumstances in which fMRI is not helpful as the BOLD response may be disrupted by several pathological processes. fMRI memory tasks have good agreement with Wada, demonstrate material specificity, show functional capacity to be more important than functional reserve, and may predict outcomes of specific memory tasks.
Rajkumar Munian Govindan and Harry T. Chugani
- Published in print:
- 2010
- Published Online:
- January 2011
- ISBN:
- 9780195342765
- eISBN:
- 9780199863617
- Item type:
- chapter
- Publisher:
- Oxford University Press
- DOI:
- 10.1093/acprof:oso/9780195342765.003.0006
- Subject:
- Neuroscience, Disorders of the Nervous System
Diffusion MRI facilitates the measurement of water diffusion in specific spatial directions and is highly sensitive to microstructural changes in neural tissue. This chapter provides an overview of ...
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Diffusion MRI facilitates the measurement of water diffusion in specific spatial directions and is highly sensitive to microstructural changes in neural tissue. This chapter provides an overview of diffusion MRI and its application in studying the epileptic brain. Using this imaging technique, one is able to study the evolution of subtle microstructural changes in the epileptic focus and in epileptic networks. The directional diffusion information also allows one to perform a virtual construction of white matter pathways in order to evaluate the diffusion changes and morphological characteristics of specific white matter tracts. Using this technique, future studies could further elucidate the role of seizures in causing tissue damage, and the possible relations between microstructural abnormalities and neuro-cognitive decline seen in patients with chronic epilepsy.Less
Diffusion MRI facilitates the measurement of water diffusion in specific spatial directions and is highly sensitive to microstructural changes in neural tissue. This chapter provides an overview of diffusion MRI and its application in studying the epileptic brain. Using this imaging technique, one is able to study the evolution of subtle microstructural changes in the epileptic focus and in epileptic networks. The directional diffusion information also allows one to perform a virtual construction of white matter pathways in order to evaluate the diffusion changes and morphological characteristics of specific white matter tracts. Using this technique, future studies could further elucidate the role of seizures in causing tissue damage, and the possible relations between microstructural abnormalities and neuro-cognitive decline seen in patients with chronic epilepsy.
Robert C. Knowlton and Lawrence W. Ver Hoef
- Published in print:
- 2010
- Published Online:
- January 2011
- ISBN:
- 9780195342765
- eISBN:
- 9780199863617
- Item type:
- chapter
- Publisher:
- Oxford University Press
- DOI:
- 10.1093/acprof:oso/9780195342765.003.0007
- Subject:
- Neuroscience, Disorders of the Nervous System
As long as valid assumptions can be made about a focal source, MEG can transform the challenge of EEG based 2D inference of lateralization or regional localization to 3D sublobar indication of ...
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As long as valid assumptions can be made about a focal source, MEG can transform the challenge of EEG based 2D inference of lateralization or regional localization to 3D sublobar indication of epilepsy-related spike generators. As such MEG spike source imaging provides a unique tool for targeting epileptogenic tissue for the surgical treatment of epilepsy. This information can be particularly valuable for patients with neocortical epilepsy in whom intracranial EEG (icEEG) investigations are commonly necessary. MEG localization of spikes may provide more accurate electrode sampling of the cortex responsible for seizures, and as a result, increase epilepsy localization and surgical resection accuracy. Combined with mapping of eloquent cortical function, MEG can play a role in multiple aspects of the preoperative (non-invasive) decision-making—potential to improve (1) patient selection, (2) ICEEG yield, and (3) increase the net number of seizure-free outcomes. Work remains to determine the validity of various analysis methods (stratified on different types of spike sources), and the cost effectiveness of MEG in epilepsy surgery, but it can be concluded that any patients able to proced to surgery that otherwise would not without MEG would contribute evidence to added clinical utility even if the cure rate is unchanged.Less
As long as valid assumptions can be made about a focal source, MEG can transform the challenge of EEG based 2D inference of lateralization or regional localization to 3D sublobar indication of epilepsy-related spike generators. As such MEG spike source imaging provides a unique tool for targeting epileptogenic tissue for the surgical treatment of epilepsy. This information can be particularly valuable for patients with neocortical epilepsy in whom intracranial EEG (icEEG) investigations are commonly necessary. MEG localization of spikes may provide more accurate electrode sampling of the cortex responsible for seizures, and as a result, increase epilepsy localization and surgical resection accuracy. Combined with mapping of eloquent cortical function, MEG can play a role in multiple aspects of the preoperative (non-invasive) decision-making—potential to improve (1) patient selection, (2) ICEEG yield, and (3) increase the net number of seizure-free outcomes. Work remains to determine the validity of various analysis methods (stratified on different types of spike sources), and the cost effectiveness of MEG in epilepsy surgery, but it can be concluded that any patients able to proced to surgery that otherwise would not without MEG would contribute evidence to added clinical utility even if the cure rate is unchanged.
Csaba Juhász and Harry T. Chugani
- Published in print:
- 2010
- Published Online:
- January 2011
- ISBN:
- 9780195342765
- eISBN:
- 9780199863617
- Item type:
- chapter
- Publisher:
- Oxford University Press
- DOI:
- 10.1093/acprof:oso/9780195342765.003.0009
- Subject:
- Neuroscience, Disorders of the Nervous System
The interictal FDG PET often shows focal cortical hypometabolism in patients with extratemporal epilepsy and can correctly regionalize neocortical epileptic foci in more than 2/3 of the cases, even ...
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The interictal FDG PET often shows focal cortical hypometabolism in patients with extratemporal epilepsy and can correctly regionalize neocortical epileptic foci in more than 2/3 of the cases, even if MRI is non-localizing. In some cases, however, FDG PET overestimates the epileptogenic region, and hypometabolism may extend progressively to involve remote cortical and subcortical regions, thus establishing an epileptic network in chronic epilepsy. On the other hand, hypometabolism can occur adjacent to, rather than completely overlap with, ictal seizure onset zones. Therefore, FDG PET is best used for presurgical evaluation in combination with other clinical, electrophysiological and imaging data to guide intracranial grid placement and optimize tailored neocortical resection. When applied in this manner, the use of FDG PET can improve outcome of extratemporal lobe epilepsy surgery.Less
The interictal FDG PET often shows focal cortical hypometabolism in patients with extratemporal epilepsy and can correctly regionalize neocortical epileptic foci in more than 2/3 of the cases, even if MRI is non-localizing. In some cases, however, FDG PET overestimates the epileptogenic region, and hypometabolism may extend progressively to involve remote cortical and subcortical regions, thus establishing an epileptic network in chronic epilepsy. On the other hand, hypometabolism can occur adjacent to, rather than completely overlap with, ictal seizure onset zones. Therefore, FDG PET is best used for presurgical evaluation in combination with other clinical, electrophysiological and imaging data to guide intracranial grid placement and optimize tailored neocortical resection. When applied in this manner, the use of FDG PET can improve outcome of extratemporal lobe epilepsy surgery.
Carlos E. A. Batista, Diane C. Chugani, and Harry T. Chugani
- Published in print:
- 2010
- Published Online:
- January 2011
- ISBN:
- 9780195342765
- eISBN:
- 9780199863617
- Item type:
- chapter
- Publisher:
- Oxford University Press
- DOI:
- 10.1093/acprof:oso/9780195342765.003.0012
- Subject:
- Neuroscience, Disorders of the Nervous System
Alpha[11C]Methyl-L-tryptophan (AMT) was developed initially as a tracer for positron emission tomography (PET) in order to measure brain serotonin synthesis, but subsequent studies have shown that it ...
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Alpha[11C]Methyl-L-tryptophan (AMT) was developed initially as a tracer for positron emission tomography (PET) in order to measure brain serotonin synthesis, but subsequent studies have shown that it also traces the kynurenine pathway. AMT PET has been applied to the study of several populations of patients being evaluated for epilepsy surgery, including lesional (tuberous sclerosis complex, tumors and malformations of cortical development) and nonlesional cases. It has shown a high specificity, but modest sensitivity, in identifying the epileptic focus in cortical regions. However, AMT PET does not have localizing value in assessment of medial temporal lobe epilepsy. AMT PET has increased our understanding of the kynurenine pathway in epilepsy suggesting new pharmacological approaches.Less
Alpha[11C]Methyl-L-tryptophan (AMT) was developed initially as a tracer for positron emission tomography (PET) in order to measure brain serotonin synthesis, but subsequent studies have shown that it also traces the kynurenine pathway. AMT PET has been applied to the study of several populations of patients being evaluated for epilepsy surgery, including lesional (tuberous sclerosis complex, tumors and malformations of cortical development) and nonlesional cases. It has shown a high specificity, but modest sensitivity, in identifying the epileptic focus in cortical regions. However, AMT PET does not have localizing value in assessment of medial temporal lobe epilepsy. AMT PET has increased our understanding of the kynurenine pathway in epilepsy suggesting new pharmacological approaches.
Otto Muzik and Harry T. Chugani
- Published in print:
- 2010
- Published Online:
- January 2011
- ISBN:
- 9780195342765
- eISBN:
- 9780199863617
- Item type:
- chapter
- Publisher:
- Oxford University Press
- DOI:
- 10.1093/acprof:oso/9780195342765.003.0015
- Subject:
- Neuroscience, Disorders of the Nervous System
Advances in imaging technologies provide today an abundance of qualitatively diverse brain data sets with the purpose to guide the placement of subdural electrodes as a pre-requisite for epilepsy ...
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Advances in imaging technologies provide today an abundance of qualitatively diverse brain data sets with the purpose to guide the placement of subdural electrodes as a pre-requisite for epilepsy surgery. Current efforts focus on the development of integrative computational frameworks that allow quantitative assessment of relationships in anatomical and functional domains between complementing modalities. It is believed that such an approach is not simply additive but possesses an amplifying effect, as the information entailed in one modality is used to both enhance and re-interpret information derived from complementing modalities. By taking advantage of these advanced data integration schemes, quantitative results are subsequently combined into data structures that provide a consistent framework for the application of advanced data mining techniques. Such multimodality database structures hold promise of providing new insights into the formation, identification and maturation of epileptic foci and might eventually lead to new approaches in epilepsy surgery that are likely to improve clinical management of patients suffering from intractable epilepsy.Less
Advances in imaging technologies provide today an abundance of qualitatively diverse brain data sets with the purpose to guide the placement of subdural electrodes as a pre-requisite for epilepsy surgery. Current efforts focus on the development of integrative computational frameworks that allow quantitative assessment of relationships in anatomical and functional domains between complementing modalities. It is believed that such an approach is not simply additive but possesses an amplifying effect, as the information entailed in one modality is used to both enhance and re-interpret information derived from complementing modalities. By taking advantage of these advanced data integration schemes, quantitative results are subsequently combined into data structures that provide a consistent framework for the application of advanced data mining techniques. Such multimodality database structures hold promise of providing new insights into the formation, identification and maturation of epileptic foci and might eventually lead to new approaches in epilepsy surgery that are likely to improve clinical management of patients suffering from intractable epilepsy.
Menno Witter and Floris Wouterlood (eds)
- Published in print:
- 2002
- Published Online:
- March 2012
- ISBN:
- 9780198509172
- eISBN:
- 9780191724626
- Item type:
- book
- Publisher:
- Oxford University Press
- DOI:
- 10.1093/acprof:oso/9780198509172.001.0001
- Subject:
- Neuroscience, Sensory and Motor Systems
Advances in imaging technologies have enabled researchers to build on the evidence obtained from lesion and behavioural studies to propose a range of functions for the parahippocampal region. It is ...
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Advances in imaging technologies have enabled researchers to build on the evidence obtained from lesion and behavioural studies to propose a range of functions for the parahippocampal region. It is now possible to image the region in healthy human subjects and to define the pathological changes occurring during the early phases of a range of neurologic and psychiatric conditions. The results have uncovered evidence suggesting that the region plays an important role in the higher cognitive processes of learning and memory, and in specific brain diseases, including Alzheimer's disease, schizophrenia, and epilepsy, as well as in the aging process itself. The book examines the architecture and activity of this section of the temporal lobe, describes the systems active in memory, perception and behaviour, and outlines the significance of its involvement in the progress of a range of disease states. It provides an overview of basic and clinical knowledge and a baseline for further expansion of the functional understanding of the region.Less
Advances in imaging technologies have enabled researchers to build on the evidence obtained from lesion and behavioural studies to propose a range of functions for the parahippocampal region. It is now possible to image the region in healthy human subjects and to define the pathological changes occurring during the early phases of a range of neurologic and psychiatric conditions. The results have uncovered evidence suggesting that the region plays an important role in the higher cognitive processes of learning and memory, and in specific brain diseases, including Alzheimer's disease, schizophrenia, and epilepsy, as well as in the aging process itself. The book examines the architecture and activity of this section of the temporal lobe, describes the systems active in memory, perception and behaviour, and outlines the significance of its involvement in the progress of a range of disease states. It provides an overview of basic and clinical knowledge and a baseline for further expansion of the functional understanding of the region.
Mary Coleman (ed.)
- Published in print:
- 2005
- Published Online:
- September 2007
- ISBN:
- 9780195182224
- eISBN:
- 9780199786701
- Item type:
- book
- Publisher:
- Oxford University Press
- DOI:
- 10.1093/acprof:oso/9780195182224.001.0001
- Subject:
- Psychology, Cognitive Neuroscience
This book uses the tools of neurological analysis to address a number of major questions that have arisen in the study of autism. The answers it presents have important implications for the ...
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This book uses the tools of neurological analysis to address a number of major questions that have arisen in the study of autism. The answers it presents have important implications for the direction of future autism research, diagnosis, and treatment. What are the neurological signs and symptoms of autism? The latest information is presented in an in-depth discussion of epilepsy, cranial circumference, changes in muscle tone, stereotypies, and mutism found in children with autism. In addition, a template is provided for practitioners to follow when conducting neurological examinations of a child with autism. What are the best options for the treatment of autism? The current medical, educational, and alternative therapies are thoroughly reviewed and evaluated. Is autism reversible? The question is explored for syndromic autism, where diseases may have a transient autistic phase, and reviewed in detail for nonsyndromic autism. Is autism primarily a single disease, as originally described by Leo Kanner? Research presented here suggests that autism is, instead, a syndrome involving many disease entities. Has the incidence of autism been increasing in recent years? An historical review of autisms prevalence rates suggests that it has never been rare. What is the relationship between autism and Asperger syndrome? The latest evidence presented here sheds light on the degree to which both syndromes share more than clinical characteristics; this evidence also show some similar findings in imaging, neuropathological, and genetic studies. Which components of the brain's neural networks need to be impaired to cause the appearance of autistic symptoms? Although there are many candidate regions, dysfunction of the cerebellum and its circuits is noted to be of great interest.Less
This book uses the tools of neurological analysis to address a number of major questions that have arisen in the study of autism. The answers it presents have important implications for the direction of future autism research, diagnosis, and treatment. What are the neurological signs and symptoms of autism? The latest information is presented in an in-depth discussion of epilepsy, cranial circumference, changes in muscle tone, stereotypies, and mutism found in children with autism. In addition, a template is provided for practitioners to follow when conducting neurological examinations of a child with autism. What are the best options for the treatment of autism? The current medical, educational, and alternative therapies are thoroughly reviewed and evaluated. Is autism reversible? The question is explored for syndromic autism, where diseases may have a transient autistic phase, and reviewed in detail for nonsyndromic autism. Is autism primarily a single disease, as originally described by Leo Kanner? Research presented here suggests that autism is, instead, a syndrome involving many disease entities. Has the incidence of autism been increasing in recent years? An historical review of autisms prevalence rates suggests that it has never been rare. What is the relationship between autism and Asperger syndrome? The latest evidence presented here sheds light on the degree to which both syndromes share more than clinical characteristics; this evidence also show some similar findings in imaging, neuropathological, and genetic studies. Which components of the brain's neural networks need to be impaired to cause the appearance of autistic symptoms? Although there are many candidate regions, dysfunction of the cerebellum and its circuits is noted to be of great interest.
Gordon M. Shepherd
- Published in print:
- 2009
- Published Online:
- February 2010
- ISBN:
- 9780195391503
- eISBN:
- 9780199863464
- Item type:
- chapter
- Publisher:
- Oxford University Press
- DOI:
- 10.1093/acprof:oso/9780195391503.003.0013
- Subject:
- Neuroscience, History of Neuroscience
This chapter focuses on the development of clinical neurology. Clinical neurology was early combined with psychiatry in the 19th century and only began to emerge as a separate specialty around 1900. ...
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This chapter focuses on the development of clinical neurology. Clinical neurology was early combined with psychiatry in the 19th century and only began to emerge as a separate specialty around 1900. In North America, the Neurological Unit of the Boston City Hospital was one of the early seeding places for the new discipline. At midcentury, a succession of neurologists in Boston, including Stanley Cobb, Tracy Putnam, Derek Denny-Brown, Raymond Adams, and C. Miller Fisher, laid the basis for modern clinical neurology as an independent discipline. The first effective drug for treatment of epilepsy was introduced. Spreading cortical depression was discovered and linked to migraine. The role of dopamine and the substantia nigra in Parkinson's disease was recognized.Less
This chapter focuses on the development of clinical neurology. Clinical neurology was early combined with psychiatry in the 19th century and only began to emerge as a separate specialty around 1900. In North America, the Neurological Unit of the Boston City Hospital was one of the early seeding places for the new discipline. At midcentury, a succession of neurologists in Boston, including Stanley Cobb, Tracy Putnam, Derek Denny-Brown, Raymond Adams, and C. Miller Fisher, laid the basis for modern clinical neurology as an independent discipline. The first effective drug for treatment of epilepsy was introduced. Spreading cortical depression was discovered and linked to migraine. The role of dopamine and the substantia nigra in Parkinson's disease was recognized.
