Language laterality determined by MEG mapping with MR-FOCUSS

Bowyer, Susan M.; Moran, John; Weiland, Barbara J.; Mason, Karen; Greenwald, Margaret; Smith, Brien; Barkley, Gregory L.; Tepley, N.

doi:10.1016/j.yebeh.2004.12.002

Cited by 85 publications

(58 citation statements)

References 25 publications

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“…These studies have demonstrated a high concordance (approximately 90%) between MEG language lateralization and the IAP (69,(91)(92)(93)(94). Other investigators have used silent verb generation and picture naming tasks with comparable results (95,96). Most studies have used equivalent current dipoles (ECD) to determine language lateralization by modeling the distribution of activity every several milliseconds separately in each hemisphere.…”

Section: Megmentioning

confidence: 99%

“…However, when cognitive processes are distributed in nature (which is likely characteristic of language), ECDs may underestimate the regions involved. To overcome this limitation, distributed source solutions have been developed and studied in patients with epilepsy (95) and healthy controls (98-100). In particular, Bowyer et al (95) studied language lateralization in patients with epilepsy using a current density technique (MR-FOCUSS) that estimates the strength of cortical activation between hemispheres.…”

Section: Megmentioning

confidence: 99%

“…To overcome this limitation, distributed source solutions have been developed and studied in patients with epilepsy (95) and healthy controls (98-100). In particular, Bowyer et al (95) studied language lateralization in patients with epilepsy using a current density technique (MR-FOCUSS) that estimates the strength of cortical activation between hemispheres. They reported 96% concordance between MEG language lateralization within Broca's area and the IAP using a verb generation task.…”

Section: Megmentioning

confidence: 99%

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The use of neuroimaging to study behavior in patients with epilepsy

McDonald¹

2008

Epilepsy & Behavior

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Structural and functional neuroimaging continue to play an increasing role in the presurgical evaluation of patients with epilepsy. In addition to their value for localizing the epileptogenic zone and eloquent cortex, neuroimaging is contributing to our understanding of mood comorbidity in epilepsy. Although the vast majority of research has focused on patients with temporal lobe epilepsy (TLE), neuroimaging studies of patients with frontal lobe epilepsy (FLE) and primary generalized epilepsy are increasing in number. In this review, structural and functional imaging modalities that have received considerable research attention in recent years are reviewed, along with an assessment of their strengths and limitations for understanding behavior in epilepsy. In addition, advances in multimodal imaging are discussed along with their potential application to the presurgical evaluation of patients with seizure disorders.

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Section: Megmentioning

confidence: 99%

Section: Megmentioning

confidence: 99%

Section: Megmentioning

confidence: 99%

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The use of neuroimaging to study behavior in patients with epilepsy

McDonald¹

2008

Epilepsy & Behavior

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show abstract

“…However, the most promising novel noninvasive methods include direct measures of physiological language activation. Some newer methods include event-related brain potentials [4] and whole-head magnetoencephalography [5][6][7]. The other alternative activation techniques are based on hemodynamic responses to language activation, such as functional transcranial Doppler [8], single-photon-emission computed tomography [9], positron emission tomography [10], near-infrared spectroscopic mapping [11], and functional magnetic resonance imaging [12].…”

Section: Introductionmentioning

confidence: 99%

Power spectral density changes and language lateralization during covert object naming tasks measured with high-density EEG recordings

Ramon

Holmes

Freeman

et al. 2009

Epilepsy & Behavior

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a b s t r a c tOur objective was to study changes in EEG time-domain power spectral density (PSDt) and localization of language areas during covert object naming tasks in human subjects with epilepsy. EEG data for subjects with epilepsy were acquired during the covert object naming tasks using a net of 256 electrodes. The trials required each subject to provide the names of common objects presented every 4 seconds on slides. Each trial comprised the 1.0 second before and 3.0 seconds after initial object presentation. PSDt values at baseline and during tasks were calculated in the h, a, b, low c, and high c bands. The spatial contour plots reveal that PSDt values during object naming were 10-20% higher than the baseline values for different bands. Language was lateralized to left frontal or temporal areas. In all cases, the Wada test disclosed language lateralization to the left hemisphere as well.

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“…Language lateralization can be determined by means of MEG using various language paradigms such as word recognition tasks, 54 silent reading, 26 picture naming, and verb generation. 7 An 89-95% concordance rate has been found between MEG language mapping and results from Wada testing. 53 Magnetoencephalographic language studies in patients with chronic seizure disorders of left hemispheric onset have demonstrated atypical language organization.…”

Section: Functional Mappingmentioning

confidence: 93%

The role of magnetoencephalography in epilepsy surgery

Tovar-Spinoza¹,

Ochi

Rutka³

et al. 2008

FOC

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Epilepsy surgery requires the precise localization of the epileptogenic zone and the anatomical localization of eloquent cortex so that these areas can be preserved during cortical resection. Magnetoencephalography (MEG) is a technique that maps interictal magnetic dipole sources onto MR imaging to produce a magnetic source image. Magneto-encephalographic spike sources can be used to localize the epileptogenic zone and be part of the workup of the patient for epilepsy surgery in conjunction with data derived from an analysis of seizure semiology, scalp video electroencephalography, PET, functional MR imaging, and neuropsychological testing. In addition, magnetoencephalographic spike sources can be linked to neuronavigation platforms for use in the neurosurgical field. Finally, paradigms have been developed so that MEG can be used to identify functional areas of the cerebral cortex including the somatosensory, motor, language, and visual evoked fields. The authors review the basic principles of MEG and the utility of MEG for presurgical planning as well as intra-operative mapping and discuss future applications of MEG technology.

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Language laterality determined by MEG mapping with MR-FOCUSS

Cited by 85 publications

References 25 publications

The use of neuroimaging to study behavior in patients with epilepsy

The use of neuroimaging to study behavior in patients with epilepsy

Power spectral density changes and language lateralization during covert object naming tasks measured with high-density EEG recordings

The role of magnetoencephalography in epilepsy surgery

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