scholarly journals Magnetoencephalographic mapping of the language-specific cortex

1998 ◽  
Vol 5 (5) ◽  
pp. E2 ◽  
Author(s):  
Andrew C. Papanicolaou ◽  
Panagiotis G. Simos ◽  
Joshua I. Breier ◽  
George Zouridakis ◽  
L. James Willmore ◽  
...  
Keyword(s):  
Receptive Language ◽  
Cortical Stimulation ◽  
Hemispheric Dominance ◽  
Mapping Technique ◽  
Dominant Hemisphere ◽  
Language Mapping ◽  
Valuable Adjunct ◽  
Simple Language ◽  
Noninvasive Mapping ◽  
Further Development

Object In this paper the authors introduce a novel use of magnetoencephalography (MEG) for noninvasive mapping of language-specific cortex in individual patients and in healthy volunteers. Methods The authors describe a series of six experiments in which normative MEG data were collected and the reliability, validity, and topographical accuracy of the data were assessed in patients who had also undergone the Wada procedure or language mapping through intraoperative cortical stimulation. Conclusions Findings include: 1) receptive language-specific areas can be reliably activated by simple language tasks and this activation can be readily recorded in short MEG sessions; 2) MEG-derived maps of each individual are reliable because they remain stable over time and are independent of whether auditory or visual stimuli are used to activate the brain; and 3) these maps are also valid because they concur with results of the Wada procedure in assessing hemispheric dominance for language and with the results of cortical stimulation in identifying the precise topography of receptive language regions within the dominant hemisphere. Although the MEG mapping technique should be further refined, it has been shown to be efficacious by correctly identifying the language-dominant hemisphere and specific language-related regions within this hemisphere. Further development of the technique may render it a valuable adjunct for routine presurgical planning in many patients who harbor tumors or have epilepsy.

Magnetoencephalographic mapping of the language-specific cortex

1999 ◽  
Vol 90 (1) ◽  
pp. 85-93 ◽  
Author(s):  
Andrew C. Papanicolaou ◽  
Panagiotis G. Simos ◽  
Joshua I. Breier ◽  
George Zouridakis ◽  
L. James Willmore ◽  
...  
Keyword(s):  
Receptive Language ◽  
Cortical Stimulation ◽  
Hemispheric Dominance ◽  
Mapping Technique ◽  
Dominant Hemisphere ◽  
Language Mapping ◽  
Content Type ◽  
Valuable Adjunct ◽  
Simple Language ◽  
Fine Print

Object. In this paper the authors introduce a novel use of magnetoencephalography (MEG) for noninvasive mapping of language-specific cortex in individual patients and in healthy volunteers.Methods. The authors describe a series of six experiments in which normative MEG data were collected and the reliability, validity, and topographical accuracy of the data were assessed in patients who had also undergone the Wada procedure or language mapping through intraoperative cortical stimulation.Conclusions. Findings include: 1) receptive language—specific areas can be reliably activated by simple language tasks and this activation can be readily recorded in short MEG sessions; 2) MEG-derived maps of each individual are reliable because they remain stable over time and are independent of whether auditory or visual stimuli are used to activate the brain; and 3) these maps are also valid because they concur with results of the Wada procedure in assessing hemispheric dominance for language and with the results of cortical stimulation in identifying the precise topography of receptive language regions within the dominant hemisphere.Although the MEG mapping technique should be further refined, it has been shown to be efficacious by correctly identifying the language-dominant hemisphere and specific language-related regions within this hemisphere. Further development of the technique may render it a valuable adjunct for routine presurgical planning in many patients who harbor tumors or have epilepsy.

scholarly journals Multimodality Word-Finding Distinctions in Cortical Stimulation Mapping

Neurosurgery ◽  
2013 ◽  
Vol 73 (1) ◽  
pp. 36-47 ◽  
Author(s):  
Sandra Serafini ◽  
Merlise Clyde ◽  
Matt Tolson ◽  
Michael M. Haglund
Keyword(s):  
Cortical Stimulation ◽  
Sentence Completion ◽  
Resection Margins ◽  
Dominant Hemisphere ◽  
Language Mapping ◽  
Hierarchical Logistic Regression ◽  
Word Finding ◽  
Cortical Stimulation Mapping ◽  
Multimodality Approach ◽  
Patients With Epilepsy

Abstract BACKGROUND: Cortical stimulation mapping (CSM) commonly uses visual naming to determine resection margins in the dominant hemisphere of patients with epilepsy. Visual naming alone may not identify all language sites in resection-prone areas, prompting additional tasks for comprehensive language mapping. OBJECTIVE: To demonstrate word-finding distinctions between visual, auditory, and reading modalities during CSM and the percentage of modality-specific language sites within dominant hemisphere subregions. METHODS: Twenty-eight patients with epilepsy underwent CSM by the use of visual, auditory, and sentence-completion tasks. Hierarchical logistic regression analyzed errors to identify language sites and provide modality-specific percentages within subregions. RESULTS: The percentage of sites classified as language sites based on auditory naming was twice as high in anterior temporal regions compared with visual naming, marginally higher in posterior temporal areas, and comparable in parietal regions. Sentence completion was comparable to visual and auditory naming in parietal regions and lower in most temporal areas. Of 470 sites tested with both visual and auditory naming, 95 sites were distinctly auditory, whereas 48 sites were distinctly visual. The remaining sites overlapped. CONCLUSION: Distinct cortical areas were found for distinct input modalities, with language sites in anterior tip regions found most often by using auditory naming. The vulnerability of anterior temporal tip regions to resection in this population and distinct sites for each modality suggest that a multimodality approach may be needed to spare crucial language sites, if sparing those sites can be shown to significantly reduce the rate of postoperative language deficits without sacrificing seizure control.

Hemispheric Dominance for Language and Side Effects in Mapping the Inferior Frontal Junction Area with Transcranial Magnetic Stimulation

2020 ◽  
Vol 81 (02) ◽  
pp. 130-137
Author(s):  
Katrin Sakreida ◽  
Johanna Blume-Schnitzler ◽  
Grit Frankemölle ◽  
Vanessa Drews ◽  
Stefan Heim ◽  
...  
Keyword(s):  
Transcranial Magnetic Stimulation ◽  
Side Effects ◽  
Magnetic Stimulation ◽  
Hemispheric Dominance ◽  
Substantial Contribution ◽  
Dominant Hemisphere ◽  
Language Mapping ◽  
Junction Area ◽  
Motor Effects ◽  
Inferior Frontal Junction

Abstract Background and Study Aims Language mapping by navigated transcranial magnetic stimulation (TMS) is commonly applied over the left language-dominant hemisphere to indicate the language-related cortex. Detailed language mapping of Broca's region including stimulation targets in the immediate vicinity to the premotor cortex may raise concern about confounding unspecific motor effects. We performed interhemispheric comparisons to delineate such possible unspecific effects from true TMS-induced language inhibition. Material and Methods Fifteen healthy German speakers named object pictures during navigated TMS over a left- and right-hemispheric target array covering the left inferior frontal junction area. Six mapping repetitions were conducted per hemisphere. Order of stimulation side was randomized between participants. Self-rating of discomfort was assessed after each stimulation; language errors and motor side effects were evaluated offline. Results Naming errors were observed significantly more frequently during left- than right-hemispheric stimulation. The same pattern was found for the most frequent error category of performance errors. Hierarchical cluster analyses of normalized ratings of error severity revealed a clear focus of TMS susceptibility for language inhibition in object naming at the dorsoposterior target sites only in the left hemisphere. We found no statistical difference in discomfort ratings between both hemispheres and also no interhemispheric difference in motor side effects, but we observed significantly stronger muscle contractions of the eyes as compared with the mouth. Conclusion Our results of (1) unspecific pre-/motor effects similarly induced in both hemispheres, and (2) a specific focus of TMS susceptibility in the language-dominant hemisphere render any substantial contribution of nonlanguage-specific effects in TMS language mapping of the inferior frontal junction area highly unlikely.

scholarly journals Impairment of preoperative language mapping by lesion location: a functional magnetic resonance imaging, navigated transcranial magnetic stimulation, and direct cortical stimulation study

2015 ◽  
Vol 123 (2) ◽  
pp. 314-324 ◽  
Author(s):  
Sebastian Ille ◽  
Nico Sollmann ◽  
Theresa Hauck ◽  
Stefanie Maurer ◽  
Noriko Tanigawa ◽  
...  
Keyword(s):  
Transcranial Magnetic Stimulation ◽  
Positive Predictive Value ◽  
Predictive Value ◽  
Magnetic Stimulation ◽  
Cortical Stimulation ◽  
Awake Surgery ◽  
Navigated Transcranial Magnetic Stimulation ◽  
Language Mapping ◽  
Direct Cortical Stimulation ◽  
Neurosurgical Patients

OBJECT Language mapping by repetitive navigated transcranial magnetic stimulation (rTMS) is increasingly used and has already replaced functional MRI (fMRI) in some institutions for preoperative mapping of neurosurgical patients. Yet some factors affect the concordance of both methods with direct cortical stimulation (DCS), most likely by lesions affecting cortical oxygenation levels. Therefore, the impairment of the accuracy of rTMS and fMRI was analyzed and compared with DCS during awake surgery in patients with intraparenchymal lesions. METHODS Language mapping was performed by DCS, rTMS, and fMRI using an object-naming task in 27 patients with left-sided perisylvian lesions, and the induced language errors of each method were assigned to the cortical parcellation system. Subsequently, the receiver operating characteristics were calculated for rTMS and fMRI and compared with DCS as ground truth for regions with (w/) and without (w/o) the lesion in the mapped regions. RESULTS The w/ subgroup revealed a sensitivity of 100% (w/o 100%), a specificity of 8% (w/o 5%), a positive predictive value of 34% (w/o: 53%), and a negative predictive value (NPV) of 100% (w/o: 100%) for the comparison of rTMS versus DCS. Findings for the comparison of fMRI versus DCS within the w/ subgroup revealed a sensitivity of 32% (w/o: 62%), a specificity of 88% (w/o: 60%), a positive predictive value of 56% (w/o: 62%), and a NPV of 73% (w/o: 60%). CONCLUSIONS Although strengths and weaknesses exist for both rTMS and fMRI, the results show that rTMS is less affected by a brain lesion than fMRI, especially when performing mapping of language-negative cortical regions based on sensitivity and NPV.

scholarly journals The ionospheric storm studies: further development of the mapping technique

1996 ◽  
Vol 39 (4) ◽  
Author(s):  
I. Kutiev ◽  
T. Samardjiev ◽  
P. A. Bradley ◽  
M. I. Dick ◽  
L. R. Cander
Keyword(s):  
Magnetic Storm ◽  
Recovery Phase ◽  
Main Phase ◽  
Mapping Technique ◽  
Ionospheric Storm ◽  
Further Development

The technique of using instantaneous maps for ionospheric storm studies is further developed. Integral parameters are introduced characterizing the main features of each map. These parameters are the net volumes of ?f0F2, ?M(3000)F2and their gradients. The magnetic storm 1-2 March, 1982 was considered and it was found that before the storm commencement and in recovery phase the Net Gradient (NG) is directed steadily to the East, while in the main phase it turns southward. NG shows where the changes of the F-layer come from. The net volume of ?f0F2 (NF) correlates well with Dst and AE indices.

scholarly journals Preoperative language mapping using navigated TMS compared with extra-operative direct cortical stimulation using intracranial electrodes: A case report

Seizure ◽  
2020 ◽  
Vol 76 ◽  
pp. 96-99
Author(s):  
Fahmida A. Chowdhury ◽  
Lorenzo Caciagli ◽  
Benjamin P. Whatley ◽  
Charlotte McLaughlin ◽  
Brett Sanders ◽  
...  
Keyword(s):  
Case Report ◽  
Cortical Stimulation ◽  
Language Mapping ◽  
Direct Cortical Stimulation ◽  
Intracranial Electrodes

A comparison of functional MRI and magnetoencephalography for receptive language mapping

2007 ◽  
Vol 161 (2) ◽  
pp. 306-313 ◽  
Author(s):  
Rebecca L. Billingsley-Marshall ◽  
Trustin Clear ◽  
W. Einar Mencl ◽  
Panagiotis G. Simos ◽  
Paul R. Swank ◽  
...  
Keyword(s):  
Functional Mri ◽  
Receptive Language ◽  
Language Mapping

Intraoperative subcortical stimulation mapping of language pathways in a consecutive series of 115 patients with Grade II glioma in the left dominant hemisphere

2008 ◽  
Vol 109 (3) ◽  
pp. 461-471 ◽  
Author(s):  
Hugues Duffau ◽  
Peggy Gatignol ◽  
Emmanuel Mandonnet ◽  
Laurent Capelle ◽  
Luc Taillandier
Keyword(s):  
Premotor Cortex ◽  
Phonological Loop ◽  
World Health ◽  
Consecutive Series ◽  
Dominant Hemisphere ◽  
Language Mapping ◽  
Subcortical Stimulation ◽  
Grade Ii ◽  
Language Pathways ◽  
Grade Ii Glioma

Object Despite better knowledge of cortical language organization, its subcortical anatomofunctional connectivity remains poorly understood. The authors used intraoperative subcortical stimulation in awake patients undergoing operation for a glioma in the left dominant hemisphere to map the language pathways and to determine the contribution of such a method to surgical results. Methods One hundred fifteen patients harboring a World Health Organization Grade II glioma within language areas underwent operation after induction of local anesthesia, using direct electrical stimulation to perform online cortical and subcortical language mapping throughout the resection. Results After detection of cortical language sites, the authors identified 1 or several of the following subcortical language pathways in all patients: 1) arcuate fasciculus, eliciting phonemic paraphasia when stimulated; 2) inferior frontooccipital fasciculus, generating semantic paraphasia when stimulated; 3) subcallosal fasciculus, inducing transcortical motor aphasia during stimulation; 4) frontoparietal phonological loop, eliciting speech apraxia during stimulation; and 5) fibers coming from the ventral premotor cortex, inducing anarthria when stimulated. These structures were preserved, representing the limits of the resection. Despite a transient immediate postoperative worsening, all but 2 patients (98%) returned to baseline or better. On control MR imaging, 83% of resections were total or subtotal. Conclusions These results represent the largest experience with human subcortical language mapping ever reported. The use of intraoperative cortical and subcortical stimulation gives a unique opportunity to perform an accurate and reliable real-time anatomofunctional study of language connectivity. Such knowledge of the individual organization of language networks enables practitioners to optimize the benefit-to-risk ratio of surgery for Grade II glioma within the left dominant hemisphere.

scholarly journals Assessment of hemispheric dominance for receptive language in pediatric patients under sedation using magnetoencephalography

2014 ◽  
Vol 8 ◽  
Author(s):  
Roozbeh Rezaie ◽  
Shalini Narayana ◽  
Katherine Schiller ◽  
Liliya Birg ◽  
James W. Wheless ◽  
...  
Keyword(s):  
Pediatric Patients ◽  
Receptive Language ◽  
Hemispheric Dominance
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