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Language mapping in multilingual patients: electrocorticography and cortical stimulation during naming.

Cervenka MC, Boatman-Reich DF, Ward J, Franaszczuk PJ, Crone NE - Front Hum Neurosci (2011)

Bottom Line: These language-specific sites were not identified using ESM.Post-operative language deficits were identified in three patients (one in L2 only).These results suggest that pre-surgical mapping should include evaluation of all utilized languages to avoid post-operative functional deficits.

View Article: PubMed Central - PubMed

Affiliation: Department of Neurology, Johns Hopkins University School of Medicine Baltimore, MD, USA.

ABSTRACT
Multilingual patients pose a unique challenge when planning epilepsy surgery near language cortex because the cortical representations of each language may be distinct. These distinctions may not be evident with routine electrocortical stimulation mapping (ESM). Electrocorticography (ECoG) has recently been used to detect task-related spectral perturbations associated with functional brain activation. We hypothesized that using broadband high gamma augmentation (HGA, 60-150 Hz) as an index of cortical activation, ECoG would complement ESM in discriminating the cortical representations of first (L1) and second (L2) languages. We studied four adult patients for whom English was a second language, in whom subdural electrodes (a total of 358) were implanted to guide epilepsy surgery. Patients underwent ECoG recordings and ESM while performing the same visual object naming task in L1 and L2. In three of four patients, ECoG found sites activated during naming in one language but not the other. These language-specific sites were not identified using ESM. In addition, ECoG HGA was observed at more sites during L2 versus L1 naming in two patients, suggesting that L2 processing required additional cortical resources compared to L1 processing in these individuals. Post-operative language deficits were identified in three patients (one in L2 only). These deficits were predicted by ECoG spectral mapping but not by ESM. These results suggest that pre-surgical mapping should include evaluation of all utilized languages to avoid post-operative functional deficits. Finally, this study suggests that ECoG spectral mapping may potentially complement the results of ESM of language.

No MeSH data available.


Related in: MedlinePlus

Electrocorticographic spectral mapping of visual object naming in L1 and L2 in Patient 1 (A), Patient 2 (B), Patient 3a (C), and Patient 4 (D). Lateral, interhemispheric and basal views are shown when applicable. Electrodes used as ground or reference electrodes and those containing electrode artifact are indicated with an “X”. Blue circles indicate HGA(+) electrodes during only L1 visual object naming. Yellow circles indicate HGA(+) electrodes during only L2 visual object naming. Green circles indicate HGA(+) electrodes during both L1 and L2 naming. As in Figure 1, areas with red shading indicate resection boundaries.
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Figure 2: Electrocorticographic spectral mapping of visual object naming in L1 and L2 in Patient 1 (A), Patient 2 (B), Patient 3a (C), and Patient 4 (D). Lateral, interhemispheric and basal views are shown when applicable. Electrodes used as ground or reference electrodes and those containing electrode artifact are indicated with an “X”. Blue circles indicate HGA(+) electrodes during only L1 visual object naming. Yellow circles indicate HGA(+) electrodes during only L2 visual object naming. Green circles indicate HGA(+) electrodes during both L1 and L2 naming. As in Figure 1, areas with red shading indicate resection boundaries.

Mentions: In Patient 1, 16 electrodes were HGA(+) during L2 visual object naming and of these, only a subset (56%) of the electrodes within posterior temporal and temporo-occipital regions were HGA(+) during L1 naming and no HGA(+) regions were unique to L1 (Figure 2A). In Patient 2, 16 (67%) electrodes were HGA(+) during both L1 and L2 naming. Four (17%) sites were HGA(+) during L1 naming only, and four (17%) sites were unique to L2 (Figure 2B). In Patient 3a, 20 electrodes were HGA(+) during L1 and/or L2 naming (Figure 2C). Twelve sites were identified over the left, and eight sites were identified over right frontal and temporal regions. Of the HGA(+) sites, 14 (70%) sites were HGA(+) during L1 naming and all 20 sites were HGA(+) during L2 naming. Note that ESM was not performed at any of these sites because the strip electrodes were implanted solely to identify the patient's ictal focus. In Patient 4, 8 electrodes were identified as HGA(+) for naming and all sites were HGA(+) during both L1 and L2 naming. Sites were identified in both perisylvian and basal temporal regions (Figure 2D).


Language mapping in multilingual patients: electrocorticography and cortical stimulation during naming.

Cervenka MC, Boatman-Reich DF, Ward J, Franaszczuk PJ, Crone NE - Front Hum Neurosci (2011)

Electrocorticographic spectral mapping of visual object naming in L1 and L2 in Patient 1 (A), Patient 2 (B), Patient 3a (C), and Patient 4 (D). Lateral, interhemispheric and basal views are shown when applicable. Electrodes used as ground or reference electrodes and those containing electrode artifact are indicated with an “X”. Blue circles indicate HGA(+) electrodes during only L1 visual object naming. Yellow circles indicate HGA(+) electrodes during only L2 visual object naming. Green circles indicate HGA(+) electrodes during both L1 and L2 naming. As in Figure 1, areas with red shading indicate resection boundaries.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC3044479&req=5

Figure 2: Electrocorticographic spectral mapping of visual object naming in L1 and L2 in Patient 1 (A), Patient 2 (B), Patient 3a (C), and Patient 4 (D). Lateral, interhemispheric and basal views are shown when applicable. Electrodes used as ground or reference electrodes and those containing electrode artifact are indicated with an “X”. Blue circles indicate HGA(+) electrodes during only L1 visual object naming. Yellow circles indicate HGA(+) electrodes during only L2 visual object naming. Green circles indicate HGA(+) electrodes during both L1 and L2 naming. As in Figure 1, areas with red shading indicate resection boundaries.
Mentions: In Patient 1, 16 electrodes were HGA(+) during L2 visual object naming and of these, only a subset (56%) of the electrodes within posterior temporal and temporo-occipital regions were HGA(+) during L1 naming and no HGA(+) regions were unique to L1 (Figure 2A). In Patient 2, 16 (67%) electrodes were HGA(+) during both L1 and L2 naming. Four (17%) sites were HGA(+) during L1 naming only, and four (17%) sites were unique to L2 (Figure 2B). In Patient 3a, 20 electrodes were HGA(+) during L1 and/or L2 naming (Figure 2C). Twelve sites were identified over the left, and eight sites were identified over right frontal and temporal regions. Of the HGA(+) sites, 14 (70%) sites were HGA(+) during L1 naming and all 20 sites were HGA(+) during L2 naming. Note that ESM was not performed at any of these sites because the strip electrodes were implanted solely to identify the patient's ictal focus. In Patient 4, 8 electrodes were identified as HGA(+) for naming and all sites were HGA(+) during both L1 and L2 naming. Sites were identified in both perisylvian and basal temporal regions (Figure 2D).

Bottom Line: These language-specific sites were not identified using ESM.Post-operative language deficits were identified in three patients (one in L2 only).These results suggest that pre-surgical mapping should include evaluation of all utilized languages to avoid post-operative functional deficits.

View Article: PubMed Central - PubMed

Affiliation: Department of Neurology, Johns Hopkins University School of Medicine Baltimore, MD, USA.

ABSTRACT
Multilingual patients pose a unique challenge when planning epilepsy surgery near language cortex because the cortical representations of each language may be distinct. These distinctions may not be evident with routine electrocortical stimulation mapping (ESM). Electrocorticography (ECoG) has recently been used to detect task-related spectral perturbations associated with functional brain activation. We hypothesized that using broadband high gamma augmentation (HGA, 60-150 Hz) as an index of cortical activation, ECoG would complement ESM in discriminating the cortical representations of first (L1) and second (L2) languages. We studied four adult patients for whom English was a second language, in whom subdural electrodes (a total of 358) were implanted to guide epilepsy surgery. Patients underwent ECoG recordings and ESM while performing the same visual object naming task in L1 and L2. In three of four patients, ECoG found sites activated during naming in one language but not the other. These language-specific sites were not identified using ESM. In addition, ECoG HGA was observed at more sites during L2 versus L1 naming in two patients, suggesting that L2 processing required additional cortical resources compared to L1 processing in these individuals. Post-operative language deficits were identified in three patients (one in L2 only). These deficits were predicted by ECoG spectral mapping but not by ESM. These results suggest that pre-surgical mapping should include evaluation of all utilized languages to avoid post-operative functional deficits. Finally, this study suggests that ECoG spectral mapping may potentially complement the results of ESM of language.

No MeSH data available.


Related in: MedlinePlus