TY - JOUR
T1 - Atypical language organization in temporal lobe epilepsy revealed by a passive semantic paradigm
AU - Miró, Júlia
AU - Ripollés, Pablo
AU - López-Barroso, Diana
AU - Vilà-Balló, Adrià
AU - Juncadella, Montse
AU - de Diego-Balaguer, Ruth
AU - Marco-Pallares, Josep
AU - Rodríguez-Fornells, Antoni
AU - Falip, Mercè
N1 - Funding Information:
This research has been supported by a predoctoral grant from the Spanish Government (FPU program AP2010-4179) to P.R., a predoctoral grant from Generalitat de Catalunya to D.L-B. (2010FI B1 00169), a predoctoral grant from the Bellvitge Biomedical Research Institute (program 06/IDB-001) to A.V.B., a Ramon y Cajal research program grant awarded to J.M.P. (RYC-2007-01614), Spanish Government grants (MICINN, PSI2011-29219 to A.R.F., PSI2009-09101 to J.M.P. and PSI2008-03885 to R.D.B.) and a grant from the Catalan Government (2009 SGR 93).We would like to thank all patients and healthy volunteers for their participation.
PY - 2014/5/6
Y1 - 2014/5/6
N2 - Background: Mesial temporal lobe epilepsy (MTLE) is the most common type of focal epilepsy in adults and can be successfully cured by surgery. One of the main complications of this surgery however is a decline in language abilities. The magnitude of this decline is related to the degree of language lateralization to the left hemisphere. Most fMRI paradigms used to determine language dominance in epileptic populations have used active language tasks. Sometimes, these paradigms are too complex and may result in patient underperformance. Only a few studies have used purely passive tasks, such as listening to standard speech.Methods: In the present study we characterized language lateralization in patients with MTLE using a rapid and passive semantic language task. We used functional magnetic resonance imaging (fMRI) to study 23 patients [12 with Left (LMTLE), 11 with Right mesial temporal lobe epilepsy (RMTLE)] and 19 healthy right-handed controls using a 6 minute long semantic task in which subjects passively listened to groups of sentences (SEN) and pseudo sentences (PSEN). A lateralization index (LI) was computed using a priori regions of interest of the temporal lobe.Results: The LI for the significant contrasts produced activations for all participants in both temporal lobes. 81.8% of RMTLE patients and 79% of healthy individuals had a bilateral language representation for this particular task. However, 50% of LMTLE patients presented an atypical right hemispheric dominance in the LI. More importantly, the degree of right lateralization in LMTLE patients was correlated with the age of epilepsy onset.Conclusions: The simple, rapid, non-collaboration dependent, passive task described in this study, produces a robust activation in the temporal lobe in both patients and controls and is capable of illustrating a pattern of atypical language organization for LMTLE patients. Furthermore, we observed that the atypical right-lateralization patterns in LMTLE patients was associated to earlier age at epilepsy onset. These results are in line with the idea that early onset of epileptic activity is associated to larger neuroplastic changes.
AB - Background: Mesial temporal lobe epilepsy (MTLE) is the most common type of focal epilepsy in adults and can be successfully cured by surgery. One of the main complications of this surgery however is a decline in language abilities. The magnitude of this decline is related to the degree of language lateralization to the left hemisphere. Most fMRI paradigms used to determine language dominance in epileptic populations have used active language tasks. Sometimes, these paradigms are too complex and may result in patient underperformance. Only a few studies have used purely passive tasks, such as listening to standard speech.Methods: In the present study we characterized language lateralization in patients with MTLE using a rapid and passive semantic language task. We used functional magnetic resonance imaging (fMRI) to study 23 patients [12 with Left (LMTLE), 11 with Right mesial temporal lobe epilepsy (RMTLE)] and 19 healthy right-handed controls using a 6 minute long semantic task in which subjects passively listened to groups of sentences (SEN) and pseudo sentences (PSEN). A lateralization index (LI) was computed using a priori regions of interest of the temporal lobe.Results: The LI for the significant contrasts produced activations for all participants in both temporal lobes. 81.8% of RMTLE patients and 79% of healthy individuals had a bilateral language representation for this particular task. However, 50% of LMTLE patients presented an atypical right hemispheric dominance in the LI. More importantly, the degree of right lateralization in LMTLE patients was correlated with the age of epilepsy onset.Conclusions: The simple, rapid, non-collaboration dependent, passive task described in this study, produces a robust activation in the temporal lobe in both patients and controls and is capable of illustrating a pattern of atypical language organization for LMTLE patients. Furthermore, we observed that the atypical right-lateralization patterns in LMTLE patients was associated to earlier age at epilepsy onset. These results are in line with the idea that early onset of epileptic activity is associated to larger neuroplastic changes.
KW - Aphasia
KW - Epilepsy surgery
KW - Functional neuroimaging
KW - Hippocampal sclerosis
KW - Plasticity
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U2 - 10.1186/1471-2377-14-98
DO - 10.1186/1471-2377-14-98
M3 - Article
C2 - 24885511
AN - SCOPUS:84899996419
SN - 1471-2377
VL - 14
JO - BMC Neurology
JF - BMC Neurology
IS - 1
M1 - 98
ER -