EPILEPTIC ACTIVITY INTERFERING WITH WORD PROCESSING IN LANDAU-KLEFFER SYNDROME: THE ROLE OF THE NON-AFFECTED HEMISPHERE IN LINGUISTIC DEFICIT MANIFESTATION
Abstract number :
2.393
Submission category :
Year :
2003
Submission ID :
3902
Source :
www.aesnet.org
Presentation date :
12/6/2003 12:00:00 AM
Published date :
Dec 1, 2003, 06:00 AM
Authors :
Eduardo M. Castillo, Panagiotis G. Simos, Joshua I. Breier, James W. Wheless, Ian J. Butler, Rebecca Billingsley, Ekaterina Pataraia, Andrew C. Papanicolaou Department of Neurosurgery, University of Texas-Houston, Medical School, Houston, TX; Department o
In this study we report two cases of Landau-Kleffner syndrome. Both patients showed a typical electroencephalographic pattern of this syndrome, consisting of frequent epileptiform discharges in the perisylvian region (over the left hemisphere) during slow sleep.
Magnetoencephalographic (MEG) scans were obtained with a whole-head 248-channel neuromagnetometer array housed in a magnetically shielded chamber. Simultaneous recording of scalp EEG and MEG were conducted in order to characterize and localize the interictal epileptiform events. Language mapping was performed using a MEG protocol developed at the University of Houston and externally validated in 84 patients using direct comparisons with Wada and electrocortical stimulation.
In both cases, MEG recordings pinpointed these epileptic events in the left primary auditory cortex. Linguistic dysfunction was severe in one case (A) and moderate in the other (B). Language-specific activation profiles showed clear differences between these two cases. Case A (with severe linguistic impairment) showed an attenuation of primary auditory responses (N1) in the left hemisphere in conjunction with an almost exclusive left hemisphere representation of receptive language functions. Case B (with a moderate linguistic deficit) showed the same attenuation of primary auditory responses in the left hemisphere and a bilateral (Right[gt]Left) representation of receptive language.
These findings suggest that epileptic activity interferes with word processing in this syndrome at the very initial stage of auditory processing. In addition, our data suggest that the linguistic regression present in the syndrome can be modulated in part by plasticity processes that allow the non-affected hemisphere to be engaged in word comprehension. A poor engagement of the non-affected hemisphere in word comprehension leads to a severe linguistic deficit in the reported case. Other implications of this data for early intervention are discussed.
[Supported by: The research presented in this report was partly supported by NIH Grant ROI N537941 to A.C. Papanicolaou.]