Atypical language representation in patients with chronic seizure disorder and achievement deficits with magnetoencephalography.
OBJECTIVE
To characterize the relation between hemispheric asymmetries in language-specific brain activity and reading/spelling achievement by using magnetoencephalography (MEG).


METHODS
Patients (n = 83) with medically intractable complex partial seizures of either left- or right-hemisphere origin were classified as having reading and/or spelling deficits (RS) or as not impaired (NI) by using standard achievement tests. All patients had undergone noninvasive functional mapping of receptive language cortex by using MEG as part of a preoperative seizure surgery evaluation.


RESULTS
RS patients with left-hemisphere seizure onset exhibited relatively greater activation and earlier onset of late, language-specific MEG activity in posterior temporal and inferior parietal areas of the right as compared with the left hemisphere than did NI patients. These findings also were evident on an individual basis and were independent of global intellectual abilities.


CONCLUSIONS
Reading and spelling achievement deficits in patients with complex partial seizures of left-hemisphere origin are associated with atypical language organization, possibly secondary to reorganization of language function to right-hemisphere areas that are not as efficient as homotopic areas in the left hemisphere in supporting reading and spelling functions.
Breier
Joshua I
JI
Vivian L. Smith Center for Neurologic Research, Department of Neurosurgery, Division of Clinical Neurosciences, The University of Texas Health Science Center at Houston, Texas 77030, USA. Joshua.I.Breier@uth.tmc.edu
Castillo
Edwardo M
EM
Simos
Panagiotis G
PG
Billingsley-Marshall
Rebecca L
RL
Pataraia
Ekaterina
E
Sarkari
Shirin
S
Wheless
James W
JW
Papanicolaou
Andrew C
AC
D000124:Achievement; D000293:Adolescent; D000328:Adult; D001931:Brain Mapping; D002648:Child; D002908:Chronic Disease; D015897:Comorbidity; D004410:Dyslexia / Q000175:diagnosis; D017029:Epilepsy, Complex Partial / Q000175:diagnosis* / Q000453:epidemiology / Q000601:surgery; D005260:Female; D007839:Functional Laterality / Q000502:physiology*; D006801:Humans; D007361:Intelligence Tests; D007802:Language; D007859:Learning Disabilities / Q000175:diagnosis* / Q000453:epidemiology; D015225:Magnetoencephalography / Q000706:statistics & numerical data*; D008297:Male; D008875:Middle Aged; D010296:Parietal Lobe / Q000502:physiology*; D011300:Preoperative Care; D012189:Retrospective Studies; D013702:Temporal Lobe / Q000502:physiology*