Temporal lobe white matter asymmetry and language laterality in epilepsy patients
نویسندگان
چکیده
Recent studies using diffusion tensor imaging (DTI) have advanced our knowledge of the organization of white matter subserving language function. It remains unclear, however, how DTI may be used to predict accurately a key feature of language organization: its asymmetric representation in one cerebral hemisphere. In this study of epilepsy patients with unambiguous lateralization on Wada testing (19 left and 4 right lateralized subjects; no bilateral subjects), the predictive value of DTI for classifying the dominant hemisphere for language was assessed relative to the existing standard-the intra-carotid Amytal (Wada) procedure. Our specific hypothesis is that language laterality in both unilateral left- and right-hemisphere language dominant subjects may be predicted by hemispheric asymmetry in the relative density of three white matter pathways terminating in the temporal lobe implicated in different aspects of language function: the arcuate (AF), uncinate (UF), and inferior longitudinal fasciculi (ILF). Laterality indices computed from asymmetry of high anisotropy AF pathways, but not the other pathways, classified the majority (19 of 23) of patients using the Wada results as the standard. A logistic regression model incorporating information from DTI of the AF, fMRI activity in Broca's area, and handedness was able to classify 22 of 23 (95.6%) patients correctly according to their Wada score. We conclude that evaluation of highly anisotropic components of the AF alone has significant predictive power for determining language laterality, and that this markedly asymmetric distribution in the dominant hemisphere may reflect enhanced connectivity between frontal and temporal sites to support fluent language processes. Given the small sample reported in this preliminary study, future research should assess this method on a larger group of patients, including subjects with bi-hemispheric dominance.
منابع مشابه
White matter pathway asymmetry underlies functional lateralization.
Structural and functional asymmetry of the human brain has been well documented using techniques such as magnetic resonance imaging (MRI). However, asymmetry of underlying white matter connections is less well understood. We applied an MRI technique known as diffusion tensor tractography to reveal the morphology of the white matter in vivo by mapping directions of maximum water diffusion in bra...
متن کاملFunctional MR evaluation of temporal and frontal language dominance compared with the Wada test.
OBJECTIVE To evaluate the reliability of temporal and frontal functional MRI (fMRI) activation for the assessment of language dominance, as compared with the Wada test. PATIENTS AND METHODS Ten patients with temporal lobe epilepsy were studied using blood oxygen level dependent fMRI and echoplanar imaging (1.5-T). Three tasks were used: semantic verbal fluency, covert sentence repetition, and...
متن کاملPredicting the laterality of temporal lobe epilepsy from PET, MRI, and DTI: A multimodal study
Pre-surgical evaluation of patients with temporal lobe epilepsy (TLE) relies on information obtained from multiple neuroimaging modalities. The relationship between modalities and their combined power in predicting the seizure focus is currently unknown. We investigated asymmetries from three different modalities, PET (glucose metabolism), MRI (cortical thickness), and diffusion tensor imaging ...
متن کاملMRI segmentation analysis in temporal lobe and idiopathic generalized epilepsy
BACKGROUND Temporal lobe epilepsy (TLE) and idiopathic generalized epilepsy (IGE) patients have each been associated with extensive brain atrophy findings, yet to date there are no reports of head to head comparison of both patient groups. Our aim was to assess and compare between tissue-specific and structural brain atrophy findings in TLE to IGE patients and to healthy controls (HC). METHOD...
متن کاملEvaluation of focus laterality in temporal lobe epilepsy: a quantitative study comparing double inversion-recovery MR imaging at 3T with FDG-PET.
PURPOSE To quantitatively compare the diagnostic capability of double inversion-recovery (DIR) with F-18 fluorodeoxyglucose positron emission tomography (FDG-PET) for detection of seizure focus laterality in temporal lobe epilepsy (TLE). METHODS This study was approved by the institutional review board, and written informed consent was obtained. Fifteen patients with TLE and 38 healthy volunt...
متن کاملذخیره در منابع من
با ذخیره ی این منبع در منابع من، دسترسی به آن را برای استفاده های بعدی آسان تر کنید
عنوان ژورنال:
- NeuroImage
دوره 49 3 شماره
صفحات -
تاریخ انتشار 2010