| MEG Assessment of Expressive Language in Children Evaluated for Epilepsy Surgery.
Foley E1, Cross JH2,3, Thai NJ4, Walsh AR5, Bill P5, Furlong P1, Wood AG1,6, Cerquiglini A7, Seri S8,9.
Author information
1Aston Brain Centre, School of Life and Health Sciences, Aston University, Birmingham, UK.2Developmental Neurosciences Programme, Institute of Child Health, University College London, London, UK.3Department of Paediatric Neurology, Great Ormond Street Hospital NHS Foundation Trust, London, UK.4CRICBristol, Bristol's Clinical Research and Imaging Centre, Bristol, UK.5Children's Epilepsy Surgery Service, Birmingham Children's and Women's Hospital NHS Foundation Trust, Birmingham, UK.6Brain and Mind, Clinical Sciences, Murdoch Children's Research Institute, Melbourne, Australia.7Developmental Neuropsychiatry Section, Dipartimento di Scienze e BiotecnologieMedico-Chirurgiche, "Sapienza" Universita' di Roma Polo Pontino, Latina, Italy.8Aston Brain Centre, School of Life and Health Sciences, Aston University, Birmingham, UK. [email protected]'s Epilepsy Surgery Service, Birmingham Children's and Women's Hospital NHS Foundation Trust, Birmingham, UK. [email protected].
Abstract
Establishing language dominance is an important step in the presurgical evaluation of patients with refractory epilepsy. In the absence of a universally accepted gold-standard non-invasive method to determine language dominance in the preoperative assessment, a range of tools and methodologies have recently received attention. When applied to pediatric age, many of the proposed methods, such as functional magnetic resonance imaging (fMRI), may present some challenges due to the time-varying effects of epileptogenic lesions and of on-going seizures on maturational phenomena. Magnetoencephalography (MEG) has the advantage of being insensitive to the distortive effects of anatomical lesions on brain microvasculature and to differences in the metabolism or vascularization of the developing brain and also provides a less intimidating recording environment for younger children. In this study we investigated the reliability of lateralized synchronous cortical activation during a verb generation task in a group of 28 children (10 males and 18 females, mean age 12 years) with refractory epilepsy who were evaluated for epilepsy surgery. The verb generation task was associated with significant decreases in beta oscillatory power (13-30 Hz) in frontal and temporal lobes. The MEG data were compared with other available presurgical non-invasive data including cortical stimulation, neuropsychological and fMRI data on language lateralization where available. We found that the lateralization of MEG beta power reduction was concordant with language dominance determined by one or more different assessment methods (i.e. cortical stimulation mapping, neuropsychological, fMRI or post-operative data) in 89% of patients. Our data suggest that qualitative hemispheric differences in task-related changes of spectral power could offer a promising insight into the contribution of dominant and non-dominant hemispheres in language processing and may help to characterize the specialization and lateralization of language processes in children.
www.ncbi.nlm.nih.gov/pubmed/30895423
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