Cortical Language Areas and Plasticity in Pediatric Patients With Epilepsy: A Review

Abstract

Chronic injury to the brain from seizure activity is associated with decreased language skills in pediatric patients, as measured on neuropsychological tests for language function and academic achievement. This makes the study of language in patients with epilepsy clinically necessary. Functional magnetic resonance imaging and direct electrical cortical stimulation have been used to evaluate aspects of cortical language processing in healthy adults and in adults with epilepsy or other neurological insults. Results of these studies help to locate cortical language areas that are involved with modality-specific language processing (visual naming, auditory naming, sentence-completion, and repetition) and the neuroplasticity of language areas in the setting of neurological injury and reorganization. A better understanding of language processing contributes to a more efficient and efficacious electrical cortical stimulation mapping of language areas for patients with intractable epilepsy who are undergoing preresection evaluation. Most of the current literature on localization and reorganization of cortical language areas in the setting of epilepsy concerns the adult patient population, whereas the literature on pediatric patients is substantially lacking in comparison. This article reviews the conclusions drawn thus far from Wada, magnetoencephalography, functional magnetic resonance imaging, and electrical cortical stimulation language studies on types of language reorganization seen in pediatric patients with intractable temporal lobe epilepsy and the clinical factors associated with reorganization, and proposes future directions of research to further the academic and clinical understanding of language processing in pediatric patients.

Concordance Between Transcranial Magnetic Stimulation and Functional Magnetic Resonance Imaging (MRI) Derived Localization of Language in a Clinical Cohort

“…By establishing that TMS can produce results concordant with functional MRI, this study aimed to increase the reliability of TMS and provide clinicians evidence for using TMS where functional MRI (or another mapping method such as magnetoencephalography) fails or is not feasible. Young children form one such group, [46][47][48] in whom cortical stimulation mapping risks are significant (ie, after discharges and seizures due to higher amperage threshold 49 ) with only a 50% success rate in children under 10 years 50 and both functional MRI and magnetoencephalography fail in *30%. 51,52 The lack of comprehensive language mapping for them frequently prevents timely surgeries that could significantly improve cognitive function 53 and quality of life 48,54 or surgery proceeds without a good language map, with increased risk of postoperative language deficits.…”

Neuroplasticity and Epilepsy Surgery in Brain Eloquent Areas: Case Report

“…CSM has long been used to identify eloquent areas in the presurgical study and to demarcate epileptogenic sites. CSM has also confirmed the plastic potential of brains in childhood and adolescence ( 7 , 8 ). There has been abundant research on the application of CSM in animal models of neuronal plasticity modification ( 9 – 11 ).…”

Development and implementation of a novel child life protocol to enhance psychosocial support for pediatric awake craniotomies: technical note

“…17 The specificity of passive mapping modalities may be further decreased in the pediatric population given developmental changes in cortical language maps. 7,9,11,17,24 Therefore, the specificity of cortical stimulation mapping over passive mapping techniques may increase the amount of tumor (or other lesion) that can be safely resected. Given the risks of extraoperative mapping with invasive electrodes, pediatric awake craniotomy may be a relatively low-risk method for localizing eloquent cortex to maximize safe resection, and comes with the benefits of not requiring multiple procedures and potentially decreased morbidity from lead placement.…”