Reading Epilepsy and Language Processing: A Proposed Role for Semantic Salience.

Abstract

Reading epilepsy is a relatively rare reflex epilepsy syndrome that typically presents as orofacial reflex myoclonus triggered by reading. Seizures are thought to be because of activation of hyperexcitable language-related pathways in the dominant hemisphere that subsequently spreads to adjacent motor cortices. More difficult reading tasks are thought to be more provocative of seizures regardless of semantic understanding of the text. The authors sought to better characterize the role of text difficulty and comprehension in triggering seizures in a 27-year-old patient with reading epilepsy. As a part of his epilepsy monitoring unit admission, the patient underwent a series of reading trials with increasing semantic salience and/or difficulty, including pseudo-reading of colors and foreign-language texts, which demonstrated a positive correlation between spike count and clinical events and increasing semantic salience. This suggests that our novel reading task may be able to differentiate between different processes in the reading pathway and that increased semantic relevance of the text, rather than increased difficulty per se, can be associated with increased seizures in reading epilepsy. The authors theorize that this may be associated with his atypical (nondominant) right hemispheric seizure focus and propose that further study of patients with reading epilepsy syndrome may help elucidate the neurobiological networks involved in reading and language processing.