Impaired language function in generalized epilepsy: inadequate suppression of the default mode network

We aimed to study the effect of a potential default mode network (DMN) dysfunction on language performance in epilepsy. Language dysfunction in focal epilepsy has previously been connected to brain damage in language-associated cortical areas. In this work, we studied generalized epilepsy (GE) without focal brain damage to see if the language function was impaired. We used functional magnetic resonance imaging (fMRI) to investigate if the DMN was involved. Eleven persons with GE and 28 healthy controls were examined with fMRI during a sentence-reading task. We demonstrated impaired language function, reduced suppression of DMN, and, specifically, an inadequate suppression of activation in the left anterior temporal lobe and the posterior cingulate cortex, as well as an aberrant activation in the right hippocampal formation. Our results highlight the presence of language decline in people with epilepsy of not only focal but also generalized origin.