To evaluate the role of semantic saliency (defined as the personal significance and knowledge of an object or idea) in seizure generation in reading epilepsy.

Reading epilepsy is a relatively rare reflex epilepsy syndrome that typically presents as orofacial reflex myoclonus triggered by reading.  Seizures are thought to be due to 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 salience of the text.  We sought to better characterize the role of text difficulty and comprehension in triggering seizures in a 27-year-old patient with reading epilepsy.

The patient underwent a series of reading trials with increasing semantic salience and/or difficulty.  Block 1: Spontaneous Speech and Passive Listening. Block 2: Pseudo-reading (Color Naming). Block 3: Foreign Language Text. Block 4: Fixed Speed List Reading. Block 5: Lay-Language (B) Non-Salient and (B)Salient Texts. Block 6: Technical Reading. Block 7: Repeat Lay-Language (Salient Only).

There is a clear positive correlation between spikes per minute (SPM), clinical events (CE), and increasing semantic salience: 6-7 SPM+CE in both salient content tasks, 1.3 SPM+CE in the non-salient lay-language task, 1.5 SPM+CE in the technical language task, and 1 SPM-CE in the foreign language task. No spikes or CE’s were observed in the other blocks; baseline SPM was 0.17. Good effort was made during all reading tasks, including pronunciation of foreign and unfamiliar technical words.

Our study demonstrated that increased semantic salience of the text can be associated with increased seizures in reading epilepsy.  We theorize that this may be associated with the patient's (less typical) 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.