Semantically-triggered reading epilepsy: An experimental case study

Primary reading epilepsy (PRE) is a rare syndrome in which epileptic seizur es are electively provoked by reading. Cognitive neuropsychology has demons trated the existence of at least two pathways for reading, the sublexical p athway involved in converting graphemes to phonemes, and the lexical pathwa y used when meaning is conveyed. Which of these specific pathways is releva nt in triggering epileptic discharges remains largely unknown. We report the case of a patient suffering from PRE in which the two routes were distinguished on the basis of the reading material employed. Significa ntly less epileptic discharges were observed when the patient read non-word s than words. In view of our findings, we tentatively contrast a lexical form of PRE, tri ggered by the activation of semantic knowledge structures, with a sublexica l form, triggered by non-word reading. Evidence from the literature suggest s that the former is characterized by bilateral EEG activating patterns, wh ereas the latter involves preferentially the left hemisphere.