The role of dominant premotor cortex and grapheme to phoneme transformation in reading epilepsy. A neuroanatomic, neurophysiologic, and neuropsychological study.

We studied a 24-year-old man who had reading epilepsy after removal of a left frontal arteriovenous malformation. Lesion analysis by means of a neuroanatomic template placed a 2-cm region of encephalomalacia anterior to the left central sulcus in premotor cortex (Brodmann's area 6). Lexical and nonlexical reading activation tests demonstrated seizures during reading and increased discharge rates when the patient was reading aloud or silently articulating. Seizures (perceived or actual jaw clicking) were electrographically characterized by brief left frontocentral epileptiform transients. Grapheme to phoneme transformation, not linguistic complexity, appears to be the critical stimulus in some reading epilepsies. The case adds anatomic relevance to the phonologic component of reading and supports the putative role of dominant premotor cortex in activation of precise sequences of motor linguistic output in reading and writing. Reading epilepsy may be a reflex or action myoclonus syndrome localized to Brodmann's area 6 (Exner's area).