The role of dominant premotor cortex and grapheme to phoneme transformation in reading epilepsy. A neuroanatomic, neurophysiologic, and neuropsychological study
A. L. Ritaccio, E. J. Hickling and V. Ramani
Department of Neurology, Albany Medical College, NY 12208.
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).
