Reading epilepsy. An appraisal of 20 patients diagnosed at the Mayo Clinic, Rochester, Minnesota, between 1949 and 1989, and delineation of the epileptic syndrome.

The clinical and EEG findings in 20 patients with reading epilepsy (RE) diagnosed at the Mayo Clinic, Rochester Minnesota, between 1949 and 1989 are documented in this study. Sixteen patients were followed for more than 10 years. The age at onset of RE ranged from 10 to 46 years (median 17.5 years). Precipitating factors other than reading, involving linguistic or non-linguistic higher cognitive processes, occurred in nine patients. Spontaneous myoclonus affecting the upper extremities, especially in the morning, indicated co-occurrence of juvenile myoclonic epilepsy (JME) in four patients. A positive family history for seizures (including one person with RE) was obtained for four patients. Interictal EEG abnormalities were present in 12 patients (60%). Ictal EEG findings were generalized and symmetric in 75% of patients, with a strictly focal (temporoparietal) discharge occurring in only two patients. Of the 11 patients who were alive and for whom recent information regarding seizure status was available, only three were symptom-free without anticonvulsant medication. Our data indicate resemblance of the clinical manifestations of RE with JME and other cognitive function-related seizures and point toward an overlap with them. We propose a classification for higher cognitive function-related epilepsies in general and RE in particular to explain the electrographic heterogeneity and clinical overlap observed. A hypothetical model to explain the ictogenesis and to encompass the electroclinical heterogeneity in RE is suggested.