Language Reorganization and Memory Function in Epileptic Patients -Knowledge Learned from the Wada Test-

Abstract

This report documents the findings related to language reorganization and memory function learned from the Wada test results of 164 epileptic patients. Four patterns of bilateral language representation were found in 25 patients (15%): Bilateral symmetrical autonomous in 2, bilateral asymmetrical autonomous in 15, bilateral symmetrical dependent in 2, and bilateral asymmetrical dependent (BAD) in 6. In patients with BAD, a shift of the perceptive language function to the opposite-side of the temporal lobe focus, was observed. These results suggested the likelihood that an early age of epilepsy onset in childhood affects language acquisition and a functional shift of the focal language function area because of brain plasticity in response to the adverse effects of epilepsy via the neural network. These findings also suggest that not only the age at the onset of epilepsy but also such factors that determine an originally left-handed person, a patient with a left-sided epileptic focus, or a female gender, may be important factors that have an effect on the language reorganization of the brain. Verbal memory dominance may depend on the language dominant hemisphere.