Neuropsychological deficits are the common "hallmark" of acquired epileptic aphasia and epilepsy with continuous spike-waves during sleep. Findings from various sources (eg, clinical cases, electrophysiological and positron emission tomography studies) indicate that the aphasia or the behavioral and intellectual deterioration are closely linked to a particular sustained focal epileptic activity. This leads to a wider concept of prolonged cognitive impairment of epileptic origin.