['Several cognitive event-related potential (ERP) components such as mismatch negativity, P300, N400, and the late positive component (LPC) have been studied in aphasia. The aim of this study was to determine whether a modified semantic incongruity paradigm can serve as a more graded differentiation of ERP changes in patients with mild versus severe comprehension deficits.', 'A total of 20 aphasic patients with minor and severe comprehension deficits and 20 young and elderly healthy controls were examined while reading 4-word sentences ending in a semantically congruent or noncongruent word.', 'In contrast to young controls and to patients with mild comprehension deficits, aphasic patients with severe comprehension deficits exhibit an early positivity in the time window from 200 to 400 milliseconds and no N400 after the presentation of nonrecurrent semantically incongruent words. Patients with mild comprehension deficits were found to have an N400 with prolonged latency in comparison with the controls. An age effect in the control groups was detected as well.'] Do semantic event-related potential components reflect severity of comprehension deficits in aphasia?