Event-related Potentials Evoked During Picture Recognition In Patients With Lacunar Infarction

The present study aimed to investigate features of memory impairment and characteristics of event-related potential in patients with lacunar infarction. The patient group comprised 30 lacunar infarction patients and the control group comprised 30 healthy, age-matched individuals. All subjects were subjected to picture recognition tasks. A total of 120 pictures were selected from the International Affective Picture System for emotional stimuli. During the learning stage, 60 random pictures were randomly programmed in triplicate using the E-Prime procedure. During this stage, subjects were asked to remember all pictures, but not provide any responses. After a 3 minute break, recognition was tested; 120 pictures were randomly presented on a screen, 60 of which had been previously shown (old pictures) and 60 new pictures. The subjects were asked to determine as quickly and accurately as possible whether the picture displayed on the screen had been previously presented (button 1)or not (button 5) and to simultaneously press the appropriate buttons. Electroencephalogram signals were simultaneously recorded. Off-line ERP was compared between patient and control groups. The reaction time of picture recognition was (746.79±62.07) ms in the patient group and (642.47±53.91) ms in the control group, with significant differences between the two groups (P < 0.01). The accuracy rate of picture recognition was (70.53±15.32) % in the lacunar infarction group and (79.29±11.01) % in the control group, with significant differences between the two groups (P < 0.05). N100, P200, and N300 were evoked in both groups and ERP N300 was related to picture recognition. Brain topographic mapping revealed that evoked N300 was focused in the frontal lobe in both groups. N300 amplitude in the frontal region was significantly less (P<0.001)in the patient group compared to the control group and latency was significantly longer (P<0.05) in the patient group compared to the control group. Lacunar infarction patients exhibited impaired memory and decreased recognition capacity. Results revealed that ERP sensitively reflected patient cognition levels and could be used as a supplementary tool for cognitive evaluation based on scale measurements. These findings indicate that event-related potential can be used as a tool to evaluate early memory function in lacunar infarction patients.