Visual cognitive function in dementia of Alzheimer’s type: a comparison of visual event‐related potentials and Stroop test

Abstract

AbstractBackground: Many published studies on dementia of Alzheimer’s type (DAT) have utilized event‐related potentials (ERP) and the Stroop test. However, most of this research has performed these analyses separately. Therefore, in the present research, these two examinations were carried out together following the same paradigm in order to clarify the characteristics of visual dysfunction in DAT patients.Methods: Subjects included 30 normal adults, 10 normal elderly and 10 DAT patients. A visual categorically deviant paradigm was utilized during ERP measurement. The target stimulus was red and non‐target stimuli were blue, yellow and green. The stimuli were displayed as square figures. During the Stroop test, the subjects read color names from word cards, named colors from color cards, and the text color of a printed color word. Reading times and differences in reading times were measured for each task.Results: Regarding ERP, the normal elderly and DAT groups displayed increased latencies and decreased amplitudes compared to the normal adult group. The normal elderly and DAT groups displayed no significant differences in N100 latencies and amplitudes. However, for P300, the DAT group displayed significantly decreased amplitudes in comparison to the normal elderly group. On the Stroop test, the normal elderly and DAT groups displayed significantly extended differences in reading times compared to the normal adult group. No significant differences were observed between the normal elderly and DAT groups.Conclusion: Age‐related changes were observed in the latency of ERP and the increase of the Stroop effect. Characteristic changes in DAT were indicated by latencies and amplitudes of P300, but were not indicated by the Stroop test. Characteristic abnormalities in the stimulation evaluation process were observed for DAT; however, changes other than those related to aging were not apparent in the selection process reaction.