Aim: In the present study, the P300 component of the emotion-loaded visual event-related potential in response to photographs of babies crying or smiling was measured to evaluate cognitive function in elderly subjects, including those with dementia. Methods:The subjects were 48 elderly people who consulted a memory disorder clinic. The visual eventrelated potential was measured using oddball tasks. Brain waves were recorded from four sites. We analyzed the P300 amplitude and latency. Subjects were divided into three groups (the dementia with Alzheimer's disease group [ADG] Results: For all subjects, there was a significant positive correlation between P300 latency and Z-score of voxel-based specific regional analysis for Alzheimer's disease for crying or smiling faces. There was a negative correlation between P300 amplitude and Z-score for the crying face. MG subjects were divided into two groups (high risk: HRMG, low risk: LRMG) based on Z-scores (HRMG ≥ 2.0). The P300 amplitude of ADG was significantly smaller than that of HG, and the P300 latency of ADG was significantly longer than those of other groups for crying or smiling faces. The P300 latency of HRMG was significantly longer than that of LRMG for the smiling face. Furthermore, the P300 latency for the crying face was significantly shorter than that for the smiling face in HG and ADG. Conclusion:These findings suggest that analysis of P300 components of the emotion-loaded visual event-related potential may be a useful neuropsychological index for the diagnosis of Alzheimer's disease and high-risk subjects.

Humans obtain a particularly large amount of information for adapting to their environment visually as opposed to other types of sensory input. Specific information is selected from a wide variety of visual stimuli, and then processed to guide behavior. Affection and emotion are critical elements of human relationships: generally, negative emotions impair quality of life, while positive emotions make life pleasurable. Affective stimuli have been shown to influence event-related potentials such as P300 components [1,2] and potentials related to eye movements [3][4][5]. The relationship between mother and baby, in particular, is of fundamental importance in the development of cognitive function and emotion [6]. Schwartz et al. [7] compared responses of healthy adults between emotional and none-motional figure Kurume Medical Journal, 58, 27-33, 2011 Summary: The relationship between mother and baby is of fundamental importance in the development of cognitive function and emotion. In this study we investigated the effects of affective photographs of a mother and baby (crying or smiling faces) and other stimuli (neutral mother or baby faces) on visual cognitive function in schizophrenic patents. We recorded exploratory eye movements in 22 healthy controls and 22 age-matched schizophrenic patients. Total number of right and left field gaze points (right TNGP, left TNGP) in the visual fields were determined using an eye-mark recorder as subjects viewed affectively charged or neutral photographs (crying, smiling or neutral faces). Left TNGP for all mother photographs (crying, smiling or neutral) were significantly larger in controls than patients, and right TNGP for neutral mother photographs were significantly larger in controls than in patients. Right TNGP for photographs of smiling babies were significantly larger in controls than patients, and left TNGP for photographs of both smiling and crying babies were significantly larger in controls than patients. Within the patient group, right TNGP were significantly larger than left TNGP for all mother photographs (crying, smiling or neutral). Left TNGP for photographs of mothers and babies correlated negatively with negative symptom scores. These results suggest that exploratory eye movements when viewing emotionally laded twin stimuli such as photographs of a mother and baby are a useful marker of visual cognitive function in both healthy controls and schizophrenic patients. Key words