[p1–374]: alteration of hippocampus and amygdala in subjective cognitive decline and mild cognitive impairment in community‐dwelling chinese

Subjective cognitive decline (SCD) may be the first clinical sign of Alzheimer's disease (AD). SCD individuals with normal cognition may already have significant hippocampal atrophy. However, few studies have been devoted to exploring the alteration of left-right asymmetry with hippocampus and amygdale. The aim of this study was to compare SCD individuals with mild cognitive impairment (MCI) patients and the normal population for volume and asymmetry of hippocampus and amygdala, and to assess their relationship with cognitive function in elderly population living in the community of China. 40 SCD, 30 MCI, and 30 matched controls underwent a standard T1-weighted MRI and were compared with volume of hippocampus and amygdala. Moreover, we also evaluated the pattern and extent of asymmetry in hippocampus and amygdale of these samples. Cognitive function was assessed with Mini-Mental State Examination (MMSE) and the Montreal Cognitive Assessment (MoCA). Then we investigated the relationship between the altered brain region and cognitive function. By using a combination of clinical investigations and laboratory testing, we found there were 30 people with normal cognition without SCD, 40 people with SCD and 30 people with MCI. There were no significant differences in sex and age between the three groups. By using ANOVA tests, we found statistically significant differences in right hippocampal volumes, mean hippocampal volumes, asymmetry of hippocampus, mean amygdale volumes and asymmetry of amygdala among three groups (P<0.05). SCD individuals showed significant decreased related volumes than controls, but increased than MCI group. For asymmetry pattern, a consistent left-less-than-right asymmetry pattern was found both in hippocampus and amygdala, but with different extents (HC>SCD>MCI, P<0.01). Furthermore, neuropsychological test results (MMSE and MoCA) were significant difference between the three groups (HC>SCD>MCI, P=0.000). Correlation analysis showed a positive correlation between right hippocampal volume and Moca score in SCD group.