Insight On Neuropsychological Characters Between Different Kinds Of Cognitive Impairment

Objective: To investigate the different patterns of cognitive impairment between aMCI, VCI-ND, AD, VaD and normal aging people.Method: Our study used neuropsychological tests, including Mini Mentle State Examination (MMSE), Auditory Verbal Learning Test (AVLT), Clock Drawing Test (CDT), Clinical Dementia Rating scales (CDR) and Hamilton Rating Scale for Depression (HAMD). Subjects with aMCI (n=23, CDR=0.5), VCI-ND (n=27, CDR=0.5), AD (n=11, CDR≥1), VaD (n=18, CDR≥1) and normal aging people (n=40, CDR=0) were all recruited from the clinic of Neurology Department, Xuanwu Hospital, Capital Medical University.Results: Analytic results showed that (1) Comparison between aMCI, VCI-ND and normal aging, there is no significant difference in sex, age and education years (P>0.05); The mean scores of all the tests in aMCI and VCI-ND groups are significant lower than normal control group (P<0.05); No significant differences in MMSE, CDT, immediate memory and delayed recall tests between aMCI and VCI-ND groups (P>0.05). However, in the recall recognition test, these three groups showed significant differences, the patients with aMCI scored (mean score=6.65) much lower than VCI-ND patients (mean score=8.67; P<0.05), and the scores of the two groups were both lower than that of the normal control (NC) group (mean score=12.83; P<0.05). (2) According to comparison between AD, VaD and NC groups, there's no significant difference in subjects'age and gender (P>0.05). The education level of AD and VaD groups is significant lower than that of NC group, however, there is no difference between AD and VaD patients in education. Respectively, in the cognition tests, the mean scores of dementia groups (AD and VaD) are significant lower than those of the normal aging group (P<0.05). However, we found no difference in every cognition tests between AD and VaD groups. (3) Comparison between aMCI, AD and NC, no significant difference exist in age, gender and recall recognition test (just between aMCI and AD). Significant differences do exist in education years (the mean education years of AD patients is much shorter than that of aMCI patients and NC people, P<0.05), MMSE, CDT, immediate memory and delayed recall tests (P<0.05). According to the mean scores of all the cognition tests, we can found that AD patients showed much lower than those of aMCI patients, and they both lower than NC group. (4) There are significant difference between VCI-ND, VaD and NC groups in age, education level, and no difference in gender; The mean age of VaD group is significant older than that of VCI-ND patients and normal elder people, and the mean education years of VaD group is much shorter than that of VCI-ND group and normal elder group (P<0.05); The mean scores of MMSE, CDT immediate memory and delayed recall tests showed that the VaD group is significant lower than VCI-ND group and they both lower than NC group (P<0.05). We found no difference in delayed memory test between VCI-ND and VaD patients (P>0.05).Conclusions: Low education level and older age are potential risk factors of cognitive impairment. Compared with normal aging, the cognition of 4 types dementia groups was impaired severely. CDT lacked sensitivity and specificity to differentiate AD from VCI patients. Furthermore, the cognition of AD and VaD patients impaired more serious than aMCI and VCI-ND patients. The memory tests suggested that compared with aMCI patients, VCI-ND patients may evolve different neuropathological changes leading to different mechanism of memory encoding and retrieval.