Cognitive function of 320 people over 65 years from longevous areas in Guangxi Zhuang Autonomous Region: Feasibility of the mini-mental state examination

摘要

BACKGROUND: Mini-mental state examination (MMSE) of Chinese version has been widely used to survey cognitive function of elder people; especially, it shows a good reliability and validity for elder people in city. However, whether it is beneficial to measure cognitive function of elder people in countries in Guangxi Zhuang Autonomous Region should be further studied. OBJECTIVE: To investigate the feasibility, reliability and validity of the cognitive function among the elderly people aged over 65 years from Jiazhuan in Bama County of Guangxi Zhuang Autonomous Region by using the MMSE of Chinese version. DESIGN: Prevalence survey. SETTING: Department of Psychology, Nanjing Municipal Social Welfare Hospital; Department of Psychology, Yizhou Municipal Jiulong Railroad Hospital; Long Life's Institute of Bama County. PARTICIPANTS: A total of 320 old persons over 65 years old were sampled on the basis of the unit of village of Jiazhuan in Bama County of Guangxi Zhuang Autonomous Region from the 12th to 28th, March 2004. All the subjects provided the confirmed consents. METHODS: ① Mental Health Questionnaire of long life's old man was adopted including demographic data and international standardized MMSE in Chinese. The survey of MMSE was divided into two phases: In the first phase, every case was examined by MMSE. The positive result was decided by the education level. Illiterate group, who was educated less than one year, then his MMSE scores must be less than 17; primary school group, who was educated from 1 to 6 years, then his MMSE must be less than 20; middle school group, who was educated more than 7 years, then his MMSE must be less than 24. In the second phase, these cases with positive MMSE score were given the neuro-psycho and mental health examination to confirm the dementia types after diagnosis. The content of the questionnaire was revised properly without changing the meaning of the questionnaire. The interclass correlation coefficient of MMSE was 0.89. ② Descriptive statistics, Chi-square test, t test, multiple stepwise regression analysis was used in the study. MAIN OUTCOME MEASURES: ① Comparisons of total scores of MMSE based on various educational degrees, sexes and ages; ② sensitivity and specificity of MMSE; ③ effect of Logistic multiple regression analysis on MMSE. RESULTS: A total of 320 questionnaires were sent out, and 318 qualified ones were retrieved after eliminating 2 not fully filled with efficient rate of 99.4%. There were 126 males and 192 females with the mean age of (86±8) years. In addition, there were 259 (81%) cases of illiteracy, 51 (16%) cases with primary school education and 8 (2%) cases with middle school education. ① Total scores of MMSE based on various educational degrees, sexes and ages: The scores of the illiteracy group were (19.37±4.28), primary school group (24.82±3.84), middle school group (25.13±5.19); the positive rates of the illiteracy group were the highest, the middle school group the higher, and the primary school group the lowest. The total scores of male MMSE were obviously higher than the female, which had significant differences [(22.33±5.61), (19.12±3.53), P 0.05); the total scores were gradually decreased with the age over 85 years. ② There were only 2 examinees were diagnosed as dementia after investigation, and 80 ones with positive scores, inducing the sensitivity of MMSE was 100%, while its specificity was 75.32%. ③ The regression equation: Y (age) =91.204+4.196 ×(often doing exercise or not) -1.827 ×(education level) -3.357×(self-mental impression) + 1.527 ×(frequency of visiting neighbors) was obtained from the Logistic multiple stepwise regression analysis influenced the cognitive function, indicating that the age of the old people in that area was positively related to the frequency of visiting their neighbor, but was negatively related to the education level and self-mental impression. CONCLUSION: ① MMSE of Chinese version with high sensitivity and low specificity is suitable for the screening of the cognitive function of rural old people. ② The general cognitive function of the old people of Jiazhuan in Bama County of Guangxi Zhuang Autonomous Region is good, and there are significant differences between sex and age.