Changes of cognitive function and their predictive value to different subtypes of mild cognitive impairment among the elderly

ObjectiveTo study the changes and determinants of cognitive function and to explore its predictive value to different subtypes of mild cognitive impairment(MCI)among the elderly in Guiyang city. MethodsUsing multistage sampling,2 197 people aged 60 years and older were selected from urban communities in Guiyang for a baseline survey in 2004-2005 and followed up in 2008.The subjects were divided into normal cognitive(NC)and different subtypes of MCI groups according to the outcomes of follow-up examination.The cognitive function was assessed by using the Mini-Mental State Examination(MMSE),and logistic regression model was used to analyze the predictive value of cognitive function for different subtypes of MCI. ResultsA total of 1 409 participants completed follow-up examination,with a follow-up rate of 64.13%.Among the elderly,there were 1 279 with normal cognitive function,72 cases of amnestic mild cognitive impairment(aMCI),34 cases of nonamnestic mild cognitive impairment(naMCI),and 24 cases of dementia.The aMCI cases had a lower score(3.65±0.56)in using vocabulary compared with the normal control group(3.78±0.46)in baseline study.The naMCI cases had lower scores in memory,computing power,visual-spatial ability,and overall cognitive function compared with the normal control group.The scores of memory,computing power,visual-spatial ability,and overall cognitive function in aMCI group decreased to 3.33±2.17,2.26±1.56,0.27±0.63,and 3.97±2.98,respectively.The scores of orientation,ability of using vocabulary,the understanding of language,and overall cognitive funciton in naMCI group declined to 1.59±1.81,0.41±0.70,0.62±1.18,and 3.82±2.61,respectively.After controlling for age,education level and occupation,the memory and ability of using vocabulary showed a value for prediction to aMCI,and so did the computing power and visual-spatial ability to naMCI. ConclusionThere are different changes in cognitive functions among the elderly with different subtypes of MCI and the changes show early predicting value to different subtypes of MCI.