The Clinical Observing On The Mild Cognitive Impairment

With the development of medicine, fast progress of the society, andcontinually increasing of the elder, the disease of dementia has come to theattention of all the world. In the study of dementia, along with deeperunderstanding it the attention of study has turned to early diagnosis andintervention for the effect of treatment in middle and latter period is bad.MCI(Mild cognitive impairment) is a new concept put forward in the nearlyyears. It is the transitional state between normally aging and dementia. thedatas of epidemiology show that the patients with MCI are high risk crowd fordementia, the average annual rate of MCI transforming into dementia is 15% ,while the healthy elder is 1%～2%. It is obvious that deeply understandingMCI will help us to identify the high risk individual for dementia and exploreeffective approaches for intervention. This study carried a clinical observationfrom diagnosis and etiology for MCI, in order to provide according forstandardizing and establishing criterion of diagnosis for MCI and help clinicto identify MCI early to intervene.This study selected the inpatients, policlinic patients and their relationswho all come from the department of neurology in China-Japan UnionHospital of Jilin University from February , 2005 to November, 2005. Theyare divided into the cerebral vascular disease group totaling 74 and the controlgroup totaling 58 to make contrasting and analyze, and also divided intosub-group to make contrast by common risk factors for the cerebral vasculardiseases including hypertension, diabetes, abnormal serum lipid. We test allsubjects' cognitive function with MMSE, CDR and GDS who are the commonscales used to diagnose MCI in current literatures. This study compared thedifference of diagnostic rate of MCI and the score of cognitive function ofevery two group when using different scales. And at the same time wecompared the difference of diagnostic rate of MCI and the score of cognitivefunction of every two group when the every risk factor for the cerebralvascular diseases exist or not. The result shown that the diagnostic rate of MCIof the patients with hypertension is significantly higher and the score ofMMSE is significantly lower than the subjects with normal blood pressure innot only the cerebral vascular disease group but also the control group,revealing hypertension works in onset of MCI and is one of risk factors forMCI. In the cerebral vascular disease group, the score of MMSE of patientswith diabetes is significantly lower than the patients without diabetes and thediagnostic rate of MCI of the patients with diabetes is significantly higher thanthe patients without diabetes. they all indicate that diabetes is related to MCI;In the cerebral vascular disease group, the diagnostic rate of MCI of thepatients with abnormal serum lipid is higher and the score of MMSE is lowerthan the patients with normal serum lipid, indicating that abnormal serum lipidis one of risk factors for mild vascular cognitive impairment. In the controlgroup the difference of the diagnostic rate of MCI and score of cognitivefunction are not significant between abnormal and normal serum lipid subjects.we consider that this result relates to the effect of abnormal normal serum lipidon different sub-type of MCI is different. It has reported that hypertension,diabetes, abnormal serum lipid are all related to cognitive impairment nearly.This study make sure farther that they relate to decline of cognition of MCI,and they are risk factors for MCI.The criterion of diagnosis for MCI has not been united for the moment.This study select the common scales used to diagnose MCI in currentliteratures including MMSE for screening, CDR and GDS as the diagnostictools of MCI. As the most common scale to diagnose dementia, MMSE areapplied to the diagnosis of MCI continually because it is simple andconvenient and saves time. MMSE≥24 is used to screen patients with MCI inmost literatures. CDR and GDS all represent a continuous course from normalto serious cognitive impairment. It is generally believed that CDR=0.5 orGDS=2 or 3 accord with the diagnosis of MCI, and this is widely applied. Inthis study, considered that the content of CDR and GDS is recapitulative andlack objective index, part of cognition test items of CDR and GDS refer toMMSE and the Blessed' behavior scale when use them to diagnose MCI. Theresult of this study shows that the score of MMSE of the cerebral vasculardisease group is significant lower than the control group confirming that thecerebral vascular disease do lead to decline of cognitive function. Contrastingto GDS, the MCI diagnostic rate of CDR is higher in the cerebral vasculardisease group, and lower in the control group. The MCI diagnostic rate ofCDR is higher than GDS in the cerebral vascular disease group whether withhypertension or not. In the control group, the MCI diagnostic rate of thepatients with hypertension is higher when use GDS, but the difference is nosignificant between these scales when use them to diagnose MCI for subjectswith normal blood pressure. The result is consistent with this when establishsub-group with the level of serum lipid. The MCI diagnostic rate of CDR ishigher than GDS in the cerebral vascular disease group whether with diabetesor not when establish sub-group with diabetes or not. To sum up the resultsabove, it can be seen that the MCI diagnostic rates of CDR and GDS aredifferent for the patients with or without different risk factors for cerebralvascular diseases. Combining the results from analysis above, we consider thatthe decline of cognition of the patients with MCI and the cerebral vasculardiseases is due to overlapped pathological changes in the brain led by thecerebral vascular disease and risk factors for it;hypertension and abnormalserum lipid not only have impact on the cognition of patients with the cerebralvascular diseases but also take part in decline of cognitive function of thepatients without the cerebral vascular diseases. So the representation of MCI isdiversified and the MCI diagnostic rate of different scales is different in thesame group. This phenomenon implies us that for different sub-type of MCIwe should use different tools for diagnosis. Petersen points out that MCI mayhave three subsets mainly: ① amnestic MCI: this form of MCI presentmainly impaired memory and other areas of cognition are relatively integrated,while subjects with amnestic MCI usually progress to AD. ② multiple areasof cognitive impairment(without requiring memory deficit) that fall outside ofpredicted norms, but none are sufficiently severe to constitute dementia.Subjects with MCI defined in this fashion may also progress to AD, but theycould also progress to forms of dementia like vascular dementia or othernondementia disorders.③ MCI could conceivably present as impairment in asingle cognitive domain other than memory. For example, a pronouncedlanguage disturbance might progress to primary progressive aphasia, or analteration in attentional abilities or comportment and a dysexecutive syndromemight progress to frontotemporal dementia.It is well known that the cognitive impairment due to neural degenerativediseases is represented by Alzheimer'disease. It shows mainly injuredmemory in early time and then develops to general cortical cognitiveimpairment and its prophase of dementia is just amnestic MCI;While thecognitive impairment related to the cerebral vascular diseases namely vascularcognitive impairment has various representation. The vascular cognitiveimpairment may be cortical, subcortical, or mixed. It can behave patchingimpairment of cognition, or show decline of not memory but attention andexecutation, and becomes the second or third type of MCI noted above. Asingle patient'cognitive impairment may widely different from the other.This characteristic of vascular cognitive impairment requires that its detectingtool could reflect decline of cognitive function all-sidedly. Seen from theforming of the scales, the cognition-testing items of CDR is morecomprehensive relatively. It tests simultaneously aspects of cognitive functionfrom mild to serious including the abilities of judgement and analysis, socialliving, individual interest live a life independently. While GDS emphasizeparticularly on memory testing especially on mild cognitive impairment. Sowe consider that CDR is fit for diagnosis of mild vascular cognitiveimpairment, while GDS is more fit for diagnostic MCI patients withoutmedical record of the cerebral vascular diseases.In summery, through clinical observing on mild cognitive impairment,we can draw conclusion as follow: hypertension, diabetes, abnormal serumlipid are all related to decline of cognitive function, and they are all riskfactors for MCI. We should take prevention and treatment on these riskfactors early;different sub-type of MCI we should use different tools fordiagnosis. The decline of cognition of patients with MCI and the cerebralvascular diseases is due to overlapped pathological changes in the braininduced by the cerebral vascular disease and risk factors for it;For differentsub-types of MCI we should use different diagnostic tools. For mild vascularcognitive impairment CDR is recommended, and for the MCI patients withoutthe cerebral vascular diseases we recommend GDS.