Study On Relationship Between Cognitive Manifestation And TCM Differentiation Of Syndromes In Vascular Dementia

BackgroundVascular dementia (VD) is one of the common senile dementia, which characteristic iscognitive impairment. The screening and diagnosis of dementia will benefit for the preventionand treatment of VD. Though many scales on cognition assessment are adopted in clinic, nounited one is consented. And the reception degree is always overlooked. It is necessary tochoose the practical scales according to the characteristic of VD for further research on largesample in multi-center. There was mass record on the etiology of dementia in TraditionalChinese Medicine long history ago, and TCM therapies are effective for the treatment of VDin clinic, but some deficits still exist, such as lack of research on relationship between manysymptoms manifested in the syndromes and the disease, which leading to the difficulty ondifferentiation of syndromes, and affecting the externalization of TCM syndromes. In additionto cognitive scales, many assessment methods such as Event-related Potential and cerebralatrophy indexes on CT measurement are applied on cognitive deficit in VD both in clinic andresearch. If these assessment methods are not only related to diagnosis of VD, but also toTCM syndromes, they may be the new evidence for TCM differentiation. The research on therelationship between these methods and TCM syndromes may benefit for further study onmechanism and rules of VD, which may provide externalized proof for the treatment based onTCM differentiation.Methods Subjects are divided into 4 groups according to Clinical Dementia Rating: normalcognition (NC), vascular cognitive impairment no dementia (VCIND), mild VD (VD1) andmiddle degree VD (VD2) groups. All the subjects accepted neuropsychological measurementscales, ERP-P300 examination, CT scan and differentiation of TCM syndrome. Therelationship between the above different indexes, cognitive impairment in VD and TCMsyndromes, and their significance on VD diagnosis and syndrome discrimination were studiedrespectively. Results (1) Compared with cases in NC group, certain cognitive deficits presented in VCINDgroup such as delayed memory, executive and spatial structure abilities, but comprehensivedeficits manifested in two VD groups, which related to the degree of dementia. (2) P3 latencysignificantly increased in stroke cases (385.64±33.69 ms), and VD cases showed moreprolongation of N2 and P3 latencies, which correlated to the degree of dementia. But P3amplitude didn't show significant difference between the 4 groups. (3) Cerebral atrophy andleukoaraiosis significantly presented in VD cases, which related to cognitive impairment,dementia degree. (4) Among the TCM syndromes, there are 3 syndromes as deficiency ofkidney essence, obstruction of phlegm in orifice and block of blood stasis in collaterals,correlated with neuropsychological scales, dementia grade, density of white matter andcerebral atrophy indexes. P3 latency was positively correlated to syndromes of kidney-essence deficiency and block of blood stasis, and P3 amplitude was correlated to syndromesof obstruction of phlegm and obstruction of turbid fluid in the fu-organs. (5) The indexes thatsignificant for discrimination of VD include CLOX2 and IQCODE among cognitive scales,the four parts of orientation, calculation, delayed memory and spatial structure among MMSE,P3 latency of ERP, frontal horn index of CT measurement, and syndromes of obstruction ofphlegm in orifice, block of blood stasis in collaterals and deficiency of qi and blood as well.Conclusion (1) The selected neuropsychological scales were more acceptable than MMSE,they were convenient for clinical application with considerable sensitivity and specificity.Combined with each other, they could reflect comprehensive cognitive impairment of VD,and enhance validity and scope of its early diagnosis. (2) The selected cognitive scales wereavailable for distinguishing VD or not, so that they could be reference for VD diagnosis.Cognitive deficits in VD affected abilities of daily life and social life. Depression might affectcognition and life activities. The scales on abilities of calculation, delayed memory and spatialstructure combined with IQCODE may helpful for clinical screening on VD. (3) P3 latencywas sensitive for cognitive deficits, and correlated to dementia degree as well, so thatERP-P300 could be one of subjective index for judgment of cognition, which combined withcognitive scales would make VD diagnosis more precise and they may be the therapeuticindexes in VD treatment. (4) The main manifestation of cerebral atrophy was central atrophy,and frontal horn index may be significant for VD discrimination, but ventrical index may be helpful for discrimination between VD and cerebral infarction. Leukoaraiosis and cerebralatrophy were correlated to dementia degree and P3 latency. Cerebral atrophy index combinedwith ERP may be helpful for research on etiology and nature of cognitive deficits upondifferent viewpoints. (5) The syndromes of deficiency of kidney essence, obstruction ofphlegm, block of blood stasis in collaterals and deficiency of qi and blood affected cognitioncomprehensively. They are main manifestation of VD syndromes, and the former 3syndromes interacted on each other. Among them, the block of blood stasis syndrome was themost impact factor on cognition. The syndromes of obstruction of phlegm, block of bloodstasis in collaterals and deficiency of qi and blood were significant for VD discrimination.Deficiency of kidney essence existed in normal elders; with the aggravation of dementia,deficiency of kidney essence and qi & blood became more deteriorative, and obstruction ofphlegm and blood stasis in collaterals also became more apparent. It seemed that excessivefactors affected VD more than deficient ones. Cognitive scales combined with differentiationof TCM syndromes may predict the change of cognitive deficits in VD. Different indexescould be evidence of different syndromes, and might enhance the accuracy and externalizationof differentiation of TCM syndromes as reference. Syndromes may be available forsimplifying on above ones. The research on correlation and discrimination about TCMsyndromes may be helpful for analyzing the nature on their functional network and theircontrol center, and the intervention on these syndromes may benefit for prevention andtreatment on cognitive impairment in VD cases in this region as well.