The Neuropsychological Features And Regional Cerebral Blood Flow Of Vascular Cognitive Impairment-no Dementia

Background:Vascular cognitive impairment(VCI) comprises a range of cognitive disorders related to cerebral vessel disease and has generally replaced the term vascular dementia(VaD).VCI has been of great interest to researchers because it is common,costly,and possibly preventable,especially VCI-ND(vascular cognitive impairment,no dementia).It is of great importance that more attention should be paid to the correct diagnosis and early identify of VCI-ND.Many earlier researches proposed that people with VCI-ND have a specific cognitive profile in which memory is preserved and executive function is impaired.But further studies suggest that VCI-ND is a heterogeneous group of cognitive disorders with different clinical features,neuropsychological deficits and prognoses.The pattern of VCI cognitive deficits may include all cognitive domains.Though there are many researches of VCI subtypes,the investigation of VCI-ND subtype is still rare.Objective:To investigate the neuropsychological features and rCBF(regional cerebral blood flow) of VCI-ND patients.VCI-ND subtypes will be distinguished from their cognitive deficits patterns.Analyze the relationships between these subtypes from clinical features,neuropsychological characteristics and rCBF.Methods:(1) We recruited 116 subjects with vascular disease presumed by medical history and neuroimaging(102 of leukoaraiosis,14 of post-stroke).We compared the clinical and neuropsychological features of the three groups:cognitive normal patients (n=25),VCI-ND patients(n=71) and VaD patients(n=18).All participants were administered neuropsychological tests covering global cognitive function,executive function,memory function,language function and visual spatial skills.(2) 69 VCI-ND patients with leukoaraiosis are subtyped basing on cognitive deficit features. We distinguished amnestic VCI from non-amnestic,and single-domain impairment from multi-domain impairment.Subtypeâ… :pure memory impairment;subtypeâ…¡: multi-domain impairment including memory deficit;subtypeâ…¢:single-domain impairment without memory disorder;subtypeâ…£:multi-domain impairment without memory disorder.Comparison was made between the four subtypes.(3) Xe-CT was used to evaluate rCBF of different cerebral regions of 31 VCI-ND patients and 10 normal controls.The relationship between cognitive function and rCBF was investigated.Results:(1)The cognition normal subjects with vascular factors performed best in all assessments while the VaD group performed worst.Comparison between the three groups shows significant differences.AVLT shows more sensitivity than LM or CFT in memory function.In executive function tests,the amount of time taken to finish the tests shows more sensitivity than correct numbers.(2) The pattern of VCI cognitive deficits is overall.It may include all cognitive domains.Subtypeâ… (n=19) andâ…¢(n=27) are mild VCI-ND while subtypeâ…¡(n=27) andâ…£(n=7) are comparatively more severe.Subtypeâ… shows episodic memory impairment only while subtypeâ…¡shows both episodic and semantic memory impairment.Subtypeâ…¢shows slowed information processing and motor speed while subtypeâ…¡andâ…£show more severe impairment including reasoning ability and conception forming ability.(3)Compared with normal controls,VCI-ND patients showed lower rCBF.Significant differences are showed in the following regions:bilateral temporal lobes,bilateral periventricular white matter,left ventricular posterior horn,bilateral caudates and thalamus.Subtypeâ… andâ…¢showed regional low rCBF.Subtypeâ…¡andâ…£showed more global low rCBF.Conclusion:All cognitive domains may be involved in VCI cognitive deficits. Subtypeâ… andâ…¢are mild VCI-ND while subtypeâ…¡andâ…£are comparatively more severe.Memory impairment develops from episodic to semantic memory deficit. Executive function can be divided into several factors,which may be impaired at different stages.Slowed information processing and motor speed may appear earlier than the impairment of reasoning and conception forming ability.The differences of the four groups in rCBF may provide evidence to this subtype classification.