Poststroke Cognitive Impairment No Dementia: A Neuropsychological Characteristics And Cerebral Blood Flow On SPECT/CT Study

PartⅠCharacteristics of cognitive impairment in patients with poststroke cognitive impairment no dementiaBackground Poststroke cognitive impairment(PS-CI) include all levels of cognitive decline resulting from acute cerebrovascular disease, ranging from mild deficits in one or more cognitive domains to a broad dementia-like syndrome.Two broad clinical subtypes are included:Poststroke cognitive impairment no dementia (PS-CIND)and Poststroke dementia(PSD).PS-CI cases that do not meet the criteria for dementia can also be labeled as Poststroke cognitive impairment no dementia (PS-CIND).Not all patients with PS-CIND progress to dementia definitely.One hundred and eighteen patients with a first ever cerebral stroke were followed up for 2 years.Neuropsychological assessment was performed at 1,6,12,and 24 months poststroke.As a results,most patients recovered from PS-CIND between the second and third assessments (19.6% versus 13.1% and 2.0% later on).As a preclinical stage of dementia,early diagnosis and intervention have a great signality in the prevention and treatment of dementia.Objective To investigate the characteristics of cognitive impairment in patients with poststroke cognitive impairment no dementia.Methods 46 patients with PS-CIND and 40 normal controls were tested with a wide neuropsychological battery of tests covering global cognitive function,memory,language,naming,executive function and visual spatial skills and the results were compared.These neuropsychological tests include Montreal cognitive assessment (MoCA),prospective memory test(PMT),clock drawing test(CDT),the Stroop color-word test (SCWT), auditory verbal learning test(AVLT),trail making test(TMT),verbal fluency tests,Boston named test,digit symbol coding subtest(DSCT),digital span test(DST) and the similarity test.Informed consent was obtained from all participants and the study was approved by the Ethics Committee.Results The cognitive test scores in multiple domains in PS-CIND group were significantly lower than those of normal control group.The results were as following:MoCA(20.48±2.92 vs27.42±1.28,F=64.501,P=0.000),PMT(6.13±1.82 vs7.42±1.57,F=3.405,P=0.013),Stroop C(115.09±31.55 vs93.77±16.52,F=5.394,P=0.001),TMT partB(160.93±30.95 vs142.37±28.54,F=7.021,P=0.002),DSCT(27.65±5.52 vs31.17±4.90,F=2.645,P=0.039),DST(3.80±0.69 vs4.87±0.85,F=10.496,P=0.000) and the similarity test (5.30±1.15 vs7.38±1.44,F=14.536,P=0.000),The scores of CDT and Boston named test in two groups were not statistically significant.Conclusions Current study indicates that there are cognitive impairment in multiple domains covering memory,attention, executive function and processing speed in patients with PS-CIND.The characteristic cognitive impairment is likely to impairments of attentional and executive performance.PartⅡThe changes of cerebral blood flow in patients with PS-CIND by SPECT/CTObjective This study investigates the changes of cerebral blood flow (CBF) in patients with PS-CIND by single photon emission computed tomography/computed tomography (SPECT/CT),and analyzes the correlation of the cognitive impairment severity with CBF changes.Methods 24 patients and 20 age-,sex- and education level matched normal controls were selected from PS-CIND group and normal control group respectively.With SPECT/CT,the average radio activity in gray matters of bilateral hemisphere,frontal,temporal,parietal,Occipital lobes as well as bilateral thalami were detected and the values of radio activity ratio(RAR) were compared in two groups(RAR1:Radio activity ratio of brain lobes and Cerebellar;RAR2:Radio activity ratio of brain lobes and Ipsilateral hemisphere).Moreover,the correlations between scores of MoCA as well as those of cognitive scales and the values of RAR were analyzed in PS-CIND group.Results Compared with control group, the mean cerebral blood flow of bilateral hemisphere and multiple regionals were both significantly decreased in patients with PS-CIND,of which left thalamus RAR1:0.76±0.08 vs0.81±0.10,t=-2.107,P<0.05and left striatum RAR1:0.81±0.11 vs0.92±0.08,t=-2.551,P<0.05;while the RAR2 vaules between two groups are no significant differences.There are positive correlations between MoCA scores and RAR1 values in left hemisphere(r=0.52,P<0.01),right hemisphere (r=0.45,P<0.01)and left thalamus(r=0.42,P<0.01).There are negatively correlations between TMT PartB scores and RAR1 values in left hemisphere(r=-0.59,P<0.01),right hemisphere(r=-0.54,P<0.01) and left thalamus(r=-0.56,P<0.01).In addition,the TMT PartB scores were negatively correlated with left striatum RAR1 values(r=0.-40,P<0.01), Stroop C scores were positively correlated with the left frontal lobe RAR1 values.Conclusions By SPECT/CT,reduction in left thalamus and left striatum may be the characteristic changes of cerebral blood flow (CBF) in patients with PS-CIND.Combining with neuropsychology assessment scales of MoCA,Stroop C,and TMT partB,the mean cerebral blood flow of bilateral hemispheric and the RAR1 of left thalamus and left striatum are helpful for early diagnosis.