The Harmful Effect Of Vascular Risk Factors On Cognitive Reserve In Elders

Objective This study aimed to investigate the effect of vascular risk factors on the cognitive reserve(CR)in the elders without stroke and dementia.Methods A sample of 64 patients with stroke-free and dementia-free were enrolled in Framingham’s 10-year cardiovascular risk assessment.The subjects were divided into low-risk,moderate-risk and high-risk groups.All subjects were evaluated for cognitive function,including the Mini Mental state examination(MMSE),the Montreal Cognitive Assessment(MoCA),the verbal fluency test(VFT),the Rey Auditory Verbal Verification(DSST),digit span test(DST),trail making test(TMT),Stroop test and so on.The differences in intelligence(Wechsler’s adult intelligence scale,WAIS-RC)were compared among three groups.Through the tract-based spatial statistics(TBSS),a significant linearity of the FA values among the three groups was evaluated by using a general linear model with threshold-free cluster enhancement(TFCE)after controlling age,sex,and educational level,the same as the correlation between FA and intelligence.Results There were 25 cases in low-risk group,17 cases in moderate-risk group and 22 cases in high-risk group.There were no significant differences between age,education and cognitive scores.The higher risk group had higher full scale IQ and verbal IQ,and the differences were statistically significant(One-way ANOVA,p<0.05).The efficiency of brain network declined as the Framingham vascular risk increased.The results of TBSS showed a significant difference in FA values in left anterior corona radiate,internal capsule,corpus callosum,posterior thalamic radiation(p<0.05,TFCE),which suggested that white matter integrity had been destroyed to a certain extent.In the correlation analysis,it was found that there was a positive correlation between intelligence and FA in genu of corpus callosum,right anterior corona radiate,external capsule,anterior limb of internal capsule,posterior limb of internal capsule,left posterior thalamic radiation(p<0.05,TFCE).Conclusions Vascular risk factors had an influence on CR and the possible impact of vascular risk factors on CR could be affected by damage to white matter integrity.