Working Memory In Patients With Cerebral Small Vessel Disease

Introduction: Cerebral small vessel disease(CSVD)is a kind of syndrome that refers to the comprehensive changes of all cerebral small vessels,which causes various clinical symptoms,cognitive impairment,imaging and pathological changes.Cognitive dysfunction has always been the focus of research.There are some impaired cognitive function in many areas of the brain in patients with CSVD,including the decline of memory function.Whether there is impairment of working memory in patients with CSVD has not been studied.Objective: The aim of this study was to investigate whether the working memory function and cognitive function of patients with CSVD were impaired compared with those of healthy subjects,and to explore their relationship with other cognitive functions,the sensitivity of the N-back paradigm related indicators to cognitive function was also evaluated.Methods: This study included 55 subjects,including 22 patients with CSVD and 23 normal controls.All participants have completed the Chinese neuropsychological battery scale for small cerebral vascular disease,the neuropsychological background tests included the Montreal Cognitive scale(MOCA),the Patient Health Questionnaire depression symptom-9(PHQ-9),the Generalized Anxiety Disorder-7(GAD-7),the Color-number-connected Test(CTT),the Stroop Color Word Test(SCWT),the Verbal flux Test(VFT),the Auditory Word memory Test(Avlt),and the Boston Naming Test(BNT).The test is used to test the participants' overall cognitive function,including attention function,memory function,information processing function and language function.Simultaneously,all participants also completed the N-back computer paradigm test.Through testing the working memory ability of the participants,two indexes of reaction time and accuracy rate were obtained,which reflected the participants' working memory ability.The following results were obtained through the analysis of the parameters of patients with CSVD and normal controls,the correlation analysis and ROC Curve Analysis.Results: Analysis of the data showed that there was no significant difference in demographic data between the patients with CSVD and the normal control group,but the results were obtained by the Chinese small vessel neuropsychological inventory,the scores of Mo CA in CSVD group were significantly lower than those in healthy control group(p< 0.01),and the scores of cognitive function in CSVD group were significantly lower than those in HC group except language ability,it is mainly embodied in attention function,memory function and executive function.For the evaluation of working memory ability,the patients with CSVD in N-back computer paradigm with different difficulty load were weaker than the healthy control group in both reaction time and accuracy rate,besides the reaction time of 2-back,the rest were statistically significant(p <0.05).At the same time,the greater the N-back load,the greater the difference in accuracy between the two groups,the smaller the difference in reaction time between the groups.The results showed that the accuracy rate of 0-back was related to CTT-B(p< 0.01),the reaction time of 0-back was related to Mo CA and CTT-B,and the accuracy rate of 2-back was related to SDMT(p<0.05),2-back reaction time was correlated with CTT-A(p<0.05).The reaction time of 0-back,1-back and 2-back was better than the accuracy rate in evaluating cognitive function of patients with CSVD.Conclusion: The results showed that the cognitive function of patients with CSVD,except language ability,was significantly lower than that of normal controls,mainly in attention function,memory function and executive function.As for working memory,the reaction time and accuracy rate of CSVD patients in N-back computer paradigm with different difficulty load were lower than those in healthy control group.At the same time,the correlation analysis showed that the working memory ability of patients with CSVD might be related to the overall cognitive function,executive function and visual perception.In terms of N-BACK assessment index,the prediction of cognitive function N-back reaction time index is more sensitive than the accuracy rate.