Short-term Effects Of Neuroplasticity-based Computerized Cognitive Remediation On The Working Memory In Patients With Major Depressive Disorder By Structural And Functional MRI

OBJECTIVE We used neuropsychological tests、structural and functional magnetic resonance imaging(f MRI)to investigate the acute mechanisms of short-term high-intensity neuroplasticitybased computerized cognitive remediation(NBCCR)to improve working memory in depressed patients.METHODS A total of 38 patients with major depressive disorder(MDD)were recruited and divided into treatment group(n CCR)and control group,among which 24 patients were in the treatment group and 14 patients were in the control group.Patients in the treatment group were required to complete10 hours’ NBCCR.An numerical n-back task-state f MRI scan,DTI,T1WI3 D and digital span test(DST)was performed before(pre)and one week after enrollment(post).We used SPM8,FSL6.0,VBM8 to analysis the MRI data.We used RStudio and SPSS22 to analysis the behavioral and neuropsychological scale(MOCA,MMSE,HAMD,MADRS,DST)results.Demographic and clinical characteristics of the two groups were compared using Student’s t tests.For the n-back tasks,response accuracy(%)and reaction times(s)were recorded.We performed paired sample t-tests to compare DST score,response accuracy(%)and reaction times(s)on tests of n-back from enrollment to the end of one week.Besides,A two sample t-test contained in SPM8 was applied to analyze the differences of activation between the control group and the n CCR group at pre and post.We performed a tract-based spatial statistics(TBSS)to comparing fractional anisotropy(FA)in each group.A two sample t-test contained in VBM8 was also applied to analyze the differences of grey matter(GM)volume between the control group and the n CCR group at pre and post.RESULTS There was no significant change in the accuracy of the n-back task in the control group before and after one week.After NBCCR,the score of digital span test(forward)(t=-2.438,p=0.025)and the response accuracy of 2-back task(t=-2.95,p=0.008)in the treatment group increased significantly.Besides,there was an increasing trend in response accuracy for 1-back(t=-2.02,p=0.058).Furthermore,n CCR patients showed increased activation in left fusiform gyrus 、 left inferior frontal gyrus and right inferior frontal gyrus in the 2back-0back condition(P<0.05,corrected by GRF).Moreover,patients in n CCR group showed significant increases in FA a week later in the left anterior thalamic radiation and forceps minor(p<0.05,corrected by TFCE and FWE).We also found that,relative to controls,patients in n CCR group had a large cluster of increases in grey matter volume in the right inferior frontal gyrus(p<0.001).CONCLUSION The findings reported here suggest that short-term and high-intensity neuroplasticity-based computerized cognitive remediation could improve working memory in depression by promoting functional and structural plasticity in prefrontal lobe.