AUTHOR=Zhang Xixue , Li Hui , Lv Yating , Zhu Zhenghong , Shen Xiaoyong , Lu Qi , Wang Wei , Wang Zhaoxin , Jiang Zhaoshun , Yang Lvjun , Lin Guangwu , Gu Weidong 

TITLE=Premorbid Alterations of Spontaneous Brain Activity in Elderly Patients With Early Post-operative Cognitive Dysfunction: A Pilot Resting-State Functional MRI Study

JOURNAL=Frontiers in Neurology

VOLUME=10

YEAR=2019

URL=https://www.frontiersin.org/journals/neurology/articles/10.3389/fneur.2019.01062

DOI=10.3389/fneur.2019.01062

ISSN=1664-2295

ABSTRACT=<p><bold>Background:</bold> Elderly patients with pre-existing cognitive impairment are susceptible to post-operative cognitive dysfunction (POCD). In this study, we investigated whether there is pre-existing local homogeneity and functional connectivity alteration in the brain before surgery for POCD patients as compared to that in non-POCD patients.</p><p><bold>Methods:</bold> Eighty elderly patients undergoing major thoracic or abdominal surgeries were recruited. Resting-state functional MRI was scanned at least 1 day before surgery. Neuropsychological tests (NPTs) were performed before surgery and at discharge, respectively. Pre-operative regional homogeneity (ReHo) and resting-state functional connectivity (RSFC) were compared between POCD patients and non-POCD patients, respectively. Partial correlation between NPTs and ReHo or RSFC was analyzed by adjusting for confounding factors.</p><p><bold>Results:</bold> Significant difference (<italic>P</italic> &lt; 0.001, Gaussian Random Field (GRF) correction which is a multiple comparisons correction method at cluster level, cluster size &gt; 49) in ReHo between POCD patients and non-POCD patients was detected in right hippocampus/parahippocampus. Pre-operative RSFC between right hippocampus/parahippocampus and right middle/inferior temporal gyrus increased in POCD patients (<italic>P</italic> &lt; 0.001, GRF correction for multiple comparisons) when compared with that in non-POCD patients.RSFC significantly correlated with composite <italic>Z</italic>-score (<italic>r</italic> = 0.46, 95% CI [0.234, 0.767], <italic>P</italic> = 0.002) or Digit Symbol Substitution Test <italic>Z</italic>-scores (<italic>r</italic> = 0.31, 95% CI [0.068, 0.643], <italic>P</italic> = 0.046) after adjusting for confounding factors.</p><p><bold>Conclusions:</bold> The results suggest that premorbid alterations of spontaneous brain activity might exist in elderly patients who develop early POCD. The neural mechanism by which patients with pre-operative abnormal spontaneous activity are susceptible to POCD requires further study.</p>