Mild Cognitive Impairment and Decline in Resting State Functional Connectivity after Total Knee Arthroplasty with General Anesthesia

Abstract

Background: Research shows that older adults can have a decline in three key resting state networks (default mode network, central executive network, and salience network) after total knee arthroplasty and that patients' pre-surgery brain and cognitive integrity predicts decline.

Objectives: First, to assess resting state network connectivity decline from the perspective of nodal connectivity changes in a larger older adult surgery sample. Second, to compare pre-post functional connectivity changes in mild cognitive impairment (MCI) versus non-MCI.

Methods: Surgery (n = 69) and non-surgery (n = 65) peers completed a comprehensive preoperative neuropsychological evaluation and pre- and acute (within 48 hours) post-surgery/pseudo-surgery functional brain magnetic resonance imaging scan. MCI was classified within both (MCI surgery, n = 13; MCI non-surgery, n = 10). Using standard coordinates, we defined default mode network, salience network, central executive network, and the visual network (serving as a control network). The functional connectivity of these networks and brain areas (nodes) that make up these networks were examined for pre-post-surgery changes through paired samples t-test and ANOVA.

Results: There was a decline in RSN connectivity after surgery (p < 0.05) only in the three cognitive networks (not the visual network). The default mode and salience network showed nodal connectivity changes (p < 0.01). MCI surgery had greater functional connectivity decline in DMN and SN. Non-surgery participants showed no significant functional connectivity change.

Conclusion: Surgery with general anesthesia selectively alters functional connectivity in major cognitive resting state networks particularly in DMN and SN. Participants with MCI appear more vulnerable to these functional changes.

Keywords: Anesthesia; cognitive dysfunction; dementia; functional magnetic resonance imaging; mild cognitive impairment; orthopedics; surgery.

Figure 1.

Schematic design of parallel surgery and non-surgery participant timelines. TKA = total knee arthroplasty.

Figure 2.

Surgery group mean node connectivity changes from pre to post time points. Line thickness between nodes is weighted by node-to-node correlation. Lowercase “r” and “l” denote right and left brain hemispheres, respectively. Node abbreviation is as follows: DMN: mPFC – medial prefrontal cortex; LT – lateral temporal; AG – angular gyrus; PCC – posterior cingulate cortex; SN: ACC – anterior cingulate cortex; IN – insula; CEN: DLPFC – dorsolateral prefrontal cortex; IPL – inferior parietal lobe; VN: ExP – extrastriate peripheral fields; V1P – peripheral visual cortex; ExC – extrastriate central fields; V1C – central visual cortex

Figure 3.

Plot of mean pre and post functional network connectivity values for MCI and non-MCI surgery (A) and non-surgery (B) groups. Thinner lines are individual participants (grey are non-MCI and dashed black are MCI). Thicker lines represent group means (grey are non-MCI and dashed black are MCI). Y-Axis is correlation coefficient. 1A = DMN connectivity surgery group; 1B = DMN connectivity non-surgery group; 2A = CEN connectivity surgery group; 2B = CEN connectivity non-surgery group 3A = SN connectivity surgery group; 3B = SN connectivity non-surgery group; 4A = VN connectivity surgery group; 4B = VN connectivity non-surgery group.