Assessment and identification of cognitive changes after surgery in older adults

<p dir="ltr">The overarching aim of this dissertation was to explore methods for assessing postoperative cognitive changes in older adults, including an evaluation of a digital cognitive test battery, and exploring psychological factors influencing cognitive outcomes.</p><p dir="ltr"><b>Study I</b> was an observational, mixed-methods study with 40 older adult patients (mean age 73, 21 women) who underwent total joint arthroplasty. Postoperative cognitive functions and neuroinflammation were assessed using an analog cognitive test battery, blood biomarkers and qualitative interviews. Five patients met criteria for delayed neurocognitive recovery, however, many patients experienced cognitive issues, especially in executive functions and fatigue. Psychological factors like low mood and sense of control played a role in recovery and daily life, while biomarkers remained normal.</p><p dir="ltr"><b>Study II</b> was a systematic review and meta-analysis synthesizing psychological factors associated with postoperative delirium, delayed neurocognitive recovery and postoperative neurocognitive disorder in older adults. In total, 27 studies involving 6146 patients were included: depression was slightly linked (OR 1.07 95% CI 0.96-1.18) to postoperative delirium, while anxiety, stress, and certain personality traits were also associated with cognitive outcomes (p < 0.001), though findings were mixed. Delirium was evaluated in all studies, delayed neurocognitive recovery and postoperative neurocognitive disorder in only two. Assessment methods and timing varied widely.</p><p dir="ltr"><b>Study III</b> was a randomized cross-over study with 50 older adult volunteers (mean age 76, 28 women). Two performance-based measures were compared, an analog cognitive test battery with a self-administered digital one. Participants were interviewed regarding their perceptions of the cognitive assessments. Correlation analyses between the tests were weak to moderate, r=0.19-0.52 and Cohen's d effect sizes were small to large, ranging from 0.25 to 1.43. Qualitative analysis identified two themes: self-competing in a safe environment and experience with technology; participants felt comfortable during the tests, and they reported high usability.</p><p dir="ltr"><b>Study IV</b> was an observational feasibility study with 24 older adult patients (mean age 77, 13 women) who underwent abdominal surgery, and 5 nurses involved in the recruitment or administration of a digital cognitive test. The feasibility, acceptability and usability of the test was assessed. The test was found feasible, acceptable, and with excellent usability (System Usability Scale mean 87), meeting criteria for a larger trial. Three patients were diagnosed with one-day postoperative delirium, and none were diagnosed with postoperative neurocognitive disorder. The participants considered the test important for assessing cognitive function and easy to use. However, several challenges regarding feasibility were expanded upon in the qualitative interviews including reasons behind low recruitment rates.</p><p dir="ltr"><b>Conclusions</b>: This dissertation advances understanding of how postoperative cognitive changes can be assessed in older adults. A digital self-administered cognitive test was shown to be feasible and acceptable in healthy older adults and in a small group of highly educated, non-frail patients undergoing abdominal surgery. Depression and postoperative delirium were most consistently studied in the current evidence base. Overall, the findings indicate that postoperative cognitive changes cannot be fully understood by test performance alone; psychological factors and subjective experiences also shape cognitive trajectories after surgery.</p><h3>List of scientific papers</h3><p dir="ltr">This dissertation is based on the following studies, referred to in text by their Roman numerals. As an author, I retain the copyright to our papers published in these open access journals and have the right to republish them.</p><p dir="ltr">I.<b> </b><b>Amirpour, A.</b>, Bergman, L., Markovic, G., Liander, K., Nilsson, U., & Eckerblad, J. (2025). Understanding neurocognitive recovery in older adults after total hip arthroplasty-neurocognitive assessment, blood biomarkers and patient experiences: a mixed-methods study. BMJ open, 15(1), e093872. <a href="https://doi.org/10.1136/bmjopen-2024-093872" rel="noreferrer" target="_blank">https://doi.org/10.1136/bmjopen-2024-093872</a></p><p dir="ltr">II.<b> </b><b>Amirpour A,</b> Bergman L, Markovic G, Eckerblad J, Nilsson, U, Falk, A. Psychological factors associated with postoperative cognitive outcomes - a systematic review and meta-analysis. [Submitted] </p><p dir="ltr">III.<b> </b><b>Amirpour, A.</b>, Eckerblad, J., Bergman, L., & Nilsson, U. (2024). Comparing analog and digital neurocognitive tests with older adults: a study of the ISPOCD battery vs. a digital test battery from Mindmore. BMC geriatrics, 24(1), 34. <a href="https://doi.org/10.1186/s12877-023-04648-w" rel="noreferrer" target="_blank">https://doi.org/10.1186/s12877-023-04648-w</a></p><p dir="ltr">IV.<b> </b><b>Amirpour A,</b> Saarijärvi M, Eckerblad J, Markovic G, Thorell A, Nilsson U, Bergman L. Evaluation of a digital, self-administered, cognitive test battery in older adult patients undergoing abdominal surgery: a non-randomized feasibility trial. [Submitted]</p>