Preoperative cognitive training improves postoperative cognitive function: a meta-analysis and systematic review of randomized controlled trials.

Randomized controlled trials (RCTs) have shown conflicting results regarding the effects of perioperative cognitive training (CT) on the incidence of postoperative cognitive dysfunction (POCD) and postoperative delirium (POD). We, therefore, performed a meta-analysis to assess the overall effects of studies on this topic. We searched PubMed, Embase, the Cochrane Library, and Web of Science for all RCTs and cohort studies that investigated the effects of perioperative CT on the incidence of POCD and POD. Data extraction and quality assessment were conducted independently by two researchers. This study included nine clinical trials with a total of 975 patients. The results showed that perioperative CT significantly reduced the incidence of POCD compared with the control group [risk ratio (RR) = 0.5, 95% CI (confidence interval): 0.28-0.89, P = 0.02]. Nevertheless, for the incidence of POD, the difference between the two groups was not statistically significant (RR = 0.64; 95% CI: 0.29-1.43, P = 0.28). In addition, the CT group had less postoperative decline in the cognitive function scores compared with the control group [mean differences (MD): 1.58, 95% CI: 0.57-2.59, P = 0.002]. In addition, there were no statistically differences in length of hospital stay between the two groups (MD: -0.18, 95% CI: -0.93-0.57, P = 0.64). Regarding CT adherence, the proportion of patients in the cognitive training group who completed the planned duration of CT was 10% (95% CI: 0.05-0.14, P = 0.258). Our meta-analysis revealed that perioperative cognitive training is possibly an effective measure to reduce the incidence of POCD, but not for the incidence of POD. https://www.crd.york.ac.uk/prospero/display_record.php?ID=CRD42022371306, identifier: CRD42022371306.

Postoperative delirium (POD) and postoperative cognitive dysfunction (POCD) are common and serious complications in elderly surgical patients, especially after prolonged procedures. Recent evidence suggests that the depth of anaesthesia may influence the risk of these adverse outcomes. This meta-analysis examined whether light versus deep anaesthesia affects the incidence of POD and POCD, as well as recovery measures such as time to post-anaesthesia care unit (PACU) discharge and length of hospital stay in elderly patients. A systematic search identified randomized controlled trials (RCTs) published in English up to May 24, 2025, involving patients aged ≥60 years undergoing major surgery. The outcomes evaluated were POD, POCD, PACU discharge time, and hospital stay. Meta-analyses were conducted using random- or fixed-effects models based on heterogeneity. Eight RCTs with a total of 1,957 elderly patients were included. Light anaesthesia was associated with a significantly lower incidence of POD (OR = 0.52; 95% CI: 0.41-0.66; P < 0.00001; I² = 0%). The incidence of POCD was also reduced with light anaesthesia (OR = 0.55; 95% CI: 0.39-0.77; P = 0.0005; I² = 15%). Time to PACU discharge was shorter under light anaesthesia (mean difference (MD) = -9.43 minutes; 95% CI: -12.87 to -5.99; P < 0.00001; I² = 66%). Although hospital stay showed a trend favouring light anaesthesia (MD = -0.81 days; 95% CI: -1.85 to 0.24; P = 0.13), this result was not statistically significant (I² = 89%). Overall, light anaesthesia appears to reduce the incidence of POD and POCD and is associated with faster early recovery in elderly surgical patients. The observed trend toward shorter hospital stays did not reach significance. These findings indicate potential benefits of lighter anaesthetic strategies, though they should not be interpreted as evidence of direct causation, as other factors such as anaesthetic drug type and surgical invasiveness may also contribute.

IntroductionCognitive changes after anaesthesia and surgery, such as delirium and postoperative cognitive dysfunction (POCD), are common and lead to poor outcomes and increased healthcare costs. While several interventions for delirium...

Background:Elderly patients undergoing pulmonary lobectomy with incision are at a high risk for postoperative cognitive dysfunction (POCD). Intraoperative esketamine may offer potential neuroprotective benefits. This study aimed to evaluate the efficacy of intraoperative esketamine in reducing the incidence of POCD in elderly patients undergoing pulmonary lobectomy with incision.Methods:In this single-blind, controlled clinical trial, patients (aged 65–75 years) undergoing conventional pulmonary lobectomy were randomly allocated to receive esketamine (0.3 mg/kg/h) or remifentanil (0.1–0.2 μg/kg/min) during surgery. Cognitive function was assessed using the mini-mental state examination (MMSE) and negative emotional scores were recorded at baseline and multiple postoperative time points. Intraoperative and postoperative parameters, including heart rate (HR) and mean arterial pressure (MAP), pain scores and adverse events, were recorded. Blood samples were collected to measure amyloid-beta (Aβ) and microtubule-associated protein tau (tau) concentrations.Results:No significant difference was found in the incidence of postoperative delirium between the two groups, but the esketamine group exhibited a significantly lower incidence of POCD on days 1 and 3 postoperatively than the control group. The esketamine group also had significantly higher serum Aβ42/40 levels and significantly lower tau levels on day 1 postoperatively. At the end of surgery, the HR, MAP and pain visual analogue scale score of the control group were significantly higher than those of the esketamine group. No significant differences were observed in terms of adverse events between the two groups.Conclusion:Intraoperative administration of esketamine (0.3 mg/kg/h) was associated with a lower incidence of POCD and more stable hemodynamic indicators in elderly patients undergoing thoracic surgery, without increasing adverse events. The application of esketamine indicates a possible benefit with a favourable safety profile in reducing postoperative cognitive decline in this population.Trial Registration:Chinese Clinical Trial Registry, ChiCTR2200065266.

Postoperative cognitive dysfunction (POCD) and postoperative delirium (POD) are common postoperative complications in elderly patients. The effect of anesthesia depth on cognitive function remains unknown. We aimed to assess the correlations between anesthesia depth, cognitive function, and inflammation. Literature searches were conducted on Web of Science, PubMed, EMBASE, and Cochrane libraries until August 2019. All studies were randomized controlled trials (RCTs). The STATA 15.0 and trial sequential analysis (TSA) version 0.9.5.10 beta software were used for data analysis. POD and POCD were calculated using a random-effects model. The combined effect estimates are expressed as risk ratios (RR) with 95% confidence intervals (CI). Ten RCTs involving 3142 patients met inclusion criteria. The meta-analysis indicated that the incidence of POCD in the light anesthesia group was significantly lower than the deep anesthesia group on days 1 (RR=0.14, 95% CI: 0.04 to 0.45; I2=0.00, P>0.10), and 90 (RR=0.72, 95% CI: 0.54 to 0.96; I2=0.00,P>0.10). Light anesthesia significantly reduced the risk of POD (RR=0.69, 95% CI: 0.58 to 0.82; I2=0.00, P>0.10). There was no statistical difference in the Mini-Mental State Examination score between the groups on postoperative day 1 (standardized mean difference (SMD)= 0.04, 95% CI: -0.25 to 0.33; I2=0.00, P>0.10).The TSA found that there was insufficient evidence on the effect of anesthesia depth on POCD, but that the conclusions on POD were reliable. Light anesthesia was associated with a decrease in POD and may promote better neurocognitive function postoperatively in comparison with deep anesthesia.

Objective To analyze the incidence and risk factors of postoperative delirium (POD) in patients with glioma and to explore the association between WHO (World Health Organization) tumor grades and POD. Methods A second analysis of clinical data from 113 adult glioma patients in a single-center, prospective cohort study of 800 neurosurgery patients was conducted from March 2017 to February 2018 at Department of Critical Medicine (ICU), Beijing Tiantan Hospital, Capital Medical University. Patients were assessed for delirium on the first to third days post surgery (twice a day) using the Richmond Agitation-Sedation Scale (RASS) and Confusion Assessment Method for the ICU (CAM-ICU). The patient was divided into delirium group (43 cases) and non-delirium group (70 cases) by whether the patient had had delirium. We collected the patient’s general preoperative information, preoperative condition, early postoperative clinical data, and neurosurgical specialty data (including WHO grades) as potential risk factors that may be associated with the occurrence of POD. The independent risk factors of POD were identified using multivariate logistic regression analysis. In particular, the relationship between WHO glioma grade and POD was explored. Results In 113 glioma patients who were admitted to the ICU for routine postoperative monitoring, the incidence of POD was 38.1% (43/113). The incidence of POD in patients with WHO grade Ⅰ-Ⅳ gliomas increased with the increase of the WHO grade: 7.7% (1/13), 14.3% (3/21), 22.7% (5/22) and 63.0% (34/57). Among the potential risk factors, age (OR=1.08, 95% CI: 1.04-1.13, P<0.001), GCS (Glasgow coma scale) score at admission to ICU (OR=0.80, 95% CI: 0.71-0.90, P<0.001) and the WHO grade of tumor (OR=2.01, 95% CI: 1.03-3.92, P=0.041) was independent risk factors for POD. Conclusions The WHO grade of glioma is an independent risk factor for POD. With the increase of tumor grade, the incidence of POD also increases. Key words: Glioma; Neurosurgical procedures; Delirium; Neoplasm grading; Compensa-tory neuroplasticity

We are uncertain whether maintenance with propofol-based TIVA or with inhalational agents affect incidences of postoperative delirium, mortality, or length of hospital stay because certainty of the evidence was very low. We found low-certainty evidence that maintenance with propofol-based TIVA may reduce POCD. We were unable to perform meta-analysis for intraoperative hypotension or length of stay in the PACU because of heterogeneity between studies. We identified 11 ongoing studies from clinical trials register searches; inclusion of these studies in future review updates may provide more certainty for the review outcomes.

Postoperative delirium (POD), emergence delirium (ED), and postoperative cognitive dysfunction (POCD) are disorders of the neuropsychiatric spectrum affecting the elderly during the postoperative period, potentially sharing a common pathophysiological pathway. Disrupted sleep postoperatively correlates with both POD and POCD, revealing overlapping risk factors. This study investigates the potential of dexmedetomidine anesthesia to reduce the incidence of POD (primary outcome), ED, POCD, impairment of sleep quality, and emergent chronic pain (secondary outcomes) in older adults undergoing major orthopedic surgery under regional anesthesia. In this double-blind randomized control trial, patients scheduled for major lower limb orthopedic surgery under regional anesthesia were randomized to receive either dexmedetomidine or propofol for sedation at a 1:1 ratio. POD, ED, and POCD were assessed with the Confusion Assessment Method tool, the Riker Sedation-Agitation scale, and the European Battery of psychometric tests, respectively. Sleep quality was assessed using the Pittsburg Sleep Quality Index and chronic pain with the painDETECT tool. Assessments of all outcome variables were performed before surgery, and at 48 hours and 3 months postoperatively. A total of 80 patients (dexmedetomidine group n = 41) were enrolled in the study and completed the follow-up. POD, ED, and early POCD incidence were significantly lower in dexmedetomidine compared to propofol group (4.8% vs 38.4%, P = .001; 2.4% vs 38.4%, P < .001; 2.4% vs 56.4%, P < .001, respectively). Patients in the dexmedetomidine group reported improved sleep quality in the immediate postoperative period (lower PSQI score) and lower painDETECT scores at 3 months (4.4 ± 0.7 vs 13.4 ± 0.8, P < .001; 2.4 ± 0.9 vs 5.3 ± 0.9, P = .023, respectively). Intraoperative bradycardia and hemodynamic instability episodes were more common in the dexmedetomidine group while a single patient presented airway obstruction (2.4% vs 30.8%, P = .002) in the dexmedetomidine group. Sedation with dexmedetomidine resulted in a statistically and clinically important reduction in the incidence of POD, ED, and early POCD, while it improved self-reported postoperative sleep quality and reduced chronic pain scores in patients undergoing major elective lower limb surgery under regional anesthesia.

Postoperative delirium (POD) commonly occurs after major abdominal surgery and is associated with increased morbidity and mortality. There have been many studies on the relationship between POD and various surgeries, but research on POD after pancreatic cancer surgery is limited. The aim of this study was to identify the incidence and risk factors of POD after pancreatic cancer surgery. The subjects of this retrospective analysis were 196 patients who were transferred for postoperative care after pancreatic cancer surgery, to a 12-bed critical care medicine ward at Shandong Provincial Hospital, affiliated with Shandong First Medical University, between January 2015 and December 2019. The patients were divided according to whether they suffered POD into a delirium group and a non-delirium group. Delirium was assessed using the Confusion Assessment Method for the Intensive Care Unit and two independent medical practitioners analyzed all the data. Univariate and multiple logistic regression analyses were performed. The overall delirium incidence was 20.41%, which increased to 29.03% for patients aged ≥ 70years. POD was associated with age, smoking, the American Society of Anesthesiologists classification, the Acute Physiology and Chronic Health Evaluation II score, and the TNM stage of the cancer. The variables concerning sex, drinking, hypertension, a history of cerebral disease, surgery type, operation time, amount of bleeding, and the intraoperative use of dexmedetomidine did not differ significantly between the two groups. There was no significant difference in the length of ICU stay, with the exclusion of long-term stay for complications, between the groups, but POD tended to prolong the postoperative hospital stay and increase the risk of mortality. There was also a gradual decline in the incidence of POD between 2015 and 2019, especially from 2015 to 2018, after preventive measures were implemented. POD is related to many risk factors and worthy of attention. Appropriate management can reduce its incidence or at least shorten its duration.

Incidence and Risk Factors of Postoperative Delirium in Lumbar Spinal Fusion Patients: A National Database Analysis

Background:Postoperative cognitive dysfunction (POCD) is a serious and frequent complication after surgery, especially in elderly patients. Ketamine is an N-methyl D-aspartic acid receptor antagonist with demonstrated neuroprotective effects. An intravenous bolus of a sub-anesthetic dose (0.5 mg/kg) of ketamine can reduce postoperative delirium (POD) and POCD after cardiac surgery. But, the influence of ketamine on early POCD after non-cardiac surgery is unclear.Objectives:The current study aimed to evaluate the influence of ketamine on early postoperative cognitive function after orthopedic surgery in elderly patients.Patients and Methods:Fifty six elderly patients (> 60-years-old), scheduled for elective orthopedic surgery during general anesthesia (duration of anesthesia > two hours) were enrolled. Patients received intravenous bolus, a total of 3 mL mixed with 0.9% normal saline and 0.5 mg/kg ketamine (K group) or 3 mL of 0.9% normal saline (N group). Three neurocognitive function tests (mini-mental status examination, trail-making test, digit substitution test), and c-reactive protein (CRP) concentration were determined before surgery and on postoperative day one (POD 1) and postoperative day six (POD 6).Results:The two groups had similar demographic characteristics except for the gender. Surgical and anesthetic data were not significantly different. A statistically significant difference was observed in comparison of trail-making test score. Trail-making test score increased more in the N group (52.5 points) than the K group (13 points) at POD 1 (P = 0.047) compared with baseline scores. There were no significant differences in the mini-mental status examination, digit substitution test and CRP concentration at POD 1 and POD 6 between the two groups. POCD (the two Z-scores in more than two tests or the combined Z-score was 1.96 or more) was present in one patient (4%) in the K group at POD 6 (P = 0.98).Conclusions:The incidence of POCD was not significantly influenced by a bolus dose of ketamine (0.5 mg/kg) after orthopedic surgery in elderly patients. There were no negative effects of ketamine on early POCD.

Effect of goal-directed fluid therapy on early cognitive function in elderly patients with spinal stenosis: A Case-Control Study

Effects of cognitive training in Parkinson's disease: A randomized controlled trial

Cognitive training in neurodegenerative diseases: a way to boost neuroprotective molecules?

This study was aimed to systematically evaluate the effects of fentanyl and sufentanil on intraoperative cerebral oxygen saturation changes and postoperative cognitive function in elderly patients undergoing open surgery. Ninety-six elderly patients who had undergone open surgery under general anesthesia were randomly divided into fentanyl group (F group, anesthesia by fentanyl, 4g/kg) and sufentanil group (S group, anesthesia by sufentanil, 0.4µg/kg). There were no significant differences between the F group and S group in the general characteristics of patients. Compared to the F group, the S group had a better effect on suppressing the stress response, maintaining a stable hemodynamic status and achieving better anesthesia effects. The anesthesia recovery time of the S group was significantly shorter than that of the F group. There was no significant difference between the two groups in the intraoperative and postoperative agitation. Patient's waking time and extubation time were significantly shorter in the S group than the F group. The VAS scores in the S group were significantly lower than those in the F group at each time point. The Ramsay scores in the S group were significantly higher than those in the F group at each time point. The cerebral oxygen saturation (SctO2) levels in both groups were significantly increased following anesthesia induction and intubation compared to that of the awake state (P < 0.05), and SctO2 was significantly decreased during the surgery in both groups. The changes in SctO2 levels were not significantly different between the two groups (P > 0.05). The SctO2 level was significantly higher during surgery than that after intubation. Compared with the F group, the relative value of SctO2 decline in the S group was smaller. Compared to the day before surgery, the Montreal Cognitive Assessment (MoCA) scores of both groups were significantly reduced after surgery. At 1day post-surgery, the MoCA scores of the S group were significantly higher and the incidence of postoperative cognitive dysfunction (POCD) was significantly lower compared to the F group. POCD occurred in three patients (6.2%) in the S group, and the ratio was significantly lower than that in the F group (11.9%) (P < 0.05). It showed a consistent trend with the SctO2 status during the surgery. The relative value of SctO2 decline in the S group was significantly smaller than that in the F group. The reduction of cognitive function in the S group was significantly lower than that in the F group. These results indicate that the changes in SctO2 are a good prediction of the incidence of POCD.