Postoperative Memory Research Articles

MEF2C Alleviates Postoperative Cognitive Dysfunction by Repressing Ferroptosis.

Ferroptosis, a form of programmed cell death featured by lipid peroxidation, has been proposed as a potential etiology for postoperative cognitive dysfunction (POCD). Myocyte-specific enhancer factor 2C (MEF2C), a transcription factor expressed in various brain cell types, has been implicated in cognitive disorders. This study sought to ascertain whether MEF2C governs postoperative cognitive capacity by affecting ferroptosis. Transcriptomic analysis of public data was used to identify MEF2C as a candidate differentially expressed gene in the hippocampus of POCD mice. The POCD mouse model was established via aseptic laparotomy under isoflurane anesthesia after treatment with recombinant adeno-associated virus 9 (AAV9)-mediated overexpression of MEF2C and/or the glutathione peroxidase 4 (GPX4) inhibitor RSL3. Cognitive performance, Nissl staining, and ferroptosis-related parameters were assessed. Dual-luciferase reporter gene assays and chromatin immunoprecipitation assays were implemented to elucidate the mechanism by which MEF2C transcriptionally activates GPX4. MEF2C mRNA and protein levels decreased in the mouse hippocampus following anesthesia and surgery. MEF2C overexpression ameliorated postoperative memory decline, hindered lipid peroxidation and iron accumulation, and enhanced antioxidant capacity, which were reversed by RSL3. Additionally, MEF2C was found to directly bind to the Gpx4 promoter and activate its transcription. Our findings suggest that MEF2C may be a promising therapeutic target for POCD through its negative modulation of ferroptosis.

The Association of Cerebral Autoregulation Dysfunction and Postoperative Memory Impairment in Cardiac Surgery Patients.

Background and Objectives: Cardiac surgery is associated with various durations of cerebral autoregulation (CA) impairment and can significantly impact cognitive function. Cognitive functions such as memory, psychomotor speed, and attention are significantly impacted after cardiac surgery, necessitating prioritization of these areas in cognitive function tests. There is a lack of research connecting cerebral autoregulation impairment to specific cognitive function domains after cardiac surgery. This study aimed to determine if impaired cerebral autoregulation is associated with postoperative memory impairment and to test the hypothesis that the duration of this impairment affects the development of postoperative memory issues. Materials and Methods: A prospective study was conducted in 2021-2023. After approval of the Ethics Committee and with patient's written consent, 83 adult patients undergoing elective on-pump coronary artery bypass graft (CABG) surgery were enrolled. All patients were assessed for cognitive function 1 day before surgery using the Mini-Mental state examination (MMSE-2) test as a screening tool and the Hopkins Verbal Learning Test-Revised (HVLT-R) to assess memory specifically. To diagnose possible memory impairment (IM), all patients underwent a repeat assessment of cognitive function on the 7th-10th postoperative day. Cerebral autoregulation monitoring using transcranial Doppler was performed. Cerebral autoregulation status index (Mx) was recorded using Intensive Care Brain Monitoring System software, 9.1.5.23 (Cambridge, UK). Results: According to our research, the incidence of postoperative memory impairment is 30.1%. Temporary cerebral autoregulation impairment occurs in all patients undergoing elective in-pump CABG surgery. The duration of the single longest CA impairment event in seconds (LCAI) and the LCAI dose were higher in patients with postoperative memory impairment, p = 0.006 and p < 0.007, respectively. Conclusions: Cerebral autoregulation impairment is important in developing memory loss after cardiac surgery. The duration and dose of the LCAI event are predictive of postoperative memory impairment.

Hippocampal activations obtained during language fMRI tasks: A complementary tool for predicting postoperative memory prognosis

In medial temporal lobe epilepsy (MTLE), the benefits of surgery must be balanced against the risk of post-operative memory decline. Prediction of postoperative outcomes based on functional magnetic resonance imaging (fMRI) tasks is increasingly common but remains uncertain. The aim of this retrospective study was to determine whether hippocampal activations elicited by fMRI language tasks could enhance or refine memory fMRI in MTLE patients candidates to surgery. Forty-six patients were included: 30 right and 16 left MTLE, mostly with hippocampal sclerosis. Preoperative assessment included neuropsychological tests and fMRI with language (syntactic verbal fluency) and memory tasks (encoding, delayed, and immediate recognition of images of objects). Thirty patients underwent surgery and had neuropsychological evaluations one year after surgery. Worsening was defined as a degradation of more than 10 % in postoperative forgetting scores compared to preoperative scores in verbal, non-verbal and global memory. Memory fMRI had the best sensitivity with hippocampal activations obtained in 95 % of patients, versus 65 % with language fMRI. Considering the patients who elicited an hippocampal activation, language fMRI led to 80 %, 65 % and 85 % of correct predictions for respectively global, verbal and non verbal memory (versus 71 %, 64 % and 68 % with memory fMRI). Memory and language fMRI predictions outperformed those made by neuropsychological tests. In summary, language fMRI was less sensitive than memory fMRI to elicit hippocampal activations but when it did, the proportion of correct memory predictions was better. Moreover, it proved to be an independent predictive factor regardless of the side of the epileptic focus. Given the ease of setting up a language task in fMRI, we recommend the systematic combination of memory and language tasks to predict the post-operative memory outcome of MTLE patients undergoing epilepsy surgery.

Impact of white matter networks on risk for memory decline following resection versus ablation in temporal lobe epilepsy

BackgroundWith expanding neurosurgical options in epilepsy, it is important to characterise each options’ risk for postoperative cognitive decline. Here, we characterise how patients’ preoperative white matter (WM) networks relates to...

Verbal memory network mapping in individual patients predicts postoperative functional impairments.

Verbal memory decline is a significant concern following temporal lobe surgeries in patients with epilepsy, emphasizing the need for precision presurgical verbal memory mapping to optimize functional outcomes. However, the inter-individual variability in functional networks and brain function-structural dissociations pose challenges when relying solely on group-level atlases or anatomical landmarks for surgical guidance. Here, we aimed to develop and validate a personalized functional mapping technique for verbal memory using precision resting-state functional MRI (rs-fMRI) and neurosurgery. A total of 38 patients with refractory epilepsy scheduled for surgical interventions were enrolled and 28 patients were analyzed in the study. Baseline 30-min rs-fMRI scanning, verbal memory and language assessments were collected for each patient before surgery. Personalized verbal memory networks (PVMN) were delineated based on preoperative rs-fMRI data for each patient. The accuracy of PVMN was assessed by comparing post-operative functional impairments and the overlapping extent between PVMN and surgical lesions. A total of 14 out of 28 patients experienced clinically meaningful declines in verbal memory after surgery. The personalized network and the group-level atlas exhibited 100% and 75.0% accuracy in predicting postoperative verbal memory declines, respectively. Moreover, six patients with extra-temporal lesions that overlapped with PVMN showed selective impairments in verbal memory. Furthermore, the lesioned ratio of the personalized network rather than the group-level atlas was significantly correlated with postoperative declines in verbal memory (personalized networks: r = -0.39, p = .038; group-level atlas: r = -0.19, p = .332). In conclusion, our personalized functional mapping technique, using precision rs-fMRI, offers valuable insights into individual variability in the verbal memory network and holds promise in precision verbal memory network mapping in individuals.

Astrocytic phagocytosis in the medial prefrontal cortex jeopardises postoperative memory consolidation in mice.

Memory impairment is one of the main characteristics of postoperative cognitive dysfunction. It remains elusive how postoperative pathological changes of the brain link to the memory impairment. The clinical setting of perioperation was mimicked via partial hepatectomy under sevoflurane anaesthesia together with preoperative restraint stress (Hep-Sev-stress) in mice. Memory changes were assessed with fear conditioning. The medial prefrontal cortex (mPFC)-dorsal hippocampus connectivity was evaluated with injecting neurotracer 28 days before surgery. Astrocytic activation was limited via injecting AAV-GFAP-hM4Di-eGFP into the mPFC. Astrocytic and microglial phagocytosis of synapses were visualised with co-labelling hippocampal neuronal axon terminals with PSD-95 and S100β or Iba1. Neuroinflammation and oxidative stress status were also detected. Hep-Sev-stress impaired the memory consolidation (mean [standard error], 49.91 [2.55]% vs. 35.40 [3.97]% in the contextual memory, p = 0.007; 40.72 [2.78]% vs. 27.77 [2.22]% in cued memory, p = 0.002) and the cued memory retrieval (39.00 [3.08]% vs. 24.11 [2.06]%, p = 0.001) in mice when compared with these in the naïve controls. Hep-Sev-stress damaged the connectivity from the dorsal hippocampus to mPFC but not from the mPFC to the dorsal hippocampus and increased the astrocytic but not microglial phagocytosis of hippocampal neuronal axon terminals in the mPFC. The intervention also induced neuroinflammation and oxidative stress in the dorsal hippocampus and the mPFC in a regional-dependent manner. Limiting astrocyte activation in the mPFC alleviated memory consolidation impairment induced by Hep-Sev-stress. Postoperative memory consolidation was impaired due to astrocytic phagocytosis-induced connectivity injury from the dorsal hippocampus to the medial prefrontal cortex.

Polygenic burden and its association with baseline cognitive function and postoperative cognitive outcome in temporal lobe epilepsy

ObjectiveDemographic and disease factors are associated with cognitive deficits and postoperative cognitive declines in adults with pharmacoresistant temporal lobe epilepsy (TLE), but the role of genetic factors in cognition in TLE is not well understood. Polygenic scores (PGS) for neurological and neuropsychiatric disorders and IQ have been associated with cognition in patient and healthy populations. In this exploratory study, we examined the relationship between PGS for Alzheimer’s disease (AD), depression, and IQ and cognitive outcomes in adults with TLE. Methods202 adults with pharmacoresistant TLE had genotyping and completed neuropsychological evaluations as part of a presurgical work-up. A subset (n = 116) underwent temporal lobe resection and returned for postoperative cognitive testing. Logistic regression was used to determine if PGS for AD, depression, and IQ predicted baseline domain-specific cognitive function and cognitive phenotypes as well as postoperative language and memory decline. ResultsNo significant findings survived correction for multiple comparisons. Prior to correction, higher PGS for AD and depression (i.e., increased genetic risk for the disorder), but lower PGS for IQ (i.e., decreased genetic likelihood of high IQ) appeared possibly associated with baseline cognitive impairment in TLE. In comparison, higher PGS for AD and IQ appeared as possible risk factors for cognitive decline following temporal lobectomy, while the possible relationship between PGS for depression and post-operative cognitive outcome was mixed. SignificanceWe did not observe any relationships of large effect between PGS and cognitive function or postsurgical outcome; however, results highlight several promising trends in the data that warrant future investigation in larger samples better powered to detect small genetic effects.

Investigating the effect of hippocampal sclerosis on parietal memory network.

We aimed to investigate differences in episodic memory networks between patients with temporal lobe epilepsy (TLE) due to hippocampal sclerosis and healthy controls, especially with regards to the parietal memory network (PMN), as well as their relation to neuropsychological memory performance after mesial temporal resection. 28 healthy subjects as well as 21 patients with TLE (12 left, 9 right) were investigated using a spatial memory fMRI paradigm, which has been shown to activate the PMN. Regions of interest (ROI) were defined based on the results of the second-level analyses and activations within the predefined ROIs were compared across groups and correlated with postoperative verbal and nonverbal memory scores. Healthy subjects showed activations within regions belonging to the dorsal visual stream and the PMN as well as the bilateral parahippocampal place area, the bilateral frontal eye field, and the bilateral middle frontal gyrus. Comparison between groups revealed that TLE patients activated significantly less in the left middle occipital gyrus and the right precuneus. The activation pattern in left TLE patients showed further reductions, mainly in areas belonging to the dorsal visual stream and the PMN within the left hemisphere. Activations within the left superior parietal lobulus, bilateral inferior parietal lobulus, bilateral middle temporal gyrus, left precuneus, left frontal eye field, and left middle frontal gyrus correlated significantly with postoperative verbal memory scores, and activations within the left superior parietal lobulus, left inferior parietal lobulus, left middle temporal gyrus, and left precuneus correlated significantly with higher performance in postoperative nonverbal memory scores. The PMN is involved in episodic memory encoding. Higher activations in areas belonging to the PMN and the dorsal visual stream, especially within the left hemisphere, before amygdalohippocampectomy may result in higher postoperative memory scores. This study aims to investigate the effects of epilepsy due to hippocampal sclerosis, i.e. scarring in the temporal lobe, on memory networks in the brain. We discovered that especially patients with left-sided hippocampal sclerosis show reduced brain activations in visual areas and memory networks within the left hemisphere of the brain during orientation in space. Importantly, higher activations within these areas may result in better memory after epilepsy surgery.

Clinical application of esketamine-induced mild sedation technique in outpatient oral surgery

Background &amp; Objective: Sedation is often required in outpatient surgical procedures, performed under local analgesia, to allay the anxiety of the patient, which may lead to involuntary movements of the patient, thus interfering in the smooth course of the surgery. Various sedative drugs have been used by the anesthetists. We compared the effects of mild sedation techniques induced by remifentanil combined with propofol and esketamine combined with propofol on the cardiopulmonary indices of intraoperative patients, and to explore the application of mild sedation techniques in oral outpatient surgery. Methodology: A total of 62 patients undergoing oral surgery were randomly divided into a control group (31 cases, receiving remifentanil combined with propofol) and an observation group (31 cases, receiving esketamine combined with propofol). The vital signs of the patients were monitored at five time points: admission (T0), anesthesia induction (T1), local anesthesia (T2), the beginning of surgery (T3), and the end of surgery (T4), including heart rate (HR), mean arterial pressure(MAP), bispectral index (BIS), respiratory rate, and oxygen saturation(SPO2). Postoperative memory of each step was recorded, and the sedative effect was evaluated by physician and patient using the visual analogue scale (VAS). Results: During surgery, 6 patients in the control group had SpO2 &lt; 90%, and 8 patients experienced coughing or tongue fall, while 1 patient in the observation group had a transient increase in blood pressure. After intravenous administration, all patients had a decrease in HR, and the decrease in the observation group was significantly less than that in the control group (P &lt; 0.05). The BIS values in the observation group were significantly higher than those in the control group during T2 and T3. Conclusion: In oral outpatient surgery, the combination of propofol and esketamine-induced mild sedation can stabilize the hemodynamic indices of patients during surgery, reduce the incidence of complications, and improve patient satisfaction. Abbreviations: BIS- Bispectral Index; HR- Heart Rate; RASS- Richmond Agitation-Sedation Scale; SBP- Systolic Blood Pressure; VAS- Visual Analogue Scale Key words: Mild Sedation; Esketamine; Propofol; Remifentanil; Oral Surgery Citation: Xin Z, Yu T, Wang LL, Qu W, Wang N, Yao M. Clinical application of esketamine-induced mild sedation technique in outpatient oral surgery. Anaesth. pain intensive care 2022;27(6):715−720; DOI: 10.35975/apic.v27i6.2234 Received: May 28, 2023; Revised: October 24, 2023; Accepted: November 08, 2023

Preoperative white matter network organization and memory decline after epilepsy surgery.

Risk for memory decline is a common concern for individuals with temporal lobe epilepsy (TLE) undergoing surgery. Global and local network abnormalities are well documented in TLE. However, it is less known whether network abnormalities predict postsurgical memory decline. The authors examined the role of preoperative global and local white matter network organization and risk of postoperative memory decline in TLE. One hundred one individuals with TLE (n = 51 with left TLE and 50 with right TLE) underwent preoperative T1-weighted MRI, diffusion MRI, and neuropsychological memory testing in a prospective longitudinal study. Fifty-six age- and sex-matched controls completed the same protocol. Forty-four patients (22 with left TLE and 22 with right TLE) subsequently underwent temporal lobe surgery and postoperative memory testing. Preoperative structural connectomes were generated via diffusion tractography and analyzed using measures of global and local (i.e., medial temporal lobe [MTL]) network organization. Global metrics measured network integration and specialization. The local metric was calculated as an asymmetry of the mean local efficiency between the ipsilateral and contralateral MTLs (i.e., MTL network asymmetry). Higher preoperative global network integration and specialization were associated with higher preoperative verbal memory function in patients with left TLE. Higher preoperative global network integration and specialization, as well as greater leftward MTL network asymmetry, predicted greater postoperative verbal memory decline for patients with left TLE. No significant effects were observed in right TLE. Accounting for preoperative memory score and hippocampal volume asymmetry, MTL network asymmetry uniquely explained 25%-33% of the variance in verbal memory decline for left TLE and outperformed hippocampal volume asymmetry and global network metrics. MTL network asymmetry alone produced good diagnostic classification of memory decline in left TLE (i.e., an area under the receiver operating characteristic curve of 0.80-0.84 and correct classification of 65%-76% of cases with cross-validation). These preliminary data suggest that global white matter network disruption contributes to verbal memory impairment preoperatively and predicts postsurgical verbal memory outcomes in left TLE. However, a leftward asymmetry of MTL white matter network organization may confer the highest risk for verbal memory decline. Although this requires replication in a larger sample, the authors demonstrate the importance of characterizing preoperative local white matter network properties within the to-be-operated hemisphere and the reserve capacity of the contralateral MTL network, which may eventually be useful in presurgical planning.

1 Network Efficiency as Structural Reserve: Pre- And Post-Operative Associations Between Network Organization and Memory in Temporal Lobe Epilepsy

Objective:Memory impairment is a common comorbidity in individuals with temporal lobe epilepsy (TLE). Further, in medication-resistant epilepsy the frontline option, neurosurgical epileptogenic zone destruction, places memory at significant risk. Research has highlighted that TLE causes whole-brain network efficiency disruption, but it is not established how this may explain pre- and post-surgical cognition. Here we examine whether white matter structural network organization predicts pre-operative memory function and/or risk for post-operative memory decline.Participants and Methods:Patients with drug-resistant TLE were recruited from two epilepsy centers in a prospective longitudinal study. The pre-operative sample included 51 individuals with left TLE (L-TLE), 52 with right TLE (R-TLE), and 57 healthy controls who underwent T1- and diffusion-weighted MRI (dMRI), and neuropsychological tests of verbal and visual memory. Forty-four patients (n=21 L-TLE) subsequently underwent temporal lobe surgery (36 anterior temporal lobectomy; 7 stereotactic laser amygdalohippocampectomy; 1 amygdalohippocampectomy) and completed post-operative memory testing. Whole-brain connectomes were generated via diffusion tractography and analyzed using graph theory, focusing on network integration (path length) and specialization (transitivity). In the preoperative dataset, first we compared TLE versus controls with analysis of covariance (ANCOVAs) controlling for age. Next, linear regressions examined the association between memory scores and network efficiency between L-TLE, R-TLE and controls. In the post-operative sample, bivariate correlations examined the association between pre- to post-operative memory change and 1) global network efficiency and 2) asymmetry of mesial temporal efficiency (i.e., local efficiency of the hippocampal, parahippocampal, and entorhinal nodes). Finally, efficiency metrics were entered into stepwise regressions along with established predictors of memory decline.Results:Compared to controls, TLE showed longer path length (p &lt; .05; ηp2 = .03) and lower transitivity (p = .01; ηp2 = .04). Pre-operatively, better verbal learning and memory were associated with both shorter path length (β = -0.23 to -0.32; psadjusted &lt; .05) and increased transitivity (β = 0.20 to 0.31; psadjusted &lt; .05). These associations were greater in L-TLE than R-TLE (i.e., a significant interaction; β = -0.29 to 0.25; psadjusted &lt;.05). Post-operatively, global metrics predicted decline on list learning for LTLEs (rs = -.57 to .58; ps &lt; .01), and were marginal on list recall (rs = -.42 to .40; ps &lt; .10). Leftward asymmetry of mesial temporal local efficiency predicted greater decline across most verbal memory measures for L-TLE (rs -.47 to -59; psadjusted &lt;.05), but not R-TLE. Asymmetry of mesial network efficiency uniquely explained at least 20 to 43% of the variance in list learning, recall, and story learning for L-TLE, outperforming hippocampal asymmetry and preoperative score (psadjusted &lt;.05).Conclusions:Our findings suggest that global white matter network abnormalities contribute to verbal memory impairment pre-operatively and vulnerability to decline post-operatively in L-TLE. Asymmetry of a predefined mesial temporal sub-network may help predict post-operative memory function following left temporal lobe surgery, such that greater efficiency in the to-beresected mesial temporal network may be an important risk factor for decline. Our findings extend the importance of network approaches in TLE to include the relationships between neurobiological networks and memory function.

4 Preoperative International Classification of Cognitive Disorder in Epilepsy (IC-CoDE) Phenotype is Associated with Postoperative Memory Decline Following Temporal Lobectomy

Objective:The International Classification of Cognitive Disorder in Epilepsy (IC-CoDE) is a new consensus-based taxonomy that classifies patients into one of four cognitive phenotypes (i.e., cognitively intact, single-domain impairment, bi-domain impairment, generalized impairment). The IC-CoDE has been effectively applied to patients with temporal lobe epilepsy (TLE), but little is known about the relationship between pre-operative cognitive phenotype and post-operative cognitive outcome following epilepsy surgery. The purpose of this study was to examine whether the IC-CoDE classifications are related to memory decline following surgery for TLE.Participants and Methods:347 patients (ages 16-66; 57% female) with pharmacoresistant TLE completed comprehensive pre- and post-surgical neuropsychological assessments. Patients were classified into IC-CoDE phenotypes based on pre-surgical pattern of cognitive impairment using a threshold of &gt;1.5 standard deviations (SD) below the normative mean. Change scores were calculated from delay trial scores of the following memory tests: Rey Auditory Verbal Learning Test (RAVLT), and Logical Memory (LM) and Verbal Paired Associates (VPA) subtests from the Wechsler Memory Scale - Third Edition (WMS-III). Cutoffs were applied using epilepsy-specific reliable change indices and patients were classified within the ‘decline’ group if they experienced significant decline on any of the three memory measures.Results:The distribution of IC-CoDE phenotypes in our sample were as follows: 57% intact, 29% single-domain, 10% bi-domain, and 5% generalized impairment. 108 patients (31%) demonstrated post-surgical memory decline. Patients who underwent dominant temporal lobectomy were more likely to show post-surgical memory decline compared to non-dominant temporal lobectomy. However, there was no significant difference in phenotype distribution between patients who underwent left versus right-sided resections; thus, analyses were conducted on the entire sample to increase power. Chi-square analyses revealed unique patterns of post-surgical memory decline across phenotypes, X2 = 8.79, p = .032. There was a significantly higher proportion of patients with memory decline in the single-domain phenotype (39%) and this was followed by the bi-domain phenotype (33%) and the intact phenotype (29%). In contrast, patients with generalized impairment were unlikely to show memory decline (.06%). Within the single domain impaired phenotype, there were no differences between the specific domains impaired and memory decline. Logistic regression model was also significant; after controlling for surgery side, the IC-CoDE phenotypes significantly predicted the likelihood of a patient experiencing post-surgical memory decline; X2 = 8.18, p = .043.Conclusions:In addition to the IC-CoDE providing a useful cognitive classification scheme in epilepsy, the IC-CoDE phenotypes appear helpful in identifying those at risk for post-operative memory decline. Previous literature has suggested that those with better pre-surgical cognition are generally at highest risk for cognitive decline. Our results generally follow this trend, but interestingly, patients with single domain impairment were at the highest risk of memory decline, even above those in the cognitively intact group. Future studies are important to confirm this pattern in other samples and examine additional contributing factors and underlying mechanisms that may influence risk of memory decline across these cognitive phenotypes.

Bilateral ictal EEG is associated with better memory outcome after hippocampal sclerosis surgery.

To compare memory outcomes after surgery for unilateral hippocampal sclerosis (HS)-associated epilepsy in patients with unilateral and bilateral ictal electrographic involvement. We prospectively evaluated HS patients, aged 18-55 years and IQ ≥70. Left (L) and right (R) surgical groups underwent noninvasive video-EEG monitoring and Wada test. We classified patients as Ipsilateral if ictal EEG was restricted to the HS side, or Bilateral, if at least one seizure onset occurred contralaterally to the HS, or if ictal discharge evolved to the opposite temporal region. Patients who declined surgery served as controls. Memory was evaluated on two occasions with Rey Auditory-Verbal Learning Test and Rey Visual-Design Learning Test. Baseline neuropsychological test scores were compared between groups. Pre- and postoperative scores were compared within each group. Reliable change index Z-scores (RCI) were obtained using controls as references, and compared between surgical groups. We evaluated 64 patients. Patients were classified as: L-Ipsilateral (9), L-Bilateral (15), L-Control (9), R-Ipsilateral (10), R-Bilateral (9), and R-Control (12). On preoperative evaluation, memory performance did not differ among surgical groups. Right HS patients did not present postoperative memory decline. L-Ipsilateral group presented postoperative decline on immediate (P = 0.036) and delayed verbal recall (P = 0.011), while L-Bilateral did not decline. L-Ipsilateral had lower RCI Z-scores, indicating delayed verbal memory decline compared to L-Bilateral (P = 0.012). Dominant HS patients with bilateral ictal involvement presented less pronounced postoperative verbal memory decline compared to patients with exclusive ipsilateral ictal activity. Surgery was indicated in these patients regardless of memory impairment on neuropsychological testing, since resection of the left sclerotic hippocampus could result in cessation of contralateral epileptiform activity, and, therefore, improved memory function.

Language MEG predicts postoperative verbal memory change in left mesial temporal lobe epilepsy

ObjectiveTo clarify whether preoperative language magnetoencephalography (MEG) predicts postoperative verbal memory (VM) changes in left mesial temporal lobe epilepsy (LMTLE). MethodsWe reviewed 18 right-handed patients with LMTLE who underwent anterior temporal lobectomy or selective amygdala hippocampectomy, 12 with (HS+) and 6 without hippocampal sclerosis (HS−). Patients underwent neuropsychological assessment before and after surgery. MEG was measured with an auditory verbal learning task in patients preoperatively and in 15 right-handed controls. Dynamic statistical parametric mapping (dSPM) was used for source imaging of task-related activity. Language laterality index (LI) was calculated by z-score of dSPM in language-related regions. LI in the region of HS+ and HS− was compared to controls. The correlation between LI and postoperative VM change was assessed in HS+ and HS−. ResultsPreoperative LI in supramarginal gyrus showed greater right-shifted lateralization in both HS+ and HS− than in controls. Right-shifted LI in supramarginal gyrus was correlated with postoperative VM increase in HS+ (p = 0.019), but not in HS−. ConclusionsRight-shifted language lateralization in dSPM of MEG signals may predict favorable VM outcome in HS+ of LMTLE. SignificanceFindings warrant further investigation of the relation between regional language laterality index and postoperative verbal memory changes.

Postoperative seizure and memory outcome of temporal lobe epilepsy with hippocampal sclerosis: A systematic review.

We conducted a systematic review and meta-analysis to evaluate postoperative seizure and memory outcomes of temporal lobe epilepsy with different hippocampal sclerosis (HS) subtypes classified by International League Against Epilepsy (ILAE) Consensus Guidelines in 2013. Following the PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) and MOOSE (Meta-Analysis of Observational Studies in Epidemiology) guidelines, we searched PubMed, Embase, Web of Science, and Cochrane Library from January 1, 2013 to August 6, 2023. Observational studies reporting seizure and memory outcomes among different HS subtypes were included. We used the Newcastle-Ottawa scale to assess the risk of bias and the Grading of Recommendations Assessment, Development, and Evaluation (GRADE) approach to grade the quality of evidence. Seizure freedom and improved outcome (Engel 1 or ILAE class 1-2) ≥1 year after surgery were defined as the primary and secondary seizure outcome. A random-effects meta-analysis by DerSimonian and Laird method was performed to obtain pooled risk ratio (RRs) with 95% confidence interval (CIs). The memory impairment was narratively reviewed because of various evaluation tools. Fifteen cohort studies with 2485 patients were eligible for the meta-analysis of seizure outcome. Six cohorts with detailed information on postoperative memory outcome were included. The pooled RRs of seizure freedom, with moderate to substantial heterogeneity, were .98 (95% CI = .84-1.15) between HS type 2 and type 1, 1.11 (95% CI = .82-1.52) between type 3 and type 1, and .80 (95% CI = .62-1.03) between the no-HS and HS groups. No significant difference of improved outcome was found between different subtypes (p > .05). The quality of evidence was deemed to be low to very low according to GRADE. The long-term seizure outcome (≥5 years after surgery) and memory impairment remained controversial.

Leveraging the resting brain to predict memory decline after temporal lobectomy.

Predicting memory morbidity after temporal lobectomy in patients with temporal lobe epilepsy (TLE) relies on indices of preoperative temporal lobe structural and functional integrity. However, epilepsy is increasingly considered a network disorder, and memory a network phenomenon. We assessed the utility of functional network measures to predict postoperative memory changes. Seventy-two adults with TLE (37 left/35 right) underwent preoperative resting-state fMRI and pre- and postoperative neuropsychological assessment. We compared functional connectivity throughout the memory network of each patient to a healthy control template (n=19) to identify differences in global organization. A second metric indicated the degree of integration of the to-be-resected temporal lobe with the rest of the memory network. We included these measures in a linear regression model alongside standard clinical variables as predictors of memory change after surgery. Left TLE patients with more atypical memory networks, and with greater functional integration of the to-be-resected region with the rest of the memory network preoperatively, experienced the greatest decline in verbal memory after surgery. Together, these two measures explained 44% of variance in verbal memory change, outperforming standard clinical and demographic variables. None of the variables examined were associated with visuospatial memory change in patients with right TLE. Resting-state connectivity provides valuable information concerning both the integrity of to-be-resected tissue and functional reserve across memory-relevant regions outside of the to-be-resected tissue. Intrinsic functional connectivity has the potential to be useful for clinical decision-making regarding memory outcomes in left TLE, and more work is needed to identify the factors responsible for differences seen in right TLE.

Cognition, Emotional States and Health-Related Quality of Life in Awake Craniotomy for Glioma: A Case Series

Awake craniotomy is an effective procedure for optimizing the onco-functional balance of resections in glioma. However, limited data exists on the cognition, emotional states, and health-related quality of life (HRQoL) of patients with glioma who undergo awake craniotomy. This study aims to describe 1) perioperative cognitive function and emotional states in a multilingual Asian population, 2) associations between perioperative cognitive function and follow-up HRQoL, and 3) associations between preoperative emotional states and follow-up HRQoL. This is a case series of 14 adult glioma patients who underwent awake craniotomy in Singapore. Cognition was assessed with the Montreal Cognitive Assessment and the Repeatable Battery for the Assessment of Neuropsychological Status, emotional states with the Depression, Anxiety and Stress Scale-21 Items, and HRQoL using the EuroQol-5D-5L, the European Organisation for Research and Treatment of Cancer (EORTC) QLQ-C30, and the European Organisation for Research and Treatment of Cancer (EORTC) QLQ-BN20. Patients with better preoperative cognitive scores on all domains reported better HRQoL. Better postoperative immediate memory and language scores were associated with better HRQoL. Moderate preoperative depression scores and mild and moderate preoperative stress scores were associated with poorer HRQoL compared to scores within the normal range. Mild preoperative anxiety scores were associated with better HRQoL compared to scores within the normal range. This descriptive case series showed that patients with higher preoperative cognitive scores reported better follow-up HRQoL, while patients who reported more preoperative depressive and stress symptomatology reported worse follow-up HRQoL. Future analytical studies may help to draw conclusions about whether perioperative cognition and emotional states predict HRQoL on follow-up.

The Effect of Anaesthesia Management with Different Fresh Gas Flows on Cognitive Functions of Geriatric Patients: A Randomized Double-blind Study.

The present study aimed to compare the effects of two different fresh gas flows (FGFs) (0.5 L min-1 and 2 L min-1) applied during maintenance of anaesthesia on recovery from anaesthesia and early cognitive functions in geriatric patients. In this prospective, randomised, double-blind study, sixty patients were divided into two groups according to the amount of FGF. Minimal-flow anaesthesia (0.5 L min-1 FGF) was applied to group I and medium-flow anaesthesia (2 L min-1 FGF) was applied to group II during maintenance of anaesthesia. Following the termination of inhalation anaesthesia, recovery times were recorded. The evaluation of cognitive functions was performed using the Addenbrooke's Cognitive Examination (ACE-R). There was no significant difference between the two groups in terms of demographic characteristics and recovery (P > 0.05). There was no significant difference between the two groups in terms of the preoperative day, the first postoperative day, and the third postoperative day; ACE-R scores (P > 0.05). In group II, on the third postoperative day ACE-R scores were found to be significantly lower than the preoperative ACE-R scores (P=0.04). In group II, third postoperative day ACE-R memory sub-scores (14.53 ± 3.34) were found to be significantly lower than preoperative ACE-R memory sub-scores (15.03 ± 3.57) (P=0.04). In geriatric patients, minimal-flow anaesthesia was not superior to medium-flow anaesthesia in terms of recovery properties and cognitive functions. Keeping in mind that hypoxaemia and changes in anaesthesia levels may occur with the reduction of FGF, both minimal- and medium-flow anaesthesia can be applied with appropriate monitoring without adverse effects on recovery and cognitive functions.

The contribution of probiotics for the double-edge effect of cefazolin on postoperative neurocognitive disorders by rebalancing the gut microbiota.

Emerging data suggest that perioperative gut dysbiosis is prevalent and may be associated with postoperative neurocognitive disorders (PND). Antibiotics and probiotics are key factors influencing the microbiota. Many antibiotics have anti-microorganisms and direct anti-inflammatory properties, which may have cognitive repercussions. NLRP3 inflammasome activation has been reported to be involved with cognitive deficits. This study aimed to determine the effect and mechanism of probiotics on neurocognitive problems associated with perioperative gut dysbiosis by the NLRP3 pathway. In a randomized, controlled trial, adult male Kunming mice undergoing surgery were administered cefazolin, FOS + probiotics, CY-09, or a placebo in four distinct experimental cohorts. Fear conditioning (FC) tests evaluate learning and memory. Following FC tests to evaluate inflammatory response (IR) and the permeability of barrier systems, the hippocampus and colon were extracted, and feces were collected for 16 s rRNA. One week after surgery, surgery/anesthesia decreased the frozen behavior. Cefazolin attenuated this declination but aggravated postoperative freezing behavior 3 weeks after surgery. Probiotics ameliorated surgery/anesthesia-induced memory deficits and perioperative cefazolin-induced postoperative memory deficits 3 weeks after surgery. NLRP3, caspase-1, Interleukin-1β (IL-1β), and Interleukin-18 (IL-18) levels were increased 1 week after the hippocampus and colon surgery, which were attenuated by CY-09 and probiotics, respectively. Probiotics could correct dysbacteria and IR caused by surgery/anesthesia stress and cefazolin alone. These findings imply that probiotics are an efficient and effective way of maintaining the balance of gut microbiota, which may reduce NLRP3-related inflammation and alleviate PND.

Comparison of the Effect of Propofol and Midazolam on Cognitive Performance in Elderly Patients Undergoing Spinal Anesthesia: A Double-Blind Clinical Trial

Background: The effects of anesthetics on memory have not yet been completely clear, and there have been some discrepancies on this issue in the literature. This study aimed to compare the effect of two sedatives, Propofol and Midazolam, on the incidence of cognitive dysfunction in elderly patients undergoing spinal anesthesia.&#x0D; Methods: This double-blind clinical trial was conducted on 136 elderly patients‏ who underwent spinal anesthesia in Besat Hospital, Hamadan, Iran, during 2020-21. The patients were randomly assigned into two groups of Propofol (0.2 mg/kg) and Midazolam (0.02 mg/kg). The Wechsler Memory Scale-III (WMS-III) were utilized to assess the cognitive dysfunction and memory coefficient in the two groups.&#x0D; Results: There was no significant difference between the two groups in terms of short and long-term memory, as well as cognitive dysfunction before and after spinal anesthesia (P&gt;0.05). The time of onset of sedation (Z=-11.11; P&lt;0.005) and recovery from sedation (Z=-10.56; P&lt;0.005) were longer in the Midazolam group, compared to the Propofol group. There were no significant differences between the two groups before and after operation regarding the WMS-III categories (P&gt;0.05). The comparison of the two groups in terms of memory coefficient after operation showed no significant differences between them in this regard (Z=-0.63; P=0.52).&#x0D; Conclusion: Midazolam and Propofol showed no differences regarding the effects on the postoperative memory coefficient or cognitive dysfunction.