Multimodal Covariance Network Reflects Individual Cognitive Flexibility

Cognitive flexibility refers to the capacity to shift between patterns of mental function and relies on functional activity supported by anatomical structures. However, how the brain's structural-functional covarying is preconfigured in the resting state to facilitate cognitive flexibility under tasks remains unrevealed. Herein, we investigated the potential relationship between individual cognitive flexibility performance during the trail-making test (TMT) and structural-functional covariation of the large-scale multimodal covariance network (MCN) using magnetic resonance imaging (MRI) and electroencephalograph (EEG) datasets of 182 healthy participants. Results show that cognitive flexibility correlated significantly with the intra-subnetwork covariation of the visual network (VN) and somatomotor network (SMN) of MCN. Meanwhile, inter-subnetwork interactions across SMN and VN/default mode network/frontoparietal network (FPN), as well as across VN and ventral attention network (VAN)/dorsal attention network (DAN) were also found to be closely related to individual cognitive flexibility. After using resting-state MCN connectivity as representative features to train a multi-layer perceptron prediction model, we achieved a reliable prediction of individual cognitive flexibility performance. Collectively, this work offers new perspectives on the structural-functional coordination of cognitive flexibility and also provides neurobiological markers to predict individual cognitive flexibility.

Cognitive impairment following sedative overdose

INTRODUCTION

Patients with sedative overdose may have residual cognitive impairment at the time they are deemed medically cleared for discharge. Impairment could affect the performance of high-risk activities, including driving. The Trail Making Test is an alpha-numeric assessment that can be performed at the bedside to assess cognitive function. We examined whether there were differences in cognitive function when medically cleared between patients that overdosed on sedative and non-sedative drugs.

METHODS

A prospective, observational study assessed cognitive function using the Trail Making Test between 2018 and 2021. Patients (16 years and greater) completed testing upon medical clearance if they spoke English and had no previous neurological injury. Continuous covariates were compared using t-tests or Mann-Whitney U tests and multiple linear regression; binary variables were modelled using logistic regression.

RESULTS

Of 171 patients enrolled, 111 (65 per cent) had sedative overdose; they were older (median 32.1 versus 22.2 years) and more likely to be male (58.6 per cent versus 36.7 per cent). Benzodiazepines and paracetamol were the commonest drug overdoses. Patients with sedative overdose performed worse on Trail Making Test part A (37.0 versus 33.1 seconds, P = 0.017) and Trail Making Test part B (112.4 versus 81.5 seconds, P = 0.004). Multiple linear regression analysis indicated that patient age (P < 0.001, 1.7 seconds slower per year, 95 per cent confidence interval: 0.9-2.6 seconds) and perception of recovery (P = 0.006, 36.4 seconds slower if perceived not recovered, 95 per cent confidence interval: 10.8-62.0 seconds) were also associated with Trail Making Test part B times. Patients with sedative overdose were more likely to be admitted to the intensive care unit (Odds Ratio: 4.9, 95 percent confidence interval: 1.1-22.0; P = 0.04).

DISCUSSION

Our results are broadly in keeping with previously published work, but include a wider range of drug overdose scenarios (polypharmacy and recreational drugs). While patients demonstrated some perception of their cognitive impairment, our model could not reliably be used to provide individual discharge advice. The study design did not allow us to prove causation of cognitive impairment, or to make comparison between the strength of an overdose to the trail making test time.

CONCLUSIONS

Trail Making Test results suggested that patients who had sedative drug overdoses may have significant cognitive deficits even when medically cleared. Risk of harm may be minimised with advice to avoid high-risk activities such as driving. More profound impacts seen on the Trail Making Test part B than A may mean higher-order thinking is more affected than simple cognitive function.

Complex executive functions assessed by the trail making test (TMT) part B improve more than those assessed by the TMT part A or digit span backward task during vagus nerve stimulation in patients with drug-resistant epilepsy

Introduction

There is a paucity of clinical studies examining the long-term effects of vagus nerve stimulation (VNS) on cognition, although a recent study of patients with drug-resistant epilepsy (DRE) treated with VNS therapy demonstrated significant improvement in executive functions as measured by the EpiTrack composite score. The present study aimed to investigate performance variability in three cognitive tests assessing executive functions and working memory in a cohort of DRE patients receiving VNS therapy during a follow-up duration of up to 5 years.

Methods

The study included 46 DRE patients who were assessed with the Trail Making Test (TMT) (Parts A and B) and Digit Span Backward (DB) task prior to VNS implantation, 6 months and 12 months after implantation, and yearly thereafter as a part of the clinical VNS protocol. A linear mixed-effects (LME) model was used to analyze changes in test z scores over time, accounting for variations in follow-up duration when predicting changes over 5 years. Additionally, we conducted descriptive analyses to illustrate individual changes.

Results

On average, TMT-A z scores improved by 0.024 units (95% confidence interval (CI): 0.006 to 0.042, p = 0.009), TMT-B z scores by 0.034 units (95% CI: 0.012 to 0.057, p = 0.003), and DB z scores by 0.019 units per month (95% CI: 0.011 to 0.028, p < 0.001). Patients with psychiatric comorbidities achieved the greatest improvements in TMT-B and DB z scores among all groups (0.0058 units/month, p = 0.036 and 0.028 units/month, p = 0.003, respectively). TMT-A z scores improved the most in patients taking 1-2 ASMs as well as in patients with psychiatric comorbidities (0.042 units/month, p = 0.002 and p = 0.003, respectively).

Conclusion

Performance in all three tests improved at the group level during the follow-up period, with the most robust improvement observed in TMT-B, which requires inhibition control and set-switching in addition to the visuoperceptual processing speed that is crucial in TMT-A and working-memory performance that is essential in DB. Moreover, the improvement in TMT-B was further enhanced if the patient had psychiatric comorbidities.

ETMT: A Tool for Eye-Tracking-Based Trail-Making Test to Detect Cognitive Impairment

The growing number of people with cognitive impairment will significantly increase healthcare demand. Screening tools are crucial for detecting cognitive impairment due to a shortage of mental health experts aiming to improve the quality of life for those living with this condition. Eye tracking is a powerful tool that can provide deeper insights into human behavior and inner cognitive processes. The proposed Eye-Tracking-Based Trail-Making Test, ETMT, is a screening tool for monitoring a person's cognitive function. The proposed system utilizes a fuzzy-inference system as an integral part of its framework to calculate comprehensive scores assessing visual search speed and focused attention. By employing an adaptive neuro-fuzzy-inference system, the tool provides an overall cognitive-impairment score, allowing psychologists to assess and quantify the extent of cognitive decline or impairment in their patients. The ETMT model offers a comprehensive understanding of cognitive abilities and identifies potential deficits in various domains. The results indicate that the ETMT model is a potential tool for evaluating cognitive impairment and can capture significant changes in eye movement behavior associated with cognitive impairment. It provides a convenient and affordable diagnosis, prioritizing healthcare resources for severe conditions while enhancing feedback to practitioners.

Effects of COVID-19 on cognition and mood after hospitalization and at 2-month follow-up

A plethora of evidence links SARS-CoV-2 infection with concomitant cognitive dysfunction, which often persists weeks to months after the acute stages of illness and affects executive function, attention, memory, orientation, and movement control. It remains largely unclear which conditions or factors exacerbate the recovery. In a cohort of N=37 Slovenian patients (5 females, aged M = 58, SD = 10.7 years) that were hospitalized because of COVID-19, the cognitive function and mood states were assessed immediately after discharge and 2-months later to investigate the early post-COVID recovery changes. We assessed the global Montreal Cognitive Assessment (MoCA), Simple and Choice Reaction Times, executive functions (Trail-Making Test - TMT-A and TMT-B), short-term memory (Auditory Verbal Learning Test - AVLT), and visuospatial memory. We monitored depressive and anxiety symptoms and applied general self-efficacy and cognitive complaints questionnaires. Our results showed a global cognitive impairment (MoCA, Z = 332.5; p = 0.012), poorer performance on executive functions (TMT-A, Z = 188; p = 0.014; and TMT-B, Z = 185; p = 0.012), verbal memory (AVLT, F = 33.4; p < 0.001), and delayed recall (AVLT7, F = 17.1; p < 0.001), and higher depressive (Z = 145; p = 0.015) and anxiety (Z = 141; p = 0.003) symptoms after hospital discharge compared to 2-month follow-up, indicating that SARS-CoV-2 may transiently impair cognitive function and adversely affect the mood. No improvement in MoCA was observed in 40.5% of the patients at follow-up, indicating possible long-term effects of COVID-19 on global cognitive performance. Medical comorbidities (p = 0.035) significantly predicted the change in MoCA score over time, while fat mass (FM, p = 0.518), Mediterranean diet index (p = .0.944), and Florida Cognitive Activities Score (p = 0.927) did not. These results suggest that the patients' medical comorbidities at the time of SARS-CoV-2 infection could importantly contribute to the acute impairment of cognitive function and stress the importance of systemic implementation of countermeasures to limit the negative consequences on public health.

Decreases in Arterial Stiffness and Wave Reflection after Isometric Handgrip Training Are Associated with Improvements in Cognitive Function in Older Adults

This study aimed to investigate whether decreases in arterial stiffness and wave reflection after isometric handgrip (IHG) training improve cognitive function in older adults. Twenty-two older adults (mean age ± standard error: 75 ± 2 years) were randomly assigned to either a group that performed IHG training (IHG group, n = 11) or a sedentary control group (CON group, n = 11). The IHG exercise comprised four unilateral 2-minute isometric contractions at 30% of maximal voluntary contraction using a programmed handgrip dynamometer with 1-minute rest periods, performed 5 days per week for 8 weeks. Carotid pulse wave velocity (cPWV) and carotid augmentation index (cAIx) were measured, and the trail-making test (TMT) parts A (TMT-A) and B (TMT-B) were performed before (baseline) and after 8 weeks of training in both groups. After 8 weeks of training, cPWV, cAIx, TMT-A, and TMT-B were significantly reduced in the IHG group (p < 0.05). Significant positive correlations were found between the amount of change in cPWV and cAIx and that in TMT-A (p < 0.05 each). In addition, positive correlation trends were observed between the amount of change in cPWV and cAIx and that in TMT-B (p = 0.06, p = 0.05, respectively). The results of the present study suggest that IHG training-induced decreases in arterial stiffness and wave reflection are associated with improvements in cognitive function in older adults.

Effects of extended abstinence on cognitive functions in tramadol-dependent patients: A cohort study

BACKGROUND

Some pieces of the literature report impaired cognitive functioning in tramadol dependence. Whether extended abstinence improves cognitive functioning or not is not well studied.

AIM

We aimed to measure the change in cognitive functioning following complete abstinence among individuals with tramadol dependence.

METHODS

Eighty-three male tramadol-dependent (TD) and 57 matched healthy controls participated in this study. Cognitive functions were assessed using: The Trail making test (TMT), Wechsler Memory Scale-Revised (WMS-R), and Wechsler Adult Intelligence Scale (WAIS). Patients were assessed in the first week immediately after the end of the in-patient treatment program (T1), and after six months of sustained abstinence (T2).

RESULTS

At T1, the TD group showed deficits on all tested cognitive parameters (visual attention, task switching, working memory, visual memory, verbal memory, verbal knowledge, Verbal IQ, Performance IQ, and Full-Scale IQ) in comparison to the control group. At T2, significant improvements had occurred in all the tested parameters except performance IQ. The cognitive performance of the abstinent individuals at T2 was comparable to the control group for the verbal subsets of WMS-R, Verbal IQ, Performance IQ, and Full-Scale IQ. Nevertheless, it was still worse than the control group in TMT, and all other WMS subsets.

CONCLUSION

tramadol dependence has negative effects on cognitive performance, which improves with extended abstinence.

Selectively Enhanced Development of Working Memory in Musically Trained Children and Adolescents

In the current longitudinal study, we investigated the development of working memory in musically trained and nontrained children and adolescents, aged 9-20. We measured working memory with the Digit Span (DS) forwards and backwards tests (N = 106) and the Trail-Making A and B (TMT-A and B; N = 104) tests three times, in 2011, 2013, and 2016. We expected that musically trained participants would outperform peers with no musical training. Indeed, we found that the younger musically trained participants, in particular, outperformed their nontrained peers in the TMT-A, TMT-B and DS forwards tests. These tests all primarily require active maintenance of a rule in memory or immediate recall. In contrast, we found no group differences in the backwards test that requires manipulation and updating of information in working memory. These results suggest that musical training is more strongly associated with heightened working memory capacity and maintenance than enhanced working memory updating, especially in late childhood and early adolescence.

Improvement of hyponatremia in cirrhosis is associated with improved complex information processing

BACKGROUND AND AIM

Hyponatremia, a cause of brain dysfunction and risk factor for hepatic encephalopathy, is frequent in patients with advanced cirrhosis and ascites. The interdependence of liver failure and hyponatremia makes it difficult to separate the effects of each on cognitive function. The objective was to assess whether an increase in plasma sodium in patients with cirrhosis and ascites leads to an improvement in cognitive function.

METHODS

This is a post-hoc analysis of 250 cirrhosis patients without overt hepatic encephalopathy randomized to receive either placebo or satavaptan, a vasopressin V₂ antagonist. The exposure was plasma sodium, and the outcome was the trail-making test (TMT) parts A and B, which assesses speed of information processing, performed before the study starts and after 14 days. The results were analyzed by initial and change to final sodium concentration.

RESULTS

At entry, the patients with normonatremia exhibited better results on both the TMT-A (median 56 vs 77.5 s for patients with sodium ≤ 130 mmol/L [P = 0.0059]) and the TMT-B (median 127 vs 170 s for patients with sodium ≤ 130 mmol/L [P = 0.0066]), unrelated to age. Improvement of hyponatremia was more common in patients who received satavaptan (59.7%) than placebo (18.5%). Correction of hyponatremia did not shorten the simple TMT-A but markedly improved the complex TMT-B by an average of 20 s compared with 6.5 s in those with continuing hyponatremia (P = 0.02). Liver status measures remained stable during the period reported.

CONCLUSIONS

These data suggest that improvement of hyponatremia in patients with cirrhosis leads to an increase in the speed of complex information processing.

Genetic analysis for cognitive flexibility in the trail-making test in attention deficit hyperactivity disorder patients from single nucleotide polymorphism, gene to pathway level

Objectives: Investigation of the genetic basis of endophenotype and analysis the pathways with multiple genes of small effects might increase the understanding of the genetic basis of attention deficit hyperactivity disorder (ADHD). Here we aimed to explore the genetic basis of cognitive flexibility in ADHD at the single nucleotide polymorphism (SNP), gene and pathway levels. Methods: The trail-making test was used to test the cognitive flexibility of 788 ADHD patients. A genome-wide association analysis of cognitive flexibility was conducted for 644,166 SNPs. Results: The top SNP rs2049161 (P = 5.08e-7) involved gene DLGAP1 and the top gene CADPS2 in the gene-based analysis resulted in much literature evidence of associations with psychiatric disorders. Gene expression and network analysis showed their contribution to cognition function. The interval-enrichment analysis highlighted a potential contribution of 'adenylate cyclase activity' and ADCY2 to cognitive flexibility. Candidate pathway-based analysis for all SNPs found that glutamate system-, neurite outgrowth- and noradrenergic system-related pathways were significantly associated with cognitive flexibility (FDR <0.05), among which the neurite outgrowth pathway was also associated with ADHD symptoms. Conclusions: This study provides evidence for the genes and pathways associated with cognitive flexibility and facilitate the uncovering of the genetic basis of ADHD.

Assessment of different anesthesia depth under total intravenous anesthesia on postoperative cognitive function in laparoscopic patients

Background:

This study aimed to compare the effects of different depths of sedation during total intravenous anesthesia (TIVA) with remifentanil and propofol given by target-controlled infusion (TCI) on postoperative cognitive function in young and middle-aged patients undergoing gynecological laparoscopic surgery.

Materials and Methods:

A total of 150 American Society of Anesthesiologists physical Status I/II patients scheduled for gynecological laparoscopic operation were randomly divided into three groups. Anesthesia was maintained with intravenous infusion of TCI propofol and remifentanil, intermittent injected intravenously with rocuronium. The infusion concentration of propofol and remifentanil was adjusted to maintain bispectral index (BIS) at 30 < BIS ≤ 40 in the first group, 40 < BIS ≤ 50 in the second group, and 50 < BIS ≤ 60 in the third group. Mini–mental state examination (MMSE) and trail-making test (TMT) were used to assess the cognitive function one day preoperatively and one day postoperatively.

Results:

MMSE scores were > 24 sores on the day before anesthesia and the day after surgery in all three groups. However, the first group had the significantly higher MMSE scores than the other two groups after surgery (P < 0.05). Compared with that before anesthesia, TMT completion time was shorter on the day after surgery in the first group, while prolonged in the third group (P < 0.05). The first group had the significantly lower TMT completion time than the other two groups (P < 0.05).

Conclusion:

The depth of sedation, 30 < BIS value ≤ 40, under TIVA with remifentanil and propofol given by TCI had the minimal influence on postoperative cognitive function.

Multi-Modal Imaging of Neural Correlates of Motor Speed Performance in the Trail Making Test

The assessment of motor and executive functions following stroke or traumatic brain injury is a key aspect of impairment evaluation and used to guide further therapy. In clinical routine, such assessments are largely dominated by pen-and-paper tests. While these provide standardized, reliable, and ecologically valid measures of the individual level of functioning, rather little is yet known about their neurobiological underpinnings. Therefore, the aim of this study was to investigate brain regions and their associated networks that are related to upper extremity motor function, as quantified by the motor speed subtest of the trail making test (TMT-MS). Whole-brain voxel-based morphometry and whole-brain tract-based spatial statistics were used to investigate the association between TMT-MS performance with gray-matter volume (GMV) and white-matter integrity, respectively. While results demonstrated no relationship to local white-matter properties, we found a significant correlation between TMT-MS performance and GMV of the lower bank of the inferior frontal sulcus, a region associated with cognitive processing, as indicated by assessing its functional profile by the BrainMap database. Using this finding as a seed region, we further examined and compared networks as reflected by resting state connectivity, meta-analytic connectivity modeling, structural covariance, and probabilistic tractography. While differences between the different approaches were observed, all approaches converged on a network comprising regions that overlap with the multiple-demand network. Our data therefore indicate that performance may primarily depend on executive function, thus suggesting that motor speed in a more naturalistic setting should be more associated with executive rather than primary motor function. Moreover, results showed that while there were differences between the approaches, a convergence indicated that common networks can be revealed across highly divergent methods.

A neurodegenerative vascular burden index and the impact on cognition

A wide range of vascular burden factors has been identified to impact vascular function and structure as indicated by carotid intima–media thickness (IMT). On the basis of their impact on IMT, vascular factors may be selected and clustered in a vascular burden index (VBI). Since many vascular factors increase the risk of Alzheimer’s disease (AD), a multifactorial neurodegenerative VBI may be related to early pathological processes in AD and cognitive decline in its preclinical stages. We investigated an elderly cohort at risk for neurodegeneration (TREND study, n = 1102) for the multifactorial influence of vascular burden factors on IMT measured by ultrasound. To create a VBI for this cohort, vascular factors and their definitions (considering medical history, medication, and/or blood marker data) were selected based on their statistical effects on IMT in multiple regressions including age and sex. The impact of the VBI on cognitive performance was assessed using the Trail-Making Test (TMT) and the consortium to establish a registry for Alzheimer’s disease (CERAD) neuropsychological battery. IMT was significantly predicted by age (standardized β = 0.26), sex (0.09; males > females) and the factors included in the VBI: obesity (0.18), hypertension (0.14), smoking (0.08), diabetes (0.07), and atherosclerosis (0.05), whereas other cardiovascular diseases or hypercholesterolemia were not significant. Individuals with 2 or more VBI factors compared to individuals without had an odds ratio of 3.17 regarding overly increased IMT ( ≥ 1.0 mm). The VBI showed an impact on executive control [log(TMT B−A), p = 0.047] and a trend toward decreased global cognitive function (CERAD total score, p = 0.057) independent of age, sex, and education. A VBI established on the basis of IMT may help to identify individuals with overly increased vascular burden linked to decreased cognitive function indicating neurodegenerative processes. The longitudinal study of this risk cohort will reveal the value of the VBI as prodromal marker for cognitive decline and AD.

Decreased serum level of NGF in alcohol-dependent patients with declined executive function

The role of neurotrophic factors has been highlighted as a cause of decline in the cognitive function of alcohol-dependent patients. It is known that nerve-growth factor (NGF), one of the neurotrophins, is related to the growth and differentiation of nerve cells, as well as to a decline in cognitive function. The purpose of this study was to investigate the relationship between decreased NGF levels and cognitive decline in alcohol-dependent patients. The serum concentration of NGF was measured in 38 patients with chronic alcohol dependence, and several neuropsychological tests were also performed for cognitive function assessment. The results indicated a significant correlation between serum NGF level and the trail-making test part B, which evaluates executive function, but did not show a significant correlation with other cognitive function tests. An increased serum level of NGF was associated with a decreased completion time in the trail-making test B, and this finding indicates that a high serum level of NGF is related to greater executive function. This finding may imply a protective role of NGF in preventing neuron damage among patients with alcohol dependence. Larger controlled studies will be necessary in the future to investigate this issue further.