Vitamin D and COVID-19 Infection

INTRODUCTION

The COVID-19 pandemic has prompted the medical world to look at factors that may influence outcomes. There have been connections made between vitamin D and COVID-19, as vitamin D has previously been shown to play a role in the maintenance of immune homeostasis.

MATERIALS AND METHODS

We performed a prospective cohort study on 103 patients at Wigan Wrightington and Leigh NHS Foundation Trust looking at serum vitamin D levels of patients with positive COVID-19 swabs. Results were collated and correlations were made to compare vitamin D levels with age; severity of illness; hospital outcomes; and frailty. Comparisons were also made between frailty and outcome.

RESULTS

The results showed that there was a significant statistical difference between vitamin D levels and severity of infection: those who were treated in the intensive care units (ICU) (severe symptoms) had lower vitamin D levels than those treated on the ward (p=0.0446). There was also a correlation between vitamin D levels and frailty: those who were more frail had higher vitamin D levels than fitter patients (P=0.005). Vitamin D and frailty had no effect on hospital outcomes of COVID-19 infection.

CONCLUSION

Ultimately, we concluded that low vitamin D can increase susceptibility of contracting COVID-19, increase severity of infection but does not affect mortality.

Monitoring cognitive change in multiple sclerosis using a computerized cognitive battery

Background

Cognitive monitoring that can detect short-term change in multiple sclerosis is challenging. Computerized cognitive batteries such as the CogState Brief Battery can rapidly assess commonly affected cognitive domains.

Objectives

The purpose of this study was to establish the acceptability and sensitivity of the CogState Brief Battery in multiple sclerosis patients compared to controls. We compared the sensitivity of the CogState Brief Battery to that of the Paced Auditory Serial Addition Test over 12 months.

Methods

Demographics, Expanded Disability Status Scale scores, depression and anxiety scores were compared with CogState Brief Battery and Paced Auditory Serial Addition Test performances of 51 patients with relapsing-remitting multiple sclerosis, 19 with secondary progressive multiple sclerosis and 40 healthy controls. Longitudinal data in 37 relapsing-remitting multiple sclerosis patients were evaluated using linear mixed models.

Results

Both the CogState Brief Battery and the Paced Auditory Serial Addition Test discriminated between multiple sclerosis and healthy controls at baseline (p<0.001). CogState Brief Battery tasks were more acceptable and caused less anxiety than the Paced Auditory Serial Addition Test (p<0.001). In relapsing-remitting multiple sclerosis patients, reaction time slowed over 12 months (p<0.001) for the CogState Brief Battery Detection (mean change -34.23 ms) and Identification (-25.31 ms) tasks. Paced Auditory Serial Addition Test scores did not change over this time.

Conclusions

The CogState Brief Battery is highly acceptable and better able to detect cognitive change than the Paced Auditory Serial Addition Test. The CogState Brief Battery could potentially be used as a practical cognitive monitoring tool in the multiple sclerosis clinic setting.

Routine measurement of plasma chromogranin B has limited clinical utility in the management of patients with neuroendocrine tumours

OBJECTIVE

Chromogranin A (CgA) and B (CgB) are markers for monitoring disease status in patients with gastroenteropancreatic neuroendocrine tumours (NETs). These are specialized diagnostic tests often necessitating referral of specimens to a supraregional assay service (SAS) laboratory for analysis. The aim of this audit was to assess whether measurement of either plasma CgA or CgB alone provides sufficient clinical information in comparison with the current practice of measuring both markers together.

DESIGN

A retrospective analysis was undertaken for all chromogranin tests requested for patients with a known NET diagnosis. Results were categorized based on whether plasma concentrations were elevated for one or both CgA and CgB.

RESULTS

A total of 325 sequential patients with a NET diagnosis had plasma chromogranin levels measured during the period of review. Baseline CgA was elevated in 60·9% of patients. Isolated elevations in CgA (with normal CgB) were found in 44·9% of patients, whilst combined elevations in both CgA and CgB were found in 16% of patients. Combined CgA and CgB concentrations within the normal range were observed for 38·5% of patients. Only two patients (0·6%) had an isolated elevation in CgB at baseline. Both patients had a diagnosis of pancreatic NET and were radiologically stable. Plasma CgA and CgB corresponded with disease stage (localized vs metastatic). CgB in addition to CgA did not provide any significant improvement in diagnostic performance for identification of metastatic disease compared to CgA alone.

CONCLUSIONS

Based on this NET population and specific assay performance characteristics, CgA alone provides sufficient information for the management of NET patients; the routine estimation of CgB in all patients is not informative in clinical practice.

A combination of physical activity and computerized brain training improves verbal memory and increases cerebral glucose metabolism in the elderly

Physical exercise interventions and cognitive training programs have individually been reported to improve cognition in the healthy elderly population; however, the clinical significance of using a combined approach is currently lacking. This study evaluated whether physical activity (PA), computerized cognitive training and/or a combination of both could improve cognition. In this nonrandomized study, 224 healthy community-dwelling older adults (60-85 years) were assigned to 16 weeks home-based PA (n=64), computerized cognitive stimulation (n=62), a combination of both (combined, n=51) or a control group (n=47). Cognition was assessed using the Rey Auditory Verbal Learning Test, Controlled Oral Word Association Test and the CogState computerized battery at baseline, 8 and 16 weeks post intervention. Physical fitness assessments were performed at all time points. A subset (total n=45) of participants underwent [(18)F] fluorodeoxyglucose positron emission tomography scans at 16 weeks (post-intervention). One hundred and ninety-one participants completed the study and the data of 172 participants were included in the final analysis. Compared with the control group, the combined group showed improved verbal episodic memory and significantly higher brain glucose metabolism in the left sensorimotor cortex after controlling for age, sex, premorbid IQ, apolipoprotein E (APOE) status and history of head injury. The higher cerebral glucose metabolism in this brain region was positively associated with improved verbal memory seen in the combined group only. Our study provides evidence that a specific combination of physical and mental exercises for 16 weeks can improve cognition and increase cerebral glucose metabolism in cognitively intact healthy older adults.

Prediction of winning amateur boxers using pretournament reaction times

AIM

Boxing requires agility and manual dexterity, which is associated with fast reflexes and reaction time. This study evaluated the relation between reaction times on cognitive tasks and competition outcomes in boxers.

METHODS

The design was a prospective cohort study. Participants were collegiate amateur boxers who won at least one bout in a single elimination tournament. Optimal pre-participation performance using a computerized cognitive assessment tool (CCAT, Axon Sports) and no significant deterioration in cognitive performance within 24 hours post-bout was required to compete in future bouts. Winners were assumed to be motivated to perform optimally on testing. Performance on speed and accuracy measures were compared in winning and non-winning boxers. Pre-competition minutes of sparring and tournament seedings were recorded.

RESULTS

There were 96 eligible boxers who won at least one of 160 bouts. The mean age was 21.3 (SD 1.9) years (range 18.5-29.7). A significant improvement in mean reaction times as a function of advancement in the boxing tournament was observed. The 18 winning boxers who advanced to the finals had significantly faster mean reaction times at the baseline assessment before the competition began (speed composite z-score F(1,94)=4.14, P<0.05, effect size 0.54). Winners also had more sparring experience (Mann-Whitney U=302.5, P<0.001) and higher pre-competition rankings (Mann-Whitney U=288.5, P<0.001).

CONCLUSION

In highly motivated amateur boxers, finalists performed significantly faster than those who failed to reach the finals on measures of pre-competition reaction time. These findings suggest that winners of boxing tournaments might be predicted using pre-competition measures of processing speed.

Abeta deposits in older non-demented individuals with cognitive decline are indicative of preclinical Alzheimer's disease

Approximately 30% of healthy persons aged over 75 years show Abeta deposition at autopsy. It is postulated that this represents preclinical Alzheimer's disease (AD). We evaluated the relationship between Abeta burden as assessed by PiB PET and cognitive decline in a well-characterized, non-demented, elderly cohort. PiB PET studies and cognitive tests were performed on 34 elderly participants (age 73+/-6) from the longitudinal Melbourne Healthy Aging Study (MHAS). Subjects were classified as being cognitively 'stable' or 'declining' by an independent behavioural neurologist based on clinical assessment and serial word-list recall scores from the preceding 6-10 years. Decline was calculated from the slope of the word-list recall scores. Abeta burden was quantified using Standardized Uptake Value normalized to cerebellar cortex. Ten subjects were clinically classified as declining. At the time of the PET scans, three of the declining subjects had mild cognitive impairment, one had AD, and six were declining but remained within the normal range for age on cognitive tests. Declining subjects were much more likely to show cortical PiB binding than stable subjects (70% vs. 17%, respectively). Neocortical Abeta burden correlated with word-list recall slopes (r=-0.78) and memory function (r=-0.85) in the declining group. No correlations were observed in the stable group. Abeta burden correlated with incident memory impairment and the rate of memory decline in the non-demented ageing population. These observations suggest that neither memory decline nor Abeta deposition are part of normal ageing and likely represent preclinical AD. Further longitudinal observations are required to confirm this hypothesis.

Imaging beta-amyloid burden in aging and dementia

OBJECTIVE

To compare brain beta-amyloid (Abeta) burden measured with [(11)C]Pittsburgh Compound B (PIB) PET in normal aging, Alzheimer disease (AD), and other dementias.

METHODS

Thirty-three subjects with dementia (17 AD, 10 dementia with Lewy bodies [DLB], 6 frontotemporal dementia [FTD]), 9 subjects with mild cognitive impairment (MCI), and 27 age-matched healthy control subjects (HCs) were studied. Abeta burden was quantified using PIB distribution volume ratio.

RESULTS

Cortical PIB binding was markedly elevated in every AD subject regardless of disease severity, generally lower and more variable in DLB, and absent in FTD, whereas subjects with MCI presented either an "AD-like" (60%) or normal pattern. Binding was greatest in the precuneus/posterior cingulate, frontal cortex, and caudate nuclei, followed by lateral temporal and parietal cortex. Six HCs (22%) showed cortical uptake despite normal neuropsychological scores. PIB binding did not correlate with dementia severity in AD or DLB but was higher in subjects with an APOE-epsilon4 allele. In DLB, binding correlated inversely with the interval from onset of cognitive impairment to diagnosis.

CONCLUSIONS

Pittsburgh Compound B PET findings match histopathologic reports of beta-amyloid (Abeta) distribution in aging and dementia. Noninvasive longitudinal studies to better understand the role of amyloid deposition in the course of neurodegeneration and to determine if Abeta deposition in nondemented subjects is preclinical AD are now feasible. Our findings also suggest that Abeta may influence the development of dementia with Lewy bodies, and therefore strategies to reduce Abeta may benefit this condition.

Cognitive deterioration associated with an expedition in an extreme desert environment

BACKGROUND

Prolonged exposure to extreme environments may result in cognitive changes that may influence decision making ability and increasing risk of injury or death.

OBJECTIVE

To measure the cognitive performance of a healthy man as he completed a 17 day desert expedition.

METHOD

A computer based cognitive test battery, subjective cognitive rating scale, and measures of physical characteristics were used. Objective cognitive performance was compared with the performance of eight age matched men who remained in their own homes.

RESULTS

The speed of psychomotor, attentional, and executive functions decreased as the expedition progressed, but the accuracy of performance remained unaffected. Although some impairments were large, they resolved completely once the expedition was completed. Subjective ratings indicated that the subject had insight into his failing cognitive performance during the expedition.

CONCLUSIONS

Cognitive performance can be measured repeatedly throughout an expedition in an extreme environment. Cognitive impairment may occur.

Subtle memory decline over 12 months in mild cognitive impairment

OBJECTIVE

Screening of normal older persons for progressive memory decline is a worthwhile strategy in the pursuit of the earliest possible stages of pre-clinical Alzheimer's disease (AD) or mild cognitive impairment (MCI). Reliable tests are needed to both detect MCI and measure the natural history of decline over months rather than years. We aimed to detect memory decline over 1 year in a group of older individuals with well-characterised amnestic MCI.

METHODS

The continuous learning task (CLT) from the CogState test battery was administered 8 times in 12 months to 15 individuals with MCI and 35 controls matched for age, education, IQ and gender. All subjects were recruited from an ongoing aging study. The rate of change in CLT performance over the year was compared between groups and also compared to that detected with a word list learning task and a computerised paired associate learning task.

RESULTS

At baseline, memory performance in the amnestic MCI group was significantly worse than controls on all memory tests. However, at 12 months the magnitude of the difference between the groups had increased significantly on the CLT due to decline in memory accuracy in the MCI group. No decline over 12 months was detectable on the routine memory tests.

CONCLUSIONS

Subtle memory decline is detectable in amnestic MCI using reliable and sensitive tests of memory. Such measures may assist in the early identification of AD and also in trials of putative disease-modifying therapies to be conducted over as little as 12 months.

Mild cognitive impairment can be detected by multiple assessments in a single day

BACKGROUND

Reliable detection of mild cognitive impairment (MCI), in many cases preceding AD, is important in determining the efficacy of emerging treatments. The operational definition of MCI is currently imprecise and would be improved by objective criteria. Inherent in the transition from MCI to AD is cognitive decline, which can be detected using multiple assessments over several years.

OBJECTIVE

To determine whether multiple assessments on the same day could also differentiate well-studied subjects with very mild MCI from normal control subjects.

METHODS

This study utilized a novel 15- to 18-minute computerized cognitive battery designed for frequent serial use, administered four times within 3 hours. Subjects were participants in a longitudinal healthy aging study (20 with MCI, 40 control subjects matched for age, gender, and education).

RESULTS

The MCI group showed significantly attenuated learning performance with repetition on accuracy and reaction time tasks. Discriminant function analysis correctly classified 95% of subjects and 80% of those with MCI.

CONCLUSIONS

Multiple assessments with standardized, repeatable cognitive measures is a promising method for reliably differentiating patients with early MCI in a single test session and deserves further study for refining patient selection in trials of therapeutic agents for MCI.

Computerised cognitive assessment of athletes with sports related head injury

Professional and amateur participants in many sports are at risk of brain injury caused by impact with other players or objects. In many cases, mild cognitive deficits may persist after the common neurological signs of brain injury have passed. In recent years, the athlete's cognitive status after concussion has been measured with conventional "paper and pencil" neuropsychological tests. However, such tests are not ideal for sporting settings, as they are designed for the detection of gross cognitive impairments at a single assessment, not for the identification of mild cognitive deficits on repeated assessment. A number of computerised cognitive assessment tests and test batteries have been developed over the past two decades. These batteries offer major scientific and practical advantages over conventional neuropsychological tests which make them ideal for the assessment of cognitive function in sportspeople. This review first describes the problems associated with cognitive assessment of people with sports related cognitive deficits, and then critically examines the utility of conventional neuropsychological and computerised cognitive tests in sporting settings.

A three-item scale for the early prediction of stroke recovery

BACKGROUND

Accurate assessment of prognosis in the first hours of stroke is desirable for best patient management. We aimed to assess whether the extent of ischaemic brain injury on magnetic reasonance diffusion-weighted imaging (MR DWI) could provide additional prognostic information to clinical factors.

METHODS

In a three-phase study we studied 66 patients from a North American teaching hospital who had: MR DWI within 36 h of stroke onset; the National Institutes of Health Stroke Scale (NIHSS) score measured at the time of scanning; and the Barthel Index measured no later than 3 months after stroke. We used logistic regression to derive a predictive model for good recovery. This logistic regression model was applied to an independent series of 63 patients from an Australian teaching hospital, and we then developed a three-item scale for the early prediction of stroke recovery.

FINDINGS

Combined measurements of the NIHSS score (p=0.01), time in hours from stroke onset to MR DWI (p=0.02), and the volume of ischaemic brain tissue on MR DWI (p=0.04) gave the best prediction of stroke recovery. The model was externally validated on the Australian sample with 0.77 sensitivity and 0.88 specificity. Three likelihood levels for stroke recovery-low (0-2), medium (3-4), and high (5-7)-were identified on the three-item scale.

INTERPRETATION

The combination of clinical and MR DWI factors provided better prediction of stroke recovery than any factor alone, shortly after admission to hospital. This information was incorporated into a three-item scale for clinical use.

Echoplanar magnetic resonance imaging in acute stroke

Echoplanar magnetic resonance imaging (EPI) enables rapid, non-invasive imaging and analysis of cerebral pathophysiology in acute stroke. It represents an important clinical advance over computed tomography (CT) and conventional magnetic resonance (MR) scanning. It can rapidly delineate infarcted cerebral tissue and distinguish acute from chronic stroke. In addition, EPI has the potential to quickly determine the presence and degree of potentially viable brain tissue in the ischaemic penumbra. Thrombolysis is thought to reperfuse the penumbra and hence reduce infarct size. The thrombolytic agent tissue plasminogen activator (t-PA) improves outcome in ischaemic stroke when administered within the first 3 hours of onset. However, there is a significant risk of haemorrhage, and the time window for benefit may well exceed 3 hours in some patients. Hence, by facilitating diagnosis of 'at-risk' tissue in the ischaemic penumbra, a major clinical role of EPI may well become the rational selection of patients for acute interventional stroke therapy.

Retention of the antibiotic teicoplanin on a hydromer-coated central venous catheter to prevent bacterial colonization in postoperative surgical patients

OBJECTIVE

Antibiotic-coated intravascular catheters may be an effective means of decreasing bacterial colonization and subsequent catheter-related infection. The present study was designed to investigate the retention of the antibiotic teicoplanin on a hydromer-coated intravenous catheter and the effect of this antibiotic coating on catheter bacterial colonization.

DESIGN

A prospective, randomized pilot study.

SETTING

Operating rooms (ORs) and an intensive care unit (ICU) at a university hospital.

PATIENTS

A consecutive group of 20 male patients undergoing major abdominal surgery.

INTERVENTIONS

Control (C; n = 10) or teicoplanin-coated (T; n = 10) single-lumen central venous catheters were inserted before surgery in the OR. Catheters were withdrawn at the discretion of the physicians in the ICU after various periods.

MEASUREMENTS

The teicoplanin content of the catheter material was assessed using a bioassay with Bacillus subtilis after complete elution of the antibiotic from the catheter. Bacterial colonization was measured using a quantitative culture technique after the catheter lumen had been flushed and the catheter segments sonicated.

MAIN RESULTS

Nearly three-quarters of the initial teicoplanin coating (374 +/- 103 micrograms; mean +/- SD) were released during the first day of catheterization, and after 36 h of intravenous catheterization, no antibiotic was retained on the catheter. No significant difference could be found either in the incidence of bacterial colonization between test (n = 3) and control (n = 4) catheters or in the number of colony-forming units (CFU) on the catheter segments (T, 263 +/- 104 CFU/cm; C, 372 +/- 294 CFU/cm; mean +/- SEM).

CONCLUSION

The retention of teicoplanin antibiotic coating on hydromer catheters is only short term if catheters are inserted intravenously. This may limit clinical antibacterial efficacy.