Use of the CogState Brief Battery in the assessment of Alzheimer's disease related cognitive impairment in the Australian Imaging, Biomarkers and Lifestyle (AIBL) study

Abstract

The primary aim of neuropsychology is the understanding of brain-behavior relationships. This necessitates confronting the mind-body problem, and the neuropsychologist must frequently cross between physical and psychological conceptual systems. The localizationist-antilocalizationist controversy can be understood, in part, as a result of different attitudes toward this conceptual difficulty. The tendency to reify the name of complex psychological constructs demonstrated by some of the localizationists continues to muddle both the thinking and research of neuropsychologists. Our increased ability to localize brain lesions through neuroradiographic tests must be paralleled by increased sophistication in analyzing psychological functions. The methods from cognitive psychology offer great promise in the study of ability and disability in neuropsychology.     

Brain amyloid imaging

Imaging of brain β-amyloid plaques with (18)F-labeled tracers for PET will likely be available in clinical practice to assist the diagnosis of Alzheimer disease (AD). With the rapidly growing prevalence of AD as the population ages, and the increasing emphasis on early diagnosis and treatment, brain amyloid imaging is set to become a widely performed investigation. All physicians reading PET scans will need to know the complex relationship between amyloid and cognitive decline, how to best acquire and display images for detection of amyloid, and how to recognize the patterns of tracer binding in AD and other causes of dementia. This article will provide nuclear medicine physicians with the background knowledge required for understanding this emerging investigation, including its appropriate use, and prepare them for practical training in scan interpretation.     

The biomechanical functional demand placed on knee and hip muscles of older adults during stair ascent and descent

Age-related decline in physical capabilities may lead to older adults experiencing difficulty in performing everyday activities due to high demands placed on the muscles of their lower extremity. This study aimed to determine the biomechanical functional demand in terms of joint moments and maximal muscle capabilities at the knee and hip joints while older adults performed stair ascent (SA) and stair descent (SD). Eighty-four healthy older adults aged 60-88 years were tested. A torque dynamometer attached to a purpose-built plinth was utilized to measure muscle moments at the knee and hip joints. Participants also underwent full body 3-D biomechanical assessment of stair ascent and descent using an 8-camera VICON system (120 Hz) with 3 Kistler force plates. Stair negotiation required knee extensor moments in excess of the maximum isometric muscle strength available (SA 103%, SD 120%). For the hip, the levels of demand were high, but were slightly lower than those of the knee joint. Stair negotiation placed a high level of demand on the knee extensors with demand in SA reaching maximal isometric capacity and demand in SD exceeding maximal isometric capacity. The levels of demand leave little reserve capacity for the older adult to draw on in unexpected situations or circumstances.     

Regular consumption of concord grape juice benefits human immunity

γδ T cells are important immune surveillance cells residing in epithelial layers lining the intestine, lung, and reproductive tract. The main objective of this study was to test the hypothesis that consumption of dietary compounds from grapes would modify γδ T-cell function. Other factors related to immune function after grape juice consumption were also tested. A randomized, double-blind, placebo-controlled, parallel intervention was conducted: 100% grape juice made from Concord grapes or a placebo beverage was consumed by 85 individuals daily for 9 weeks. Subjects were asked not to consume other red, blue, and purple fruits during the study. Blood samples, taken at the beginning and the end, were analyzed for γδ T-cell numbers and proliferation, vitamin C, antioxidant capacity, and the ability to protect DNA from strand breaks. Those consuming the grape juice had significantly greater numbers of circulating γδ T cells and higher serum vitamin C levels compared to the placebo by two-way repeated-measure analysis of variance (P?相似文献   

The efficacy of the OSA-18 as a waiting list triage tool for OSA in children

Purpose

Sleep disordered breathing (SDB) is common in children, resulting in extensive waiting lists for specialist clinics. There is an urgent need for a valid method of triaging patients and the OSA-18, a disease-specific tool, is an attractive candidate for this role. We aimed to examine the OSA-18 as a measurement tool in detail and to determine whether the score or aspects of it could be used as a screening tool for SDB in children.

Methods

Retrospective analysis of 582 children (6 months to 16.4 years)—216 underwent overnight PSG and 366 overnight oximetry. Confirmatory factor analysis (CFA) and exploratory factor analysis (EFA) were conducted. Receiver operating characteristic curve analysis assessed the diagnostic accuracy of the factors for the presence of OSA. Rasch analysis was used to assess the structure of the items (1–18) and categories of response (Likert scale).

Results

The CFA with a forced five-factor structure, revealed three factors with Eigenvalues >1, and explained 73.7 % of the variance. EFA resulted in a two-factor structure, explaining 60.3 % of the variance. Assessment of sensitivity and specificity showed a high false-positive rate, irrespective of the factor structure tested. Rasch analysis showed poor discrimination between adjacent categories on the Likert scale.

Conclusion

This study confirmed that the predictive value of the OSA-18 for SDB severity is weak. Some questions perform better than others statistically, and the seven categories of response introduce significant statistical noise, raising the possibility that modification of the OSA-18 may improve its performance in the prediction of OSA severity.

     

Research Synthesis of Recommended Acetabular Cup Orientations for Total Hip Arthroplasty

Total hip arthroplasty (THA) is regarded as one of the most successful surgical procedures of modern times yet continues to be associated with a small but significant complication rate. Many early failures may be associated with poor component positioning with, in particular, acetabular component orientation dependent on the subjective judgement of the surgeon. In this paper, we compare the manufacturers' instructions on acetabular cup orientation with the literature-based recommended safety zones and surgical technique, by transforming them onto a single, clinically-relevant framework in which the different reference systems, safety guidelines and current instrumentation surgical techniques can be evaluated. The observed limited consensus between results reflects ongoing uncertainty regarding the optimum acetabular component positioning. As malpositioning of the acetabular cup increases the risk of revision surgery, any ambiguity over the correct position can have a causal effect. Our analysis highlights the need for a surgical reference system which can be used to describe the position of the acetabular cup intra-operatively.     

The Emerging Role of Vitamin C in the Prevention and Treatment of COVID-19

Investigation into the role of vitamin C in the prevention and treatment of pneumonia and sepsis has been underway for many decades. This research has laid a strong foundation for translation of these findings into patients with severe coronavirus disease (COVID-19). Research has indicated that patients with pneumonia and sepsis have low vitamin C status and elevated oxidative stress. Administration of vitamin C to patients with pneumonia can decrease the severity and duration of the disease. Critically ill patients with sepsis require intravenous administration of gram amounts of the vitamin to normalize plasma levels, an intervention that some studies suggest reduces mortality. The vitamin has pleiotropic physiological functions, many of which are relevant to COVID-19. These include its antioxidant, anti-inflammatory, antithrombotic and immuno-modulatory functions. Preliminary observational studies indicate low vitamin C status in critically ill patients with COVID-19. There are currently a number of randomized controlled trials (RCTs) registered globally that are assessing intravenous vitamin C monotherapy in patients with COVID-19. Since hypovitaminosis C and deficiency are common in low–middle-income settings, and many of the risk factors for vitamin C deficiency overlap with COVID-19 risk factors, it is possible that trials carried out in populations with chronic hypovitaminosis C may show greater efficacy. This is particularly relevant for the global research effort since COVID-19 is disproportionately affecting low–middle-income countries and low-income groups globally. One small trial from China has finished early and the findings are currently under peer review. There was significantly decreased mortality in the more severely ill patients who received vitamin C intervention. The upcoming findings from the larger RCTs currently underway will provide more definitive evidence. Optimization of the intervention protocols in future trials, e.g., earlier and sustained administration, is warranted to potentially improve its efficacy. Due to the excellent safety profile, low cost, and potential for rapid upscaling of production, administration of vitamin C to patients with hypovitaminosis C and severe respiratory infections, e.g., COVID-19, appears warranted.     

Longitudinal Trends in Enrollees’ Employment and Student Status after Medicaid Expansion

Medicaid “community engagement” requirement (work, school, job training, job searching, or volunteering) waivers have received CMS approval in nine states, but there are little data on current trends in Medicaid enrollees’ engagement in these activities. Our objective was to assess longitudinal changes in enrollees’ employment and student status after implementation of Michigan’s Medicaid expansion, which expanded coverage in 2014 and now covers ~664,000 individuals. We conducted a longitudinal telephone survey in English, Spanish, and Arabic with a cohort of Medicaid expansion enrollees at 3 time points in 2016 (N = 4090, RR = 53.7%), 2017 (N = 3104; RR = 83.4%), and 2018 (N = 2608, RR = 89.4%). Survey items measured employment status and student status; demographic characteristics were obtained from Michigan Medicaid program files. We used mixed models with year as a fixed effect to assess changes in the proportion of enrollees who were employed or students, incorporating weights adjusting for sample design and nonresponse. Enrollees aged 19-64, with incomes up to 133% of the federal poverty level (FPL). Most respondents had incomes under 100% FPL (61.7% with 0-35% FPL, 22.9% with 36-99% FPL, and 15.4% with 100-133% FPL), 89.3% had at least a high school diploma/equivalent, and respondents ranged in age (39.6%, age 19-34; 34.5%, age 35-50; and 25.9%, age 51-64). From 2016 to 2018, the proportion of enrollees who were employed or students increased from 54.5% to 61.4% (P < .001). Increases were observed in subgroups with lower baseline rates of employment or student status, including those with a chronic condition (47.8% to 53.8%, P < .001) and those with a mental health or substance use disorder (48.5% to 56.0% P < .001). Employed enrollees worked 34.7 mean hours per week on all paid jobs in 2018. Among enrollees who were in school, 57.7% were full-time and 42.3% were part-time students. Enrollees who were not employed or students in 2018 (38.6%) reported being unable to work (47.3%), out of work (40.4%), or retired (12.3%). Among enrollees who reported being unable to work, primary reasons included poor health/disability (91.4%) and caregiving responsibilities (7.1%). Among all enrollees who were not employed in 2018, 36.8% were searching for a job and 9.1% had completed or were enrolled in job training. From 2016 to 2018, employment or student status increased among Michigan Medicaid expansion enrollees, including among subgroups with comorbidities. This occurred prior to implementation of the state’s planned community engagement requirement in January 2020. Federal courts are currently weighing whether community engagement requirements will promote the Medicaid program’s goals of improved coverage and health, as well as associated improvements in employment and related activities. Three of the approved state waivers have been set aside by the courts and two have been delayed or suspended, while nine additional states have pending waivers seeking approval for similar requirements. Our findings suggest that Medicaid expansion itself was associated with the desired outcome of employment and related activities. The value of Medicaid community engagement requirements should be considered along with the additional administrative burden on individuals and states. The University of Michigan Institute for Healthcare Policy and Innovation (IHPI) is conducting the evaluation required by the Centers for Medicare and Medicaid Services (CMS) of the Healthy Michigan Plan (HMP) under contract with MDHHS. Data collected for this paper were funded by MDHHS and CMS for the purposes of the evaluation but do not represent the official views of either agency.