Gait and Balance in Alzheimer\u27s Disease: A Retrospective Analysis Across Varying Levels of Cognitive Impairment

Background: It was once thought that Alzheimer’s disease (AD) affected mostly cognition with minor motor impairment; however, it is becoming apparent that motor impairment may also be a prominent feature. Determining the extent of motor impairments throughout the continuum of cognitive impairment is critical in developing timely interventions for this population. Purpose/Hypothesis: The aim of this study was to gain a greater understanding of motor impairment in AD by exploring the relationships among gait, balance, and falls. Specifically, we explored the association of fall history to measures of cognition and performance-based balance measures in individuals with AD. We hypothesized that falls would increase as balance impairments became more severe. Additionally, we mapped the trajectory of gait and balance function along the continuum of cognitive impairment in individuals with AD. We hypothesized that balance and gait would be worse for those in the lower quartiles of cognitive function compared to those in the upper quartiles. Lastly, we sought to determine if fall history worsened as cognition declined. We hypothesized that falls history would be worse in lower quartiles of cognitive impairment compared to upper quartiles of cognitive impairment. Subjects: Retrospective data of 419 patients with brain health conditions and an initial evaluation for physical therapy at the Cleveland Clinic Lou Ruvo Center for Brain Health were extracted from electronic records. Of those 419, 155 were diagnosed by a neurologist with AD (age=77.4 ± 9.5; 69 males, 86 females) and were subsequently analyzed for this study. Materials/Methods: Patients were stratified into cognitive quartiles using scores from the Montreal Cognitive Assessment (MoCA): 0-9 (very severe cognitive impairment), 10-14 (severe cognitive impairment), 15-20 (Moderate to severe impairment), 21-30 (mild to moderate impairment). These cognitive function quartiles were then compared across the following measures: fall history (falls in last year, falls in the last 30 days, and fall injuries in the last year), 5 times Sit To Stand (5STS), Timed Up and Go (TUG), TUG cognitive (TUGcog), Preferred Gait Speed (PGS), Fast Gait Speed (FGS), 6 Minute Walk Test (6MWT), and Mini Balance Evaluation Systems Test (MBT). Results: For our first aim, there were no statistically significant differences between fallers and non-fallers for cognition, age, and measures of gait and balance (ps≥.068), except non-fallers walked farther on the 6MWT (p=.030). There were no statistically significant differences for recent (last 30 days) fallers and non-fallers across the same measures (ps≥.082). Fallers who had experienced an injury as a result of a fall in the last year performed more poorly on the 6MWT (p=.034) and MBT SOT (p=.008); all other comparisons were not statistically significant (ps≥.085). For our second aim, there were no statistically significant differences among the four cognitive quartiles for 5STS (p=.456), TUG (p=.060), FGS (p=.181), 6MWT (p=.468), MBT (p=.321); however, there were for TUGcog (p=.046) and PGS (p=.033). The mild to moderate impairment quartile was significantly faster than the severe quartile (p=.006) for the TUGcog. For PGS, the mild to moderate was significantly faster than the very severe quartile (p=.039) and the moderate to severe was significantly faster than the severe and the very severe quartiles (severe, p=.036; and, very severe, p=.016). For our third aim, there were no statistically significant differences in the proportions of fallers (p=.636), recent fallers (p=.868), and injured fallers (p=.565) across the four cognitive quartiles. Discussion: Despite impairments recognized in our study compared to normative data, patients in the study with a fall history were not significantly worse across most measures of gait and balance, except fallers had poorer walking endurance as measured in the 6MWT. Additionally, the proportion of fallers did not increase as severity of cognitive impairment increased, although walking impairment as measured with PGS and TUGcog, especially with cognitive demand, is more prominent in those with more severe cognitive impairment. Conclusions: Balance and gait dysfunction were prominent at all levels of cognitive impairment in our study of patients with AD and appears to become more prominent at the most severe cognitive impairment levels. These progressive deficits represent potentially mitigable motor impairment features of AD that warrant physical therapy

Aggregate Effects of Proliferating Low-Earth-Orbit Objects and Implications for Astronomical Data Lost in the Noise

The rising population of artificial satellites and associated debris in low-altitude orbits is increasing the overall brightness of the night sky, threatening ground-based astronomy as well as a diversity of stakeholders and ecosystems reliant on dark skies. We present calculations of the potentially large rise in global sky brightness from space objects in low Earth orbit, including qualitative and quantitative assessments of how professional astronomy may be affected. Debris proliferation is of special concern: we calculate that all log-decades in debris size contribute approximately the same amount of night sky radiance, so debris-generating events are expected to lead to a rapid rise in night sky brightness along with serious collision risks for satellites from centimetre-sized objects. This increase in low-Earth-orbit traffic will lead to loss of astronomical data and diminish opportunities for ground-based discoveries as faint astrophysical signals become increasingly lost in the noise. Lastly, we discuss the broader consequences of brighter skies for a range of sky constituencies, equity/inclusion and accessibility for Earth- and space-based science, and cultural sky traditions. Space and dark skies represent an intangible heritage that deserves intentional preservation and safeguarding for future generations

Development and first validation of the Refined Alcohol Expectancy Task (RAET).

Addressing limitations of existing self-report measures of alcohol-related thoughts and behaviours, researchers have begun to measure these pictographically. To date, however, these novel measures have been developed somewhat unsystematically and are predicated on a number of potentially problematic assumptions, meaning that researchers have not been able to assess their reliability or validity fully. This report therefore documents the development of a Refined Alcohol Expectancy Task through (1) selection (2) development and (3) testing of stimuli for inclusion of this pictograph-based tasks. It also provides initial validation data. Key findings: • This paper outlines the development and initial validation of a pictorial measure of alcohol-related beliefs, namely the Refined Alcohol Expectancy Task (RAET) • Participants were equally efficient in recognising the alcoholic and non-alcoholic pictures and could identify the emotions in the pictographic representations • The RAET has adequate psychometric properties and successfully assesses alcohol expectancies • Expectancy dimensions assessed by the RAET seemed to be independent of drinking habit

Evidence for the formation of comet 67P/Churyumov-Gerasimenko through gravitational collapse of a bound clump of pebbles

The processes that led to the formation of the planetary bodies in the Solar System are still not fully understood. Using the results obtained with the comprehensive suite of instruments on-board ESA’s Rosetta mission, we present evidence that comet 67P/Churyumov-Gerasimenko likely formed through the gentle gravitational collapse of a bound clump of mm-sized dust aggregates (“pebbles”), intermixed with microscopic ice particles. This formation scenario leads to a cometary make-up that is simultaneously compatible with the global porosity, homogeneity, tensile strength, thermal inertia, vertical temperature profiles, sizes and porosities of emitted dust, and the steep increase in water-vapour production rate with decreasing heliocentric distance, measured by the instruments on-board the Rosetta spacecraft and the Philae lander. Our findings suggest that the pebbles observed to be abundant in protoplanetary discs around young stars provide the building material for comets and other minor bodies

Measurement of cortisol in saliva: a comparison of measurement error within and between international academic-research laboratories

Objective: Hundreds of scientific publications are produced annually that involve the measurement of cortisol in saliva. Intra- and inter-laboratory variation in salivary cortisol results has the potential to contribute to cross- study inconsistencies in findings, and the perception that salivary cortisol results are unreliable. This study rigor- ously estimates sources of measurement variability in the assay of salivary cortisol within and between established international academic-based laboratories that specialize in saliva analyses. One hundred young adults (Mean age: 23.10 years; 62 females) donated 2 mL of whole saliva by passive drool. Each sample was split into multiple- 100 µL aliquots and immediately frozen. One aliquot of each of the 100 participants’ saliva was transported to academic laboratories (N = 9) in the United States, Canada, UK, and Germany and assayed for cortisol by the same commercially available immunoassay. Results: 1.76% of the variance in salivary cortisol levels was attributable to differences between duplicate assays of the same sample within laboratories, 7.93% of the variance was associated with differences between laboratories, and 90.31% to differences between samples. In established-qualified laboratories, measurement error of salivary cortisol is minimal, and inter-laboratory differences in measurement are unlikely to have a major influence on the determined values

The state of the Martian climate

60°N was +2.0°C, relative to the 1981–2010 average value (Fig. 5.1). This marks a new high for the record. The average annual surface air temperature (SAT) anomaly for 2016 for land stations north of starting in 1900, and is a significant increase over the previous highest value of +1.2°C, which was observed in 2007, 2011, and 2015. Average global annual temperatures also showed record values in 2015 and 2016. Currently, the Arctic is warming at more than twice the rate of lower latitudes

Domains of Chronic Stress, Lifestyle Factors, and Allostatic Load in Middle-Aged Mexican-American Women

Abstract available at publisher's website

Search for dark matter produced in association with bottom or top quarks in √s = 13 TeV pp collisions with the ATLAS detector

A search for weakly interacting massive particle dark matter produced in association with bottom or top quarks is presented. Final states containing third-generation quarks and miss- ing transverse momentum are considered. The analysis uses 36.1 fb−1 of proton–proton collision data recorded by the ATLAS experiment at √s = 13 TeV in 2015 and 2016. No significant excess of events above the estimated backgrounds is observed. The results are in- terpreted in the framework of simplified models of spin-0 dark-matter mediators. For colour- neutral spin-0 mediators produced in association with top quarks and decaying into a pair of dark-matter particles, mediator masses below 50 GeV are excluded assuming a dark-matter candidate mass of 1 GeV and unitary couplings. For scalar and pseudoscalar mediators produced in association with bottom quarks, the search sets limits on the production cross- section of 300 times the predicted rate for mediators with masses between 10 and 50 GeV and assuming a dark-matter mass of 1 GeV and unitary coupling. Constraints on colour- charged scalar simplified models are also presented. Assuming a dark-matter particle mass of 35 GeV, mediator particles with mass below 1.1 TeV are excluded for couplings yielding a dark-matter relic density consistent with measurements