Short-term effectiveness of music therapy songwriting for mental health outcomes of at-risk parents in the NICU: a study protocol of an international multicenter mixed-methods trial.

BACKGROUND: Preterm birth contributes to adverse mental health outcomes of parents dealing with a premature neonate. The main objective of this study is to determine whether music therapy (MT) songwriting during the infants' stay in the neonatal intensive care unit (NICU) is superior to standard care in reducing the risk of postpartum depression in high-risk parents of preterm children throughout the hospital treatment. The secondary objectives include assessment of effectiveness of MT in other aspects of mental health (anxiety level, perceived stress, mental wellbeing, coping, resilience). Furthermore, this trial will evaluate the medical and social factors that may be associated with the effects of MT songwriting. PARTICIPANTS AND PROCEDURE: The study design is a sequential mixed method study with a dominant status QUAN to qual. The quantitative trial was designed as a parallel, multicenter, pragmatic, randomized controlled trial. The qualitative study is a descriptive phenomenological study that seeks to understand the lived experiences of participants exposed to songwriting. Participants are parents of premature infants hospitalized in NICU (106 families) in 5 hospitals, in Colombia and Poland. Intervention: 3 MT songwriting sessions per week across 3 weeks. Primary outcome: the risk of postnatal depression; secondary outcomes: anxiety level, mental wellbeing, resilience, stress, coping. RESULTS: The results will be analyzed quantitatively and qualitatively. CONCLUSIONS: This study will provide a report on the effectiveness of MT songwriting on mental health in at-risk parents of preterm infants.

Opioid-related mortality after occupational injury in Washington State: accounting for preinjury opioid use.

OBJECTIVES: To estimate the impact of occupational injury and illness on opioid-related mortality while accounting for confounding by preinjury opioid use. METHODS: We employed a retrospective cohort study design using Washington State workers' compensation data for 1994-2000 injuries linked to US Social Security Administration earnings and mortality data and National Death Index (NDI) cause of death data from 1994 to 2018. We categorised injuries as lost-time versus medical-only, where the former involved more than 3 days off work or permanent disability. We determined death status and cause of death from NDI records. We modelled separate Fine and Gray subdistribution hazard ratios (sHRs) and 95% CIs for injured men and women for opioid-related and all drug-related mortality through 2018. We used quantitative bias analysis to account for unmeasured confounding by preinjury opioid use. RESULTS: The hazard of opioid-related mortality was elevated for workers with lost-time relative to medical-only injuries: sHR for men: 1.53, 95% CI 1.41 to 1.66; for women: 1.31, 95% CI 1.16 to 1.48. Accounting for preinjury opioid use, effect sizes were reduced but remained elevated: sHR for men was 1.43, 95% simulation interval (SI) 1.20 to 1.69; for women: 1.27, 95% SI 1.10 to 1.45. CONCLUSIONS: Occupational injuries and illnesses severe enough to require more than 3 days off work are associated with an increase in the hazard of opioid-related mortality. The estimated increase is reduced when we account for preinjury opioid use, but it remains substantial. Reducing work-related injuries and postinjury opioid prescribing and improving employment and income security may decrease opioid-related mortality.

Predicting COVID-19 Cases in Nursing Homes of California and Ohio: Does the Work Environment Matter?

OBJECTIVE: The cross-sectional study evaluates if the pre-pandemic work environments in nursing homes predict COVID-19 cases among residents and staff, accounting for other factors. METHOD: Leveraging data from a survey of California and Ohio nursing homes (n = 340), we examined if Workplace Integrated Safety and Health domains - Leadership, Participation, and Comprehensive and Collaborative strategies predicted cumulative COVID-19 cases among nursing home residents and staff. RESULTS: In Ohio, a 1-unit increase in Leadership score was associated with 2 fewer staff cases and 4 fewer resident cases. A 1-unit increase in Comprehensive and Collaborative Strategies score in California showed an average marginal effect of approximately 1 less staff case and 2 fewer resident cases. CONCLUSION: These findings suggest that leadership commitment and inter-department collaboration to prioritize worker safety, may have protected against COVID-19 cases in nursing homes.

Who do you ask? predicting injury rates from survey responses.

BACKGROUND: Few studies have addressed whether using manager or worker perceptions of safety policies and practices alone predict reported injury rates less accurately than using both. OBJECTIVE: This study provides an example and describes a method that can be used to address this issue with survey instruments designed to measure safety climate, policies, or practices. METHODS: Using multilevel logistic regression, we estimated the relationship between worker and manager perceptions of a given exposure and the odds of worker injury during the post-survey year for three safety scales. We tested whether surveying both workers and managers provides additional predictive value compared with surveying just one group. RESULTS: Injury in the year following the survey was significantly associated with worker scores on two of the three scales. Manager responses were not significantly associated with injury and did not significantly improve injury rate prediction when added to a model with only worker survey responses. CONCLUSIONS: The capacity of manager-only or worker-only perceptions of safety policies and practices to predict worker injuries should be established before choosing to survey just one or the other. The approach and findings in this paper can be applied to other survey instruments and in other settings to help make this choice.

Adding injury to insult: Unfair treatment at work and occupational injury among hospital patient-care workers.

BACKGROUND: Hospital patient-care workers have high occupational injury rates. While physical hazards within hospital work environments are established determinants of injury, social exposures may also contribute. This study examined how reports of unfair treatment at work, a dimension of work-related experiences of discrimination, were associated with injury among hospital-based patient-care workers. METHODS: We used data from the Boston Hospital Workers Health Study, a longitudinal cohort of nurses and nursing assistants at two Boston-area hospitals. In 2018, we conducted a worker survey asking about three types of unfair treatment at work and occupational injuries during the past year. We used mixed-effects logistic regression models to evaluate associations between specific types, total load, and high-frequency exposure of unfair treatment with injury, adjusting for age, gender, race and ethnicity, job title, and unit type. RESULTS: Among 1001 respondents, 21% reported being humiliated in front of others at work, 28% reported being watched more closely than other workers, and 47% reported having to work twice as hard as others for the same treatment. For each type of unfair treatment, we observed a monotonic relationship with occupational injury wherein increasing frequency of exposure was associated with increased odds of injury. We also observed monotonic relationships between total load and high-frequency exposure to unfair treatment and odds of injury. CONCLUSIONS: Work-related unfair treatment is associated with injury among hospital workers. Programs and policies that focus on preventing unfair treatment may lessen injury burden in hospital workers.

Interactive Relations of Body Mass Index, Cardiorespiratory Fitness, and Sex to Cognitive Function in Older Adults.

OBJECTIVE: The course of cognitive aging is influenced by multiple health factors. This cross-sectional study investigated the interactive relations between body mass index (BMI), maximum oxygen consumption (VO2max), and sex on neuropsychological outcomes in community-dwelling predominantly older adults. METHODS: Participants were 164 healthy adults [M (SD) = 64.6 (12.5) years, 56% men, 87% white] who participated in an investigation of cardiovascular risk factors and brain health. Multivariable regression analysis, adjusted for age, education, ethnicity, smoking, alcohol consumption, and depression, examined the interactive relations of BMI, VO2max, and sex to multiple neuropsychological outcomes. RESULTS: Significant BMI*VO2max*sex interactions for Grooved Pegboard dominant (p = .019) and nondominant (p = .005) hands revealed that men with lower VO2max (l/min) displayed worse performance with each hand as BMI increased (p's < .02). A significant BMI*sex interaction for Logical Memory-Delayed Recall (p = .036) (after adjustment for blood glucose) showed that men, but not women, with higher BMI demonstrated worse performance (p = .036). Lastly, significant main effects indicated that lower VO2max was related to poorer logical memory, and higher BMI was associated with poorer Trail Making B and Stroop interference scores (p's < .05). CONCLUSIONS: Among men, higher cardiorespiratory fitness may protect against the negative impact of greater BMI on manual dexterity and motor speed, making VO2max a target for intervention. Higher BMI is further associated with poorer executive function and verbal memory (in men), and lower VO2max is associated with poorer verbal memory.

Can Better Leadership Reduce Nursing Home Staff Turnover?

OBJECTIVES: To assess whether a measure of leadership support for worker safety, health, and well-being predicts staff turnover in nursing homes after controlling for other factors. DESIGN: This paper uses administrative payroll data to measure facility-level turnover and uses a survey measure of nursing home leadership commitment to workers. In addition, we use data from Medicare to measure various nursing home characteristics. SETTING AND PARTICIPANTS: Nursing homes with at least 30 beds serving adults in California, Ohio, and Massachusetts were invited to participate in the survey. The analysis sample included 495 nursing homes. METHODS: We used a multivariable ordinary least squares model with turnover rate as the dependent variable. We used an indicator for nursing homes who scored above the median on the measure of leadership that supports worker safety, health, and well-being. Control variables include bed count (deciles), ownership (corporate/noncorporate × for-profit/not-for-profit), percent of residents on Medicaid, state, being in a nonmetropolitan county, and total nurse staffing per patient day in the 2 quarters before the survey. RESULTS: The unadjusted turnover rate was lower for those nursing homes that scored higher on leadership commitment to worker safety, health, and well-being. After controlling for additional variables, greater leadership commitment was still associated with lower turnover but with some attenuation. CONCLUSIONS AND IMPLICATIONS: We find that nursing homes with leadership that communicated and demonstrated commitment to worker safety, health, and well-being had relatively fewer nurses leave during the study period, with turnover rates approximately 10% lower than homes without. These findings suggest that leadership may be a valuable tool for reducing staff turnover.

Calreticulin accelerates corneal wound closure and mitigates fibrosis: Potential therapeutic applications.

The processes involved in regeneration of cutaneous compared to corneal tissues involve different intrinsic mechanisms. Importantly, cutaneous wounds involve healing by angiogenesis but vascularization of the cornea obscures vision. Previous studies showed that topically applied calreticulin (CALR) healed full-thickness excisional animal wounds by a tissue regenerative process markedly enhancing repair without evoking angiogenesis. In the current study, the application of CALR in a rabbit corneal injury model: (1) accelerated full wound closure by 3 days (2) accelerated delayed healing caused by corticosteroids, routinely used to prevent post-injury inflammation, by 6 days and (3) healed wounds without vascularization or fibrosis/hazing. In vitro, CALR stimulated proliferation of human corneal epithelial cells (CE) and corneal stromal cells (keratocytes) by 1.5-fold and 1.4-fold, respectively and induced migration of CE cells and keratocytes, by 72% and 85% compared to controls of 44% and 59%, respectively. As a marker of decreased fibrosis, CALR treated corneal wounds showed decreased immunostaining for α-smooth muscle actin (α-SMA) by keratocytes and following CALR treatment in vitro, decreased the levels of TGF-ß2 in human CE cells and α-SMA in keratocytes. CALR has the potential to be a novel therapeutic both, to accelerate corneal healing from various injuries and in conjunction with corticosteroids.

Plasma neurofilament light and brain volumetric outcomes among middle-aged urban adults.

Elevated plasma neurofilament light chain (NfL) is associated with dementia though underlying mechanisms remain unknown. We examined cross-sectional relationships of time-dependent plasma NfL with selected brain structural magnetic resonance imaging (sMRI) prognostic markers of dementia. The sample was drawn from the Healthy Aging in Neighborhoods of Diversity Across the Life Span (HANDLS) study, selecting participants with complete v1 (2004-2009) and v2 (2009-2013) plasma NfL exposure and ancillary sMRI data at vscan (2011-2015, n = 179, mean v1 to vscan time: 5.4 years). Multivariable-adjusted linear regression models were conducted, overall, by sex, and race, correcting for multiple testing with q-values. NfL(v1) was associated with larger WMLV (both Loge transformed), after 5-6 years' follow-up, overall (ß = +2.131 ± 0.660, b = +0.29, p = 0.001, and q = 0.0029) and among females. NfLv2 was linked to a 125 mm3 lower left hippocampal volume (p = 0.004 and q = 0.015) in reduced models, mainly among males, as was observed for annualized longitudinal change in NfL (δNfLbayes). Among African American adults, NfLv1 was inversely related to total, gray and white matter volumes. Plasma NfL may reflect future brain pathologies in middle-aged adults.

Plasma neurofilament light as blood marker for poor brain white matter integrity among middle-aged urban adults.

Plasma neurofilament light chain (NfL)'s link to dementia may be mediated through white matter integrity (WMI). In this study, we examined plasma NfL's relationships with diffusion tensor magnetic resonance imaging markers: global and cortical white matter fractional anisotropy (FA) and trace (TR). Plasma NfL measurements at 2 times (v1: 2004-2009 and v2: 2009-2013) and ancillary dMRI (vscan: 2011-2015) were considered (n = 163, mean time v1 to vscan = 5.4 years and v2 to vscan: 1.1 years). Multivariable-adjusted regression models, correcting for multiple-testing revealed that, overall, higher NfLv1 was associated with greater global TR (ß ± SE: +0.0000560 ± 0.0000186, b = 0.27, p = 0.003, q = 0.012), left frontal WM TR (ß ± SE: + 0.0000706 ± 0.0000201, b ± 0.30, p = 0.001, q = 0.0093) and right frontal WM TR (ß ± SE: + 0.0000767 ± 0.000021, b ± 0.31, p < 0.001, q = 0.0093). These associations were mainly among males and White adults. Among African American adults only, NfLv2 was associated with greater left temporal lobe TR. "Tracking high" in NfL was associated with reduced left frontal FA (Model 2, body mass index-adjusted: ß ± SE:-0.01084 ± 0.00408, p = 0.009). Plasma NfL is a promising biomarker predicting future brain white matter integrity (WMI) in middle-aged adults.

Effect of Long-term Exercise Training on Physical Performance and Cardiorespiratory Function in Adults With CKD: A Randomized Controlled Trial.

RATIONALE & OBJECTIVE: The safety and efficacy of long-term exercise training in reducing physical functional loss in older adults with advanced CKD and comorbidity is uncertain. STUDY DESIGN: Multicenter, parallel group, randomized controlled trial. SETTINGS & PARTICIPANTS: Adults 55 years and older with estimated glomerular filtration rate (eGFR) of 15 to <45 mL/min/1.73 m2 enrolled from centers in Baltimore and Boston. INTERVENTION: Twelve months of in-center supervised exercise training incorporating majority aerobic but also muscle strengthening activities or a group health education control intervention, randomly assigned in 1:1 ratio. OUTCOME: Primary outcomes were cardiorespiratory fitness and submaximal gait at 6 and 12 months quantified by peak oxygen consumption (Vo2peak) on graded exercise treadmill test and distance walked on the 6-minute walk test, respectively. Secondary outcomes were changes in lower extremity function, eGFR, albuminuria, glycemia, blood pressure, and body mass index. RESULTS: Among 99 participants, the mean age was 68 years, 62% were African American, and the mean eGFR was 33 mL/min/1.73 m2; 59% had diabetes, and 29% had coronary artery disease. Among those randomized to exercise, 59% of exercise sessions were attended in the initial 6 months. Exercise was well tolerated without excess occurrence of adverse events. At 6 months, aerobic capacity was higher among exercise participants (17.9 ± 5.5 vs 15.9 ± 7.0 mL/kg/min, P = 0.03), but the differences were not sustained at 12 months. The 6-minute walk distance improved more in the exercise group (adjusted difference: 98 feet [P = 0.02; P = 0.03 for treatment-by-time interaction]). The exercise group had greater improvements on the Timed Up and Go Test (P = 0.04) but not the Short Physical Performance Battery (P = 0.8). LIMITATIONS: Planned sample size was not reached. Loss to follow-up and dropout were greater than anticipated. CONCLUSIONS: Among adults aged ≥55 years with CKD stages 3b-4 and a high level of medical comorbidity, a 12-month program of in-center aerobic and resistance exercise training was safe and associated with improvements in physical functioning. FUNDING: Government grants (National Institutes of Health). TRIAL REGISTRATION: Registered at ClinicalTrials.gov with study number NCT01462097.

White matter integrity as a mediator between socioeconomic status and executive function.

Introduction: Lower socioeconomic status (SES) is associated with poorer executive function, but the neural mechanisms of this association remain unclear. As healthy brain communication is essential to our cognitive abilities, white matter integrity may be key to understanding socioeconomic disparities. Methods: Participants were 201 African American and White adults (ages 33-72) from the Healthy Aging in Neighborhoods of Diversity across the Life Span (HANDLS) SCAN study. Diffusion tensor imaging was used to estimate regional fractional anisotropy as a measure of white matter integrity. Adjusting for age, analyses examined if integrity of the anterior limb of the internal capsule (ALIC), external capsule (EC), superior longitudinal fasciculus (SLF), and cingulum mediated SES-executive function relations. Results: Lower SES was related to poorer cognitive performance and white matter integrity. Lower Trails B performance was related to poorer integrity of the ALIC, EC, and SLF, and lower Stroop performance was associated with poorer integrity of the ALIC and EC. ALIC mediated the SES-Trails B relation, and EC mediated the SES-Trails B and SES-Stroop relations. Sensitivity analyses revealed that (1) adjustment for race rendered the EC mediations non-significant, (2) when using poverty status and continuous education as predictors, results were largely the same, (3) at least some of the study's findings may generalize to processing speed, (4) mediations are not age-dependent in our sample, and (5) more research is needed to understand the role of cardiovascular risk factors in these models. Discussion: Findings demonstrate that poorer white matter integrity helps explain SES disparities in executive function and highlight the need for further clarification of the biopsychosocial mechanisms of the SES-cognition association.

Biomimetic Extracellular Matrix Nanofibers Electrospun with Calreticulin Promote Synergistic Activity for Tissue Regeneration.

In recognition of the potential of calreticulin (CRT) protein in enhancing the rate and quality of wound healing in excisional animal wound models, this study was to incorporate CRT via polyblend electrospinning into polycaprolactone (PCL)/type 1 collagen (Col1) nanofibers (NFs; 334 ± 75 nm diameter) as biomimetic extracellular matrices to provide a novel mode of delivery and protection of CRT with enhanced synergistic activities for tissue regeneration. Release kinetic studies using fluoresceinated CRT (CRT-FITC) polyblend NFs showed a burst release within 4 h reaching a plateau at 72 h, with further intervals of release upon incubation with fresh phosphate buffered saline for up to 8 weeks. By measuring fluorescence during the first 4 h of release, CRT-FITC-containing NFs were shown to protect CRT from proteolytic digestion (e.g., by subtilisin) compared to CRT-FITC in solution. CRT incorporated into NFs (CRT-NFs) also showed retention of biological activities and potency for stimulating proliferation and migration of human keratinocytes and fibroblasts. Fibroblasts seeded on CRT-NFs, after 2 days, showed increased amounts of fibronectin, TGF-ß1, and integrin ß1 in cell lysates by immunoblotting. Compared to NFs without CRT, CRT-NFs supported cell responses consistent with greater cell polarization and increased laminin-5 deposition of keratinocytes and a more motile phenotype of fibroblasts, as suggested by vinculin-capping F-actin fibers nonuniformly located throughout the cell body and the secretion of phosphorylated focal adhesion kinase-enriched migrasomes. Altogether, CRT electrospun into PCL/Col1 NFs retained its structural integrity and biological functions while having additional benefits of customizable loading, protection of CRT from proteolytic degradation, and sustained release of CRT from NFs, coupled with innate physicochemical cues of biomimetic PCL/Col1 NFs. Such synergistic activities have potential for healing recalcitrant wounds such as diabetic foot ulcers.

Increased all-cause mortality following occupational injury: a comparison of two states.

OBJECTIVES: To measure the impact of lost-time occupational injuries on all-cause mortality in Washington State and, using the same data elements and study design, to determine whether the estimated impact was similar to previous estimates for New Mexico. METHODS: We linked injuries in the Washington workers' compensation system with Social Security Administration data on earnings and mortality. We estimated Cox survival models of mortality for women and men with lost-time compared with medical-only injuries, adjusting for age, pre-injury earnings and industry. We used quantitative bias analysis to account for confounding by pre-injury smoking and obesity. RESULTS: The estimated mortality HR was 1.24 for women (95% CI 1.21 to 1.28) and 1.22 for men (95% CI 1.20 to 1.24). After adjusting for unmeasured pre-injury smoking and obesity, the estimated HR for women was 1.10, 95% simulation interval (SI) 1.00 to 1.21; for men, it was 1.15, 95% SI 1.04 to 1.27. CONCLUSIONS: All-cause mortality for Washington workers with lost-time injuries was higher than for those with medical-only injuries. Estimated HRs for Washington were consistent with those previously estimated for New Mexico, a less populous state with lower median wages and a different workers' compensation insurance mechanism. This suggests that the relationship between workplace injury and long-term mortality may be generalisable to other US states. These findings support greater efforts to enhance safety and to investigate factors that improve postinjury employment opportunities and long-term health. This association should be examined in additional locations, with different study conditions, or using additional data on pre-injury risk factors.

Synergistic Associations of Depressive Symptoms and Executive Functions With Longitudinal Trajectories of Diabetes Biomarkers Among Urban-Dwelling Adults Without Diabetes.

OBJECTIVE: Depressive symptoms and executive functions (EFs) have recently emerged as novel risk factors for type 2 diabetes, but it is unknown if these factors interact to influence diabetes pathophysiology across the life span. We examined the synergistic associations of depressive symptoms and EFs with longitudinal trajectories of diabetes diagnostic criteria among middle-aged and older adults without diabetes. METHODS: Participants were 1257 African American and White, urban-dwelling adults from the Healthy Aging in Neighborhoods of Diversity across the Life Span study who were assessed up to three times over a 13-year period (2004-2017). At baseline, participants completed the Center for Epidemiological Studies-Depression scale and measures of EFs-Trail Making Test Part B, verbal fluency, and Digit Span Backward-for a composite EFs score, and provided blood samples at each follow-up for glycated hemoglobin and fasting serum glucose. RESULTS: A total of 155 and 220 individuals developed diabetes or prediabetes at wave 3 and wave 4, respectively. Linear mixed-effects regression models adjusting for sociodemographic factors, diabetes risk factors, and antidepressant medications revealed significant three-way interactions of Center for Epidemiological Studies-Depression, EFs, and age on change in glycated hemoglobin (b = -0.0001, p = .005) and in fasting serum glucose (b = -0.0004, p < .001), such that among individuals with lower but not higher EFs, elevated depressive symptoms were associated with steeper age-related increases in diabetes biomarkers over time. CONCLUSIONS: Depressive symptoms and lower EFs may interactively accelerate trajectories of key diagnostic criteria, thereby increasing the risk for earlier diabetes incidence. Identifying individuals in this high-risk group may be an important clinical priority for earlier intervention, which has the promise of preventing or delaying this debilitating disease.

Workplace Integrated Safety and Health Program Uptake in Nursing Homes: Associations with Ownership.

Workers in nursing homes are at high risk of occupational injury. Understanding whether-and which-nursing homes implement integrated policies to protect and promote worker health is crucial. We surveyed Directors of Nursing (DON) at nursing homes in three US states with the Workplace Integrated Safety and Health (WISH) assessment, a recently developed and validated instrument that assesses workplace policies, programs, and practices that affect worker safety, health, and wellbeing. We hypothesized that corporate and for-profit nursing homes would be less likely to report policies consistent with Total Worker Health (TWH) approaches. For each of the five validated WISH domains, we assessed the association between being in the lowest quartile of WISH score and ownership status using multivariable logistic regression. Our sample included 543 nursing homes, 83% which were corporate owned and 77% which were for-profit. On average, DONs reported a high implementation of TWH policies, as measured by the WISH. We did not find an association between either corporate ownership or for-profit status and WISH score for any WISH domain. Results were consistent across numerous sensitivity analyses. For-profit status and corporate ownership status do not identify nursing homes that may benefit from additional TWH approaches.

Mortality following workplace injury: Quantitative bias analysis.

PURPOSE: Recent studies have shown increased all-cause mortality among workers following disabling workplace injury. These studies did not account for 2 potentially important confounders, smoking and obesity. We estimated injury-related mortality accounting for these factors. METHODS: We followed workers receiving New Mexico workers' compensation benefits (1994-2000) through 2013. Using data from the Panel Study of Income Dynamics, we derived the joint distribution of smoking status and obesity for workers with and without lost-time injuries. We conducted a quantitative bias analysis (QBA) to determine the adjusted relationship of injury and mortality. RESULTS: We observed hazard ratios after adjusting for smoking and obesity of 1.13 for women (95% simulation interval (SI) 0.97 to 1.31) and 1.12 for men (95% SI 1.00 to 1.27). The estimated fully adjusted excess hazard was about half the estimates not adjusted for these factors. CONCLUSIONS: Using QBA to adjust for smoking and obesity reduced the estimated mortality hazard from lost-time injuries and widened the simulation interval. The adjusted estimate still showed more than a 10 percent increase for both women and men. The change in estimates reveals the importance of accounting for these confounders. Of course, the results depend on the methods and assumptions used.

Evaluating Test-Retest Reliability of Fatigability in Chronic Stroke.

OBJECTIVES: The subjective nature of fatigue may contribute to inconsistencies in prevalence rates for post-stroke fatigue. More objective performance fatigue measures may offer a more reliable construct of fatigue. Our goal was to establish test-retest reliability of fatigability in stroke during 6-minute walk (6MW) testing. Relationships between post-stoke fatigability and other constructs were assessed. MATERIALS AND METHODS: Twenty-three hemiparetic stroke survivors underwent two 6MW tests with portable metabolic monitoring performed at least 48 hours apart. Fatigability was defined as ratio of change in walking speed to distance covered during the 6MW. 6MW oxygen consumption (VO2), peak aerobic capacity (VO2peak), walking speed over-ground, dynamic gait index, fatigue, falls efficacy, and BMI were measured. RESULTS: Fatigability was highly correlated between both 6MW trials (ICC = 0.99, p < 0.001) with no significant difference between trials (0.08, p = 0.48). The strongest correlation was between fatigability and 6MW VO2 trial 1 and 2 (r = 0.92, p < 0.001 and r = 0.95, p < 0.001, respectively). Moderate-to-strong relationships were observed between fatigability for 6MW and fastest-comfortable walking speed (r = -0.82 and -0.77), self-selected walking speed (r = -7.8 and -0.78), 6MW walking speed (r = -0.80 and 0.80, VO2peak (r = -0.47 and -0.48) (p < 0.001), and DGI (r = -0.70 and -0.68, p < 0.001). CONCLUSION: This study establishes test-retest reliability for an objective measure of fatigue in stroke-related disability. The strong correlations between fatigability and other functional measures also provides insight into the contributors underlying fatigability in this population. REGISTRATION: URL: http://www.clinicaltrials.gov. Unique identifier: NCT01322607.

A hidden Markov model for estimating age-specific survival when age and size are uncertain.

Estimates of age-specific survival probabilities are needed for age-structured population models and to inform conservation decisions. However, determining the age of individuals in wildlife populations is often problematic. We present a hidden Markov model for estimating age-specific survival from capture-recapture or capture-recapture-recovery data when age is unknown and indicators of age, such as size and growth layer counts, are imprecise. The model is evaluated through simulations, and its implementation is illustrated with maximum likelihood and Bayesian approaches in commonly used software. The model is then applied to genetic capture-recapture data of Florida manatees to estimate age- and time-variant survival probabilities. The approach is broadly applicable to studies aiming to quantify age-specific effects of environmental change and management actions on population dynamics, including studies that rely on minimally invasive methods such as genetic and photo identification.