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Background: The effects of clinical-trial funding on the interpretation of trial results are poorly understood. We examined how such support affects physicians' reactions to trials with a high, medium, or low level of methodologic rigor.Methods: We presented 503 board-certified internists with abstracts that we designed describing clinical trials of three hypothetical drugs. The trials had high, medium, or low methodologic rigor, and each report included one of three support disclosures: funding from a pharmaceutical company, NIH funding, or none. For both factors studied (rigor and funding), one of the three possible variations was randomly selected for inclusion in the abstracts. Follow-up questions assessed the physicians' impressions of the trials' rigor, their confidence in the results, and their willingness to prescribe the drugs.Results: The 269 respondents (53.5% response rate) perceived the level of study rigor accurately. Physicians reported that they would be less willing to prescribe drugs tested in low-rigor trials than those tested in medium-rigor trials (odds ratio, 0.64; 95% confidence interval [CI], 0.46 to 0.89; P=0.008) and would be more willing to prescribe drugs tested in high-rigor trials than those tested in medium-rigor trials (odds ratio, 3.07; 95% CI, 2.18 to 4.32; P<0.001). Disclosure of industry funding, as compared with no disclosure of funding, led physicians to downgrade the rigor of a trial (odds ratio, 0.63; 95% CI, 0.46 to 0.87; P=0.006), their confidence in the results (odds ratio, 0.71; 95% CI, 0.51 to 0.98; P=0.04), and their willingness to prescribe the hypothetical drugs (odds ratio, 0.68; 95% CI, 0.49 to 0.94; P=0.02). Physicians were half as willing to prescribe drugs studied in industry-funded trials as they were to prescribe drugs studied in NIH-funded trials (odds ratio, 0.52; 95% CI, 0.37 to 0.71; P<0.001). These effects were consistent across all levels of methodologic rigor.Conclusions: Physicians discriminate among trials of varying degrees of rigor, but industry sponsorship negatively influences their perception of methodologic quality and reduces their willingness to believe and act on trial findings, independently of the trial's quality. These effects may influence the translation of clinical research into practice. [ABSTRACT FROM AUTHOR]

The present study examined a procedure for measuring perceived labeling. An index comprised of six contrasting descriptive adjectives was used to measure incarcerated youths' perceived negative labeling from the perspective of parents, teachers, and peers. The results provided partial support for the hypothesis that juveniles who choose a greater number of negative labels for their self-concepts will report more frequent delinquent involvement. Labeling variables were significant predictors of general and serious delinquency but did not predict drug-related offenses. [ABSTRACT FROM AUTHOR]

Surveys often estimate vaccination intentions using dichotomous ("Yes"/"No") or trichotomous ("Yes," "Unsure," "No") response options presented in different orders. Do survey results depend on these variations? This controlled experiment randomized participants to dichotomous or trichotomous measures of vaccine intentions (with "Yes" and "No" options presented in different orders). Intentions were measured separately for COVID-19, its booster, and influenza vaccines. Among a sample of U.S. adults (N = 4,764), estimates of vaccine intention varied as much as 37.5 ± 17.4 percentage points as a function of the dichotomous or trichotomous response set. Among participants who had not received the COVID-19 vaccine, the "Unsure" option was more likely to reduce the share of "No" (versus "Yes") responses, whereas among participants who had received the COVID-19 vaccine, the "Unsure" option was more likely to reduce the share of "Yes" (versus "No") responses. The "Unsure" category may increase doubt and decrease reliance on past vaccination behavior when forming intentions. The order of "Yes" and "No" responses had no significant effect. Future research is needed to further evaluate why the effects of including the "Unsure" option vary in direction and magnitude., (© 2024. The Author(s).)

Financial incentives are a controversial strategy for increasing vaccination. In this systematic review, we evaluated: 1) the effects of incentives on COVID-19 vaccinations; 2) whether effects differed based on study outcome, study design, incentive type and timing, or sample sociodemographic characteristics; and 3) the cost of incentives per additional vaccine administered. We searched PubMed, EMBASE, Scopus, and Econlit up to March 2022 for terms related to COVID, vaccines, and financial incentives, and identified 38 peer-reviewed, quantitative studies. Independent raters extracted study data and evaluated study quality. Studies examined the impact of financial incentives on COVID-19 vaccine uptake (k = 18), related psychological outcomes (e.g., vaccine intentions, k = 19), or both types of outcomes. For studies of vaccine uptake, none found that financial incentives had a negative effect on uptake, and most rigorous studies found that incentives had a positive effect on uptake. By contrast, studies of vaccine intentions were inconclusive. While three studies concluded that incentives may negatively impact vaccine intentions for some individuals, they had methodological limitations. Study outcomes (uptake versus intentions) and study design (experimental versus observational frameworks) appeared to influence results more than incentive type or timing. Additionally, income and political affiliation may moderate responses to incentives. Most studies evaluating cost per additional vaccine administered found that they ranged from $49-75. Overall, fears about financial incentives decreasing COVID-19 vaccine uptake are not supported by the evidence. Financial incentives likely increase COVID-19 vaccine uptake. While these increases appear to be small, they may be meaningful across populations. Registration: PROSPERO, CRD42022316086 (https://www.crd.york.ac.uk/prospero/display&#95;record.php?ID=CRD42022316086)., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Published by Elsevier Inc.)

Experts debate whether COVID-19 vaccine mandates or financial incentives will reduce, rather than increase, interest in vaccination. Among 3,698 unvaccinated U.S. residents, we conducted a randomized, controlled survey-embedded experiment to estimate the absolute and relative psychological effects of vaccine policies specifying: mandates by employers or airlines, bars, and restaurants; lotteries for $1 million, $200,000, or $100,000; guaranteed cash for $1000, $200, or $100; and $1,000 as either a tax credit or penalty. Vaccine intention -the study outcome- predicts uptake and provides insight into the psychological mechanism that is most proximal to behavior (i.e., vaccination). Compared to controls, those who learned about the $1,000 cash reward policy were 17.1 (±5.3)% more likely to want vaccination. Employer mandates are more promising than other mandate policies (8.6 [+/- 7.4]% vs. 1.4 [+/- 6.0]%). The full results suggest that neither mandates nor financial incentives are likely to have counterproductive psychological effects. These policies are not mutually exclusive and, if implemented well, they may increase vaccine uptake., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2022 Elsevier Ltd. All rights reserved.)

Recent research indicates that distance running stride-to-stride variability (SSV) is related to performance and injury. Previous studies have primarily focused on stride characteristics (stride length and time). We assessed SSV for sagittal plane joint angles with the primary purpose of testing for significant differences among the lower body joints. The secondary purpose was to determine if strong correlations exist among joint SSV measures. Thirty recreational adult runners participated in the study (8 females, 22 males, 39 ± 10 years; 53.1 ± 25.7 km/week). A 6-camera motion capture system (200 Hz) collected kinematic data during treadmill running at a preferred pace. A 2 by 3 repeated measures factorial ANOVA (phase-stance, swing; joint-hip, knee, ankle) was run ( p = 0.05). There was a significant interaction effect (p < 0.001) and post hoc analysis revealed knee swing to be the most variable condition by far. For all three joints, there were strong correlations between stance and swing SSV (r = 0.80 to r = 0.88) and correlations among the joints were moderate to strong (r = 0.55 to 0.86). This study helps to better understand the joints/phases that contribute most to variability in the overall stride. Also, the strong correlations suggest that runners appear to have an overall SSV pattern that is similar across joints/phases.

Reform requires clarity about whether, when, and how meaningful postapproval trials are possible.

To increase COVID-19 vaccine uptake in resistant populations, such as Republicans, focus groups suggest that it is best to de-politicize the issue by sharing five facts from a public health expert. Yet polls suggest that Trump voters trust former President Donald Trump for medical advice more than they trust experts. We conducted an online, randomized, national experiment among 387 non-vaccinated Trump voters, using two brief audiovisual artifacts from Spring 2021, either facts delivered by an expert versus political claims delivered by President Trump. Relative to the control group, Trump voters who viewed the video of Trump endorsing the vaccine were 85% more likely to answer "yes" as opposed to "no" in their intention to get fully vaccinated (RRR = 1.85, 95% CI 1.01 to 3.40; P = .048). There were no significant differences between those hearing the public health expert excerpt and the control group (for "yes" relative to "no" RRR = 1.14, 95% CI 0.61 to 2.12; P = .68). These findings suggest that a political speaker's endorsement of the COVID-19 vaccine may increase uptake among those who identify with that speaker. Contrary to highly-publicized focus group findings, our randomized experiment found that an expert's factually accurate message may not be effectual to increase vaccination intentions., Competing Interests: The authors have declared that no competing interests exist.

There is an acknowledged need for higher-quality evidence to quantify the benefit of surgical procedures, yet not enough has been done to improve the evidence base. This lack of evidence can prevent fully informed decision-making, lead to unnecessary or even harmful treatment, and contribute to wasteful expenditures of scare health care resources. Barriers to evidence generation include not only the long-recognized technical difficulties and ethical challenges of conducting randomized surgical trials, but also legal challenges that limit incentives to conduct surgical research as well as market-based challenges that make it difficult for those funding surgical research to recoup investment costs. These legal and market dynamics differ substantially from those surrounding new drug or device development. Nevertheless, obstacles could be overcome and overall expenditures could be reduced if a share of federal health care agency budgets were reallocated to generating randomized trial data, standardizing outcome measures, and conducting observational studies analogous to those that have been facilitated for drugs via the Food and Drug Administration's Sentinel Initiative. Until better quality evidence is available, ethical principles require adequate disclosure of the limited evidence base supporting current surgical procedures.

Economic insights are powerful for understanding the challenge of managing a highly infectious disease, such as COVID-19, through behavioral precautions including social distancing. One problem is a form of moral hazard, which arises when some individuals face less personal risk of harm or bear greater personal costs of taking precautions. Without legal intervention, some individuals will see socially risky behaviors as personally less costly than socially beneficial behaviors, a balance that makes those beneficial behaviors unsustainable. For insights, we review health insurance moral hazard, agricultural infectious disease policy, and deterrence theory, but find that classic enforcement strategies of punishing noncompliant people are stymied. One mechanism is for policymakers to indemnify individuals for losses associated with taking those socially desirable behaviors to reduce the spread. We develop a coherent approach for doing so, based on conditional cash payments and precommitments by citizens, which may also be reinforced by social norms., (© The Author(s) 2020. Published by Oxford University Press on behalf of Duke University School of Law, Harvard Law School, Oxford University Press, and Stanford Law School. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.)

Telehealth continues to experience substantial investment, innovation, and unprecedented growth. However, telehealth has been slow to transform healthcare. Recent developments in telehealth technologies suggest great potential for chronic care management, mental health services, and care delivery in the home-all of which should be particularly impactful for an aging population with physical and cognitive limitations. While this alignment of technological capacity and market demand is promising, legal barriers remain for telehealth operators to scale up across large geographic areas. To better understand how federal and state law can be reformed to enable greater telehealth utilization, we review and extract lessons from (1) establishment of a healthcare relationship, (2) state licensure laws, and (3) reimbursement. We analyze these areas because of the legal ambiguities or inconsistencies they raise depending on the state, which seem to be hampering telehealth growth without necessarily improving quality of care. We propose several solutions for a more unified approach to telehealth regulation that incorporate core bioethics principles of doctor-patient relationship, competence, patient autonomy, as well as population-wide questions of resource allocation and access. Lawmakers should clarify that healthcare relationships may be established outside of in-person meetings, align licensure laws via an interstate compact or federal preemption, and expand Centers for Medicare and Medicaid plans to reimburse telehealth delivery in the home.

Context: Health policy has long been preoccupied with the problem that health insurance stimulates spending ("moral hazard"). However, much health spending is costly healthcare that uninsured individuals could not otherwise access. Field studies comparing those with more or less insurance cannot disaggregate moral hazard versus access. Moreover, studies of patients consuming routine low-dollar healthcare are not informative for the high-dollar healthcare that drives most of aggregate healthcare spending in the United States., Methods: We test indemnities as an alternative theory-driven counterfactual. Such conditional cash transfers would maintain an opportunity cost for patients, unlike standard insurance, but also guarantee access to the care. Since indemnities do not exist in U.S. healthcare, we fielded two blinded vignette-based survey experiments with 3,000 respondents, randomized to eight clinical vignettes and three insurance types. Our replication uses a population that is weighted to national demographics on three dimensions., Findings: Most or all of the spending due to insurance would occur even under an indemnity. The waste attributable to moral hazard is undetectable., Conclusions: For high-cost care, policymakers should be more concerned about the foregone efficient spending for those lacking full insurance, rather than the wasteful spending that occurs with full insurance., Competing Interests: The authors have declared that no competing interests exist.

During interceptive motor tasks, experts demonstrate distinct visual search behavior (from novices) that is reflective of information extraction from optimal environmental cues, which subsequently aids anticipatory movements. While some forms of visual training have been employed in sport, over-speed video training is rarely applied to perceptual-cognitive sport contexts. The purpose of the present study was to determine whether over-speed video training can enhance visual information processing and augment visual behavior for a pitch-recognition task. Twelve collegiate softball players were recruited for the study. A between-subjects, repeated measures design was implemented to assess changes in participants' pitch recognition on a video-based occlusion task after one of two training interventions: (A) over-speed video training (n = 6) or (B) regular video training (n = 6). Both training interventions required individuals to view 400 videos of different pitches over the span of 10 days. The over-speed group viewed the videos at gradually increasing video speeds (+ 0.05 × each day). Performance (i.e., identifying pitch type and location), quiet-eye duration (i.e., total QE, QE-early and QE-late) and cortical activation (i.e., alpha wave activity/asymmetry; F3/F4 and P7/P8) were measured during the pitch-recognition tasks. Results showed significant performance improvements across groups, but no differences between groups. Both interventions were associated with a reduction in alpha wave activity for P8, an increase in alpha activity for F3, and a significant increase in QE-late. An increase in QE-late was associated with a decrease in P7/P8 alpha asymmetry and improvements in pitch-type recognition. Consistent with the extant literature, our results support the importance of a later QE offset for successful performance on perceptual tasks, potentially extending to perceputal-motor tasks. Although participants in the over-speed condition did not experience significantly larger improvements in performance than controls, this study highlights the association between QE and brain activity reflective of expertise.

In September, the U.S. Department of Health and Human Services, together with other federal agencies, announced proposed changes to the rules governing human subjects research. This Commentary discusses how the proposals would affect research using biospecimens that is essential to the future success of precision medicine. We argue that the proposed changes unnecessarily burden such research, without meaningfully advancing the interests of donors. They should be revised before being finalized.

Medical and public health research includes surveys, interviews, and biospecimens - techniques that do not present substantial risks to subjects. Consequently, this research is exempt from regulation under the Federal Common Rule. Nevertheless, at many institutions, exempt research is frequently subject to the same regulatory process that is required for non-exempt research, requiring the consumption of time and resources for review by Institutional Review Board members or staff. The federal government has indicated an intention to reform and centralize this system, but has not yet specified the form that it will use instead. By examining the policies of the top 50 research institutions, this article assesses institutional practices surrounding exempt research, quantifies the extent of exempt-research review requirements, documents a problem of "over-compliance," and makes recommendations for reform., (© 2016 American Society of Law, Medicine & Ethics.)

This Article explores two ways in which airline travel is an important vector for the spread of infectious disease, and argues that airlines have market-based and liability-based reasons to require that passengers be vaccinated. Going further, the Article explores whether the federal government has the legal and constitutional authority-especially under the Commerce Clause-to encourage or mandate that airlines implement such a vaccine screen. By disrupting the spread of disease at key network nodes where individuals interact and then connect with other geographic regions, and by creating another incentive for adult vaccination, an airline vaccine screen could be an effective and legally viable tool for the protection of public health.

In recent decades, social scientists have shown that the reliability of eyewitness identifications is much worse than laypersons tend to believe. Although courts have only recently begun to react to this evidence, the New Jersey judiciary has reformed its jury instructions to notify jurors about the frailties of human memory, the potential for lineup administrators to nudge witnesses towards suspects that they police have already identified, and the advantages of alternative lineup procedures, including blinding of the administrator. This experiment tested the efficacy of New Jersey's jury instruction. In a 2×2 between-subjects design, mock jurors (N = 335) watched a 35-minute murder trial, wherein identification quality was either "weak" or "strong" and either the New Jersey or a "standard" instruction was delivered. Jurors were more than twice as likely to convict when the standard instruction was used (OR = 2.55; 95% CI = 1.37-4.89, p < 0.001). The New Jersey instruction, however, did not improve juror's ability to discern quality; rather, jurors receiving those instructions indiscriminatingly discounted "weak" and "strong" testimony in equal measure.

Purpose: Impaired reflex regulation is assumed to contribute to upper-extremity motor impairment poststroke; however, the relationship between reflex inhibition and motor function remains unclear. To address this question, it is first necessary to determine the reproducibility of reflex responses. The objective of this study was to establish the test-retest reliability of flexor carpi radialis H-reflex inhibition in healthy control and stroke participants and investigate the correlation between H-reflex inhibition and grip strength., Materials and Methods: Eighteen persons poststroke (mean ± SD: age 63 ± 13 years; 6 ± 5 years poststroke; 13 males) and 16 healthy controls (age: 62 ± 12 years) participated. Reflex inhibition was tested on 2 separate days by conditioning the H-reflex with radial nerve stimulation at two different interstimulus intervals: 13 ms (presynaptic Ia inhibition-PSI) and 0 ms (disynaptic inhibition). Pearson's and intraclass correlation coefficients [two-way mixed model-ICC (1, 2)], and standard error of measurement (SEM) were calculated., Results: Relative reliability (ICCs) ranged from good to excellent (0.61-0.78). SEM was low (range 10-19%, stroke; 15-20%, healthy controls). Paretic grip strength and paretic limb PSI revealed a positive correlation (r = 0.70; p < 0.0125). Disynaptic inhibition and paretic grip strength were not correlated., Conclusions: To our knowledge, this is the first study to demonstrate reproducibility of reflex inhibition in individuals poststroke. Furthermore, we quantify smallest real differences, which provide an estimate of the magnitude of effect required to determine a meaningful change, exceeding measurement error. The correlation between PSI and grip strength suggests the potential contribution of PSI to grip force production and upper-extremity motor function.

α-helices are the most common form of secondary structure found in proteins. In order to study controlled protein folding, as well as manipulate the interface of helical peptides with targets in protein-protein interactions, many techniques have been developed to induce and stabilize α-helical structure in short synthetic peptides. Furthermore, short, non-natural β-peptides have been established that fold into predictable 14-helices that mimic α-helical structure. We created a panel of short 6-8 residue α- and β-peptides that used confirmed primary sequence design features which influence helical control and directly compared the helicity across peptides with the most minimal epitopes. Using CD spectroscopy, we found that both α- and β-peptides abided by their respective design principles, with no significant "cross-helicity" inducing an α- or a β-peptide to fold into the oppositely controlled helix. Generally, the β-peptide of the most optimal sequence displayed the largest percent of 14-helicity, whereas the two α-peptides of most favorable design showed some α-helicity and a marked 310-helical contribution. Overall, the results can inform future peptidomimetic designs, especially in the development of short, structured peptides with biological function.

Like all physicians, radiologists in the United States are subject to frequent and costly medical malpractice claims. Legal scholars and physicians concur that the US civil justice system is neither precise nor accurate in determining whether malpractice has truly occurred in cases in which claims are made. Sometimes, this inaccuracy is driven by biases inherent in medical expert-witness opinions. For example, expert-witness testimony involving "missed" radiology findings can be negatively affected by several cognitive biases, such as contextual bias, hindsight bias, and outcome bias. Biases inherent in the US legal system, such as selection bias, compensation bias, and affiliation bias, also play important roles. Fortunately, many of these biases can be significantly mitigated or eliminated through the use of appropriate blinding techniques. This paper reviews the major works on expert-witness blinding in the legal scholarship and the radiology professional literature. Its purpose is to acquaint the reader with the evidence that unblinded expert-witness testimony is tainted by multiple sources of bias and to examine proposed strategies for addressing these biases through blinding., (Copyright © 2014 American College of Radiology. Published by Elsevier Inc. All rights reserved.)

Although the Federal Common Rule requires that informed consent documents include all material information, it does not specify the content of materials used to recruit human subjects. In particular, there is no federal regulation relating to how payment for research participation is to be advertised. Rather, the FDA has issued guidance, advising researchers not to emphasize payment information. In order to determine how IRBs have interpreted this guidance, we coded the policies of the top 100 institutions by receipt of NIH funding, in order to determine whether they require, permit, or forbid researchers to disclose the amount of compensation in their recruitment materials. We found that the vast majority of institutions implicitly or explicitly permit such disclosures; however, there are a significant number of IRBs at each extreme, some discouraging or forbidding with others encouraging or mandating such disclosures. Such heterogeneity in local regulations suggests that IRB discretion may be imposing costs on human subjects and the scientific enterprise that outweigh the benefits. We suggest that this heterogeneity should be resolved towards a national consensus on permissibility., (© 2014 American Society of Law, Medicine & Ethics, Inc.)

In the employer-sponsored insurance market that covers most Americans; many workers are "underinsured." The evidence shows onerous out-of-pocket payments causing them to forgo needed care, miss work, and fall into bankruptcies and foreclosures. Nonetheless, many higher-paid workers are "overinsured": the evidence shows that in this domain, surplus insurance stimulates spending and price inflation without improving health. Employers can solve these problems together by scaling cost-sharing to wages. This reform would make insurance better protect against risk and guarantee access to care, while maintaining or even reducing insurance premiums. Yet, there are legal obstacles to scaled cost-sharing. The group-based nature of employer health insurance, reinforced by federal law, makes it difficult for scaling to be achieved through individual choices. The Affordable Care Act's (ACA) "essential coverage" mandate also caps cost-sharing even for wealthy workers that need no such cap. Additionally, there is a tax distortion in favor of highly paid workers purchasing healthcare through insurance rather than out-of-pocket. These problems are all surmountable. In particular, the ACA has expanded the applicability of an unenforced employee-benefits rule that prohibits "discrimination" in favor of highly compensated workers. A novel analysis shows that this statute gives the Internal Revenue Service the authority to require scaling and to thereby eliminate the current inequities and inefficiencies caused by the tax distortion. The promise is smarter insurance for over 150 million Americans.

Synaptic efficacy associated with muscle spindle feedback is partly regulated via depression at the Ia-motorneuron synapse through paired reflex depression (PRD) and presynaptic inhibition (PI). The purpose of this study was to examine PRD and PI of the soleus H-reflex at rest and with a background voluntary muscle contraction. The experiment was conducted on 10 healthy males with no history of neurological deficits. Soleus H-reflex and M-wave curves were elicited in three conditions: unconditioned, PRD (two consecutive H-reflexes with 100 ms interval), and PI (1.2 × MT to tibialis anterior 100 ms prior to soleus H-reflex). Each condition was tested at rest and with a 10% soleus contraction. PRD and PI both produced a pronounced inhibition to the soleus motor pool at rest, with a significant difference observed between threshold values (78.9, 89.3, and 90.4% for unconditioned, PRD, and PI reflexes, respectively). During the voluntary contraction the threshold for both inhibitory mechanisms was significantly reduced, and were not different from the unconditioned H-reflex (74.5, 78.9, and 77.0% for unconditioned, PRD, and PI reflexes, respectively). The slope of PI and the PI Hmax/Mmax ratio were significantly altered during contraction whereas no differences were observed for PRD. The results suggest these inhibitory mechanisms depend on the interaction between background voluntary activation and stimulus intensity. This behavior of these inhibitory mechanisms underscores the specificity of spinal circuitry in the control of motor behaviors.

Objective: To establish test-retest reliability of flexor carpi radialis (FCR) H-reflexes in non-disabled and stroke participants. We also investigated inter-limb differences and effects of chronicity post-stroke compared to non-disabled group and age-related effects in the non-disabled group., Methods: Sixteen chronic stroke and twenty-two non-disabled participants were recruited. Bilateral FCR H-reflexes were tested on two separate days by stimulating the median nerve and recording surface electromyography responses. FCR recruitment curves were plotted for H-reflex (H) and motor (M) waves and normalized as a percentage of maximal M-wave (ordinate) and motor threshold (abscissa)., Statistics: Intraclass correlation coefficients [two-way mixed model-ICC (1, 2)], one-way ANOVA, Bland-Altman plots, standard error of measurement (SEM), and smallest real difference (SRD)., Results: ICCs ranged from 0.55 to 0.95 (stroke) and 0.69-0.88 (non-disabled). SEM% (% of the mean) ranged from 9% to 24% (stroke) and 18-38% (non-disabled); SRD% ranged from 18% to 66% (stroke) and 6% to 50% (non-disabled). H-reflex amplitude and slope were greater in the paretic vs. non-paretic arm post-stroke (p=0.07 and 0.01, respectively) and the paretic arm vs. non-disabled participants (p=0.007 and 0.002, respectively). Stroke participants with longer chronicity (mean 9.4 years) revealed a significantly greater Hslp/Mslp on the paretic side compared to shorter chronicity (2.5 years; p=0.05). Mean Hslp/Mslp was significantly greater in the young (mean 29 years) compared to the older group (62 years; p=0.045)., Conclusions: These results establish reliability of FCR H-reflexes in stroke and non-disabled participants. SEM and SRD measurements can be used to interpret recovery patterns and longitudinal effects of therapeutic interventions., Significance: FCR H-reflex amplitude and slope can be reliably measured and used to investigate neurophysiological mechanisms of motor recovery post-stroke., (Published by Elsevier Ireland Ltd.)

Synaptic efficacy associated with muscle spindle feedback is regulated via depression at the Ia-motoneurone synapse. The inhibitory effects of repetitive Ia afferent discharge on target motoneurones of different sizes were investigated during a passive stretch of ankle extensors in humans. H-reflex recruitment curves were collected from the soleus muscle for two conditions in ten subjects. H-reflexes were elicited during passive stretch at latencies of 50, 100, 300, and 500 ms after a slow (20°/s) dorsiflexion about the right ankle (from 100 to 90°). Control H-reflexes were recorded at corresponding static (without movement) ankle angles of 99, 98, 94, and 90° of flexion. The slope of the H-reflex recruitment curves (Hslp) was then calculated for both conditions. H-reflex values were similar for the static and passive stretch conditions prior to 50-100 ms, not showing the early facilitation typical of increased muscle spindle discharge rates. However, the H-reflex was significantly depressed by 300 ms and persisted through 500 ms. Furthermore, less than 300 ms into the stretch, there was significantly greater H-reflex depression with a lower stimulus intensity (20 % Mmax) versus a higher stimulus intensity (Hmax), though the effects begin to converge at later latencies (>300 ms). This suggests there is a distinct two-stage temporal process in the depression observed in the Ia afferent pathway for all motoneurones during a passive stretch. Additionally, there is not a single mechanism responsible for the depression, but rather both heterosynaptic presynaptic inhibition and homosynaptic post-activation depression are independently influencing the Ia-motoneurone pathway temporally during movement.

The pharmaceutical and medical device industries use billions of dollars to support the biomedical science that physicians, regulators, and patients use to make healthcare decisions--the decisions that drive an increasingly large portion of the American economy. Compelling evidence suggests that this industry money buys favorable results, biasing the outcomes of scientific research. Current efforts to manage the problem, including disclosure mandates and peer reviews, are ineffective. A blinding mechanism, operating through an intermediary such as the National Institutes of Health, could instead be developed to allow industry support of science without allowing undue influence. If the editors of biomedical journals fail to mandate that industry funders utilize such a solution, the federal government has several regulatory levers available, including conditioning federal funding and direct regulation, both of which could be done without violating the First Amendment.

Spinal modulation of motoneuron excitability has been extensively investigated during various tasks in humans. Previous studies have revealed that balance tasks induce a decrease in Ia-motoneuron communication which has been attributed to increased levels of presynaptic inhibition (PI). Moreover, this depression in Ia-motoneuron connectivity takes place subsequent to the elevation of muscle activity. Therefore, it is hypothesized that motor learning has inhibitory effects on the spinal mechanisms in spite of the increased muscle activity during a motor task. The purpose of this study was to explore the effects of a complex balance task on the H-reflex. Soleus H-reflexes were measured from 11 healthy adult subjects both before and after 20 minutes of a complex balance task. A commonly reported H-reflex conditioning technique was applied in order to measure changes in spinal PI: an electrical volley to the heteronymous Ia (common peroneal nerve conditioning, CPN). Subjects stood on a custom designed balance board and performed a continuous series of plantar and dorsiflexion. To ensure that the task was performed similarly between subjects, auditory cues for movement were given by a metronome with a frequency of 1 Hz. The initial amplitude of the unconditioned soleus H-reflex was set at 50% of H-max, and unconditioned and conditioned (PI) reflexes were recorded before, during, and after the balance task. The unconditioned soleus H-reflex was significantly decreased 59% after the balance task and PI was increased by 50%. Further, during a period of rest following the task (20 minutes) the unconditioned H-reflex returned to near baseline levels whereas the PI conditioned H-reflex was not altered The results suggest that the initial depression in motoneuron excitability immediately after the balance task is accompanied by an increase in PI, but also that the recovery of the depressed H-reflex after the task appears to be independent of PI.

Fluctuating asymmetry (FA), the small random deviations from perfect morphological symmetry that result during development, is ubiquitous throughout the animal kingdom. In many species, FA seems to play a role in mate choice, perhaps because it signals an individual's genetic quality and health. However, the relationship between an individual's FA and behaviour is generally unknown: what do more asymmetric individuals do about their own asymmetry? We now show for the first time that individuals respond behaviourally to their own morphological FA in what appears to be an adaptive manner. During courtship, male guppies exhibiting high FA in ornamental colour, bias their displays towards their more colourful body side, thus potentially increasing their attractiveness by exaggerating the quantity of their orange signal. This appears to be a strictly behavioural male response to cues provided by females, as it does not occur when males court a non-reactive model female. Whether inferior males realize any mating advantage remains uncertain, but our study clearly demonstrates a behavioural response to random morphological asymmetries that appears to be adaptive. We propose that the tendency to show or otherwise use a 'best side' is common in nature, with implications for sexual signalling and the evolution of more pronounced asymmetries.

The H-max/M-max ratio has long been used to understand motoneuron excitability induced by the Ia fibers. However, we contend that when comparing young and elderly subjects, this measurement can be controversial. We compared the modulation of the soleus H-max and M-max at five different muscle lengths between elderly and young subjects. The young subjects demonstrated a significant modulation of both H-max and M-max between dorsiflexion (DF) and plantarflexion (PF) positions. In contrast, the elderly subjects demonstrated no difference in H-max and M-max between DF and PF positions. However, it was more interesting to note that those elderly subjects who had similar H-max/M-max ratios to the young subjects at 0 deg showed identical modulation of H-max and M-max to that of the young In this paper, we discuss that H-reflex comparisons between young and elderly subjects may be confounded by the initial H-max/M-max ratio. This finding has implications for both the statistical analysis of this data as well as the theoretical interpretation of H-reflex measurements.

The factors that are responsible for the relationship between motoneuron excitability and muscle length may have both mechanical and/or neurophysiologic origins. The aim of the study was to investigate the changes in the level of presynaptic inhibition, as measured with a soleus H-reflex conditioning protocol, and muscle length. Ten healthy volunteers were measured at three different ankle angles: 30 degrees plantar flexion, neutral position (0 degrees) and 15 degrees dorsiflexion. At each position the soleus H-reflex and the maximum M-wave were measured while the limb was relaxed. The H-reflex was conditioned by a stimulation of the common peroneal nerve, 100 ms prior to the tibial nerve stimulation. The results revealed that the level of presynaptic inhibition was higher at the neutral position in comparison to the dorsiflexed or plantarflexed positions. Additionally, the HMAX/MMAX ratio was significantly decreased when the joint position was set at dorsiflexion. Further, there was a significant correlation, independent of ankle joint angle, between presynaptic inhibition levels and the HMAX/MMAX ratio. The above findings support the concept that peripheral feedback from passive, static modifications in the joint angle and consequently in muscle length, can modify the input/output threshold of the motoneurons on a presynaptic level.

In response to chronic physical training, the human neuromuscular system undergoes significant and specific adaptations. More importantly, these influences are the result of the type and quantity of physical activity. One of the simplest neuromuscular mechanisms is the spinal stretch reflex. The reflex system was previously viewed as inflexible, with a relatively fixed response that could vary only slightly. However, more recent data have identified an adaptive plasticity in the reflex system. In this respect, the reflex system can be used to assess training and aging adaptations of the human neuromuscular system. Due to their methodological simplicity, both the tendon-tap reflex and the electrically evoked Hoffmann reflex (H-reflex) can be used to assess training adaptations of the human neuromuscular system. The purpose of this paper is to review briefly the tendon-tap and H-reflex paradigms and delineate the research findings pertaining to changes in the reflex system with physical training. For purposes of clarity, this discussion will be divided into the following: (a) differences observed in the tendon-tap reflex, (b) differences observed in the H-reflex, and (c) role of interneurons in mediating these changes.

Objectives: This study examined the effect of age on the spinal mechanism post-activation depression (PD) and its relationship with postural sway., Methods: Two groups, young (n = 10, 25.2 +/- 5.2 yr) and elderly (n = 10, 74.6 +/- 6.3 yr) participated in this study. Soleus H-reflex amplitude (peak-to-peak EMG) was measured prior to and after a passive dorsiflexion about the ankle (from 120 degrees plantarflexion to 110 degrees plantarflexion at 15 degrees/s). All H-reflex measurements were recorded at an ankle joint angle of 110 degrees. For each group, stimulus intensity was set at 25% of maximal motor response (M-max) and PD measurement intervals were randomly assigned at 0, 1, 2, 3, 4, 5, 10, 15, and 18 seconds post-movement. To ascertain whether PD was related to postural sway, standing sway area (mm2) was also measured. Subjects stood motionless (20 second duration) on a Kistler force platform during two conditions: with and without vision., Results: A split-plot ANOVA (Group x Interval) indicated significant differences (F(1.18) = 14.80, p < 0.05) in PD between young and elderly, as well as a Group x Interval interaction (F(10, 180) = 16.02, p < 0.05). Simple main effects identified significant (p < 0.05) intervals at 0, 1, 2, and 3 seconds. The elderly had on average 16.1% less H-reflex depression during the first three seconds after muscle activation. Additionally, a split-plot ANOVA (Group x Condition) indicated significant differences (F(1, 18) = 10.72, p < 0.05) in sway area between young and elderly, but regression analysis indicated post-activation depression and postural sway were not significantly correlated., Conclusions: It is concluded that the integrity of the Ia-motoneuron synapse as measured with a PD protocol, is different between young and elderly subjects, but that this difference is not related to postural sway.

The authors have studied the value of preoperative radiotherapy in 125 patients with cancer of the rectum. The patients were divided into two groups, control (no irradiation) and experimental (irradiation), and according to Dukes' pathological stage. The crude survival indicated no difference between the two groups, but analysis by stage and group demonstrated that for patients with a Dukes' stage C lesion, 500 rads of cobalt-60 gamma irradiation a few hours before excision of the lesion approximately doubles the probability of survival at 5 years. The prospect of surgical cure is three times higher in cancers arising above the peritoneal reflection than in those arising below it. If the practice of abdominoperineal resection is to continue the authors recommend that preoperative irradiation become a routine procedure.