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Background: Mixed martial arts (MMA) fighters, due to exposure to repetitive head impacts, are at risk for brain atrophy and neurodegenerative sequelae. Simultaneously, motor skills training and cognition-rich activities have been linked with larger regional brain volumes. The majority of an MMA fighter's sporting activity occurs during practice (e.g., sparring) rather than formal competition. This study, therefore, aims to be the first to explore regional brain volumes associated with sparring in MMA fighters. Methods: Ninety-four active, professional MMA fighters from the Professional Fighters Brain Health Study met inclusion criteria for this cross-sectional analysis. Adjusted multivariable regression analyses were utilized to examine the relationship between the number of sparring practice rounds per week during typical training and a select number of regional brain volumes (i.e., caudate, thalamus, putamen, hippocampus, amygdala). Results: A higher number of weekly sparring rounds during training was significantly associated with larger left (beta = 13.5 µL/round, 95% CI 2.26–24.8) and right (beta = 14.9 µL/round, 95% CI 3.64–26.2) caudate volumes. Sparring was not significantly associated with left or right thalamus, putamen, hippocampus, or amygdala volumes. Conclusions: More weekly rounds of sparring was not significantly associated with smaller volumes in any of the brain regions studied in active, professional MMA fighters. Sparring's significant association with larger caudate volume raises questions about whether fighters who spar more experience attenuated trauma-related decreases in caudate volume relative to fighters who spar less, whether fighters who spar more experience minimal or even positive changes to caudate volume, whether baseline differences in caudate size may have mediated results, or whether some other mechanism may be at play. Given limitations inherent to the cross-sectional study design, more research is needed to further explore the brain effects of sparring in MMA. [ABSTRACT FROM AUTHOR]

Confidence interval for the difference of two proportions has been studied for decades. Many methods were developed to improve the approximation of the limiting distribution of test statistics, such as the profile likelihood method, the score method, and the Wilson method. For the Wilson interval developed by Beal (Biometrics 43:941, 1987), the approximation of the Z test statistic to the standard normal distribution may be further improved by utilizing the continuity correction, in the observation of anti-conservative intervals from the Wilson interval. We theoretically prove that the Wilson interval is nested in the continuity corrected Wilson interval under mild conditions. We compare the continuity corrected Wilson interval with the commonly used methods with regards to coverage probability, interval width, and mean squared error of coverage probability. The proposed interval has good performance in many configurations. An example from a Phase II cancer trial is used to illustrate the application of these methods. [ABSTRACT FROM AUTHOR]

Biomedical studies, such as clinical trials, often require the comparison of measurements from two correlated tests in which each unit of observation is associated with a binary outcome of interest via relative risk. The associated confidence interval is crucial because it provides an appreciation of the spectrum of possible values, allowing for a more robust interpretation of relative risk. Of the available confidence interval methods for relative risk, the asymptotic score interval is the most widely recommended for practical use. We propose a modified score interval for relative risk and we also extend an existing nonparametric U-statistic-based confidence interval to relative risk. In addition, we theoretically prove that the original asymptotic score interval is equivalent to the constrained maximum likelihood-based interval proposed by Nam and Blackwelder. Two clinically relevant oncology trials are used to demonstrate the real-world performance of our methods. The finite sample properties of the new approaches, the current standard of practice, and other alternatives are studied via extensive simulation studies. We show that, as the strength of correlation increases, when the sample size is not too large the new score-based intervals outperform the existing intervals in terms of coverage probability. Moreover, our results indicate that the new nonparametric interval provides the coverage that most consistently meets or exceeds the nominal coverage probability. [ABSTRACT FROM AUTHOR]

Background: Severe headaches are common after subarachnoid hemorrhage. Guidelines recommend treatment with acetaminophen and opioids, but patient data show that headaches often persist despite multimodal treatment approaches. Considering an overall slim body of data for a common complaint affecting patients with SAH during their intensive care stay, we set out to assess practice patterns in headache management among clinicians who treat patients with SAH. Methods: We conducted an international cross-sectional study through a 37-question Web-based survey distributed to members of five professional societies relevant to intensive and neurocritical care from November 2021 to January 2022. Responses were characterized through descriptive analyses. Fisher's exact test was used to test associations. Results: Of 516 respondents, 329 of 497 (66%) were from North America and 121 of 497 (24%) from Europe. Of 435 respondents, 379 (87%) reported headache as a major management concern for patients with SAH. Intensive care teams were primarily responsible for analgesia during hospitalization (249 of 435, 57%), whereas responsibility shifted to neurosurgery at discharge (233 of 501, 47%). Most used medications were acetaminophen (90%), opioids (66%), corticosteroids (28%), and antiseizure medications (28%). Opioids or medication combinations including opioids were most frequently perceived as most effective by 169 of 433 respondents (39%, predominantly intensivists), followed by corticosteroids or combinations with corticosteroids (96 of 433, 22%, predominantly neurologists). Of medications prescribed at discharge, acetaminophen was most common (303 of 381, 80%), followed by opioids (175 of 381, 46%) and antiseizure medications (173 of 381, 45%). Opioids during hospitalization were significantly more prescribed by intensivists, by providers managing higher numbers of patients with SAH, and in Europe. At discharge, opioids were more frequently prescribed in North America. Of 435 respondents, 299 (69%) indicated no change in prescription practice of opioids with the opioid crisis. Additional differences in prescription patterns between continents and providers and while inpatient versus at discharge were found. Conclusions: Post-SAH headache in the intensive care setting is a major clinical concern. Analgesia heavily relies on opioids both in use and in perception of efficacy, with no reported change in prescription patterns for opioids for most providers despite the significant drawbacks of opioids. Responsibility for analgesia shifts between hospitalization and discharge. International and provider-related differences are evident. Novel treatment strategies and alignment of prescription between providers are urgently needed. [ABSTRACT FROM AUTHOR]

Repeated measures designs are widely used in practice to increase power, reduce sample size, and increase efficiency in data collection. Correlation between repeated measurements is one of the first research questions that needs to be addressed in a repeated-measure study. In addition to an estimate for correlation, confidence interval should be computed and reported for statistical inference. The asymptotic interval based on the delta method is traditionally calculated due to its simplicity. However, this interval is often criticized for its unsatisfactory performance with regards to coverage and interval width. Bootstrap could be utilized to reduce the interval width, and the widely used bootstrap intervals include the percentile interval, the bias-corrected interval, and the bias-corrected with acceleration interval. Wilcox (Comput Stat Data Anal 22:89–98,1996) suggested a modified percentile interval with the interval levels adjusted by sample size to have the coverage probability close to the nominal level. For a study with repeated measures, more parameters in addition to sample size would affect the coverage probability. For these reasons, we propose modifying the percentiles in the percentile interval to guarantee the coverage probability based on simulation studies. We analyze the correlation between imaging volumes and memory scores from the Alzheimer's Disease Neuroimaging Initiative (ADNI) study to illustrate the application of the considered intervals. The proposed interval is exact with the coverage probability guaranteed, and is recommended for use in practice. [ABSTRACT FROM AUTHOR]