Tag: statistics

Appl Ergon. 2022 Feb 21;101:103717. doi: 10.1016/j.apergo.2022.103717. Online ahead of print.

ABSTRACT

The aim of this study was to examine the impact of backpack load carriage on lower limb strength and loading rate change in a cohort that match military recruit profiles. Twenty-six participants walked on a treadmill either carrying a military load carriage system (32 kg) or unloaded for 2 h on two consecutive days. Participants ground reaction forces and strength measures were assessed using a force platform and dynamometry, respectively. Testing included assessments before and after treadmill walking on days one and two, and 24 h following day 2. When assessed by mixed methods ANOVA (alpha: 0.05) statistically significant interaction effects were observed for loading peak (p = 0.031), loading rate (p = 0.035) and plantarflexor torque dynamometry variables at 60°s^-1 (p = 0.011) and 120°s^-1 (p = 0.024). Repeated measures correlation highlighted associations between plantarflexor torque at 60°s^-1 and loading rate (r = -0.901, p < 0.001). Load carriage reduced lower limb torque which did not recover between days. Plantarflexor torque reductions were associated with increases in loading rate. Practitioners should consider that load bearers are more likely to experience lower limb injury during multi-day load carriage. Future work should develop protocols to reduce plantarflexor torque loss in order to reduce ground reaction force change.

PMID:35202961 | DOI:10.1016/j.apergo.2022.103717

Seizure. 2022 Feb 11;96:121-127. doi: 10.1016/j.seizure.2022.02.004. Online ahead of print.

ABSTRACT

PURPOSE: Between 16-77% of patients with newly diagnosed epilepsy report seizures before diagnosis but little is known about the risk factors for diagnostic delay. Here, we examined the association between prior seizures and neuroimaging findings in newly diagnosed focal epilepsy.

METHODS: Adults diagnosed with focal epilepsy at First Seizure Clinics (FSC) at the Royal Melbourne Hospital or Austin Health, Melbourne, Australia, between 2000 and 2010 were included. Medical records were audited for seizure history accrued from the detailed FSC interview. Potentially epileptogenic brain abnormality type, location and extent was determined from neuroimaging. Statistical analysis comprised multivariate logistic regression.

RESULTS: Of 735 patients, 44% reported seizure/s before the index seizure. Among the 260 individuals with a potentially epileptogenic brain imaging abnormality, 34% reported prior seizures. Of 475 individuals with no abnormality, 50% reported prior seizures (p < 0.001). Patients with post-stroke changes had lower odds of prior seizures (n = 24/95, OR 0.5, p = 0.005) compared to patients without abnormalities, as did patients with high-grade tumors (n = 1/10, OR 0.1, p = 0.04). Abnormality location or extent was not associated with seizures. Prior seizures were inversely associated with age, patients aged >50 years had lower odds compared to those 18-30 years (OR 0.5, p = 0.01).

CONCLUSIONS: A history of prior seizures is less common in patients with newly diagnosed focal epilepsy associated with antecedent stroke or high-grade tumor than in those without a lesion, and is also less common in older individuals. These findings may be related to age, biological mechanisms or aspects of diagnosis and assessment of these events.

PMID:35202928 | DOI:10.1016/j.seizure.2022.02.004

Accid Anal Prev. 2022 Feb 21;168:106617. doi: 10.1016/j.aap.2022.106617. Online ahead of print.

ABSTRACT

Machine learning (ML) model interpretability has attracted much attention recently given the promising performance of ML methods in crash frequency studies. Extracting accurate relationship between risk factors and crash frequency is important for understanding the causal effects of risk factors and developing safety countermeasures. However, there is no study that comprehensively summarizes ML model interpretation methods and provides guidance for safety researchers and practitioners. This research aims to fill this gap. Model-based and post-hoc ML interpretation methods are critically evaluated and compared to study their suitability in crash frequency modeling. These methods include classification and regression tree (CART), multivariate adaptive regression splines (MARS), Local Interpretable Model-agnostic Explanations (LIME), Local Sensitivity Analysis (LSA), Partial Dependence Plots (PDP), Global Sensitivity Analysis (GSA), and SHapley Additive exPlanations (SHAP). Model-based interpretation methods cannot reveal the detailed interaction relationships among risk factors. LIME can only be used to analyze the effects of a risk factor at the prediction level. LSA and PDP assume that different risk factors are independently distributed. Both GSA and SHAP can account for the potential correlation among risk factors. However, only SHAP can visualize the detailed relationships between crash outcomes and risk factors. This study also demonstrates the potential and benefits of using ML and SHAP to derive Crash Modification Factors (CMF). Finally, it is emphasized that statistical and ML models may not directly differentiate causation from correlation. Understanding the differences between them is critical for developing reliable safety countermeasures.

PMID:35202941 | DOI:10.1016/j.aap.2022.106617

Sleep Med. 2022 Feb 7;90:204-213. doi: 10.1016/j.sleep.2021.11.014. Online ahead of print.

ABSTRACT

BACKGROUND: Sleep apnea is one of the most common sleep disorders in the United States (US). Although the prevalence, risk factors, and clinical presentations of sleep apnea vary by racial groups, the racial disparity in sleep apnea-related mortality remains unclear.

METHODS: Sleep apnea-related mortality for 1999-2019 was obtained from the National Center for Health Statistics provided by the Centers for Disease Control and Prevention. We examined the mortality trends for sleep apnea using Joinpoint regression analysis and compared the associated outcomes and multiple causes of death between Blacks and Whites.

RESULTS: For 1999-2019, sleep apnea was documented as the underlying cause of death in 17,053 decedents, with 2593 Blacks and 14,127 Whites. The overall age-adjusted mortality rates in all population, Blacks, and Whites were 2.5, 3.5, and 2.4 per 1,000,000 population, respectively (P < 0.001). Both Blacks and Whites had the highest mortality rates in the Midwest and the lowest in the Northeast. Despite the flattened mortality trend in the last decade overall, Black males had a continuous mortality increase over the study period (Annual Percentage Change 2.7%, 95% CI: 1.2-4.2). For both genders of sleep apnea decedents, Blacks were more likely to have multiple cause of death of Cardiac Arrest, Hypertension, Obesity, and Chronic Renal Failure, but Arrhythmia was more common in Whites (P < 0.05).

CONCLUSIONS: There is a significant racial disparity in sleep apnea-related mortality in the US. The uptrend in mortality in Black males and associated outcomes related to cardiovascular disease should raise concerns specifically in Blacks with sleep apnea.

PMID:35202926 | DOI:10.1016/j.sleep.2021.11.014

J Magn Reson. 2022 Feb 17;337:107165. doi: 10.1016/j.jmr.2022.107165. Online ahead of print.

ABSTRACT

We present here a novel protocol for quantitating changes in the NMR spectra, which is based on Mahalanobis statistics. In a two dimensional NMR spectrum, the various peaks are taken to represent a distribution, and the two chemical shifts along the orthogonal axes and the peak intensities constitute three observables. All these observables vary in a correlated manner. Taking account of these, the Mahalanobis distance (MD) reflects the distance of any chosen peak from the centre of the distribution. For quantitating changes in a particular spectrum (say A) with N peaks (altered protein NMR spectrum) with respect to a reference spectrum (say B) with M peaks (original protein NMR spectrum), a composite spectrum with N + M peaks is generated. A one-to-one correspondence between N MD values considering all the N peaks in A and the same N peaks in the composite spectrum (A + B) is calculated. The MD distance of corresponding peaks in two different distributions can be correlated to assess the changes in the spectra during the course of a biological phenomenon, or as a result of biomolecular interactions. We have demonstrated these ideas, first, using the ¹H-¹⁵N HSQC spectrum of Ubiquitin, and then application of these has been demonstrated for monitoring progression of fibrillation of the protein α-Synuclein, in absence and presence of safranal, a known inhibitor of fibrillation of the protein. The method is in general applicable to multidimensional NMR spectra, does not require extensive data collection, and allows quantitative assessment of spectral changes via a single parameter. We believe that the method will have wide ranging applications to monitor many biological phenomena, and will also be useful in an industrial environment for mass comparison of molecules in a rapid manner.

PMID:35202919 | DOI:10.1016/j.jmr.2022.107165

Int J Pediatr Otorhinolaryngol. 2022 Feb 15;155:111062. doi: 10.1016/j.ijporl.2022.111062. Online ahead of print.

ABSTRACT

OBJECTIVE: To determine the cumulative 24-month incidence of middle ear effusion (MEE) among tracheostomy-dependent children requiring ventilatory support.

METHODS: A prospective longitudinal cohort study included all children under 2 years of age with a tracheostomy placed at a tertiary care children’s hospital between 2015 and 2020 that obtained at least one tympanometry exam. The development of MEE, defined as a flat tympanogram with normal external canal volume, and mechanical ventilation requirement at examination were recorded.

RESULTS: Ninety-four children with a mean age at tracheostomy of 5.4 months (SD: 3.7) were included. During a mean follow-up of 18.3 months (SD: 14.6) (median: 14.1 months, interquartile range: 6.6-27.8), 192 tympanometry examinations were obtained with 59% (114/192) while requiring mechanical ventilation. Within 24 months after tracheostomy, 56.5% (95% CI: 48.9-64.4%) of children developed at least one MEE. Among those on mechanical ventilation, 74.0% (95% CI: 65.6-82.5%) developed MEE compared to 31.2% (95% CI: 21.4-44.0%) not on mechanical ventilation (HR: 2.97, 95% CI: 1.46-6.05, P = .003). A persistent MEE on two consecutive exams was not statistically more common for children on a ventilator (OR: 0.64, 95% CI: 0.01-6.95, P = .70). When controlling for age at exam, craniofacial syndrome, and newborn hearing test results on logistic regression, ventilator-dependence significantly predicted the presence of MEE (OR: 2.34, 95% CI: 1.18-4.68, P = .02).

CONCLUSION: Children with a tracheostomy were more likely to develop MEE when requiring mechanical ventilation. Clinicians should recognize this risk factor and appropriately assess for development of MEE to mitigate adverse speech and language development outcomes in this vulnerable population.

PMID:35202901 | DOI:10.1016/j.ijporl.2022.111062

Int J Pediatr Otorhinolaryngol. 2022 Feb 15;155:111068. doi: 10.1016/j.ijporl.2022.111068. Online ahead of print.

ABSTRACT

OBJECTIVES: We aim to describe types of hearing loss associated with Fanconi anemia patients who underwent a bone marrow transplant (BMT) to identify possible etiologies of hearing loss. Additionally, we hope to investigate hearing loss early in life as a potential predictor of needing a BMT surgery. Fanconi anemia is a rare autosomal recessive disease that is the most common inherited bone marrow failure syndrome, characterized by bone marrow failure and multiple congenital anomalies, including hearing loss. This is the largest study to date reviewing types of hearing loss in patients with Fanconi anemia, specifically in those who have undergone BMTs.

METHODS: A retrospective chart review of patients diagnosed with Fanconi anemia at a single institution, tertiary, referral-based children’s hospital with a bone marrow transplant team specializing in Fanconi anemia was conducted from 4/19/1976 to 10/19/2015. History, physical examination, audiometry, and imaging findings were reviewed in patients with and without history of bone marrow transplant. Patient hearing levels, as measured by pure tone audiometry at 500 Hz, 1, 2, and 4 kHz, were evaluated. Patients were grouped by transplant status and results and were assessed to determine type and degree of hearing loss. Statistical analysis was performed to compare the likelihood of bone marrow transplant procedures in Fanconi anemia patients with normal and abnormal hearing.

RESULTS: There were 252 patients with Fanconi anemia identified via diagnosis search in institutional electronic medical records using CPT codes and cross referencing with the Fanconi Anemia database, 58 of whom had available audiometric data. Of the 58 Fanconi anemia patients with available audiograms, 21 (36%) had abnormal audiograms; 37 patients had normal audiograms. Twenty out of 21 (95%) patients who had abnormal audiograms had undergone bone marrow transplants. Thirty-one of 37 (84%) patients with normal audiograms had received bone marrow transplants. Statistical analysis showed that patients with hearing loss were more likely to require a BMT in the future (OR = 3.87, p = 0.05). Of the patients with abnormal audiograms and a bone marrow transplant (n = 20), 14 (70%) had conductive hearing loss, 5 (25%) had mixed hearing loss, and 1 patient (5%) had sensorineural hearing loss. 13 of 20 patients (65%) had bilateral hearing loss and eight of 20 (40%) had unilateral hearing loss. Of those patients with conductive hearing loss (n = 15), the most common etiologies were Eustachian tube dysfunction (47%), external auditory canal stenosis (33%), and abnormal middle ear anatomy (13%).

CONCLUSIONS: Hearing loss is a common finding in Fanconi anemia patients who have undergone BMTs with conductive hearing loss being the most common audiologic manifestation in our cohort of patients. This demonstrates the necessity of frequent hearing screenings in this population and close collaboration with audiology throughout patient care. Our study indicates that hearing status early in life may be a predictor of needing a bone marrow transplant in the future. Further studies should explore the long-term impact of BMT surgery on hearing status.

PMID:35202898 | DOI:10.1016/j.ijporl.2022.111068

Int J Pediatr Otorhinolaryngol. 2022 Feb 4;155:111060. doi: 10.1016/j.ijporl.2022.111060. Online ahead of print.

ABSTRACT

INTRODUCTION: Clinical experience shows that children with functional dysphonia often present disorders that are associated with abnormal auditory and emotional development. These children also struggle with voice therapy, perhaps because of difficulties with auditory control during speech. It has been hypothesized that difficulties in auditory processing in children may be an important factor in the pathogenesis of childhood dysphonia.

OBJECTIVE: The study aimed to assess selected auditory functions in children with hyperfunctional dysphonia.

MATERIALS AND METHOD: The study group consisted of 331 children aged from 7 to 12 years suffering from hyperfunctional dysphonia. The control group consisted of 213 children aged 7-12 years. All patients underwent ENT and phoniatric examination. All children underwent two standardized psychoacoustic tests: the Frequency Pattern Test (FPT) and the Duration Pattern Test (DPT).

RESULTS: In the examined material, 223 children had edematous vocal fold nodules. The largest statistically significant differences were seen in the acoustic parameters describing relative frequency changes. FPT and DPT showed statistically significant differences in children with hyperfunctional dysphonia compared to the control group. At all ages the percentage of correctly identified tone sequences was significantly lower in children with dysphonia.

CONCLUSION: Children with hyperfunctional dysphonia have difficulties in judging the pitch and duration of auditory stimuli. Difficulties in auditory processing appear to be important in the pathomechanism of functional voice disorders. Impaired hearing processes in children with hyperfunctional dysphonia can make it difficult to obtain positive and lasting effects from voice therapy.

PMID:35202899 | DOI:10.1016/j.ijporl.2022.111060

World Neurosurg. 2022 Feb 21:S1878-8750(22)00208-X. doi: 10.1016/j.wneu.2022.02.061. Online ahead of print.

ABSTRACT

Malignant ischemic stroke occurs in a subgroup of patients with cerebrovascular accident who suffer massive/significant cerebral infarction. It is characterized by neurological deterioration due to progressive edema, raised intracranial pressure, and cerebral herniation. Decompressive craniectomy (DC) is a surgical technique that can be used in treating select cases of this condition in the presence of medically refractory intracranial hypertension. This study aimed to identify prognostic factors associated with clinical outcome, such as timing of the procedure, and post-operative lethality. We analyzed surgical characteristics associated with the prognosis in 145 patients who underwent DC secondary to Malignant Ischemic Stroke (MIS) between 2013 and 2018, associating clinical outcome in discharge, 6 and 12 months after discharge. Our inclusion criteria were DC secondary to MIS in adult patients with raised intracranial pressure signs. This study reviewed a total of 145 patients who underwent DC to treat MIS. Our analysis showed that; even though patients from cities with more than 100 km from the neurosurgical center have a worse prognosis, only the surgical head side (left versus right,p=0.001), hospitalization length (p<0.001) and earlier timing of procedure (p<0.001) were statistically relevant in having worse outcomes. Patients who took more time to get started with the neurosurgical procedure, such as living in a distant city or taking more time to be seen by a specialist, tended to have a worse prognosis. The timing of procedure, surgical side, and hospitalization length were independent predictors in determining the prognosis of the patient who underwent DC after an MIS.

PMID:35202880 | DOI:10.1016/j.wneu.2022.02.061

Fish Shellfish Immunol. 2022 Feb 21:S1050-4648(22)00089-4. doi: 10.1016/j.fsi.2022.02.027. Online ahead of print.

ABSTRACT

In aquatic animals, dietary protein plays a crucial role in their growth and immunity. A feeding trial was conducted on soft-shelled turtles (Pelodiscus sinensis) to assess the effects of various levels of protein on the specific growth rate (SGR), ambient water quality (total ammonia nitrogen (TAN), total nitrogen (TN) and total phosphorus (TP)), hematological parameters (respiratory burst (RB), red blood cell count (RBC), albumin content (Alb), hemoglobin level (Hb) and osmolality), plasma immunoglobulin M (IgM) levels and lysozyme activity. Soft-shelled turtles weighing about 4.02 g were fed fish meal-based diets with 14.38%, 20.41%, 26.19%, 32.23%, 37.63% and 45.23% protein for 8 weeks. SGR, RBC, Hb, Alb, RB, IgM and lysozyme activity were enhanced as the dietary protein was increased from 14.38% to 26.19%, then reached a plateau. For identical feeding times, TAN and TN were increased with elevating dietary protein levels. While, no statistically significant differences were observed among the 26.19%, 32.23% and 37.63% groups. When the turtles were cultivated for 56 days and fed with 45.23% protein, the TP in the culturing water was higher than that in the other groups. An increase in dietary protein level up to 26.19% increased the RNA/DNA ratio, which subsequently plateaued at a steady level. The levels of dietary protein had no impact on osmolality or alkaline phosphatase (AKP) activity. On the basis of broken-line analyses derived from SGR, the optimum dietary protein level for soft-shelled turtles was found to be 27.11% protein.

PMID:35202804 | DOI:10.1016/j.fsi.2022.02.027