Category: Statistics

Epilepsy Behav. 2021 Apr 9;118:107945. doi: 10.1016/j.yebeh.2021.107945. Online ahead of print.

ABSTRACT

BACKGROUND: The identification of hyperperfusion on ictal single-photon emission computed tomography (SPECT) scan is a technique for the localization of the epileptogenic zone (EZ) in patients with focal epilepsy undergoing presurgical evaluation. The accuracy of this technique has been improved by subtraction from an interictal image and coregistration with magnetic resonance imaging (MRI) (subtraction ictal SPECT coregistered to MRI (SISCOM)), and subsequently by the development of Statistical Ictal SPECT Co-registered to MRI (STATISCOM) which is reported to further improve localization accuracy by statistically accounting for random variation between images. However, the use of ictal SPECT is limited by the necessity for rapid injection of the radiotracer. The purpose of this study was to investigate the effect of tracer injection time on EZ localization rates using both STATISCOM and SISCOM.

METHODS: Consecutive patients with drug-resistant focal epilepsy who had an ictal SPECT scan while admitted to the video-electroencephalography (EEG) monitoring unit at the Royal Melbourne Hospital, Victoria, Australia, and a subsequent interictal scan, between 2009 and 2017 were included. The information collected included age, sex, seizure type, epilepsy diagnosis, and injection time. Statistical Ictal SPECT Co-registered to MRI and SISCOM images were generated and reviewed by two blinded reviewers. The rates of potential localization of the EZ, and the agreement with the EEG, were determined for each scan. Localization rates were compared between ictal scans with different radiotracer injection time windows (<30 s, 30-45 s, 45-60 s, 60-90 s, 90-120 s, >120 s).

RESULTS: Seventy patients (male = 32, 16-67 years) were included in the study. Overall agreement between the primary raters was moderate for STATISCOM (k = 0.44) and SISCOM (k = 0.57). The ability of SPECT to localize the potential EZ was 69% (48/70) for STATISCOM and 59% (41/70) for SISCOM. Injection time was not associated with the rate of localizing the potential EZ for STATISCOM (p = 0.64), whereas for SISCOM there was a trend that shorter injection times were associated with better ability to localize the potential EZ (p = 0.06). Agreement between SPECT and video-EEG data was 54% (38/70) for STATISCOM and 39% (27/70) for SISCOM. Statistical Ictal SPECT Co-registered to MRI did not show any difference of agreement across injection time groups (p = 0.42) whereas SISCOM showed better agreement with video-EEG data in the earlier injection time groups (p = 0.02). No differences in agreement between SPECT and video-EEG data were seen between patients with and without MRI lesions for either STATISCOM or SISCOM. Statistical Ictal SPECT Co-registered to MRI showed significantly better agreement for temporal than extratemporal seizures, with no difference of agreement between early (<45 s) and late (>45 s) injections.

CONCLUSION: Statistical Ictal SPECT Co-registered to MRI showed overall higher agreement rates with EZ localization by video-EEG than SISCOM, which was not affected by the injection times. Statistical Ictal SPECT Co-registered to MRI may provide localizing information for “late” injections where visual reads and SISCOM are inconclusive.

PMID:33845344 | DOI:10.1016/j.yebeh.2021.107945

Clin Biomech (Bristol, Avon). 2021 Mar 24;84:105333. doi: 10.1016/j.clinbiomech.2021.105333. Online ahead of print.

ABSTRACT

BACKGROUND: Patellar instability is a considerable problem that leads to pain and anxiety during simple functional tasks. Femoral derotational osteotomy has become a common surgical procedure to improve patella mechanics, stability and loading. However, it remains unclear if static (MRI measured) femoral anteversion is sufficient to capture the dynamic femoral rotation during walking and represents a good indication for the surgical procedure. This research investigates the relationship between static femoral anteversion and internally rotated gait in adolescents with patellofemoral instability.

METHODS: This retrospective study included 30 adolescents with recurrent patella instability (minimum three patella dislocations) aged 12 to 18 years (28 female/2 male; 22 unilateral/8 bilateral). All participants were assessed with 3D gait analysis and the femoral anteversion was examined using a rotational MRI. Multiple kinematic parameter were correlated with the ipsilateral femoral anteversion and tibia torsion using the Pearson coefficient.

FINDINGS: The correlation between parameters of dynamic hip rotation (e.g. maximum and mean internal hip rotation in stance and swing) and MRI measured femoral anteversion (mean 26.5° ± 9°) was weak and did not reach statistical significance. We found 47% (14 out of 30) subjects with increased femoral anteversion but normal hip rotation in stance.

INTERPRETATION: There was no relationship between increased femoral anteversion and dynamic hip rotation. Consequently, femoral anteversion should not be used as the only indication for femoral derotational osteotomy. Three-dimensional gait analysis might be necessary to assess the appropriate surgical intervention in adolescents with patello femoral instability.

PMID:33845347 | DOI:10.1016/j.clinbiomech.2021.105333

J Pediatr Nurs. 2021 Apr 9;59:103-109. doi: 10.1016/j.pedn.2021.03.019. Online ahead of print.

ABSTRACT

PURPOSE: The aim of this study was to establish content validity of a developmentally based assessment tool of readiness for medical independence for specialty providers.

DESIGN AND METHODS: The validation process used expert panel evaluation to assess the items believed to measure the desired content in the nine age-based scales within the RAISE (Readiness Assessment of Independence for Specialty Encounters) tool. Experts in child development and transition rated items on relevance, clarity and developmental appropriateness via electronic survey. Statistical analyses included calculation of interrater agreement (IRA), content validity indices (CVIs), and factorial validity indices (FVI).

RESULTS: A total of 135 items were rated by 36 experts. Mean I-CVIs for 123 items across nine developmental scales met criteria for retention, ranging from 0.76 (threshold) to 1.00 (excellent). Mean I-CVIs for all 25 items across the five psychosocial stressor scales met criteria for retention, ranging from 0.92 to 1.00 (excellent).

CONCLUSIONS: Findings from the current content validation study suggest that items on the revised RAISE tool are relevant, clear, and developmentally-appropriate as rated by experts in the fields of child development and transition. The tool, consisting of age based scales (ages birth-2, 3-4, 5-6, 7-8, 9-11, 12-13, 14-15, 16-17, 18-21), is shown to have content validity of the retained items meeting criteria.

PRACTICE IMPLICATIONS: With content validity of the RAISE tool established by experts, this developmentally based assessment tool can be integrated into practice to assist providers in educating patients around skills of medical independence which could improve transition outcomes.

PMID:33845322 | DOI:10.1016/j.pedn.2021.03.019

Plant Physiol Biochem. 2021 Apr 4;163:139-153. doi: 10.1016/j.plaphy.2021.03.059. Online ahead of print.

ABSTRACT

In this study, the effects of three halotolerant rhizobacterial isolates AL, HR, and SB, which are able to grow at a salinity level of 1600 mM NaCl, with multiple plant growth promoting (PGP) traits on some seed and forage quality attributes, and vegetative, reproductive, biochemical and physiological characteristics of wheat plant irrigated with saline water (0, 40, 80, and 160 mM NaCl) were investigated. The ability of halotolerant bacterial isolates to produce PGP traits was affected by salinity levels, depending upon the bacterial isolates. Salinity stress significantly affected the yield, quality, and growth of wheat by modifying the morpho-physiological and biochemical traits of the exposed plants. However, all three bacterial isolates, especially isolate AL, significantly improved the biochemical (an increase in K⁺/Na⁺ ratio by 55%, plant P content by 50%, and plant Ca content by 31%), morphological (an increase in stem dry weight by 52%, root dry weight by 44%, spike dry weight by 34%, and grain dry weight by 43%), and physiological (an increase in leaf proline content by 50% and total phenol in leaf by 42%) attributes of wheat and aided the plant to tolerate salinity stress in contrast to un-inoculated plant. Plants inoculated with bacterial isolates showed significantly improved seed amylose by 36%, leaf crude protein by 30%, leaf metabolic energy by 37%, and leaf water-soluble sugar content by 34%. Among the measured PGP and plant attributes, bacterial auxin and plant K content were of key importance in increasing reproductive performance of wheat. The bacterial isolates AL, HR, and SB were identified as Bacillus safensis, B. pumilus, and Zhihengliuella halotolerans, respectively, based on 16 S rDNA sequence. The study reveals that application of halotolerant plant growth-promoting rhizobacteria isolated from halophytic rangeland plants can be a cost effective and ecological sustainable method to improve wheat productivity, especially the attributes related to seed and forage quality, under salinity stress conditions.

PMID:33845330 | DOI:10.1016/j.plaphy.2021.03.059

J Mech Behav Biomed Mater. 2021 Apr 3;119:104503. doi: 10.1016/j.jmbbm.2021.104503. Online ahead of print.

ABSTRACT

This in vitro study used the same frequency and duration of acid contact as a previous in situ/in vivo study to evaluate the effect of erosion on CAD/CAM restorative materials and human enamel and to compare the effects of in vitro and in situ/in vivo acid challenges on CAD/CAM restorative materials and human enamel. The CAD/CAM restorative materials (IPS e.max CAD, Lava Ultimate, and PMMA block) and human enamel were eroded by immersion in 150 ml of cola drink for 14 days (4 × 5 min/day). The surface microhardness and surface roughness of the specimens were measured at baseline (T1), day 7 (T2), and day 14 (T3). The substance losses were measured at T2 and T3. The data were statistically analyzed using repeated measures ANOVA and Bonferroni’s test (α = 0.05). Erosion significantly decreased the surface microhardness of the CAD/CAM restorative materials and human enamel (all P < 0.001). The overall percentage of surface microhardness loss (%SMH_l) of the PMMA block and enamel due to in vitro erosion was significantly higher than that due to in situ/in vivo erosion (P = 0.02 and P < 0.001, respectively). Consistent with in situ/in vivo erosion, the surface roughness and profile of the tested restorative materials remained unchanged after in vitro erosion. A significant increase in the surface roughness and substance loss was observed for enamel after in vitro erosion (all P < 0.001). The overall substance loss of enamel due to in vitro erosion was significantly higher than that due to in situ/in vivo erosion (P < 0.001). In conclusion, erosion decreased the surface microhardness of the CAD/CAM restorative materials and human enamel. Moreover, erosion negatively influenced the substance loss and surface roughness of human enamel. For the substance loss of enamel and %SMH_l of PMMA block and enamel, the in vitro erosive effects were approximately 1-2 times greater than the in situ/in vivo effects. However, for the surface roughness and profile of the CAD/CAM restorative materials, no significant difference was found between in vitro and in situ/in vivo erosion.

PMID:33845297 | DOI:10.1016/j.jmbbm.2021.104503

Neural Netw. 2021 Mar 26;141:11-29. doi: 10.1016/j.neunet.2021.03.025. Online ahead of print.

ABSTRACT

In deep learning tasks, the update step size determined by the learning rate at each iteration plays a critical role in gradient-based optimization. However, determining the appropriate learning rate in practice typically relies on subjective judgment. In this work, we propose a novel optimization method based on local quadratic approximation (LQA). In each update step, we locally approximate the loss function along the gradient direction by using a standard quadratic function of the learning rate. Subsequently, we propose an approximation step to obtain a nearly optimal learning rate in a computationally efficient manner. The proposed LQA method has three important features. First, the learning rate is automatically determined in each update step. Second, it is dynamically adjusted according to the current loss function value and parameter estimates. Third, with the gradient direction fixed, the proposed method attains a nearly maximum reduction in the loss function. Extensive experiments were conducted to prove the effectiveness of the proposed LQA method.

PMID:33845311 | DOI:10.1016/j.neunet.2021.03.025

Turk J Med Sci. 2021 Apr 12. doi: 10.3906/sag-2010-237. Online ahead of print.

ABSTRACT

AIM: Headache is one of the most common neurological symptoms. It adversely affects daily life, reduces the workforce, and has high health costs. Managing this symptom in primary care will free up secondary and tertiary health services to better treat patients who need follow-up by specialists. In the present study, we aim to show the rate at which this problem can be solved in primary care for patients who applied tertiary care services with a headache for the first time.

MATERIALS AND METHODS: Our research is a cross-sectional study of 207 patients who applied to the neurology clinics for the first time with headache. Two questionnaires were prepared by the researchers. IBM SPSS 21 was used for statistical analysis, and the level of significance was p<0.05.

RESULTS: The opinions of the patients on the evaluability of headache in primary care were compared. Family physicians and neurologists gave similar responses about the disease management, at a rate of 96.6%, this was found to be statistically significant and shows strong agreement. Both groups of physicians thought that 70% of patients, on average, who applied to the neurology clinics with headache could be managed in primary care. However, only 9.2% of the patients share this opinion with physicians. Primary headache cases constitute most of the cases that are thought to be solved in primary care. It was revealed that the number of patients seeking primary care with this complaint was lower than expected.

CONCLUSION: Patients with headache applied tertiary care instead of primary care for different reasons. Both neurologists and family physicians stated that most patients evaluated in tertiary care could be managed in primary care.

PMID:33843173 | DOI:10.3906/sag-2010-237

J Pediatr Gastroenterol Nutr. 2021 Jan 14. doi: 10.1097/MPG.0000000000003047. Online ahead of print.

ABSTRACT

OBJECTIVES: While the algorithm to diagnose celiac disease (CD) in children with elevated anti-transglutaminase IgA (TGA-IgA) titers (> 10 times upper limit of normal, ULN) is well defined, the management of children with low TGA-IgA values represents a clinical challenge. We aimed to identify the diagnostic value of persistently low positive TGA-IgA titers in predicting CD in children.

METHODS: We retrospectively analyzed children with symptoms or signs of CD, not eligible for a no-biopsy approach. We included children with at least two TGA-IgA measurements, EMA assessment and esophagogastroduodenoscopy (EGD) with biopsies. TGA-IgA values were provided as multiples of upper limit normal (ULN). Patients were classified in groups according to median TGA-IgA values: A (TGA-IgA>1 ≤ 5 x ULN; defined as “low-positive”), B (TGA-IgA > 5 < 10 x ULN; “moderate-positive”) and C (controls).

RESULTS: Data of 281 children were analyzed. Of 162 children in Group A, CD was diagnosed in 142 (87.7%), while normal duodenal mucosa was found in 20. In Group B, all 62 children (100%) received a CD diagnosis. Group C included 57 controls. EMA were undetectable in 31 (15%) of mucosal atrophy cases. On the ROC curve (AUC = 0.910), a mean value of 1.7 ULN showed a sensitivity of 81.4% and specificity of 81.8% to predict mucosal damage.

CONCLUSIONS: Repeated low or moderate TGA-IgA values (< 5 ULN or <10 ULN) are good predictors of a CD diagnosis. Symptomatic children with persistently low positive TGA-IgA titers should undergo EGD regardless of their EMA status.

PMID:33843181 | DOI:10.1097/MPG.0000000000003047

Stat Med. 2021 Apr 11. doi: 10.1002/sim.8976. Online ahead of print.

ABSTRACT

We propose a multithreshold change plane regression model which naturally partitions the observed subjects into subgroups with different covariate effects. The underlying grouping variable is a linear function of observed covariates and thus multiple thresholds produce change planes in the covariate space. We contribute a novel two-stage estimation approach to determine the number of subgroups, the location of thresholds, and all other regression parameters. In the first stage we adopt a group selection principle to consistently identify the number of subgroups, while in the second stage change point locations and model parameter estimates are refined by a penalized induced smoothing technique. Our procedure allows sparse solutions for relatively moderate- or high-dimensional covariates. We further establish the asymptotic properties of our proposed estimators under appropriate technical conditions. We evaluate the performance of the proposed methods by simulation studies and provide illustrations using two medical data examples. Our proposal for subgroup identification may lead to an immediate application in personalized medicine.

PMID:33843100 | DOI:10.1002/sim.8976

J Prosthodont. 2021 Apr 12. doi: 10.1111/jopr.13363. Online ahead of print.

ABSTRACT

To evaluate the correlation between students’ achieved grades in a preclinical fixed prosthodontics course and their performance in the same discipline’s clinical courses MATERIALS AND METHODS: This study was conducted in 2019 on seventy-six students who passed all preclinical and clinical fixed prosthodontics courses. Their final examination grades in preclinical and clinical prosthodontics courses were compiled and made anonymous. The Statistical Package for the Social Sciences (SPSS Version 23) was used to analyze the data. Descriptive statistics and correlation coefficient were used to assess the relation between preclinical and clinical grades RESULTS: A statistically significant positive correlation existed between the students’ preclinical and combined clinical final examination grades (r = 0.45, p<0.001). In relation to sex, females showed a significantly higher correlation (r = 0.56, p = 0.001) compared to males (r = 0.25, p = 0.1). In addition, students’ clinical grade prediction from their preclinical performance was 20.5% CONCLUSION: These findings emphasize the importance of preclinical courses and suggest that maximizing preclinical years’ efforts can reflect positively on students’ competence in their future clinical practice. This article is protected by copyright. All rights reserved.

PMID:33843102 | DOI:10.1111/jopr.13363