Formative evaluation of a patient-specific clinical knowledge summarization tool

ObjectiveTo iteratively design a prototype of a computerized clinical knowledge summarization (CKS) tool aimed at helping clinicians finding answers to their clinical questions; and to conduct a formative assessment of the usability, usefulness, efficiency, and impact of the CKS prototype on physicians’ perceived decision quality compared with standard search of UpToDate and PubMed.Materials and methodsMixed-methods observations of the interactions of 10 physicians with the CKS prototype vs. standard search in an effort to solve clinical problems posed as case vignettes.ResultsThe CKS tool automatically summarizes patient-specific and actionable clinical recommendations from PubMed (high quality randomized controlled trials and systematic reviews) and UpToDate. Two thirds of the study participants completed 15 out of 17 usability tasks. The median time to task completion was less than 10 s for 12 of the 17 tasks. The difference in search time between the CKS and standard search was not significant (median = 4.9 vs. 4.5 min). Physician’s perceived decision quality was significantly higher with the CKS than with manual search (mean = 16.6 vs. 14.4; p = 0.036).ConclusionsThe CKS prototype was well-accepted by physicians both in terms of usability and usefulness. Physicians perceived better decision quality with the CKS prototype compared to standard search of PubMed and UpToDate within a similar search time. Due to the formative nature of this study and a small sample size, conclusions regarding efficiency and efficacy are exploratory.     

Insulin growth factor (IGF) 1, IGF-binding proteins and ovarian cancer risk: A systematic review and meta-analysis

BackgroundInsulin resistance (IR) has been implicated in carcinogenesis, but there is no consensus regarding its involvement in ovarian cancer. We performed a systematic review and meta-analysis to evaluate the association between IR and ovarian cancer.MethodsSearches were conducted in five databases for studies evaluating IR markers (levels of serum insulin, C peptide, insulin growth factor [IGF] 1 and IGF-binding proteins [IGFBPs], homeostatic model assessment insulin resistance, and quantitative insulin-sensitivity check index) and ovarian cancer risk. Study selection, data extraction and an assessment of risk of bias were performed independently by three researchers. The associations between IR markers and ovarian cancer were quantified as mean differences (MDs) or standardized MDs (SMDs) and their 95% CIs using random-effects models.ResultsFourteen case-control studies satisfied our inclusion criteria (n = 8130). There was little information on IR markers with the exception of the IGF system. Ovarian cancer was associated with lower IGF-1 levels (SMD −0.43 ng/mL, 95% CI −0.67 to −0.18; p = 0.0006), and lower IGFBP-3 levels (SMD −0.11 ng/mL, 95% CI −0.21 to −0.00; p = 0.04). However, ovarian cancer was associated with higher levels of IGFBP-2 and IGFBP-1 (MD 527.3 ng/mL, 95%CI 473.6, 581.0; p < 0.00001, and MD 3.47 ng/mL, 95%CI 1.42, 5.52; p = 0.0009 respectively). Subgroup analyses by menopausal status and age (≤55 vs >55y) for IGF-1 and IGFBP-3 showed the subgroups were similar, although heterogeneity remained high.ConclusionThe evidence suggests that levels of IGF-1 and IGFBP-3 are lower in patients with ovarian cancer. In contrast, higher levels of IGBP-2 and IGBP-1 are found in patients with ovarian cancer.     

AM bundle controls the anterior–posterior and rotational stability to a greater extent than the PL bundle — A cadaver study

BackgroundThe purpose of this study was to evaluate the influence of both bundles of the anterior cruciate ligament (ACL) on knee stability, anterior–posterior translation (APT) and internal (IR) and external (ER) rotation in cadaveric knees using a computer navigation system.MethodsThe APT, IR, and ER of the knees were recorded in the intact condition, the anterolateral bundle (AM) or the posterolateral bundle (PL) deficit condition and in the ACL-deficient condition. The KT-1000 arthrometer was used for APT evaluation. The measurement of rotational movements was done using a rollimeter. All tests were performed at 30°, 60° and 90° of flexion.ResultsAt 30° of flexion: In the intact knee APT was 5.8 mm, IR 12.1°, ER 10.1°. After the AM was cut, the APT increased to 9.1 mm, IR to 13.9° and ER to 12.6°. After the PL was cut, the APT was 6.4 mm, IR 13.1° and ER 10.6°. After the AM and PL were cut, the APT was 10.8 mm, IR 15.7° and the ER was 12.9° on average.ConclusionsThe AM has a greater impact on the APT than the PL in all knee joint flexion angles. The PL does not resist the rotational stability more than the AM. The rotational stability is better controlled by both bundles of ACL as compared to one bundle of the ACL.Clinical RelevanceThis study acknowledges the fact that the both bundles of the ACL are importants for AP and rotational stability of the knee joint.     

The accuracy of Internet search engines to predict diagnoses from symptoms can be assessed with a validated scoring system

PurposeTo validate a scoring system that evaluates the ability of Internet search engines to correctly predict diagnoses when symptoms are used as search terms.MethodsWe developed a five point scoring system to evaluate the diagnostic accuracy of Internet search engines. We identified twenty diagnoses common to a primary care setting to validate the scoring system. One investigator entered the symptoms for each diagnosis into three Internet search engines (Google, Bing, and Ask) and saved the first five webpages from each search. Other investigators reviewed the webpages and assigned a diagnostic accuracy score. They rescored a random sample of webpages two weeks later. To validate the five point scoring system, we calculated convergent validity and test–retest reliability using Kendall's W and Spearman's rho, respectively. We used the Kruskal–Wallis test to look for differences in accuracy scores for the three Internet search engines.ResultsA total of 600 webpages were reviewed. Kendall's W for the raters was 0.71 (p < 0.0001). Spearman's rho for test–retest reliability was 0.72 (p < 0.0001). There was no difference in scores based on Internet search engine. We found a significant difference in scores based on the webpage's order on the Internet search engine webpage (p = 0.007). Pairwise comparisons revealed higher scores in the first webpages vs. the fourth (corr p = 0.009) and fifth (corr p = 0.017). However, this significance was lost when creating composite scores.ConclusionsThe five point scoring system to assess diagnostic accuracy of Internet search engines is a valid and reliable instrument. The scoring system may be used in future Internet research.     

Impact of stem cell graft on early viral infections and immune reconstitution after allogeneic transplantation in adults

BackgroundViral infections are well-known complications after allogeneic stem cell transplant (allo-SCT).ObjectivesWe compared prospectively incidences of DNAemia and active infections (AI) for five opportunistic viruses (Human Herpesvirus 6 (HHV-6), Epstein-Barr virus (EBV), BK polyomavirus (BKPyV), Cytomegalovirus (CMV) and Adenovirus (ADV)) and kinetics of immune reconstitution (IR) in adults receiving either double umbilical cord blood (dUCB group) or unrelated peripheral blood stem cell (uPBSC group) allo-SCT after a reduced-intensity conditioning (RIC) regimen.Study designWhole blood samples were collected at transplant, every 15 days during the first 3 months and at 4, 5 and 6 months post-transplant.ResultsSixty-five patients were enrolled (uPBSC n = 34; dUCB n = 31). Incidences of HHV-6 and BKPyV DNAemia were significantly higher for dUCB (97% vs 23.5% and 58% vs 32%, respectively) while EBV DNAemia was more frequently detected in uPBSC (71% vs 26%). The incidence of CMV DNAemia was similar between both groups. ADV AI developed only in dUCB. HHV-6 AI were also higher in dUCB (84% vs 21%). In multivariate analysis, dUCB graft was the only independent factor associated with HHV-6 DNAemia (OR: 19.0; 95%CI: 5.2–69.1; p < 0.0001) while EBV DNAemia were significantly associated with uPBSC (OR: 29.9; 95%CI: 5.68–158; p < 0.0001). dUCB graft was also the only factor associated with HHV-6 AI. Finally, higher counts and faster recoveries of B lymphocytes (p<0.0001) and monocytes (p = 0.0007) were observed in the dUCB group.ConclusionWe demonstrate a strong correlation between sources of graft and patterns of viral DNAemia and AI and IR after RIC allo-SCT.     

Automatically finding relevant citations for clinical guideline development

ObjectiveLiterature database search is a crucial step in the development of clinical practice guidelines and systematic reviews. In the age of information technology, the process of literature search is still conducted manually, therefore it is costly, slow and subject to human errors. In this research, we sought to improve the traditional search approach using innovative query expansion and citation ranking approaches.MethodsWe developed a citation retrieval system composed of query expansion and citation ranking methods. The methods are unsupervised and easily integrated over the PubMed search engine. To validate the system, we developed a gold standard consisting of citations that were systematically searched and screened to support the development of cardiovascular clinical practice guidelines. The expansion and ranking methods were evaluated separately and compared with baseline approaches.ResultsCompared with the baseline PubMed expansion, the query expansion algorithm improved recall (80.2% vs. 51.5%) with small loss on precision (0.4% vs. 0.6%). The algorithm could find all citations used to support a larger number of guideline recommendations than the baseline approach (64.5% vs. 37.2%, p < 0.001). In addition, the citation ranking approach performed better than PubMed’s “most recent” ranking (average precision +6.5%, recall@k +21.1%, p < 0.001), PubMed’s rank by “relevance” (average precision +6.1%, recall@k +14.8%, p < 0.001), and the machine learning classifier that identifies scientifically sound studies from MEDLINE citations (average precision +4.9%, recall@k +4.2%, p < 0.001).ConclusionsOur unsupervised query expansion and ranking techniques are more flexible and effective than PubMed’s default search engine behavior and the machine learning classifier. Automated citation finding is promising to augment the traditional literature search.     

The effect of tourniquet use on fixation quality in cemented total knee arthroplasty a prospective randomized clinical controlled RSA trial

BackgroundA concern that arises with any change in technique is whether it affects the long-term implant stability. The objective of this study was to evaluate the early migration, measured by radiostereometric analysis (RSA), and the functional outcome of the Triathlon™ cemented knee prosthesis, operated on with or without a tourniquet. During the last decades RSA has emerged as a way to assess prosthetic fixation and long time prognosis. The method has been used extensively in both hip and knee arthroplasty.MethodThis was a single centre prospective study including 60 patients randomized into two groups operated on either with or without tourniquet. RSA investigation was done within 2–3 days postoperatively after full weight bearing, and then at 3 months, 1 year and 2 years postoperatively.ResultsThere were no differences between the groups regarding the translation along or rotation around the three coordinal axes, or in maximum total point motion (MTPM). At 2 years the mean MTPM (SD) was 0.71 mm (0.64) for the tourniquet-group and 0.53 mm (0.21) for the non-tourniquet-group.ConclusionsThe tibial tray of the Triathlon™ cemented knee prosthesis showed similar early stability whether operated on with or without tourniquet.Level of evidenceLevel I.Article summaryArticle focus: A safety study for total knee replacement operated on with or without perioperative tourniquet regarding the prosthetic fixation.Strengths and limitations: Strength of this study is that it is a randomized prospective trial using an objective measuring tool. The sample size of 25–30 patients is reportedly sufficient for the screening of implants using RSA (1–3).Trial registration: Clinical trials NCT01604382, Ethics Committee approval D-nr: 144/20085.     

A systematic review of leukocyte telomere length and age in adults

ObjectiveTo provide a systematic review of the relationship between age and leukocyte telomere length (LTL) in adults.MethodsRelevant studies were identified by a systematic search of Medline, EMBASE and ISI Web of Knowledge databases. Key data, such as age and LTL, were extracted from the studies along with correlation coefficients and yearly attrition rates where available. Obtained data were used to calculate weighted means and correlation coefficients.ResultsOverall, 124 cross-sectional studies and 5 longitudinal studies were identified. A statistically significant inverse correlation between mean age and mean LTL across cross-sectional studies was observed for both absolute (r = ?0.338, p < 0.0001) and relative LTL (r = ?0.295, p = 0.0088). From mean LTL and ages, a yearly telomere loss of 24.7 base pairs (BP)/year was estimated by weighted linear regression. Weighted means of within study correlation of age and TL and yearly telomere loss rate estimates from cross-sectional studies were also in a similar order of magnitude (?0.380 and 21.91 BP/year). The few longitudinal studies reported somewhat higher mean telomere loss rates (between 32.2 and 45.5 BP/year).ConclusionWhile a decrease of LTL with age is out of question, data on variation of the decrease according to sex, age and other potential determinants especially from longitudinal data are still sparse.     

Toward verified and validated FE simulations of a femur with a cemented hip prosthesis

BackgroundVerified and validated CT-based high-order finite element (FE) methods were developed that predict accurately the mechanical response of patient-specific intact femurs. Here we extend these capabilities to human femurs undergoing a total hip replacement using cemented prostheses.MethodsA fresh-frozen human femur was CT-scanned and thereafter in vitro loaded in a stance position until fracture at the neck. The head and neck were removed and the femur was implanted with a cemented prosthesis. The fixed femur was CT-scanned and loaded through the prosthesis so that strains and displacements were measured. High-order FE models based on the CT scans, mimicking the experiments, were constructed to check the simulations prediction capabilities.ResultsThe FE models were verified and results were compared to the experimental observations. The correlation between the experimental and FE strains and displacements were (R² = 0.97, EXP = 0.96FE + 0.02) for the intact femur and (R² = 0.90, EXP = 0.946FE + 0.0012) for the implanted femur. This is considered a good agreement considering the uncertainties encountered by the heavy distortion embedded in the CT scan of the metallic prosthesis.DiscussionThe patient-specific FE model of the fresh-frozen femur with the cemented metallic prosthesis showed a good correlation to experimental observations, both when considering surface strains, displacements and strains on the prosthesis. The relatively short timescale to generate and analyze such femurs (about 6 h) make these analyses a very attractive tool to be used in clinical practice for optimization prostheses (dimensions, location and configuration), and allow to quantify the stress shielding.     

Clinical trainees’ responses to parents who question evidence-based recommendations

ObjectiveWe examined clinicians’ attitudes, beliefs, and behavioral intentions about discussing evidence and eliciting values when patients question recommendations.MethodsWe randomized trainees to read one of three scenarios about a parent of a one-year-old: 1) overuse (parent requests antibiotics for presumed viral infection); 2) equipoise (tubes for recurrent ear infections); 3) underuse (parent hesitates about vaccination). Participants then answered survey questions. Outcomes included time spent clarifying values (primary), attitudes and beliefs about the parent (secondary).Results132 medical students and pediatric residents enrolled; 119 (90%) completed the study. There were no differences in time participants would spend clarifying values (antibiotics 26 ± 12%; equipoise 28 ± 11%; vaccine-hesitancy 22 ± 11%; p = 0.058). Participants in the vaccine-hesitancy group (vs. other groups) would spend less time answering questions (p = 0.006). Participants in the antibiotics (vs. equipoise) group perceived the parent as difficult (p = 0.0002). Those in the vaccine-hesitancy group (vs. other groups) perceived the parent as difficult, saw less value in the conversation, and had lower respect for the parent’s views (all ps < 0.0001). Most (76%) wanted additional training navigating these discussions.ConclusionClinicians’ attitudes may impact conversations when patients question evidence-based recommendations.Practice implicationsClinicians should consider ways to discuss evidence and clarify patients’ values to optimize health without damaging patient-clinician relationships.     

Audit and feedback using the brief Decision Support Analysis Tool (DSAT-10) to evaluate nurse–standardized patient encounters

ObjectiveTo evaluate the brief Decision Support Analysis Tool (DSAT-10) for auditing the quality of nurse–standardized patient encounters, structuring feedback for nurses, and testing instrument reliability.MethodsA systematic process was used to develop standardized patient scenarios, pilot-test scenarios, calibrate DSAT-10 coders, analyze taped telephone encounters using DSAT-10, and provide feedback. Inter-rater reliability was calculated using coder agreement, kappa, and intra-class correlation coefficients.ResultsSix scenarios portrayed patients’ decisional uncertainty from either: pressure from others (n = 2), unclear values (n = 2), or inadequate information (n = 2). Scenarios were easy to use over the telephone, produced realistic role performance, and were practical for audio-recording interactions. DSAT-10 analysis of 76 nurse–standardized patient encounters revealed nurses’ strengths (e.g., information provision) and their limitations (e.g., lack of discussion of values and/or support needs). Scores discriminated between trained and untrained nurses. The kappa coefficient over all items was 0.55 (95% CI: 0.49, 0.61) with higher agreement for encounters involving trained nurses (0.62; 95% CI: 0.43, 0.80).ConclusionAuditing nurse–standardized patient encounters using DSAT-10 and providing feedback to nurses was feasible. Although DSAT-10 items had adequate inter-rater reliability and discriminated between trained/untrained nurses, some items were problematic.Practice implicationsProviding feedback on nurse encounters with standardized patients experiencing uncertainty has the potential to enhance nurses’ decision support skills.     

A method for carpal motion hysteresis quantification in 4-dimensional imaging of the wrist

IntroductionCarpal bones motions exhibit hysteresis that is dependent on the direction of wrist motion, which can be seen during 4-dimensional (3D plus time) imaging of the wrist. In vitro studies have demonstrated the phenomenon of carpal hysteresis and have reported that hysteresis area increases with carpal instabilities. However, their techniques required implantation of bone markers and thus cannot be used clinically. The objective of this study is to use noninvasive 4-dimensional computed tomography (4DCT) technique to quantify carpal hysteresis, and to determine the reliability of this method.MethodA cadaveric wrist mounted on a custom motion simulator was imaged using a dual-source CT scanner while undergoing periodic radioulnar deviation. Ten image phases of this motion was reconstructed through retrospective cardiac gating. The rotational angles of scaphoid, lunate and triquetrum in each phase were derived through manual registration using Matlab after segmenting the bones in Analyze 8.1. These angles were then plotted against global wrist positional angles to produce the hysteresis curves and the area was calculated. The image segmentation and measurements were repeated by 2 raters to derive intra- and inter-rater reliability assessments.ResultsThe hysteresis area was found to be larger in the lunate (96.5 deg²) followed by triquetrum (92.3 deg²) and scaphoid (67.5 deg²). The measurement of the total hysteresis area of the scaphoid had the highest reliability with intra- and inter-rater reliability of 95.5% and 95.4% respectively.DiscussionWe have demonstrated that our approach of using 4DCT imaging can be used to assess and quantify the hysteresis of the carpal motion with good reliability.     

Clinical code set engineering for reusing EHR data for research: A review

IntroductionThe construction of reliable, reusable clinical code sets is essential when re-using Electronic Health Record (EHR) data for research. Yet code set definitions are rarely transparent and their sharing is almost non-existent. There is a lack of methodological standards for the management (construction, sharing, revision and reuse) of clinical code sets which needs to be addressed to ensure the reliability and credibility of studies which use code sets.ObjectiveTo review methodological literature on the management of sets of clinical codes used in research on clinical databases and to provide a list of best practice recommendations for future studies and software tools.MethodsWe performed an exhaustive search for methodological papers about clinical code set engineering for re-using EHR data in research. This was supplemented with papers identified by snowball sampling. In addition, a list of e-phenotyping systems was constructed by merging references from several systematic reviews on this topic, and the processes adopted by those systems for code set management was reviewed.ResultsThirty methodological papers were reviewed. Common approaches included: creating an initial list of synonyms for the condition of interest (n = 20); making use of the hierarchical nature of coding terminologies during searching (n = 23); reviewing sets with clinician input (n = 20); and reusing and updating an existing code set (n = 20). Several open source software tools (n = 3) were discovered.DiscussionThere is a need for software tools that enable users to easily and quickly create, revise, extend, review and share code sets and we provide a list of recommendations for their design and implementation.ConclusionResearch re-using EHR data could be improved through the further development, more widespread use and routine reporting of the methods by which clinical codes were selected.     

Topical tranexamic acid in total knee replacement: A systematic review and meta-analysis

BackgroundTo examine the safety and efficacy of topical use of tranexamic acid (TA) in total knee arthroplasty (TKA).MethodsAn electronic literature search of PubMed Medline; Ovid Medline; Embase; and the Cochrane Library was performed, identifying studies published in any language from 1966 to February 2013. The studies enrolled adults undergoing a primary TKA, where topical TA was used. Inverse variance statistical method and either a fixed or random effect model, depending on the absence or presence of statistical heterogeneity were used; subgroup analysis was performed when possible.ResultsWe identified a total of seven eligible reports for analysis. Our meta-analysis indicated that when compared with the control group, topical application of TA limited significantly postoperative drain output (mean difference: ? 268.36 ml), total blood loss (mean difference = ? 220.08 ml), Hb drop (mean difference = ? 0.94 g/dL) and lowered the risk of transfusion requirements (risk ratio = 0.47, 95CI = 0.26–0.84), without increased risk of thromboembolic events. Sub-group analysis indicated that a higher dose of topical TA (> 2 g) significantly reduced transfusion requirements.ConclusionsAlthough the present meta-analysis proved a statistically significant reduction of postoperative blood loss and transfusion requirements with topical use of TA in TKA, the clinical importance of the respective estimates of effect size should be interpreted with caution.Level of evidenceI, II.     

Comprehensive review of genetic association studies and meta-analysis on miRNA polymorphisms and rheumatoid arthritis and systemic lupus erythematosus susceptibility

BackgroundMicroRNAs (miRNAs), small RNA molecules, play a role in the development and differentiation of immune cells in both innate and adaptive immune responses. Our study was aimed to investigate the association between three miRNA polymorphism and rheumatoid arthritis (RA) or systemic lupus erythematosus (SLE) by using meta-analysis approach.MethodsA PubMed database search was conducted during August 2013 to identify case–control studies of miRNAs and RA or SLE risk. Two authors independently extracted information on the study design, the characteristics of the study participants, exposure and outcome assessments. The fix-effects and random-effects models were used for the risk estimates by Stata 11.0 software.ResultsOur meta-analysis of six case–control studies involving a total of 998 RA cases and 1493 controls identified no significant association between mir-146a rs2910164 and RA, with an overall OR of 0.843 (95% CI = 0.642–1.105; CC vs. GG). No association was observed in three studies with a total of 1532 cases and 2168 controls between miR-146a rs2910164 and SLE risk (OR = 0.911, 95% CI = 0.710–1.171; CC vs. GG). Three studies with a total of 529 cases and 595 controls evaluated the mir-499 rs3746444 polymorphism and its association with RA. There was a decreased overall risk of RA under the allelic and genotypic models [OR = 0.616, 95% CI = 0.384–0.981, (T vs. C allele) and OR = 0.386, 95% CI = 0.226–0.659, (TT vs. CC)]. Two studies with 4826 cases and 4181 controls evaluated miR-146a rs57095329 and its association with SLE. There was a significant association between miR-146a rs57095329 and SLE (OR = 1.263, 95% CI = 1.136–1.405, G vs. A allele).ConclusionsThe present meta-analysis suggests important roles for the mir-499 rs3746444 polymorphism in RA, especially in the Caucasian population and for miR-146a rs57095329 polymorphism in SLE. Further studies with large sample size are needed to confirm these associations.     

Association between IFNL4 rs368234815 polymorphism and sustained virological response in chronic hepatitis C patients undergoing PEGylated interferon/ribavirin therapy: A meta-analysis

Background and aimsMany studies have been published on the association between IFNL4 rs368234815 single-nucleotide polymorphism (SNP) and sustained virological response (SVR) in chronic hepatitis C (CHC) patients undergoing treatment with PEGylated interferon (PEG-IFN) plus ribavirin (RBV). Because of the variable and sometimes inconsistent results, we performed a meta-analysis to estimate the association between these factors.MethodsWe conducted a search of the literature published prior to July 1, 2014. The pooled results were analyzed as the odds ratios (ORs) and corresponding 95% confidence intervals (CIs) using random-effect model.ResultsThe pooled results revealed that the rs368234815 TT/TT genotype was significantly correlated with SVR in HCV-1/4-infected Caucasian patients (OR = 4.65, 95% CI = 3.36–6.42, P < 0.00001) but not in HCV-2/3-infected Caucasian patients (OR = 1.44, 95% CI: 0.89–2.33, P = 0.13). Conversely, the rs368234815 ΔG/ΔG genotype was significantly linked to treatment failure in Caucasian patients (OR = 0.49, 95% CI: 0.38–0.64, P < 0.00001), regardless of the HCV genotype.ConclusionThe results of the meta-analysis suggest that IFNL4 rs368234815 polymorphism may be a predictor of SVR in Caucasian HCV-1/4-infected patients.     

Static autoregulation in humans: a review and reanalysis

IntroductionCerebral autoregulation (CA) is a theoretical construct characterized by the relationship between mean arterial pressure (MAP) and cerebral blood flow (CBF). We performed a comprehensive literature search to provide an up-to-date review on the static relationship between MAP and CBF.MethodsThe results are based on 40 studies (49 individual experimental protocols) in healthy subjects between 18 and 65 years. Exclusion criteria were: a ΔMAP <5%, hypoxia/hyperoxia or hypo/hypercapnia, and unstable levels (<2 min stages). The partial pressure of arterial CO₂ (PaCO₂) was measured in a subset of the included studies (n = 28); therefore, CBF was also adjusted to account for small changes in PaCO₂.ResultsThe linear regression coefficient between MAP and CBF (or velocity) of 0.82 ± 0.77%ΔCBF/%ΔMAP during decreases in MAP (n = 23 experiments) was significantly different than the relationship of 0.21 ± 0.47%ΔCBF/%ΔMAP during increases (n = 26 experiments; p < 0.001). After correction for increases/decreases in PaCO₂, the slopes were not significantly different: 0.64 ± 1.16%ΔCBF/%ΔMAP (n = 16) and 0.39 ± 0.30%ΔCBF/%ΔMAP (n = 12) for increased vs. decreased MAP changes, respectively (p = 0.60).ConclusionThe autoregulatory ability of the cerebral circulation appears to be more active in buffering increases in MAP as compared to reductions in MAP. However, the statistical finding of hysteresis is lost following an attempt to correct for PaCO₂.     

Detection and characterization of usability problems in structured data entry interfaces in dentistry

BackgroundPoor usability is one of the major barriers for optimally using electronic health records (EHRs). Dentists are increasingly adopting EHRs, and are using structured data entry interfaces to enter data such that the data can be easily retrieved and exchanged. Until recently, dentists have lacked a standardized terminology to consistently represent oral health diagnoses.ObjectivesIn this study we evaluated the usability of a widely used EHR interface that allow the entry of diagnostic terms, using multi-faceted methods to identify problems and work with the vendor to correct them using an iterative design method.MethodsFieldwork was undertaken at two clinical sites, and dental providers as subjects participated in user testing (n = 32), interviews (n = 36) and observations (n = 24).ResultsUser testing revealed that only 22–41% of users were able to successfully complete a simple task of entering one diagnosis, while no user was able to complete a more complex task. We identified and characterized 24 high-level usability problems reducing efficiency and causing user errors. Interface-related problems included unexpected approaches for displaying diagnosis, lack of visibility, and inconsistent use of UI widgets. Terminology related issues included missing and mis-categorized concepts. Work domain issues involved both absent and superfluous functions. In collaboration with the vendor, each usability problem was prioritized and a timeline set to resolve the concerns.DiscussionMixed methods evaluations identified a number of critical usability issues relating to the user interface, underlying terminology of the work domain. The usability challenges were found to prevent most users from successfully completing the tasks. Our further work we will determine if changes to the interface, terminology and work domain do result in improved usability.     

A comparative analysis of chaotic particle swarm optimizations for detecting single nucleotide polymorphism barcodes

ObjectiveEvolutionary algorithms could overcome the computational limitations for the statistical evaluation of large datasets for high-order single nucleotide polymorphism (SNP) barcodes. Previous studies have proposed several chaotic particle swarm optimization (CPSO) methods to detect SNP barcodes for disease analysis (e.g., for breast cancer and chronic diseases). This work evaluated additional chaotic maps combined with the particle swarm optimization (PSO) method to detect SNP barcodes using a high-dimensional dataset.Methods and materialNine chaotic maps were used to improve PSO method results and compared the searching ability amongst all CPSO methods. The XOR and ZZ disease models were used to compare all chaotic maps combined with PSO method. Efficacy evaluations of CPSO methods were based on statistical values from the chi-square test (χ²).ResultsThe results showed that chaotic maps could improve the searching ability of PSO method when population are trapped in the local optimum. The minor allele frequency (MAF) indicated that, amongst all CPSO methods, the numbers of SNPs, sample size, and the highest χ² value in all datasets were found in the Sinai chaotic map combined with PSO method. We used the simple linear regression results of the gbest values in all generations to compare the all methods. Sinai chaotic map combined with PSO method provided the highest β values (β ≥ 0.32 in XOR disease model and β ≥ 0.04 in ZZ disease model) and the significant p-value (p-value < 0.001 in both the XOR and ZZ disease models).ConclusionThe Sinai chaotic map was found to effectively enhance the fitness values (χ²) of PSO method, indicating that the Sinai chaotic map combined with PSO method is more effective at detecting potential SNP barcodes in both the XOR and ZZ disease models.