Bayesian estimation and classification with incomplete data using mixture models

©2004 IEEE. Personal use of this material is permitted. Permission from IEEE must be obtained for all other users, including reprinting/ republishing this material for advertising or promotional purposes, creating new collective works for resale or redistribution to servers or lists, or reuse of any copyrighted components of this work in other works.Reasoning from data in practical problems is frequently hampered by missing observations. Mixture models provide a powerful general semi-parametric method for modelling densities and have close links to radial basis function neural networks (RBFs). We extend the Data Augmentation (DA) technique for multiple imputation to Gaussian mixture models to permit fully Bayesian inference of model parameters and estimation of the missing values. The method is compared to imputation using a single normal density on synthetic and real-world data. In addition to a lower mean squared error than can be achieved by simple imputation methods, mixture Models provide valuable information on the potentially multi-modal nature of imputed values. The DA formalism is extended to a classifier closely related to RBF networks permitting Bayesian classification with incomplete data; the technique is illustrated on synthetic and real datasets

Blood Pressure Estimation using Photoplethysmography only: Comparison between Different Machine Learning Approaches

Introduction: Blood pressure (BP) has been a potential risk factor for cardiovascular diseases. BP measurement is one of the useful parameters for early diagnosis, prevention, and treatment of cardiovascular diseases. At present, BP measurement mainly relies on cuff-based techniques that cause inconvenience and discomfort to users. Although some of the present prototype cuffless BP measurement techniques are able to reach overall acceptable accuracies, they require an electrocardiogram (ECG) and photoplethysmograph (PPG) that makes them unsuitable for true wearable applications. Therefore, developing a single PPG based cuffless BP estimation algorithm with enough accuracy would be clinically and practically useful. Methods: The University of Queensland vital sign dataset (Online database) was accessed to extract raw PPG signals and its corresponding reference BPs (Systolic BP & Diastolic BP). The online database consisted of PPG waveforms of 32 cases from whom 8133 (good quality) signal segments (5s for each) were extracted, pre-processed and normalised in both width and amplitude. Three most significant features (Pulse area, Pulse Rising Time and Width 25%) with their corresponding reference BPs were used to train and test three machine learning algorithms (Regression Tree, Multiple Linear Regression (MLR) and Support Vector Machine (SVM)). A 10-fold cross-validation was applied to obtain over-all BP estimation accuracy, separately for the three machine learning algorithms. Their estimation accuracies were further analysed separately for three clinical BP categories (Normotensive, Hypertensive and Hypotensive). Finally, they were compared with the ISO standard for non-invasive BP device validation (average difference no greater than 5mmHg and SD no greater than 8mmHg). Results: In terms of overall measurement accuracy, the Regression Tree achieved the best overall accuracy for SBP (mean and SD of difference: -0.1±6.5mmHg) & DBP (mean and SD of difference: -0.6±5.2mmHg). MLR and SVM achieved the overall mean difference less than 5mmHg for both SBP and DBP but their SD of difference was >8mmHg. Regarding the measurement accuracy in each BP categories, only the Regression Tree achieved acceptable ISO standard for SBP (-1.1±5.7mmHg) & DBP (-0.03±5.6 mmHg) in the Normotensive category. MLR and SVM did not achieve acceptable accuracies in any BP categories. Conclusion: This study developed and compared three machine learning algorithms to estimate BPs using PPG only, and revealed that the Regression Tree algorithm was the best approach with overall acceptable accuracy to ISO standard for BP device validation. Furthermore, this study demonstrated that the Regression Tree algorithm achieved acceptable measurement accuracy only in the Normotensive category, suggesting that future algorithm development for BP estimation should be more specific for different BP categories

Dance for Health: the impact of creative dance sessions on older people in an acute hospital setting

Background: This service evaluation examined the impact of Dance for Health, a programme of weekly group dance sessions for older patients, which took place on wards in an acute hospital setting. Methods: Qualitative and quantitative observations using the ArtsObs scale were undertaken of 64 dance sessions over a 12-week period involving seven different hospital wards encompassing 313 patient attendances. Results: Statistically significant improvements were observed in the mood of the majority of patients taking part. People engaged mentally and physically with the activity were distracted from their medical condition and from what was happening on the ward. Patients appeared relaxed and were willing to express themselves creatively. Conclusion: The Dance for Health programme had a positive impact on group participants, promoting movement and physical activity for older patients. It is a meaningful and enjoyable activity, which encourages social interaction and provides respite from the medical environment

Agreement and classification performance of malnutrition tools in patients with chronic heart failure

Background: Malnutrition is common in chronic heart failure (CHF) patients and is associated with adverse outcome, but few data exist. Objectives: To report the prevalence of malnutrition and classification performance of 6 malnutrition tools in CHF patients. Methods: Controlling nutritional status index (CONUT); geriatric nutritional risk index (GNRI); prognostic nutritional index (PNI); malnutrition universal screening tool (MUST); mini nutritional assessment-short form (MNA-SF); and subjective global assessment (SGA) were used to evaluate malnutrition. Since there is no “gold-standard” for malnutrition evaluation, for each of the malnutrition tools, we used the results of the other 5 tools to produce a standard combined index. Subjects were ‘malnourished’ if so identified by ≥3/5 tools. Results: We studied 467 consecutive ambulatory CHF patients (67% male, median age 76 (IQR: 69–82) years, median NTproBNP 1156 (IQR: 469–2463) ng/L). The prevalence of any degree and at least moderate malnutrition ranged between 6–60% and 3–9% respectively, with CONUT classifying the highest proportion of subjects as malnourished. Malnourished patients tended to be older, have worse symptoms, higher NT-proBNP and more co-morbidities. CONUT had the highest sensitivity (80%), MNA-SF and SGA had the highest specificity (99%) and MNA-SF had the lowest misclassification rate (2%) in identifying at least moderate malnutrition as defined by the combined index. Conclusion: Malnutrition is common in CHF patients. The prevalence of malnutrition varies depending on the tool used. Amongst the 6 malnutrition tool studied, MNA-SF has the best classification performance in identifying significant malnutrition as defined by the combined index

Preplanned Studies: Orofacial Clefts in High Prevalence Area of Birth Defects — Five Counties, Shanxi Province, China, 2000–2020

What is already known on this topic?: The prevalence of structural birth defects, especially neural tube defects, decreased after national folic acid (FA) supplementation initiation. / What is added by this report?: The prevalence of orofacial clefts (OFCs) in five counties of Shanxi Province in northern China, including most subtypes except cleft palate, showed a downward trend in the past two decades. In this study, pre-perinatal prevalence increased due to earlier detection. / What are the implications for public health practice?: Periconceptional supplementation with FA may contribute to the decline in OFCs prevalence, while the effect on the OFCs subtype needs further investigation. Continuing to advocate for earlier supplementation (3 months before conception) and increased supplementation frequency (daily consumption) could promote further reduction in the prevalence of OFCs. Specific surveillance of this effect in the era of universal three-child policy is warranted

Feasibility-Usability Study of a Tablet App Adapted Specifically for Persons with Cognitive Impairment—SMART4MD (Support Monitoring and Reminder Technology for Mild Dementia)

Population ageing within Europe has major social and economic consequences. One of the most devastating conditions that predominantly affects older people is dementia. The SMART4MD (Support Monitoring and Reminder Technology for Mild Dementia) project aims to develop and test a health application specifically designed for people with mild dementia. The aim of this feasibility study was to evaluate the design of the SMART4MD protocol, including recruitment, screening, baseline examination and data management, and to test the SMART4MD application for functionality and usability before utilization in a full-scale study. The feasibility study tested the protocol and the app in Spain and Sweden. A total of nineteen persons with cognitive impairment, and their informal caregivers, individually performed a task-based usability test of the SMART4MD app model in a clinical environment, followed by four-week testing of the app in the home environment. By employing a user-centered design approach, the SMART4MD application proved to be an adequate and feasible interface for an eHealth intervention. In the final usability test, a score of 81% satisfied users was obtained. The possibility to test the application in all the procedures included in the study generated important information on how to present the technology to the users and how to improve these procedures

A Randomised Controlled Trial Comparing Microthin Descemet Stripping Automated Endothelial Keratoplasty (MT-DSAEK) with Descemet Membrane Endothelial Keratoplasty: 2 year report

Purpose: The purpose of this study was to report the 2-year outcomes of a double-blinded randomized controlled trial comparing Descemet membrane endothelial keratoplasty (DMEK) and microthin Descemet stripping automated endothelial keratoplasty (MT-DSAEK). Methods: Fifty-six eyes of 56 patients were randomized to DMEK or microthin DSAEK (MT-DSAEK). The main outcome measure was best spectacle-corrected visual acuity (BSCVA) at 24 months. Other secondary outcomes included complications, endothelial cell density, and vision-related quality-of-life (vQoL) scores. Results: There was no statistically significant difference in BSCVA between the DMEK and MT-DSAEK groups at the 2-year time point (mean ± SD; 0.04 ± 0.14 vs. 0.12± 0.19, P = 0.061) in contrast to the 1-year results (mean ± SD; 0.04 ± 0.13 vs. 0.11 ± 0.09, P = 0.002) previously reported. Endothelial cell density did not show a statistically significant difference at 24 months between the DMEK and MT-DSAEK groups (1522 ± 293 cell/mm2 vs. 1432 ± 327 cells/mm2, P = 0.27). There were 2 additional graft rejection episodes in the MT-DSAEK group between the 1- and 2-year follow-up periods, but this did not result in graft failure. The mean vQoL scores between DMEK and MT-DSAEK indicated similar patient satisfaction between the groups (97.1 ± 4.0 vs. 92.6 ± 10.2, P = 0.13). Conclusions: In summary, the trial showed no significant difference in BSCVA at 24 months between the DMEK and MT-DSAEK groups. Both techniques continued to demonstrate comparable outcomes for complication rates, endothelial cell loss, and patient-reported vQoL scores

Sore eyes as the most significant symptom experienced by people with COVID-19. A comparison between pre- and during-COVID-19 states

Objective: Conjunctivitis has been reported in people suffering from COVID-19. However, many ocular symptoms are associated with the term ‘conjunctivitis’ which may be misleading. It is also unknown whether ocular symptoms were different in chronic sufferers of anterior eye diseases, when they were experienced or how long they lasted for compared with other COVID-19 symptoms. Methods: An online structured questionnaire obtained self-report data from people who had a confirmed diagnosis of COVID-19. Data for the type, frequency and duration of different COVID-19 symptoms were ascertained. Anterior eye symptoms experienced by participants in the pre-COVID-19 state were compared with during the COVID-19 state. Results: Data from 83 participants showed that the most reported COVID-19 symptoms were dry cough (66%), fever (76%), fatigue (90%) and loss of smell/taste (70%). The three most common ocular symptoms experienced by participants were photophobia (18%), sore eyes (16%) and itchy eyes (17%). The frequency of sore eyes was significantly higher (p=0.002) during COVID-19 state (16%) compared with pre-COVID-19 state (5%). There were no differences between males and females (p>0.05). 81% of participants reported to have experienced ocular symptoms within 2 weeks of other COVID-19 symptoms, and 80% reported they lasted for less than 2 weeks. Conclusion: The most significant ocular symptom experienced by people suffering from COVID-19 was sore eyes. Other symptoms associated with other types of conjunctivitis, such as mucous discharge and gritty eyes linked to bacterial infection, did not reach significance. The term ‘conjunctivitis’ is too broad and should be used with caution

Non-Isolated Neural Tube Defects with Comorbid Malformations Are Responsive to Population-Level Folic Acid Supplementation in Northern China

Objective: Comorbid congenital malformation of multiple organs may indicate a shared genetic/teratogenic causality. Folic acid supplementation reduces the population-level prevalence of isolated neural tube defects (NTDs), but whether complex cases involving independent malformations are also responsive is unknown. We aimed to describe the epidemiology of NTDs with comorbid malformations in a Chinese population and assess the impact of folic acid supplementation. Study Design: Data from five counties in Northern China were obtained between 2002 and 2021 through a population-based birth defects surveillance system. All live births, stillbirths, and terminations because of NTDs at any gestational age were recorded. NTDs were classified as spina bifida, anencephaly, or encephalocele. Isolated NTDs included spina bifida cases with presumed secondary malformations (hydrocephalus, hip dislocation, talipes). Non-isolated NTDs were those with independent concomitant malformations. Results: A total of 296,306 births and 2031 cases of NTDs were recorded from 2002–2021. A total of 4.8% of NTDs (97/2031) had comorbid defects, which primarily affected the abdominal wall (25/97), musculoskeletal system (24/97), central nervous system (22/97), and face (15/97). The relative risk of cleft lip and/or palate, limb reduction defects, hip dislocation, gastroschisis, omphalocele, hydrocephalus, and urogenital system defects was significantly greater in infants with NTDs than in the general population. Population-level folic acid supplementation significantly reduced the prevalence of both isolated and non-isolated NTDs. Conclusion: Epidemiologically, non-isolated NTDs follow similar trends as isolated cases and are responsive to primary prevention by folic acid supplementation. Various clinically-important congenital malformations are over-represented in individuals with NTDs, suggesting a common etiology

The association between blood groups and COVID-19 infection: a study from the UK Biobank

Blood groups might influence susceptibility to COVID‐19 [1‐7]. We investigated associations between blood groups and COVID‐19 infection in UK Biobank participants, a prospective population‐based study that, between 2006 and 2010, enrolled 502,620 people aged 38–73 years in the United Kingdom. All participants gave written informed consent for their data to be used for research purposes, which was also approved by an ethics committee