Developing realistic benchmarks for glaucoma care delivery

CLINICAL RELEVANCE

Realistic benchmarks can serve as comparators for optometrists wishing to engage in clinical practice audits of their glaucoma care.

BACKGROUND

The iCareTrack study established the appropriateness of glaucoma care delivery through clinical record audits of Australian optometry practices. Benchmarks required for monitoring and improving glaucoma care delivery do not exist. This study developed realistic benchmarks for glaucoma care and then benchmarked the performance of practices from the iCareTrack study to establish aspects of care that warrant attention from quality improvement initiatives.

METHODS

Benchmarks were developed from the pre-existing iCareTrack dataset using the Achievable Benchmarks of Care (ABC) method. The iCareTrack study had audited the appropriateness of glaucoma care delivery against 37 clinical indicators for 420 randomly sampled glaucoma patient records from 42 Australian optometry practices. The four-step ABC method calculates benchmarks based on the top 10% of best-performing practices adjusted for low patient encounter numbers. iCareTrack results were compared to the benchmarks to explore the distribution of practices that were at, above or below benchmark.

RESULTS

Benchmarks were developed for 34 of 37 iCareTrack indicators. For 26 (of 34) indicators, the benchmarks were at or above 90% appropriateness. The benchmarks for 14 (of 34) iCareTrack indicators were met by more than 80% of eligible practices, indicating excellent performance. Some aspects of glaucoma care such as peripheral anterior angle assessment, applanation tonometry, and visual field assessment appeared to be delivered sub-optimally by optometrists when compared to the benchmarks.

CONCLUSION

This study established benchmarks for glaucoma care delivery in optometry practices that reflect realistic and top achievable performance. The large number of indicators with benchmarks above 90% confirmed that glaucoma care can and should be delivered by optometrists at very high levels of appropriateness. Benchmarking identified pockets of sub-optimal performance that can now be targeted by quality improvement initiatives.

Healthcare costs following falls and cataract surgery in older adults using Australian linked health data from 2012-2019

OBJECTIVES

To investigate publicly funded healthcare costs according to faller status and the periods pre- and post-cataract surgeries, and identify factors associated with higher monthly costs in older people with bilateral cataract.

METHODS

This prospective cohort study included community-dwelling older people aged 65 and over (between 2012 and 2019); at baseline participants had bilateral cataract and were waiting for cataract surgery in New South Wales (NSW) public hospitals. Participants were followed for 24 months. The study used self-reported and linked data (Medicare Benefits Schedule, Pharmaceutical Benefits Scheme, NSW Admitted Patient and Emergency Department Data Collections) to identify falls, cataract surgeries and healthcare costs incurred by the Australian and NSW Governments, all costs were inflated to 2018-19 Australian dollars (AUD). Median monthly healthcare costs were calculated for faller status (non-faller, non-medically treated faller, medically treated faller) and surgery periods (pre-surgery, post-first surgery, post-second surgery). Costs in the 30 days following a medically treated fall were estimated. A generalised linear model was used to investigate predictors of healthcare costs.

RESULTS

During the median follow-up period of 24 months, 274 participants suffered 448 falls, with 95 falls requiring medical treatment. For medically treated falls, the mean cost in the 30 days after treatment was A$3779 (95% confidence interval $2485, $5074). Higher monthly healthcare costs were associated with a higher number of medications, being of the male sex, having one or more medically treated falls and having bilateral cataract surgery. After excluding the cost of cataract surgery, there were no significant differences in healthcare costs between the pre-cataract surgery, post-first eye cataract surgery and post-second eye cataract surgery periods.

CONCLUSIONS

To our knowledge, this is the first study investigating publicly funded costs related to falls and cataract surgery in older people with bilateral cataract. This information enhances our understanding of healthcare costs in this group. The patterns in costs associated with falls can guide future government healthcare expenditure on falls treatment and prevention, including timely cataract surgery.

Knowledge, attitudes and practices towards COVID-19 among multiethnic elderly Asian residents in Singapore: a mixed-methods study

Introduction

We investigated the knowledge, attitudes and practice (KAP) towards coronavirus disease 2019 (COVID-19) and its related preventive measures in Singaporeans aged ≥60 years.

Methods

This was a population-based, cross-sectional, mixed-methods study (13 May 2020-9 June 2020) of participants aged ≥ 60 years. Self-reported KAP about ten symptoms and six government-endorsed preventive measures related to COVID-19 were evaluated. Multivariable regression models were used to identify sociodemographic and health-related factors associated with KAP in our sample. Associations between knowledge/attitude scores and practice categories were determined using logistic regression. Seventy-eight participants were interviewed qualitatively about the practice of additional preventive measures and data were analysed thematically.

Results

Mean awareness score of COVID-19 symptoms was 7.2/10. The most known symptom was fever (93.0%) and the least known was diarrhoea (33.5%). Most participants knew all six preventive measures (90.4%), perceived them as effective (78.7%) and practised 'wear a mask' (97.2%). Indians, Malays and participants living in smaller housing had poorer mean scores for knowledge of COVID-19 symptoms. Older participants had poorer attitudes towards preventive measures. Compared to Chinese, Indians had lower odds of practising three out of six recommendations. A one-point increase in score for knowledge and attitudes regarding preventive measures resulted in higher odds of always practising three of six and two of six measures, respectively. Qualitative interviews revealed use of other preventive measures, for example, maintaining a healthy lifestyle.

Conclusions

Elderly Singaporeans displayed high levels of KAP about COVID-19 and its related preventive measures, with a positive association between levels of knowledge/attitude and practice. However, important ethnic and socioeconomic disparities were evident, indicating that key vulnerabilities remain, which require immediate attention.

Clinical indicators for diabetic eyecare delivered by optometrists in Australia: a Delphi study

CLINICAL RELEVANCE

Valid and updated clinical indicators can serve as important tools in assessing and improving eyecare delivery.

BACKGROUND

Indicators for diabetic eyecare in Australia were previously developed from guidelines published before 2013 and then used to assess the appropriateness of care delivery through a nationwide patient record card audit (the iCareTrack study). To reflect emerging evidence and contemporary practice, this study aimed to update clinical indicators for optometric care for people with type 2 diabetes in Australia.

METHODS

Forty-five candidate indicators, including existing iCareTrack and new indicators derived from nine high-quality evidence-based guidelines, were generated. A two-round modified Delphi process where expert panel members rated the impact, acceptability, and feasibility of the indicators on a 9-point scale and voted for inclusion or exclusion of the candidate indicators was used. Consensus on inclusion was reached when the median scores for impact, acceptability, and feasibility were ≥7 and >75% of experts voted for inclusion.

RESULTS

Thirty-two clinical indicators with high acceptability, impact and feasibility ratings (all median scores: 9) were developed. The final indicators were related to history taking (n = 12), physical examination (n = 8), recall period (n = 5), referral (n = 5), and patient education/communication (n = 2). Most (14 of 15) iCareTrack indicators were retained either in the original format or with modifications. New indicators included documenting the type of diabetes, serum lipid level, pregnancy, systemic medications, nephropathy, Indigenous status, general practitioner details, pupil examination, intraocular pressure, optical coherence tomography, diabetic retinopathy grading, recall period for high-risk diabetic patients without retinopathy, referral of high-risk proliferative retinopathy, communication with the general practitioner, and patient education.

CONCLUSION

A set of 32 updated diabetic eyecare clinical indicators was developed based on contemporary evidence and expert consensus. These updated indicators inform the development of programs to assess and enhance the eyecare delivery for people with diabetes in Australia.

Awareness and attitudes of elderly Southeast Asian adults towards telehealth during the COVID-19 pandemic: a qualitative study

Introduction

We aimed to understand the awareness and attitudes of elderly Southeast Asians towards telehealth services during the coronavirus disease 2019 (COVID-19) pandemic in this study.

Methods

In this qualitative study, 78 individuals from Singapore (51.3% female, mean age 73.0 ± 7.6 years) were interviewed via telephone between 13 May 2020 and 9 June 2020 during Singapore's first COVID-19 'circuit breaker'. Participants were asked to describe their understanding of telehealth, their experience of and willingness to utilise these services, and the barriers and facilitators underlying their decision. Transcripts were analysed using thematic analysis, guided by the United Theory of Acceptance Use of Technology framework.

Results

Of the 78 participants, 24 (30.8%) were able to describe the range of telehealth services available and 15 (19.2%) had previously utilised these services. Conversely, 14 (17.9%) participants thought that telehealth comprised solely home medication delivery and 50 (51.3%) participants did not know about telehealth. Despite the advantages offered by telehealth services, participants preferred in-person consultations due to a perceived lack of human interaction and accuracy of diagnoses, poor digital literacy and a lack of access to telehealth-capable devices.

Conclusion

Our results showed poor overall awareness of the range of telehealth services available among elderly Asian individuals, with many harbouring erroneous views regarding their use. These data suggest that public health education campaigns are needed to improve awareness of and correct negative perceptions towards telehealth services in elderly Asians.

Approaches to characterizing oscillatory burst detection algorithms for electrophysiological recordings

BACKGROUND

Cognitive processes are associated with fast oscillations of the local field potential and electroencephalogram. There is a growing interest in targeting them because these are disrupted by aging and disease. This has proven challenging because they often occur as short-lasting bursts. Moreover, they are obscured by broad-band aperiodic activity reflecting other neural processes. These attributes have made it exceedingly difficult to develop analytical tools for estimating the reliability of detection methods.

NEW METHOD

To address this challenge, we developed an open-source toolkit with four processing steps, that can be tailored to specific brain states and individuals. First, the power spectrum is decomposed into periodic and aperiodic components, each of whose properties are estimated. Second, the properties of the transient oscillatory bursts that contribute to the periodic component are derived and optimized to account for contamination from the aperiodic component. Third, using the burst properties and aperiodic power spectrum, surrogate neural signals are synthesized that match the observed signal's spectrotemporal properties. Lastly, oscillatory burst detection algorithms run on the surrogate signals are subjected to a receiver operating characteristic analysis, providing insight into their performance.

RESULTS

The characterization algorithm extracted features of oscillatory bursts across multiple frequency bands and brain regions, allowing for recording-specific evaluation of detection performance. For our dataset, the optimal detection threshold for gamma bursts was found to be lower than the one commonly used.

COMPARISON WITH EXISTING METHODS

Existing methods characterize the power spectrum, while ours evaluates the detection of oscillatory bursts.

CONCLUSIONS

This pipeline facilitates the evaluation of thresholds for detection algorithms from individual recordings.

Robust Ellipse Fitting Based on Maximum Correntropy Criterion With Variable Center

The presence of radically irregular data points (RIDPs), which are referred to as the subset of measurements that represents no or little information, can significantly degrade the performance of ellipse fitting methods. We develop an ellipse fitting method that is robust to RIDPs based on the maximum correntropy criterion with variable center (MCC-VC), where an adaptable Laplacian kernel is used. For single ellipse fitting, we formulate a non-convex optimization problem and divide it into two subproblems, one to estimate the kernel bandwidth and the other the kernel center. We design sufficiently accurate convex approximation to each subproblem that will lead to computationally efficient closed-form solutions. The two subproblems are solved in an alternate manner until convergence is reached. We also investigate coupled ellipses fitting. While there exist multiple ellipses fitting methods in the literature, we develop a coupled ellipses fitting method by exploiting the underlying special structure, where the associations between the data points and ellipses are absent in the problem. The proposed method first introduces an association vector for each data point and then formulates a non-convex mixed-integer optimization problem to establish the data associations, which is approximately solved by relaxing it into a second-order cone program. Using the estimated data associations, we then extend the proposed single ellipse fitting method to accomplish the final coupled ellipses fitting. The proposed method is shown to perform significantly better than the existing methods using both simulated data and real images.

Developing refractive management recommendations for patients undergoing cataract surgery: A Delphi study

PURPOSE

Currently, there are no UK optometric guidelines regarding the pre and postoperative refractive management of patients undergoing cataract surgery. This study used a Delphi method to gain consensus on best practice.

METHODS

Eighteen recommendations targeted areas of concern/variability in advice that were highlighted in an earlier focus group study of refractive management for patients who had received cataract surgery. These covered three topics: preoperative target refraction discussions, postoperative refractive management and driving advice postoperatively. The recommendations were then developed using evidence from optometry and ophthalmology clinical expertise and the research literature. Eighteen recommendations underwent a process of agreement and modification using a Delphi study consisting of a panel of 22 highly experienced optometrists (N = 11, 25 years mean clinical experience) and ophthalmologists (N = 11, 17 years mean clinical experience) who rated and commented upon the importance and feasibility of each recommendation. The responses were considered by the research team and the recommendations modified and/or removed prior to a second Delphi round of responses to a modified series of recommendations. Consensus of opinion was defined as greater than 80% of panellists 'agreed' or 'strongly agreed' on the recommendation for both importance and feasibility.

RESULTS

Fourteen of the 18 recommendations reached consensus in the first round. A second round of the Delphi method saw 17 modified recommendations scored and commented upon by 20 clinicians. Fifteen recommendations reached consensus after two rounds of the Delphi method.

CONCLUSIONS

Recommendations to guide the pre and postoperative refractive management of patients undergoing cataract surgery were agreed between highly experienced optometrists and ophthalmologists using a 2-round Delphi method. Patients would benefit from consistent target refraction discussions, postoperative refractive management and driving advice, and recommendations were of particular benefit to less experienced optometrists.

The incidence of falls after first and second eye cataract surgery: a longitudinal cohort study

OBJECTIVE

To compare fall incidence, and visual acuity and refractive status, before surgery and after first and second eye cataract surgery.

DESIGN, SETTING

Prospective observational study in eight tertiary referral ophthalmology clinics in public hospitals in Sydney, Melbourne, and Perth.

PARTICIPANTS

People aged 65 years or more referred for bilateral age-related cataract surgery during 2013-16, followed for maximum of 24 months after study entry or until six months after second eye surgery, whichever was shorter.

MAIN OUTCOME MEASURES

Primary outcome: age- and sex-adjusted incidence of falls.

SECONDARY OUTCOMES

visual acuity and refractive error.

RESULTS

The mean age of the 409 included participants was 75.4 years (SD, 5.4 years); 220 were women (54%). Age- and sex-adjusted fall incidence prior to surgery was 1.17 (95% CI, 0.95-1.43) per year, 0.81 (95% CI, 0.63-1.04) per year after first eye surgery, and 0.41 (95% CI, 0.29-0.57) per year after second eye surgery. For the 118 participants who underwent second eye surgery and participated in all follow-up visits, age- and sex-adjusted incidence before (0.80 [95% CI, 0.55-1.15] falls per year) and after first eye surgery (0.81 [95% CI, 0.57-1.15] falls per year) was similar, but was lower after second eye surgery (0.32 [95% CI 0.21-0.50] falls per year). Mean habitual binocular visual acuity (logMAR) was 0.32 (SD, 0.21) before surgery, 0.15 (SD, 0.17) after first eye surgery, and 0.07 (SD, 0.15) after second eye surgery.

CONCLUSIONS

First eye surgery substantially improves vision in older people with cataract, but second eye surgery is required to minimise fall incidence. Timely cataract surgery for both eyes not only optimises vision in older people with cataract, but also reduces their risk of injury from falls.

Association between age-related sensory impairment with sarcopenia and its related components in older adults: a systematic review

Sensory impairments and sarcopenia are both highly prevalent age-related conditions, with the former having been postulated to contribute to the pathogenesis of the latter condition. Confirming this hypothesis may therefore help to better inform strategies for early treatment and intervention of sarcopenia. We performed a systematic review of the current literature examining the relationships between four major sensory impairments [vision (VI), hearing (HI), smell (SI), and taste (TI)] with (i) sarcopenia; and (ii) its associated components (low handgrip strength, slow gait speed, and low muscle mass). PubMed, EMBASE, CINAHL, and Cochrane Library databases were searched for observational studies investigating the relationship of VI, HI, SI, and TI with sarcopenia, low handgrip strength, slow gait speed, and low muscle mass, in adults aged 50 years or older, from inception until 24 May 2021. The risk of bias of the included studies was assessed using the Newcastle-Ottawa Scale. This study was registered with PROSPERO, reference CRD42021247967. Ten cross-sectional and three longitudinal population-based studies of community-dwelling adults (N = 68 235) were included, with five studies investigating more than one sensory impairment. In total, 8, 6, 3, and 1 studies investigated the relationship between VI, HI, SI, and TI and sarcopenia and its related components, respectively. Follow-up duration for the longitudinal studies ranged from 4 to 11 years. All studies had a low or moderate risk of bias. We found that the presence of VI and SI, but not TI, independently increased the odds of sarcopenia. In addition, VI and SI were each independently associated with low muscle mass; and VI, HI, and SI were each independently associated with slow gait speed. However, we found inconclusive evidence for the associations between VI, HI and SI, and low handgrip strength. Our systematic review suggests a potential association between the presence of single or multiple sensory impairments and a greater likelihood of sarcopenia and/or deficits in its associated components, especially for VI, HI, and SI. Prospective studies are needed to untangle the relationship between sensory impairment and sarcopenia to better inform clinical guidelines for disease prevention and management.

Level of appropriate primary diabetic eyecare delivered and achievable in optometry practices in Australia

CLINICAL RELEVANCE

Current levels of appropriateness for primary diabetic eyecare delivered by Australian optometrists are presented along with realistic targets (benchmarks) for quality improvement. The demonstrated methods can be used in practice evaluation and benchmarking of other clinical practice areas and settings.

BACKGROUND

To examine the appropriateness of diabetic eye-care delivery and establish achievable benchmarks of care (ABCs) for optometry practices in Australia.

METHOD

In a retrospective audit, clinical records of patients with type-II diabetes obtained from a randomly selected nationally representative sample of optometry practices were assessed against evidence-based clinical indicators. Appropriate care is defined as care delivered in compliance with the indicators. The ABC for each indicator was calculated as the average performance for the top 10% of optometry practices after Bayesian adjustment to account for a low number of eligible records.

RESULTS

The audit of 420 randomly selected patient records from 42 practices against 12 clinical indicators showed an overall appropriateness of 69% (95% confidence interval (CI) 66%, 73%) for overall diabetic eye care. While a high level of appropriateness was identified for recall period (93%, 95% CI 85%, 100%) and referral (100%, 95% CI 38%, 100%), larger gaps existed in history taking (46%, 95% CI 44%, 52%), dilated fundus examination (80%, 95% CI 76%, 84%) and iris examination (0%, 95% CI 0%, 56%). The ABCs for 8 of 12 indicators were 100%, and the remaining three indicators had ABCs above 80%. An ABC for the iris examination indicator could not be calculated owing to the low number of eligible patient record cards.

CONCLUSIONS

This study demonstrated a systematic process of practice evaluation and benchmarking in optometry practices. The diabetic eye care delivered by Australian optometrists was largely appropriate; however, improvement opportunities exist for history taking and physical examination. The ABCs demonstrate that excellence in primary diabetic eye care is attainable and will serve as an important tool in future initiatives to reduce the identified evidence-to-practice gaps.

The appropriateness of and barriers to glaucoma care delivery by Australian optometrists

CLINICAL RELEVANCE

Establishing the level of appropriateness and barriers to glaucoma care delivery by Australian optometrists are important first steps in developing tailored interventions aimed at improving glaucoma care delivery.

BACKGROUND

To determine the appropriateness of and barriers to glaucoma care by optometrists.

METHODS

A mixed method study was conducted. Phase I was a retrospective cross-sectional medical record audit that assessed glaucoma care appropriateness against 37 clinical indicators from a nationally representative sample of 42 optometry practices. In Phase II, focus groups and interviews involving 31 optometrists explored audit findings to identify barriers to appropriate glaucoma care. Barriers were analysed by deductive and inductive qualitative analysis. Saliency analysis was used to identify key domains that influence glaucoma care.

RESULTS

Appropriate glaucoma care was delivered for 63% (95% CI 61%, 64%) of the 420 patient encounters audited. Appropriate care was delivered above 80% for most (57%) indicators, while 14 (38%) indicators were delivered below 60% appropriateness. Good compliance to appropriate care was noted for key indicators of intraocular pressure measurement (90%, 95% CI 87%, 93%) and optic nerve head/retinal nerve fibre layer imaging (78%, 95% CI 74%, 82%). Important barriers identified were beliefs about expected outcomes, lack of perceived relevancy, time constraints, poor organisational culture, knowledge gaps, focusing on some aspects of glaucoma care to the detriment of others, the complexity of glaucoma care, information recall, and social norms.

CONCLUSION

Glaucoma care was appropriate in most patient encounters, with opportunity to improve some aspects of history taking and physical examinations. Barriers to glaucoma care were diverse, existing at both the practitioner and organisational levels. These findings provide direction for the development of a tailored improvement intervention.

Feasibility of Implementing Recommendations to Reduce Fall Risk in Older People: A Delphi Study

SIGNIFICANCE

This study provides guidance for the implementation of recommendations for falls prevention in optometry practice, through synthesis with the optometrists' viewpoint as a major stakeholder. Educators and clinicians can adopt the revised recommendations and associated implementation strategies in this research for successful integration into optometric practice.

PURPOSE

Recommendations for optometrists to help prevent falls in older patients were published in 2019 by Optometry Australia. This study used the Delphi technique to gain perspectives on the feasibility of implementing the recommendations in optometric practice.

METHODS

A Delphi consensus process consisted of two rounds of anonymous questionnaires administered between October 2019 and February 2020. A panel of 12 optometrists scored and commented on the importance and feasibility of 28 recommendations based on a published evidence synthesis by Optometry Australia and a pilot Delphi round. Panelists were invited if they had at least 5-year experience in optometry practice and were involved in post-cataract surgery refractive management regularly in the past 12 months.

RESULTS

Twenty-four recommendations reached consensus after the Delphi process. Recommendations that reached consensus but had low uptake in the panelists' practices were history taking about risk of falls and provision of advice to patients to seek professional home modification. Four recommendations did not reach consensus because they were perceived to be too prescriptive and less feasible to execute in real-world settings. To improve the compliance of patients to recommendations to reduce the risk of falls, panelists recommended involving patients in decision making and practice staff should be involved in falls prevention messaging.

CONCLUSIONS

The Delphi panel supported the feasibility of most of the recommendations in optometric practice and provided suggestions to improve their implementation. Further research is needed to evaluate the implementation and benefits of these recommendations, designed to make optometric practice more effective in preventing patient falls.

Multiple things going on at the same time: determinants of appropriate primary diabetic eyecare delivery

PURPOSE

A recent nationwide medical record audit of optometry practices has identified an evidence-to-practice gap in primary diabetic eyecare delivery. This study aimed to explore the determinants (barriers and enablers) to appropriate diabetic eyecare delivery in Australia.

METHODS

A qualitative study involving focus-group discussions and interviews of a purposeful sample of Australian optometrists was conducted. Participants were asked about the perceived barriers to adherence to four underperforming clinical indicators related to primary diabetic eyecare identified by the recent national optometry practice audit. The Theoretical Domain Framework was used for thematic analysis and coding salience to identify key behavioural determinants.

RESULTS

Optometrists participated in eight focus groups (n = 27) and individual interviews (n = 4). The most salient barriers were related to Environmental resources (e.g., limited chair time); Beliefs about consequences (e.g., lack of perceived importance); Knowledge (e.g., poor understanding); Professional role/identity (e.g., the perceived role of optometry in care process); Social influences (e.g., the influence of senior optometrists) and Intentions (e.g., apathy). Key enablers were Environmental resources (e.g., electronic record system and practice aids); Knowledge (e.g., keeping up with knowledge/professional development); reinforcements (e.g., fear of legal actions) and behavioural regulations (e.g., self-monitoring/audit).

CONCLUSIONS

This study shows that the evidence-to-practice gap in primary diabetic eyecare delivery in Australia can be attributed in part to several interconnected factors related to optometrists' individual capability and motivation as well as the social and practice environment within which they sit. These behavioural determinants will inform the design of an intervention to improve the appropriateness of primary diabetic eyecare delivery.

The longitudinal psychological, physical activity, and financial impact of a COVID-19 lockdown on older adults in Singapore: The PIONEER-COVID population-based study

BACKGROUND

Several countries have implemented 'lockdown' measures to curb the spread of the coronavirus disease 2019 (COVID-19).

AIMS

To examine the psychological, physical activity (PA), and financial impact of a 2-month COVID-19 lockdown on older adults aged ≥60 years in Singapore, and to identify factors associated with adverse lockdown-related outcomes.

METHOD

We interviewed 496 community-dwelling adults (mean age [standard deviation]: 73.8 [7.6] years; 54.8% female) during the lockdown who had previously participated in a population-based epidemiological study. Validated questionnaires were utilised to assess loneliness and depressive symptoms at both timepoints, while inhouse questionnaires were used to assess PA and financial difficulty during lockdown. Multivariable regression models determined the lockdown-related change in loneliness and depression scores, and the factors associated with adverse outcomes.

RESULTS

Loneliness increased significantly during the lockdown period (p < 0.001) while depressive symptoms decreased (p = 0.022). Decreased PA, greater financial problems, male gender, Indian ethnicity, living alone, having a greater body mass index and perceived susceptibility to COVID-19 were all associated with worsening loneliness scores. A total of 36.9% and 19.6% participants reported decreased PA and had financial problems during the lockdown, respectively. Unemployment was associated with decreased PA, while self-employed individuals, cleaners, retail workers and smokers had greater odds of experiencing financial difficulty.

CONCLUSION

Despite a decrease in depressive symptoms, our population of older Asians reported a significant increase in loneliness and decreased PA, with one-fifth experiencing financial problems during lockdown. Our data suggest that more targeted public health efforts are needed to reduce repercussions of future lockdowns.

Identifying the content for an item bank and computerized adaptive testing system to measure the impact of age-related macular degeneration on health-related quality of life

PURPOSE

We are developing an age-related macular degeneration (AMD) health-related quality of life (HRQoL) item bank, applicable to Western and Asian populations. We report primarily on content generation and refinement, but also compare the HRQoL issues reported in our study with Western studies and current AMD-HRQoL questionnaires.

METHODS

In this cross-sectional, qualitative study of AMD patients attending the Singapore National Eye Centre (May-December 2019), items/domains were generated from: (1) AMD-specific questionnaires; (2) published articles; (3) focus groups/semi-structured interviews with AMD patients (n = 27); and (4) written feedback from retinal experts. Following thematic analysis, items were systematically refined to a minimally representative set and pre-tested using cognitive interviews with 16 AMD patients.

RESULTS

Of the 27 patients (mean ± standard deviation age 67.9 ± 7.0; 59.2% male), 18 (66.7%), two (7.4%), and seven (25.9%) had no, early-intermediate, and late/advanced AMD (better eye), respectively. Whilst some HRQoL issues, e.g. activity limitation, mobility, lighting, and concerns were similarly reported by Western patients and covered by other questionnaires, others like anxiety about intravitreal injections, work tasks, and financial dependency were novel. Overall, 462 items within seven independent HRQoL domains were identified: Activity limitation, Lighting, Mobility, Emotional, Concerns, AMD management, and Work. Following item refinement, items were reduced to 219, with 31 items undergoing amendment.

CONCLUSION

Our 7-domain, 219-item AMD-specific HRQoL instrument will undergo psychometric testing and calibration for computerized adaptive testing. The future instrument will enable users to precisely, rapidly, and comprehensively quantify the HRQoL impact of AMD and associated treatments, with item coverage relevant across several populations.

Non-Invasive Heart Rate Estimation From Ballistocardiograms Using Bidirectional LSTM Regression

Non-invasive heart rate estimation is of great importance in daily monitoring of cardiovascular diseases. In this paper, a bidirectional long short term memory (bi-LSTM) regression network is developed for non-invasive heart rate estimation from the ballistocardiograms (BCG) signals. The proposed deep regression model provides an effective solution to the existing challenges in BCG heart rate estimation, such as the mismatch between the BCG signals and ground-truth reference, multi-sensor fusion and effective time series feature learning. Allowing label uncertainty in the estimation can reduce the manual cost of data annotation while further improving the heart rate estimation performance. Compared with the state-of-the-art BCG heart rate estimation methods, the strong fitting and generalization ability of the proposed deep regression model maintains better robustness to noise (e.g., sensor noise) and perturbations (e.g., body movements) in the BCG signals and provides a more reliable solution for long term heart rate monitoring.

Systematic review of diabetic eye disease practice guidelines: more applicability, transparency and development rigor are needed

OBJECTIVES

To assess the quality of diabetic eye disease clinical practice guidelines.

STUDY DESIGN AND SETTING

A systematic search of diabetic eye disease guidelines was conducted on six online databases and guideline repositories. Four reviewers independently rated quality using the Appraisal of Guidelines, Research, and Evaluation (AGREE II) instrument. Aggregate scores (%) for six domains and overall quality assessment were calculated. A "good quality" guideline was one with ≥60% score for "rigor of development" and in at least two other domains.

RESULTS

Eighteen guidelines met the inclusion criteria, of which 13 were evidence-based guidelines (involved systematic search and grading of evidence). The median scores (interquartile range (IQR)) for "scope and purpose," "stakeholder involvement," "rigor of development," "clarity of presentation," "applicability" and "editorial independence" were 73.6% (54.2%-80.6%), 48.6% (29.2%-71.5%), 60.2% (30.9%-78.1%), 86.6% (76.7%-94.4%), 28.6% (18.0%-37.8%) and 60.2% (30.9%-78.1%), respectively. The median overall score (out of 7) of all guidelines was 5.1 (IQR: 3.7-5.8). Evidence-based guidelines scored significantly higher compared to expert-consensus guidelines. Half (n = 9) of the guidelines (all evidence-based) were of "good quality."

CONCLUSION

A wide variation in methodological quality exists among diabetic eyecare guidelines, with nine demonstrating "good quality." Future iterations of guidelines could improve by appropriately engaging stakeholders, following a rigorous development process, including support for application in clinical practice and ensuring editorial transparency.

Prevalence, Associated Factors and Health-related Quality of Life of Dual Sensory Impairment in Residential Care Facilities in Singapore

Purpose: To investigate the prevalence of dual sensory impairment (DSI), its associated factors and relationship with health-related quality of life (HR-QoL) in residential care facilities (RCF) in Singapore.Methods: This was a cross-sectional study of 123 residents aged ≥40 years from six RCFs, conducted between 2016 and 2018. DSI was defined as concomitant presenting visual acuity (better-eye) >0.3 logarithm of the minimum angle of resolution and a pure-tone air conduction threshold (better-ear) >40 dB HL in any of the four tested frequencies (500, 1000, 2000 and 4000 Hz). HR-QoL was quantified using the EuroQol five-dimension questionnaire. Multivariable Poisson regression was used to determine the associated factors of DSI. Multivariable linear regression was used to determine the association between DSI and HR-QoL adjusted for traditional confounders.Results: Of the 123 residents (age [mean±standard deviation] 75.3 ± 10.8 years; 56.9% male), 97 (78.9%[95% confidence interval(CI):71.6%, 86.1%]) had DSI, with 110 (98.2%) not on follow-up care for their sensory disabilities. In multivariable models, male gender (prevalence ratio(PR) [95%CI] = 1.3[1.1, 1.6]), older age (per 10-year increase (1.2[1.1, 1.3])), education ≤6 years (1.3[1.1, 1.7]) and the presence of cataract (1.3[1.0, 1.7]) were independently associated with DSI. DSI was independently associated with a substantial worsening in HR-QoL (β = -0.61; 95%CI: -0.76, -0.45; p < .001).Conclusions: DSI affects four in five residential care residents and is substantially associated with reductions in HR-QoL in these residents. Our finding highlights an urgent need for the implementation of routine vision and hearing screening and follow-up care for residents living in these facilities.

Facilitators and barriers to the delivery of eye care by optometrists: a systematic review using the theoretical domains framework

PURPOSE

Evidence-based practice is fundamental to providing quality care, patient satisfaction and judicious use of limited healthcare resources. However, variability in evidence-based eye care delivery has been reported. Given the important role of optometrists in delivering primary eye care, a better understanding of the barriers and facilitators to providing optometric care is required. This systematic review aimed to identify determinants (barriers and facilitators) of eye care delivery by optometrists and interventions that may improve eye care delivery.

RECENT FINDINGS

PubMed, MEDLINE, EMBASE, CINAHL, SCOPUS, PsychINFO, ProQuest and Web of Science were searched for studies reporting barriers and facilitators to eye care delivery published between 1999 and 2020. The Theoretical Domains Framework (TDF) was used to analyse data (quotations, interpretive summaries, survey result) with barriers and facilitators coded to one or more of the 14 domains, and used to identify the key behavioural domains influencing eye care delivery based on frequency of coding, elaboration and stated importance in the study. Influential domains were mapped to the Behaviour Change Wheel to identify potential interventions to improve eye care delivery. Of the 802 studies retrieved from the search, 30 were included. Frequently identified barriers were time constraints, resources and equipment issues, patient factors, lack of awareness, skill proficiency deficits and negative attitudes and beliefs. Frequently identified facilitators were adequate time, resources and equipment, education, skill proficiency and understanding the relevancy of the eye care provided. The key TDF domains influencing eye care delivery were 'environmental context and resources' (time, resources, equipment issues, patient factors), 'knowledge' (awareness issues), 'skills' (skills proficiency) and 'belief about consequences' (beliefs and relevancy). Intervention functions that may improve eye care delivery were education, training, restriction, environmental restructuring, enablement, persuasion and modelling.

SUMMARY

The barriers and facilitators identified in this review were diverse and located at both the practitioner and organisational levels. Four TDF domains were found to be influential determinants of eye care practice. Intervention functions identified in this study can be used to improve the appropriateness of primary eye care delivery.

The Bidirectional Relationship between Vision and Cognition: A Systematic Review and Meta-analysis

TOPIC

Visual impairment (VI) and cognitive impairment (CIM) are prevalent age-related conditions that impose substantial burden on the society. Findings on the hypothesized bidirectional association of VI and CIM remains equivocal. Hence, we conducted a systematic review and meta-analysis to examine this bidirectional relationship.

CLINICAL RELEVANCE

Sixty percent risk of CIM has not been well elucidated in the literature. A bidirectional relationship between VI and CIM may support the development of strategies for early detection and management of risk factors for both conditions in older people.

METHODS

PubMed, Embase, and Cochrane Central registers were searched systematically for observational studies, published from inception until April 6, 2020, in adults 40 years of age or older reporting objectively measured VI and CIM assessment using clinically validated cognitive screening tests or diagnostic evaluation. Meta-analyses on cross-sectional and longitudinal associations between VI and CIM outcomes (any CIM assessed using screening tests and clinically diagnosed dementia) were examined. Random effect models were used to generate pooled odds ratios (ORs) and 95% confidence intervals (CIs). We also examined study quality, publication bias, and heterogeneity.

RESULTS

Forty studies were included (n = 47 913 570). Meta-analyses confirmed that persons with VI were more likely to have CIM, with significantly higher odds of: (1) any CIM (cross-sectional: OR, 2.38 [95% CI, 1.84-3.07]; longitudinal: OR, 1.66 [95% CI, 1.46-1.89]) and (2) clinically diagnosed dementia (cross-sectional: OR, 2.43 [95% CI, 1.48-4.01]; longitudinal: OR, 2.09 [95% CI, 1.37-3.21]) compared with persons without VI. Significant heterogeneity was explained partially by differences in age, sex, and follow-up duration. Also, some evidence suggested that individuals with CIM, relative to cognitively intact persons, were more likely to have VI, with most articles (8/9 [89%]) reporting significantly positive associations; however, meta-analyses on this association could not be conducted because of insufficient data.

DISCUSSION

Overall, our work suggests that VI is a risk factor of CIM, although further work is needed to confirm the association of CIM as a risk factor for VI. Strategies for early detection and management of both conditions in older people may minimize individual clinical and public health consequences.

Robust Ellipse Fitting With Laplacian Kernel Based Maximum Correntropy Criterion

The performance of ellipse fitting may significantly degrade in the presence of outliers, which can be caused by occlusion of the object, mirror reflection or other objects in the process of edge detection. In this paper, we propose an ellipse fitting method that is robust against the outliers, and thus maintaining stable performance when outliers can be present. We formulate an optimization problem for ellipse fitting based on the maximum entropy criterion (MCC), having the Laplacian as the kernel function from the well-known fact that the l₁ -norm error measure is robust to outliers. The optimization problem is highly nonlinear and non-convex, and thus is very difficult to solve. To handle this difficulty, we divide it into two subproblems and solve the two subproblems in an alternate manner through iterations. The first subproblem has a closed-form solution and the second one is cast as a convex second-order cone program (SOCP) that can reach the global solution. By so doing, the alternate iterations always converge to an optimal solution, although it can be local instead of global. Furthermore, we propose a procedure to identify failed fitting of the algorithm caused by local convergence to a wrong solution, and thus, it reduces the probability of fitting failure by restarting the algorithm at a different initialization. The proposed robust ellipse fitting method is next extended to the coupled ellipses fitting problem. Both simulated and real data verify the superior performance of the proposed ellipse fitting method over the existing methods.

Life cycle assessment (LCA) of electrically-enhanced POME filtration: Environmental impacts of conductive-membrane formulation and process operating parameters

This study assessed the environmental impacts of the formulation of graphene oxide (GO)/multi-walled carbon nanotubes (MWCNTs) conductive membranes and of the process operating parameters of electrically-enhanced palm oil mill effluent (POME) filtration. Two different analyses approaches were employed, cradle-to-gate approach for conductive membrane production and gate-to-gate approach for the POME filtration process. The parameters in conductive-membrane formulation (e.g. the weight ratio of carbon nanomaterials, and concentration of GO/MWCNT nanohybrids) and process operating parameters (e.g. electric field strength and electricity operating mode) were investigated. The findings herein are twofold. Firstly, for the fabrication of GO/MWCNT conductive membranes, the best weight ratio of GO:MWCNTs was found to be 1:9, given its superior membrane electrical conductivity with lower environmental impacts by 8.51% compared to pristine MWCNTs. The most suitable concentration of carbon nanomaterials was found to be 5 wt%, given its lowest impacts on resource depletion, human health, and ecosystems. Secondly, for the electrically-enhanced POME filtration, the optimum process operating parameters were found to be the application of an electric field of 300 V/cm in the continuous mode, given its lower environmental impacts (22.99%-89.30%) secondary to its requirement of the least electricity to produce permeate. The present study has established not only the optimized conditions in membrane formulation but also the operating parameters of electrically-enhanced filtration; such findings enable the use of cleaner production and sustainable approach to minimize fouling for industrial applications, whilst maintaining excellent efficiency.

Systematic review of the appropriateness of eye care delivery in eye care practice

BACKGROUND

Health care systems are continually being reformed, however care improvement and intervention effectiveness are often assumed, not measured. This paper aimed to review findings from published studies about the appropriateness of eye care delivery, using existing published evidence and/or experts' practice and to describe the methods used to measure appropriateness of eye care.

METHODS

A systematic search was conducted using Medline, Embase and CINAHL (2006 to September 2016). Studies reporting the processes of eye care delivery against existing published evidence and/or experts' practice were selected. Data was extracted from published reports and the methodological quality using a modified critical appraisal tool. The primary outcomes were percentage of appropriateness of eye care delivery. This study was registered with PROSPERO, reference CRD42016049974.

RESULTS

Fifty-seven studies were included. Most studies assessed glaucoma and diabetic retinopathy and the overall methodological quality for most studies was moderate. The ranges of appropriateness of care delivery were 2-100% for glaucoma, 0-100% for diabetic retinopathy and 0-100% for other miscellaneous conditions. Published studies assessed a single ocular condition, a sample from a single centre or a single domain of care, but no study has attempted to measure the overall appropriateness of eye care delivery.

CONCLUSIONS

These findings indicated a wide range of appropriateness of eye care delivery, for glaucoma and diabetic eye care. Future research would benefit from a comprehensive approach where appropriateness of eye care is measured across multiple conditions with a single methodology, to guide priorities within eye care delivery and monitor quality improvement initiatives.

Standardising the cataract referral process for public hospitals: perspectives of optometrists in New South Wales, Australia

BACKGROUND

Previous research has shown that cataract surgery referral letters to major metropolitan public hospitals in New South Wales have insufficient detail to inform patient triage or apply prioritisation tools. This study aimed to canvass the views of optometrists working in New South Wales and the Australian Capital Territory (NSW/ACT) on standardising the referral process for public hospital cataract surgery.

METHODS

An online survey was sent to all NSW/ACT members of Optometry Australia in October 2017. Respondents were asked to select clinical and personal information to be included on a referral template using a list of 25 items. Data were also gathered on preferences for the cataract referral process and sources of cataract referral guidelines.

RESULTS

Two hundred and thirteen (response rate 13 per cent) optometrists completed the survey. There was close to universal support for inclusion of items like visual acuity (99 per cent), whereas other items had low support, including the date and details of previous refraction (26 per cent), history of falls (29 per cent) and health insurance status (29 per cent). Three-quarters of optometrists stated they would be willing to administer and report data from a patient survey about the functional impact of their cataract and level of visual disability. The preferred format of a standardised cataract referral template varied, although time efficiency and ease of completion were commonly cited reasons for preferences. Confirmation of receipt of referral from the public hospital, and a copy of the referral letter for the optometrist's records were also desirable. For the 61 per cent of respondents who reported accessing guidelines for cataract referral, 69 per cent stated the main source was Optometry NSW/ACT with fewer accessing guidelines directly from a public hospital or the NSW Health website.

CONCLUSION

Optometrists' preferences will be useful to inform the design and implementation of a standardised cataract referral template.

Can the appropriateness of eye care be measured through cross-sectional retrospective patient record review in eye care practices in Australia? The iCareTrack feasibility study

OBJECTIVES

The CareTrack study found that a wide range of appropriateness of care (ie, care in line with evidence-based or consensus-based guidelines) was delivered across many health conditions in Australia. This study therefore aimed to demonstrate the feasibility of using the CareTrack method (a retrospective onsite record review) to measure the appropriateness of eye care delivery.

DESIGN

Cross-sectional feasibility study.

SETTING AND PARTICIPANTS

Two hundred and thirteen patient records randomly selected from eight optometry and ophthalmology practices in Australia, selected through a combination of convenience and maximum variation sampling.

METHODS

Retrospective record review designed to assess the alignment between eye care delivered and 93 clinical indicators (Delphi method involving 11 experts) extracted from evidence-based clinical practice guidelines.

PRIMARY OUTCOME MEASURE

Number of eligible patient records, sampling rates and data collection time. This feasibility study also tested the ability of 93 clinical indicators to measure percentage appropriate eye care for preventative, glaucoma and diabetic eye care. A secondary outcome was the percentage of practitioner-patient encounters at which appropriate eye care was received.

RESULTS

A median of 20 records (range 9 to 63) per practice were reviewed. Data collection time ranged from 3 to 5.5 hours (median 3.5). The most effective sampling strategy involved random letter generation followed by sequential sampling. The appropriateness of care was 69% (95% CI 67% to 70%) for preventative eye care, 60% (95% CI 56% to 58%) for glaucoma and 63% (95% CI 57% to 69%) for diabetic eye care.

CONCLUSIONS

Appropriateness of eye care can be measured effectively using retrospective record review of eye care practices and consensus-based care indicators.

Monitoring the Relative Blood Pressure Using a Hydraulic Bed Sensor System

We propose a nonwearable hydraulic bed sensor system that is placed underneath the mattress to estimate the relative systolic blood pressure of a subject, which only differs from the actual blood pressure by a scaling and an offset factor. Two types of features are proposed to obtain the relative blood pressure, one based on the strength and the other on the morphology of the bed sensor ballistocardiogram pulses. The relative blood pressure is related to the actual by a scale and an offset factor that can be obtained through calibration. The proposed system is able to extract the relative blood pressure more accurately with a less sophisticated sensor system compared to those from the literature. We tested the system using a dataset collected from 48 subjects right after active exercises. Comparison with the ground truth obtained from the blood pressure cuff validates the promising performance of the proposed system, where the mean correlation between the estimate and the ground truth is near to 90% for the strength feature and 83% for the morphology feature.

Multiple Instance Dictionary Learning for Beat-to-Beat Heart Rate Monitoring From Ballistocardiograms

A multiple instance dictionary learning approach, dictionary learning using functions of multiple instances (DL-FUMI), is used to perform beat-to-beat heart rate estimation and to characterize heartbeat signatures from ballistocardiogram (BCG) signals collected with a hydraulic bed sensor. DL-FUMI estimates a "heartbeat concept" that represents an individual's personal ballistocardiogram heartbeat pattern. DL-FUMI formulates heartbeat detection and heartbeat characterization as a multiple instance learning problem to address the uncertainty inherent in aligning BCG signals with ground truth during training. Experimental results show that the estimated heartbeat concept obtained by DL-FUMI is an effective heartbeat prototype and achieves superior performance over comparison algorithms.

Testing non-wearable fall detection methods in the homes of older adults

In this paper, we describe two longitudinal studies in which fall detection sensor technology was tested in the homes of older adults. The first study tested Doppler radar, a two-webcam system, and a depth camera system in ten apartments for two years. This continuous data collection allowed us to investigate the real-world setting of target users and compare the advantages and limitations of each sensor modality. Based on this study, the depth camera was chosen for a current ongoing study in which depth camera systems have been installed in 94 additional older adult apartments. We include a discussion of the different sensor systems, the pros and cons of each, and results of the fall detection and false alarms in the older adult homes.

Enhancement of Chlorella vulgaris harvesting via the electro-coagulation-flotation (ECF) method

This article explores the potential of using an electro-coagulation-flotation (ECF) harvester to allow flotation of microalgae cells for surface harvesting. A response surface methodology (RSM) model was used to optimize ECF harvesting by adjusting electrode plate material, electrode plate number, charge of the electrodes, electrolyte concentration, and pH value of the culture solution. The result revealed that three aluminum electrode plates (one anode and two cathodes), brine solution (8 g/L), and acidity (pH = 4) of culture solution (optimized ECF harvester) The highest flocculant concentration was measured at 2966 mg/L after 60 min and showed a 79.8 % increase of flocculation concentration. Such results can provide a basis for designing a large-scale microalgae harvester for commercial use in the future.

Maximization of cell growth and lipid production of freshwater microalga Chlorella vulgaris by enrichment technique for biodiesel production

Chlorella vulgaris was cultivated under limitation and starvation and under controlled conditions using different concentrations of nitrate (NaNO₃) and phosphate (K₂HPO₄ and KH₂PO₄) chemicals in modified Bold basal medium (BBM). The biomass and lipid production responses to different media were examined in terms of optical density, cell density, dry biomass, and lipid productivity. In the 12-day batch culture period, the highest biomass productivity obtained was 72.083 mg L^-1 day^-1 under BBM - N_controlP_limited condition. The highest lipid content, lipid concentration, and lipid productivity obtained were 53.202 %, 287.291 mg/L, and 23.449 mg L^-1 day^-1 under BBM - N_ControlP_Deprivation condition, respectively. Nitrogen had a major effect in the biomass concentration of C. vulgaris, while no significant effect was found for phosphorus. Nitrogen and phosphorus starvation was found to be the strategy affecting the lipid accumulation and affected the lipid composition of C. vulgaris cultures.

Robust heartbeat detection from in-home ballistocardiogram signals of older adults using a bed sensor

We propose a simple and robust method to detect heartbeats using the ballistocardiogram (BCG) signal that is produced by a hydraulic bed sensor placed under the mattress. The proposed method is found beneficial especially when the BCG signal does not display consistent J-peaks, which can often be the case for overnight, in-home monitoring, especially with frail seniors. Heartbeat detection is based on the short-time energy of the BCG signal. Compared with previous methods that rely on the J-peaks observed from the BCG amplitude, we are able to achieve considerable improvement even when significant distortions are present. Test results are included for different BCG waveform patterns from older adults.

Cultivation of Chlorella vulgaris in Column Photobioreactor for Biomass Production and Lipid Accumulation

Microalgae have been used as energy resources in recent decades to mitigate the global energy crisis. As the demand for pure microalgae strains for commercial use increases, designing an effective photobioreactor (PBR) for mass cultivation is important. Chlorella vulgaris, a local freshwater microalga, was used to study the algal biomass cultivation and lipid production using various PBR configurations (bubbling, air-lift, porous air-lift). The results show that a bubbling column design is a better choice for the cultivation of Chlorella vulgaris than an air-lift one. The highest biomass concentration in the bubbling PBR was 0.78 g/L while the air-lift PBR had a value of 0.09 g/L. Key operating parameters, including draft-tube length and bubbling flowrate, were then optimized based on biomass production and lipid yield. The highest lipid content was in the porous air-lift PBR and the air-lift PBR with shorter draft tube (35 cm) was also better than a longer one (50 cm) for algal cultivation, but the microalgae attachment on the inner tube of PBR always occurred. The highest biomass concentration could be produced under the highest gas flowrate of 2.7 L/min, whereas the lowest dry cell mass was under the lowest gas flowrate of 0.2 L/min.

Scenedesmus quadricauda for Nutrient Removal and Lipid Production in Wastewater

Scenedesmus quadricauda, a local freshwater microalga, was used to treat primary settled and filtrate wastewater and to produce algal lipid. For the primary settled wastewater, the maximum biomass concentrations of acclimated and unacclimated microalgae were 0.995 g/L and 0.940 g/L, respectively. Over 90% orthophosphate and 95% ammonia nitrogen in the acclimated and unacclimated cultures, respectively, were removed after five days. The lipid contents of the microalgae were higher than 13% in all cultures. The highest growth rate occurred in the 25% filtrate culture. Over 80% phosphate was removed under the 25% and 50% filtrate cultures within six days, while over 90% ammonia nitrogen was removed within five days under both conditions. The lipid content was the highest (18.1%) under the 50% filtrate condition. C16:0, C18:2n6, and C18:3n3 were dominant fatty acids. In conclusion, S. quadricauda is a viable candidate for wastewater treatment and lipid production.

A theoretical study on the placement of microphone arrays for improving the localization accuracy of a fall

Falling is a common health problem for elderly. To address the problem, we are currently developing an acoustic fall detection system, FADE, which automatically detects a fall and reports to the caregiver. Of great importance of the fall detection system is a low false alarm rate that can be achieved by knowing where the acoustic signal comes from. The previous work showed the sound source localization can be determined by using an 8-microphone circular array, but the accuracy varies when placing the array at different positions. To further improve the localization accuracy, a second array can be added. In this paper we investigate the variations of localization accuracy of a fall signal when one or two arrays are placed at different positions in a room. The accuracy is evaluated by the Cramér-Rao Lower Bound (CRLB). The CRLB aids the determination of the best theoretical placement of one or two arrays in a room for locating the sound source.

Doppler radar fall activity detection using the wavelet transform

We propose in this paper the use of Wavelet transform (WT) to detect human falls using a ceiling mounted Doppler range control radar. The radar senses any motions from falls as well as nonfalls due to the Doppler effect. The WT is very effective in distinguishing the falls from other activities, making it a promising technique for radar fall detection in nonobtrusive inhome elder care applications. The proposed radar fall detector consists of two stages. The prescreen stage uses the coefficients of wavelet decomposition at a given scale to identify the time locations in which fall activities may have occurred. The classification stage extracts the time-frequency content from the wavelet coefficients at many scales to form a feature vector for fall versus nonfall classification. The selection of different wavelet functions is examined to achieve better performance. Experimental results using the data from the laboratory and real inhome environments validate the promising and robust performance of the proposed detector.

Assessment of heavy metals/metalloid (As, Pb, Cd, Ni, Zn, Cr, Cu, Mn) concentrations in edible fish species tissue in the Pearl River Delta (PRD), China

The major aim of this study was to investigate heavy metal content of edible fish in the PRD. Eleven species of fish (consisting of 711 individuals) [catfish (Clarias fuscus), tilapia (Oreochromis mossambicus), grass carp (Ctenopharyngodon idellus), bighead carp (Aristichthys nobilis), mandarin fish (Siniperca kneri), snakehead (Channa asiatiea), black bass (Micropterus salmoides), mangrove snapper (Lutjanus griseus), star snapper (Lutjanu stellatus), snubnose pompano (Trachinotus blochii) and orange-spotted grouper (Epinephelus coioides)] were collected for the analyses of heavy metals. Overall concentrations (mg/kg, ww) in the fish muscles were: As (0.03-1.53), Pb (0.03-8.62), Cd (0.02-0.06), Ni (0.44-9.75), Zn (15.7-29.5), Cr (0.22-0.65), Cu (0.79-2.26), Mn (0.82-6.91). Significant level of Pb were found in tilapia at all locations. It is recommended that heavy metal concentrations in different fish species must be determined on a regular basis in the future so as to reduce human health risks from acute and chronic food intoxication.

Efficient source separation algorithms for acoustic fall detection using a microsoft kinect

Falls have become a common health problem among older adults. In previous study, we proposed an acoustic fall detection system (acoustic FADE) that employed a microphone array and beamforming to provide automatic fall detection. However, the previous acoustic FADE had difficulties in detecting the fall signal in environments where interference comes from the fall direction, the number of interferences exceeds FADE's ability to handle or a fall is occluded. To address these issues, in this paper, we propose two blind source separation (BSS) methods for extracting the fall signal out of the interferences to improve the fall classification task. We first propose the single-channel BSS by using nonnegative matrix factorization (NMF) to automatically decompose the mixture into a linear combination of several basis components. Based on the distinct patterns of the bases of falls, we identify them efficiently and then construct the interference free fall signal. Next, we extend the single-channel BSS to the multichannel case through a joint NMF over all channels followed by a delay-and-sum beamformer for additional ambient noise reduction. In our experiments, we used the Microsoft Kinect to collect the acoustic data in real-home environments. The results show that in environments with high interference and background noise levels, the fall detection performance is significantly improved using the proposed BSS approaches.

Pulse rate estimation using hydraulic bed sensor

We propose in this paper an effective method to obtain the pulse rate from a hydraulic sensor that is placed under the mattress. The sensor captures the superposition of the ballistocardiogram (BCG) and the respiration signals. The BCG is modeled as the j-peak with a frequency modulation component. The proposed method utilizes the Hilbert transform to effectively capture the j-peak, which allows the pulse rate information to come out distinctively in the frequency domain. Among the five subjects tested, the error in pulse rate estimation is less than 1%.

Doppler radar sensor positioning in a fall detection system

Falling is a common health problem for more than a third of the United States population over 65. We are currently developing a Doppler radar based fall detection system that already has showed promising results. In this paper, we study the sensor positioning in the environment with respect to the subject. We investigate three sensor positions, floor, wall and ceiling of the room, in two experimental configurations. Within each system configuration, subjects performed falls towards or across the radar sensors. We collected 90 falls and 341 non falls for the first configuration and 126 falls and 817 non falls for the second one. Radar signature classification was performed using a SVM classifier. Fall detection performance was evaluated using the area under the ROC curves (AUCs) for each sensor deployment. We found that a fall is more likely to be detected if the subject is falling toward or away from the sensor and a ceiling Doppler radar is more reliable for fall detection than a wall mounted one.

Improving automatic sound-based fall detection using iVAT clustering and GA-based feature selection

Falls represent an important health problem for older adults. This issue continues to generate interest in the research and development of fall detection systems. In previous work we proposed an acoustic fall detection system (acoustic-FADE) that employs an 8-microphone circular array to automatically detect falls. Acoustic-FADE has achieved encouraging results: 100% detection at 3% false alarm rate in laboratory tests. In this paper, we use a dataset from previous work to investigate how to further improve AFADE performance. To analyze the relationship between fall and non-fall signatures we used the improved visual assessment of tendency (iVAT) clustering algorithm in conjunction with a nearest neighbor based distance to find the most challenging false alarms. Then, we employed a genetic algorithm (GA) framework to perform feature selection and find the mel-frequency cepstral coefficients (MFCC) that improve the classification performance. We found that using only three MFCC coefficients (1, 28, 29) instead of our previous choice (1,2,3,4,5,6) improves the classification performance.

A microphone array system for automatic fall detection

More than a third of elderly fall each year in the United States. It has been shown that the longer the lie on the floor, the poorer is the outcome of the medical intervention. To reduce delay of the medical intervention, we have developed an acoustic fall detection system (acoustic-FADE) that automatically detects a fall and reports it promptly to the caregiver. Acoustic-FADE consists of a circular microphone array that captures the sounds in a room. When a sound is detected, acoustic-FADE locates the source, enhances the signal, and classifies it as "fall" or "nonfall." The sound source is located using the steered response power with phase transform technique, which has been shown to be robust under noisy environments and resilient to reverberation effects. Signal enhancement is performed by the beamforming technique based on the estimated sound source location. Height information is used to increase the specificity. The mel-frequency cepstral coefficient features computed from the enhanced signal are utilized in the classification process. We have evaluated the performance of acoustic-FADE using simulated fall and nonfall sounds performed by three stunt actors trained to behave like elderly under different environmental conditions. Using a dataset consisting of 120 falls and 120 nonfalls, the acoustic-FADE achieves 100% sensitivity at a specificity of 97%.

Improving acoustic fall recognition by adaptive signal windowing

Each year more than a third of elderly fall in the United States. To address this problem we are developing an acoustic fall detection system based on a microphone array. The main task of the acoustic system is to detect all the falls that occur in an indoor environment while producing as few as possible false alarms. One of the challenges of this task is to accurately locate where the fall signal comes from so that beamforming can be applied to improve the recognition of fall signals. In this paper we describe a simple fall signal location procedure that proved effective in preliminary testing.

Acoustic fall detection using a circular microphone array

Falling is a common health problem for elderly. It is reported that more than one third of adults 65 and older fall each year in the United States. To address the problem, we are currently developing an acoustic fall detection system, FADE, which automatically detects a fall and reports it to the caregiver. In a previous version, FADE used a 3-microphone linear array to eliminate the false alarms produced by sounds produced well above the floor level. To improve the fall detection in noisy and reverberant environments, we replaced the linear array by an 8-microphone circular array that can provide a better 3-D estimation of the sound location. Preliminary experiments show that the sound location estimation performed by the circular array is reliable and robust to interference. We obtained encouraging classification results on a pilot dataset with 55 falls and 120 non-fall sounds.

Potential clinical role of 18F FDG-PET/CT in detecting hip prosthesis infection: a study in patients undergoing two-stage revision arthroplasty with an interim spacer

AIM

We evaluated the potential role of [18F]fluorodeoxyglucose-positron emission tomography/computed tomography ([18F]FDG-PET/CT) to identify latent infections at the site of an interim hip spacer after resection arthroplasty for hip prosthesis infection.

METHODS

Twelve patients with an interim hip spacer following resection arthroplasty (Group A) were investigated. Twelve patients with painful primary hip prostheses served as controls (Group B). All underwent PET/CT before surgery. Both non-attenuation-corrected (NAC) and attenuation-corrected (AC) images were analyzed. Serum C-reactive protein (CRP) levels were measured in 22 patients. Elevated CRP level was defined as >/=10 mg/L. The diagnosis of infection was based on the results of intraoperative tissue cultures, intraoperative pathology, and clinical follow-up.

RESULTS

FDG-PET/CT had 100% sensitivity and 100% negative predictive value for detection of latent infection in both groups. However, there were 4 and 3 false positive cases in Group A and Group B, respectively. Specificity improved from 50% to 62.5% in Group A, and from 62.5% to 87.5% in Group B when using NAC instead of AC. Seventeen patients had CRP values >/=10 mg/L, but only 8 were true positive for infection. FDG-PET/CT ruled out infection in 77.8% (7/9) of false-positive cases identified by CRP levels.

CONCLUSION

FDG-PET/CT is highly sensitive to detect latent infections in prosthetic hips and in interim hip spacers. The high negative predictive value of PET/CT scans is useful to rule out infections in patients with persistently elevated CRP levels. PET/CT might serve as an auxiliary tool to exclude latent infections in patients posing a clinical diagnostic dilemma.

A formal selection and pruning algorithm for feedforward artificial neural network optimization

A formal selection and pruning technique based on the concept of local relative sensitivity index is proposed for feedforward artificial neural networks. The mechanism of backpropagation training algorithm is revisited and the theoretical foundation of the improved selection and pruning technique is presented. This technique is based on parallel pruning of weights which are relatively redundant in a subgroup of a feedforward neural network. Comparative studies with a similar technique proposed in the literature show that the improved technique provides better pruning results in terms of reduction of model residues, improvement of generalization capability and reduction of network complexity. The effectiveness of the improved technique is demonstrated in developing neural network (NN) models of a number of nonlinear systems including three bit parity problem, Van der Pol equation, a chemical processes and two nonlinear discrete-time systems using the backpropagation training algorithm with adaptive learning rate.

Prognostic factors and adjuvant therapy in uterine carcinosarcoma

PURPOSE OF INVESTIGATION

The objective of this retrospective study was to investigate prognostic variables and impact of adjuvant therapy in uterine carcinosarcoma.

METHODS

The clinical information and pathological confirmation were reviewed for cases with uterine carcinosarcoma from 1984 to 2005. A total of 45 patients were eligible for analysis.

RESULTS

The median follow-up for survivors was 84 months. Five-year overall survival and progression-free survival (PFS) rates were 36.5% and 33.8%, respectively for Stage I-IV. Distant site metastasis with/without pelvic failure occurred in 83.3% of those with recurrence/progression. By multivariate analysis, older age (p = 0.001) and more than half of myometrial invasion (p = 0.002) were significant predictors of death, while only myometrial invasion (p = 0.022) was significantly associated with PFS. Stratified analyses demonstrated a monotonic trend of chemotherapy or chemoradiation to decrease death.

CONCLUSIONS

Our results suggested that age and depth of myometrial invasion were significant prognostic factors, and chemotherapy or chemoradiation seemed to be beneficial for uterine carcinosarcoma.

Spatial correlation coefficient images for ultrasonic detection

In ultrasonics, image formation and detection are generally based on signal amplitude. In this paper, we introduce correlation coefficient images as a signal-amplitude independent approach for image formation. The correlation coefficients are calculated between A-scans digitized at adjacent measurement positions. In these images, defects are revealed as regions of high or low correlation relative to the background correlations associated with noise. Correlation coefficient and C-scan images are shown to demonstrate flat-bottom-hole detection in a stainless steel annular ring and crack detection in an aluminum aircraft structure.