Predictive saccades and decision making in the beetle-predating saffron robber fly.

Internal predictions about the sensory consequences of self-motion, encoded by corollary discharge, are ubiquitous in the animal kingdom, including for fruit flies, dragonflies, and humans. In contrast, predicting the future location of an independently moving external target requires an internal model. With the use of internal models for predictive gaze control, vertebrate predatory species compensate for their sluggish visual systems and long sensorimotor latencies. This ability is crucial for the timely and accurate decisions that underpin a successful attack. Here, we directly demonstrate that the robber fly Laphria saffrana, a specialized beetle predator, also uses predictive gaze control when head tracking potential prey. Laphria uses this predictive ability to perform the difficult categorization and perceptual decision task of differentiating a beetle from other flying insects with a low spatial resolution retina. Specifically, we show that (1) this predictive behavior is part of a saccade-and-fixate strategy, (2) the relative target angular position and velocity, acquired during fixation, inform the subsequent predictive saccade, and (3) the predictive saccade provides Laphria with additional fixation time to sample the frequency of the prey's specular wing reflections. We also demonstrate that Laphria uses such wing reflections as a proxy for the wingbeat frequency of the potential prey and that consecutively flashing LEDs to produce apparent motion elicits attacks when the LED flicker frequency matches that of the beetle's wingbeat cycle.

A comparison of odor plume-tracking behavior of walking and flying insects in different turbulent environments.

Many animals locate food, mates and territories by following plumes of attractive odors. There are clear differences in the structure of this plume-tracking behavior depending on whether an animal is flying, swimming, walking or crawling. These differences could arise from different control rules used by the central nervous system during these different modes of locomotion or one set of rules interacting with the different environments while walking on the surface versus flying or swimming. Flow speeds and turbulence that characterize the environments where walking and flying insects track plumes may alter the structure of odor plumes in an environment-specific way that results in the same control rules generating behaviors that appear quite different. We tested these ideas by challenging walking male cockroaches, Periplaneta americana, and flying male moths, Manduca sexta, to track plumes of their species' sex pheromones in low wind speeds characteristic of cockroach experimental environments, higher wind speeds characteristic of moth experimental environments, and conditions ranging from low to high turbulence. Introducing a turbulence-generating structure into the flow significantly improved the flying plume tracker's ability to locate the odor source, and changed the structure of the behavior of both flying and walking plume trackers. Our results support the idea that plume trackers moving slowly along the substrate may use the spatial distribution of odor, while faster moving flying plume trackers may use the timing of odor encounters to steer to locate the source.

Evolution of visual system specialization in predatory arthropods.

Under strong selective pressure for survival, image-forming vision set off an ongoing predatory arms race 500 million years ago. Since then, and particularly so in the arthropods, predatory behavior has driven a myriad of eye adaptations that increase visual performance. In this review, we provide examples of how different arthropod predators have achieved improvements in key visual features such as spatial and temporal resolution of their retina. We then describe morphological, neural and behavioral strategies used by animals in this group to gather crucial information about the prey, such as its distance, velocity and size. We also highlight the importance of head and body tracking movements to aid in categorizing the potential prey, and briefly mention the ongoing work on the sensorimotor transformations necessary for target interception.

Infrared object classification with a hybrid optical convolution neural network.

Recent advancements in machine vision have enabled a great range of applications from image classification to autonomous driving. However, there is still a dilemma between the pursuit of higher-resolution training images that require a detector array with more pixels on the front end, and the demands on acquisition for embedded systems restrained by power, transmission bandwidth, and storage. In this paper, a multi-pixel hybrid optical convolutional neural network machine vision system was designed and validated to perform high-speed infrared object detection. The proposed system replicates the front convolution layer in a convolutional neural network utilizing a high-speed digital micro-mirror device to display the first layer of kernels at a resolution greater than the subsequent detector. After this, further convolutions are carried out in software to perform the object recognition. An infrared vehicle dataset was used to validate the performance of the hybrid system through simulation. We also tested this in hardware by performing infrared classification on toy vehicles to showcase the feasibility of such a design.

PRISM, a Patient-Reported Outcome Instrument, Accurately Measures Symptom Change in Refractory Gastroesophageal Reflux Disease.

BACKGROUND: Most patients with gastroesophageal reflux disease (GERD) experience relief following treatment with proton pump inhibitors (PPIs) (Vakil et al. in Am J Gastroenterol 101:1900-1920, 2006; Everhart and Ruhl in Gastroenterology 136:376-386, 2009). As many as 17-44% of patients, however, exhibit only partial response to therapy. Most extant GERD patient-reported outcome (PRO) instruments fail to meet development best practices as described by the FDA (Talley and Wiklund in Qual Life Res 14:21-33, 2005; Van Pinxteren et al. in Cochrane Database Syst Rev 18:CD002095, 2004; El-Serag et al. in Aliment Pharmacol Ther 32:720-737, 2010). AIM: To develop and validate a PRO instrument for clinical trials involving patients with GERD who are PPI partial responders. METHODS: We prepared a systematic literature review, held patient focus groups, convened an expert panel, and conducted cognitive interviews to establish content validity. Eligible participants took PPI therapy for at least 8 weeks, had undergone an upper endoscopy, and scored at least 8 points on the GerdQ [6]. Qualitative data guided development of 26 draft items. Items were reviewed by expert panels and debriefed with patients. The resulting 21-item instrument underwent psychometric evaluation during a Phase IIB trial. RESULTS: During the trial, confirmatory factor analysis (n = 220) resulted in a four-factor model displaying the highest goodness of fit. All domains had a high inter-item correlation (Cronbach's α > 0.8). Test-retest reliability and convergent validity were strong, with highly significant (p < 0.01) correlations between average weekly PRISM scores and severity anchors and significant (p < 0.05) correlations with anchor subscales. Cumulative distribution functions revealed significant differences between responders and non-responders. CONCLUSIONS: Analysis in a clinical trial setting demonstrated strong psychometric properties suggesting validity of PRISM. Developed in line with FDA guidance on PROs, PRISM represents an important new outcome measure for patients with GERD with a partial response to PPI therapy.

Development and validation of a disease-targeted quality of life instrument for chronic diverticular disease: the DV-QOL.

BACKGROUND: Colonic diverticular disease is typically conceived as acute diverticulitis attacks surrounded by periods of clinical silence. However, evolving data indicate that many patients have persistent symptoms and diminished health-related quality of life (HRQOL) long after acute attacks. We developed a disease-targeted HRQOL measure for symptomatic uncomplicated diverticular disease (SUDD)-the diverticulitis quality of life (DV-QOL) instrument. METHODS: We conducted a systematic literature review to craft a conceptual model of SUDD HRQOL. This was complemented by three focus groups including 45 SUDD patients. We developed items based on our literature search, focus groups, and cognitive debriefings. We administered the items to SUDD patients with persistent symptoms following a confirmed diverticulitis event. We created scales based on factor analysis and evaluated the scales for reliability and validity. RESULTS: Concept elicitation revealed a range of illness experiences attributed to SUDD. Coding of 20,490 transcribed words yielded a 52-code network with four primary, condition-related concepts: (1) physical symptoms (e.g., bloating); (2) behaviors (e.g., restrictions); (3) cognitions and concerns (e.g., fear); and (4) impact and consequences (e.g., absenteeism, anxiety). Based on patient language, we developed the 17-item DV-QOL instrument. In a cross-sectional validation sample of 197 patients, DV-QOL discriminated between patients with recent versus distant diverticulitis events and correlated highly with Short Form 36 and hospital anxiety and depression scores. CONCLUSIONS: Patients with SUDD attribute a wide range of negative psychological, social, and physical symptoms to their condition, both during and after acute attacks; DV-QOL captures these symptoms in a valid, reliable manner.

Computer-generated vs. physician-documented history of present illness (HPI): results of a blinded comparison.

OBJECTIVES: Healthcare delivery now mandates shorter visits with higher documentation requirements, undermining the patient-provider interaction. To improve clinic visit efficiency, we developed a patient-provider portal that systematically collects patient symptoms using a computer algorithm called Automated Evaluation of Gastrointestinal Symptoms (AEGIS). AEGIS also automatically "translates" the patient report into a full narrative history of present illness (HPI). We aimed to compare the quality of computer-generated vs. physician-documented HPIs. METHODS: We performed a cross-sectional study with a paired sample design among individuals visiting outpatient adult gastrointestinal (GI) clinics for evaluation of active GI symptoms. Participants first underwent usual care and then subsequently completed AEGIS. Each individual thereby had both a physician-documented and a computer-generated HPI. Forty-eight blinded physicians assessed HPI quality across six domains using 5-point scales: (i) overall impression, (ii) thoroughness, (iii) usefulness, (iv) organization, (v) succinctness, and (vi) comprehensibility. We compared HPI scores within patient using a repeated measures model. RESULTS: Seventy-five patients had both computer-generated and physician-documented HPIs. The mean overall impression score for computer-generated HPIs was higher than physician HPIs (3.68 vs. 2.80; P<0.001), even after adjusting for physician and visit type, location, mode of transcription, and demographics. Computer-generated HPIs were also judged more complete (3.70 vs. 2.73; P<0.001), more useful (3.82 vs. 3.04; P<0.001), better organized (3.66 vs. 2.80; P<0.001), more succinct (3.55 vs. 3.17; P<0.001), and more comprehensible (3.66 vs. 2.97; P<0.001). CONCLUSIONS: Computer-generated HPIs were of higher overall quality, better organized, and more succinct, comprehensible, complete, and useful compared with HPIs written by physicians during usual care in GI clinics.

Validation of an acoustic gastrointestinal surveillance biosensor for postoperative ileus.

BACKGROUND: Postoperative ileus (POI) can worsen outcomes, increase cost, and prolong hospitalization. An objective marker could help identify POI patients who should not be prematurely fed. We developed a disposable, non-invasive acoustic gastro-intestinal surveillance (AGIS) biosensor. We tested whether AGIS can distinguish healthy controls from patients recovering from abdominal surgery. STUDY DESIGN: AGIS is a disposable plastic device embedded with a microphone that adheres to the abdominal wall and connects to a computer that measures acoustic event rates. We compared intestinal rates of healthy subjects using AGIS for 60 min after a standardized meal to recordings of two postoperative groups: (1) patients tolerating standardized feeding and (2) POI patients. We compared intestinal rates among groups using ANOVA and t tests. RESULTS: There were 8 healthy controls, 7 patients tolerating feeding, and 25 with POI; mean intestinal rates were 0.14, 0.03, and 0.016 events per second, respectively (ANOVA p < 0.001). AGIS separated patients from controls with 100 % sensitivity and 97 % specificity. Among patients, rates were higher in fed versus POI subjects (p = 0.017). CONCLUSION: Non-invasive, abdominal acoustic monitoring distinguishes POI from non-POI subjects. Future research will test whether AGIS can identify patients at risk for development of POI and assist with postoperative feeding decisions.

Development and validation of a novel patient educational booklet to enhance colonoscopy preparation.

OBJECTIVES: The success of colonoscopy depends on high-quality bowel preparation by patients; yet inadequate preparation is common. We developed and tested an educational booklet to improve bowel preparation quality. METHODS: We conducted patient cognitive interviews to identify knowledge and belief barriers to colonoscopy preparation. We used these interviews to create an educational booklet to enhance preparatory behaviors. We then prospectively randomized patients scheduled for outpatient colonoscopy at a VA Medical Center to receive usual instructions vs. the booklet before colonoscopy. Patients in both groups received standard pharmacy instructions for single-dose bowel preparation; the protocol did not specify which purgatives to prescribe. The primary outcome was preparation quality based on blinded ratings using the validated Ottawa score. We performed bivariate analyses to compare mean scores between groups using a t-test, and logistic regression to measure the booklet effect on preparation quality, adjusting for potential confounders. RESULTS: A total of 436 patients were randomized between arms. In an intention-to-treat analysis of the primary outcome, mean Ottawa scores were superior in patients allocated to booklet vs. controls (P=0.03). An intention-to-treat analysis of the secondary outcome revealed a "good" preparation in 68 vs. 46% of booklet and control patients, respectively (P=0.054). In a per-protocol analysis limited to patients who actually received the booklet, preparation was good in 76 vs. 46% patients, respectively (P<0.00001). Regression analysis revealed that booklet receipt increased the odds of good preparation by 3.7 times (95% confidence interval=2.3-5.8). CONCLUSIONS: Provision of a novel educational booklet considerably improves preparation quality in patients receiving single-dose purgatives. The effect of the booklet on split-dose purgatives remains untested and will be evaluated in future research.

Dialysis practices that distinguish facilities with below- versus above-expected mortality.

BACKGROUND AND OBJECTIVES: Mortality rates vary widely among dialysis facilities even after adjustment with standardized mortality ratios (SMRs). This variation may occur because top-performing facilities use practices not shared by others, because the SMR fails to capture key patient characteristics, or both. Practices were identified that distinguish top- from bottom-performing facilities by SMR. DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS: A cross-sectional survey was performed of staff across three organizations. Staff members rated the perceived quality of their units' patient-, provider-, and facility-level practices using a six-point Likert scale. Facilities were divided into those with above- versus below-expected mortality on the basis of SMRs from U.S. Renal Data Service facility reports. Mean Likert scores were computed for each practice using t tests. Practices that were statistically significant (P ≤ 0.05) and achieved at least a medium effect size of ≥0.4 were reported. Significant predictors were entered into a linear regression model. RESULTS: Dialysis facilities with below-expected mortality reported that patients in their unit were more activated and engaged, physician communication and interpersonal relationships were stronger, dieticians were more resourceful and knowledgeable, and overall coordination and staff management were superior versus facilities with above-expected mortality. Staff ratings of these practices explained 31% of the variance in SMRs. CONCLUSIONS: Patient-, provider-, and facility-level practices partly explain SMR variation among facilities. Improving SMRs may require processes that reflect a coordinated, multidisciplinary environment (i.e., no one group, practice, or characteristic will drive facility-level SMRs). Understanding and improving SMRs will require a holistic view of the facility.

Dialysis practices that distinguish top- versus bottom-performing facilities by hemoglobin outcomes.

BACKGROUND: Because there is wide variation in outcomes across dialysis facilities, it is possible that top-performing units use practices not shared by others. The Identifying Best Practices in Dialysis (IBPiD) Study seeks to identify practices that distinguish top- from bottom-performing facilities by key outcomes, including achievement of recommended hemoglobin targets. STUDY DESIGN: Observational study with cross-sectional study ascertainment of predictors and outcomes. PREDICTORS: Facility dialysis practices ascertained using practice surveys of dialysis staff who indicated their level of agreement that each practice occurs in their facility (1-6 on a Likert scale). SETTING & PARTICIPANTS: 423 personnel in 90 dialysis facilities from 1 for-profit and 2 not-for-profit dialysis organizations. OUTCOMES: Percentage of patients per month per facility with hemoglobin levels of 11-12 g/dL. We divided facilities by median into top- versus bottom-performing groups and compared mean scores for each practice using t tests. We report practices that were statistically significant and achieved at least a medium effect size (ES) >or=0.4. RESULTS: 17 of 155 tested predictors were significant. Achievement of hemoglobin level targets was related most strongly to the use of chairside computers (ES, 0.8 [95% CI, 0.4-1.4]), extent/quality of educational videos (ES, 0.6 [95% CI, 0.2-1.1]), frequency of calling per diem staff if short staffed (ES, 0.6 [95% CI, 0.21-1.1]), policy that nurses pass written competency examinations before hire (ES, 0.6 [95% CI, 0.2-1.0]), and technician cannulation mastery (ES, 0.6 [95% CI, 0.2-1.1]). LIMITATIONS: This is a cross-sectional study that can address only associations, not causations. Future research should measure the longitudinal predictive value of these practices. CONCLUSIONS: High-performing facilities report more effective education programs, better staff management, higher staff competency, and higher use of chairside computers, a potential marker of information technology proficiency. This suggests that hemoglobin level management is enhanced by processes reflecting a coordinated multidisciplinary environment.

Is irritable bowel syndrome a diagnosis of exclusion?: a survey of primary care providers, gastroenterologists, and IBS experts.

OBJECTIVES: Guidelines emphasize that irritable bowel syndrome (IBS) is not a diagnosis of exclusion and encourage clinicians to make a positive diagnosis using the Rome criteria alone. Yet many clinicians are concerned about overlooking alternative diagnoses. We measured beliefs about whether IBS is a diagnosis of exclusion, and measured testing proclivity between IBS experts and community providers. METHODS: We developed a survey to measure decision-making in two standardized patients with Rome III-positive IBS, including IBS with diarrhea (D-IBS) and IBS with constipation (C-IBS). The survey elicited provider knowledge and beliefs about IBS, including testing proclivity and beliefs regarding IBS as a diagnosis of exclusion. We surveyed nurse practitioners, primary care physicians, community gastroenterologists, and IBS experts. RESULTS: Experts were less likely than nonexperts to endorse IBS as a diagnosis of exclusion (8 vs. 72%; P<0.0001). In the D-IBS vignette, experts were more likely to make a positive diagnosis of IBS (67 vs. 38%; P<0.001), to perform fewer tests (2.0 vs. 4.1; P<0.01), and to expend less money on testing (US$297 vs. $658; P<0.01). Providers who believed IBS is a diagnosis of exclusion ordered 1.6 more tests and consumed $364 more than others (P<0.0001). Experts only rated celiac sprue screening and complete blood count as appropriate in D-IBS; nonexperts rated most tests as appropriate. Parallel results were found in the C-IBS vignette. CONCLUSIONS: Most community providers believe IBS is a diagnosis of exclusion; this belief is associated with increased resource use. Experts comply more closely with guidelines to diagnose IBS with minimal testing. This disconnect suggests that better implementation of guidelines is warranted to minimize variation and improve cost-effectiveness of care.

Developing valid and reliable health utilities in irritable bowel syndrome: results from the IBS PROOF Cohort.

OBJECTIVES: A "utility" is a measure of health-related quality of life (HRQOL) that ranges between 0 (death) and 1 (perfect health). Disease-targeted utilities are mandatory to conduct cost-utility analyses. Given the economic and healthcare burden of irritable bowel syndrome (IBS), cost-utility analyses will play an important role in guiding health economic decision-making. To inform future cost-utility analyses in IBS, we measured and validated the IBS utilities. METHODS: We analyzed data from Rome III IBS patients in the Patient Reported Observed Outcomes and Function (PROOF) Cohort-a longitudinal multi-center IBS registry. At entry, the patients completed a multi-attribute utility instrument (EuroQOL), bowel symptom items, IBS severity measurements (IBS Severity Scale (IBSSS), Functional Bowel Disease Severity Index (FBDSI)), HRQOL indexes (IBS quality-of-life instrument (IBS-QOL), Center for disease control-4 (CDC-4)), and the Worker Productivity Activity Index for IBS (WPAI). We repeated assessments at 3 months. RESULTS: There were 257 patients (79% women; age=43+/-15 years) at baseline and 85 at 3 months. The mean utilities in patients with severe vs. non-severe IBS were 0.70 and 0.80, respectively (P<0.001). There were no differences in utilities among IBS with constipation (IBS-C), IBS with diarrhea (IBS-D), and mixed IBS (IBS-M) subgroups. EuroQOL utilities correlated with FBDSI (r=0.31; P<0.01), IBSSS (r=0.36; P<0.01), IBS-QOL (r=0.36; P<0.01), CDC-4 (r=0.44; P<0.01), WPAI presenteeism (r=0.16; P<0.01), abdominal pain (r=0.43; P<0.01), and distension (r=0.18; P=0.01). The utilities in patients reporting "considerable relief" of symptoms at 3 months vs. those without considerable relief were 0.78 and 0.73, respectively (P=0.02). CONCLUSIONS: EuroQOL utilities are valid and reliable in IBS. The utility of severe IBS (0.7) is similar to Class III congestive heart failure and rheumatoid arthritis. These validated utilities can be employed in future IBS cost-utility analyses.

Is there "cherry picking" in the ESRD Program? Perceptions from a Dialysis Provider Survey.

BACKGROUND AND OBJECTIVES: Changes in ESRD reimbursement policy, including proposed bundled payment, have raised concern that dialysis facilities may use "cherry picking" practices to attract a healthier, better insured, or more adherent patient population. DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS: As part of a national survey to measure beliefs about drivers of quality in dialysis, respondents were asked about their perceptions of cherry picking, including the frequency and effect of various cherry picking strategies on dialysis outcomes. We surveyed a random sample of 250 nurse members of the American Nephrology Nurses Association, 250 nephrologist members of the American Medical Association, 50 key opinion leaders, and 2000 physician members of the Renal Physicians Association. We tested hypothesized predictors of perception, including provider group, region, age, experience, and the main practice facility features. RESULTS: Three-quarters of respondents reported that cherry picking occurred "sometimes" or "frequently." There were no differences in perceptions by provider or facility characteristics, insurance status, or health status. In multivariable regression, perceived cherry picking was 2.8- and 3.5-fold higher in the northeast and Midwest, respectively, versus the west. Among various cherry picking strategies, having a "low threshold to 'fire' chronic no-shows/late arrivers," and having a "low threshold to 'fire' for noncompliance with diet and meds" had the largest perceived association with outcomes. CONCLUSIONS: Under current reimbursement practices, dialysis caregivers perceive that cherry picking is common and important. An improved understanding of cherry picking practices, if evident, may help to protect vulnerable patients if reimbursement practices were to change.

Identifying best practices in dialysis care: results of cognitive interviews and a national survey of dialysis providers.

BACKGROUND AND OBJECTIVES: Because there is wide variation in case-mix adjusted outcomes across dialysis facilities, it is possible that top-performing facilities use practices not shared by others. We sought to catalogue "best practices" that may account for interfacility variations in outcomes. DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS: This multidisciplinary study identified candidate best practices in dialysis through a staged process, including systematic review, cognitive interviews, and a national "virtual focus group" of dialysis providers. The resulting candidate practices were rank-ordered by perceived importance as determined by mean RAND Appropriateness Scores from a national survey of nephrologists, nurses, and opinion leaders. RESULTS: A total of 155 candidate best practices were identified. Among these, respondents believed dialysis outcomes are most strongly related to 1) characteristics of multidisciplinary care conferences, 2) technician proficiency in protecting vascular access, 3) training of nurses to provide education in fluid management, vascular access, and nutrition, 4) use of random and blinded audits of staff performance, and 5) communication and teamwork among staff. In contrast, there was wide disagreement about the importance of facility-based health maintenance practices, optimal staffing ratios, frequency of dialysis-based physician visits, and optimal frequency of multidisciplinary care. CONCLUSIONS: This study provides a "conceptual map" of candidate dialysis best practices and highlights areas of general agreement and disagreement. These findings can help the dialysis community think critically about what may define "best practice" and provide targets for future research in quality improvement.

Development and validation of a disease-targeted quality of life instrument in chronic hepatitis B: the hepatitis B quality of life instrument, version 1.0.

UNLABELLED: Despite the increasing realization that health-related quality of life (HRQOL) is an important outcome in chronic HBV infection, there are no validated, disease-targeted instruments currently available. We sought to develop and validate the first disease-targeted HRQOL instrument in noncirrhotic HBV: the Hepatitis B Quality of Life instrument, version 1.0 (HBQOL v1.0). We established content validity for the HBQOL v1.0 by conducting a systematic literature review, an expert focus group, and cognitive interviews with HBV patients. We administered the resultant questionnaire to 138 HBV patients. We used factor analysis to test hypotheses regarding HRQOL domains and measured construct validity by comparing HBQOL v1.0 scores across several anchors, including viral response to treatment, SF-36 scores, and global health. Finally, we measured test-retest and internal consistency reliability. Content validation revealed that HBV affects multiple aspects of psychological, social, and physical health. The resultant questionnaire summarized this HRQOL impact with 31 items across six subscales: psychological well-being, anticipation anxiety, vitality, disease stigma, vulnerability, and transmissibility. Internal consistency and test-retest reliability were excellent. The HBQOL v1.0 discriminated between viral responders versus nonresponders and correlated highly with SF-36 scores and global health. CONCLUSION: Patients with chronic HBV infection attribute a wide range of negative psychological, social, and physical symptoms to their condition, even in the absence of cirrhosis or cancer. The HBQOL v1.0 is a valid and reliable measure that captures this HRQOL decrement. This instrument may be useful in everyday clinical practice and in future clinical trials.