Webcam-based eye tracking to detect mind wandering and comprehension errors

Recent advances in computer vision have opened the door for scalable eye tracking using only a webcam. Such solutions are particularly useful for online educational technologies, in which a goal is to respond adaptively to students' ongoing experiences. We used WebGazer, a webcam-based eye-tracker, to automatically detect covert cognitive states during an online reading-comprehension task related to task-unrelated thought and comprehension. We present data from two studies using different populations: (1) a relatively homogenous sample of university students (N = 105), and (2) a more diverse sample from Prolific (N = 173, with < 20% White participants). Across both studies, the webcam-based eye-tracker provided sufficiently accurate and precise gaze measurements to predict both task-unrelated thought and reading comprehension from a single calibration. We also present initial evidence of predictive validity, including a positive correlation between predicted rates of task-unrelated thought and comprehension scores. Finally, we present slicing analyses to determine how performance changed under certain conditions (lighting, glasses, etc.) and generalizability of the results across the two datasets (e.g., training on the data Study 1 and testing on data from Study 2, and vice versa). We conclude by discussing results in the context of remote research and learning technologies.

Supporting student success on the practical nurse (PN) licensure exam: The Health Education Systems Incorporated (HESI) PN Exit Exam Study

BACKGROUND

Practical Nurses or Vocational Nurses (PNs/VNs) complete a 12-month certificate program and must successfully complete the National Council Licensure Exam for Practical Nurses (NCLEX-PN) prior to practice. While the scope of their practice is more circumscribed than the Registered Nurse (RN), they contribute significantly to healthcare throughout the U.S.A. Current research to support their learning and success is needed. Elsevier's Health Education Systems Incorporated (HESI) PN Exit Exam (E2) has been used to determine students' NCLEX-PN readiness for over 20 years. Given regular updates to the NCLEX test plan, ongoing research is needed to assess the E2's continued predictive validity and examine E2 program policies to enhance PN/VN student success.

OBJECTIVES

To examine the predictive validity of the E2 on NCLEX-PN first-time pass rates (NCLEX-PN FTPR) and determine which E2-related program policies are related to higher E2 scores and NCLEX-PN FTPR.

METHOD

Sixteen PN/VN program directors participated in the study, providing E2 program policy information and NCLEX-FTPR outcomes for 1371 students who took the E2 between 2018 and 2021.

RESULTS

Students passed the NCLEX-PN 96-98 % of the time when they scored 900 or higher on the E2 and passed 94 %-96 % of the time when they scored 850 or higher. Out of 16 programs, most required E2 test preparation (n = 13, 81.25 %) and allowed students more than one E2 attempt (n = 11; 68.75 %). Requiring minimum E2 scores and specific E2 test preparation were associated with higher NCLEX-PN pass rates, in each case mediated by higher E2 scores. Requiring remediation for students with low initial E2 scores led to higher E2 scores but not higher NCLEX-PN pass rates.

CONCLUSIONS

This study provides evidence for program policies and educational resources to support students' NCLEX-PN success. Setting an expected performance benchmark and requiring PN students to engage in E2 preparation prior to their first attempt are recommended strategies emerging from this study.

The impacts of learning analytics and A/B testing research: a case study in differential scientometrics

BACKGROUND

In recent years, research on online learning platforms has exploded in quantity. More and more researchers are using these platforms to conduct A/B tests on the impact of different designs, and multiple scientific communities have emerged around studying the big data becoming available from these platforms. However, it is not yet fully understood how each type of research influences future scientific discourse within the broader field. To address this gap, this paper presents the first scientometric study on how researchers build on the contributions of these two types of online learning platform research (particularly in STEM education). We selected a pair of papers (one using A/B testing, the other conducting learning analytics (LA), on platform data of an online STEM education platform), published in the same year, by the same research group, at the same conference. We then analyzed each of the papers that cited these two papers, coding from the paper text (with inter-rater reliability checks) the reason for each citation made.

RESULTS

After statistically comparing the frequency of each category of citation between papers, we found that the A/B test paper was self-cited more and that citing papers built on its work directly more frequently, whereas the LA paper was more often cited without discussion.

CONCLUSIONS

Hence, the A/B test paper appeared to have had a larger impact on future work than the learning analytics (LA) paper, even though the LA paper had a higher count of total citations with a lower degree of self-citation. This paper also established a novel method for understanding how different types of research make different contributions in learning analytics, and the broader online learning research space of STEM education.

Note-taking and science inquiry in an open-ended learning environment

•

Usage of digital notepad is related to performance in science inquiry tasks in OELE.

•

Both taking and reaccessing notes facilitate science inquiry performance.

•

Elaborative and reproductive notes’ relationship with success is content dependent.

Note-taking is important for academic success and has been thoroughly studied in traditional classroom contexts. Recent advancements of technology have led to more students taking notes on computers, and in different situations than are common in traditional instructional contexts. However, research on computer-based note-taking is still an emerging area, and findings from these studies are mixed. In this exploratory study, we conducted multilevel analysis to comprehensively investigate the relationship between note-taking measures and subsequent student success at science inquiry among middle school students, using two scenarios of an open-ended learning environment named Virtual Performance Assessments. Analysis revealed an advantage for content elaborative note-taking over content reproductive note-taking conditional on the source of notes taken, but other measures were less consistent between the two scenarios. Implications of the findings and limitations of this research are also discussed.

Designing and testing an educational innovation

Technology provides an opportunity to develop innovations to improve the way we teach. Developing educational innovations must be approached in a methodical and thorough manner to identify the educational gap and validate the innovation's success in filling the gap. A successful educational innovation requires a stepwise approach that includes needs assessment, design of intervention, testing and analysis, evaluation of intervention, and determination of learning retention.

Using Video to Automatically Detect Learner Affect in Computer-Enabled Classrooms

Affect detection is a key component in intelligent educational interfaces that respond to students’ affective states. We use computer vision and machine-learning techniques to detect students’ affect from facial expressions (primary channel) and gross body movements (secondary channel) during interactions with an educational physics game. We collected data in the real-world environment of a school computer lab with up to 30 students simultaneously playing the game while moving around, gesturing, and talking to each other. The results were cross-validated at the student level to ensure generalization to new students. Classification accuracies, quantified as area under the receiver operating characteristic curve (AUC), were above chance (AUC of 0.5) for all the affective states observed, namely, boredom (AUC = .610), confusion (AUC = .649), delight (AUC = .867), engagement (AUC = .679), frustration (AUC = .631), and for off-task behavior (AUC = .816). Furthermore, the detectors showed temporal generalizability in that there was less than a 2% decrease in accuracy when tested on data collected from different times of the day and from different days. There was also some evidence of generalizability across ethnicity (as perceived by human coders) and gender, although with a higher degree of variability attributable to differences in affect base rates across subpopulations. In summary, our results demonstrate the feasibility of generalizable video-based detectors of naturalistic affect in a real-world setting, suggesting that the time is ripe for affect-sensitive interventions in educational games and other intelligent interfaces.

Use of "Near Middle East Antivenom" to treat African bush viper envenomation

Venom from an African bush viper is primarily hemotoxic and potentially life threatening. Existing, commercialy available antivenoms may not neutralize venom of this genus. A 25-y-old male was brought to the emergency room diaphoretic and hypotensive (70/40 mmHg) after a bite from a pet African bush viper. A puncture wound on the left thumb was leaking slightly, but there was no evidence of blood loss, edema or bruising. Approximately 100 min after exposure, the patient experienced a small amount of proximal swelling. Six h after envenomation, he was admitted to the intensive care unit for monitoring. At 10 h after the bite prothrombin time (PT > 100 sec) and international ratio (INR = 9.2) were elevated. The patient was unable to coagulate. He received fresh frozen plasma, cryoprecipitate, and Near Middle East Antivenom. Improvement in clinical status and laboratory parameters were observed after each of 3 doses of antivenom (d-dimer > 1000 and fibrinogen = 137 mg/dL). The patient was monitored overnight, did not require additional antivenom and was discharged as laboratory parameters, vital signs and spread of the necrotic lesion stabilized. Near Middle East Antivenom appears effective in treatment of the hematologic sequelae secondary to African bush viper envenomation.

Mammography screening and breast self-examination among minority women in public housing projects: the impact of physician recommendation

This exploratory study examined the impact of physician recommendations and other factors on mammography screening and breast-self examination (BSE) among African American and Hispanic women in public housing communities. We surveyed a randomly selected sample of low-income households from three low-income communities (n = 291), which included both African Americans and Hispanic women. Data for this paper are reported only on women who were 40 years and older head of the households (n = 120 women, including 74 Hispanics and 46 African Americans), since they meet the age criterion for mammography screening. Our analyses indicated that only 46% of women obtained mammography in the previous 12 months, with no significant differences between the Hispanic and African American women in mammography rates. Physicians' recommendations were among the most significant and substantial predictors of obtaining a mammogram or performing BSE. Further, odds were also higher for those who had insurance coverage. In addition, our data also indicated that almost one out of four women, aged 40 and older participants in this study, claimed that their health care providers never told them they needed a mammogram or never told them that they should perform BSE, with no significant differences between Hispanic and African Americans. Our analyses points to an urgent need for intervention to inform and motivate the service providers in underserved communities to motivate breast cancer screening (BCS) among minority women. Additionally, our examination points to the need for urgent interventions targeting minority women, particularly women with no medical insurance for breast cancer screening.

Multigroup discrete ordinates modeling of 125I 6702 seed dose distributions using a broad energy-group cross section representation

Our purpose in this work is to demonstrate that the efficiency of dose-rate computations in 125I brachytherapy, using multigroup discrete ordinates radiation transport simulations, can be significantly enhanced using broad energy group cross sections without a loss of accuracy. To this end, the DANTSYS multigroup discrete ordinates neutral particle transport code was used to estimate the absorbed dose-rate distributions around an 125I-model 6702 seed in two-dimensional (2-D) cylindrical R-Z geometry for four different problems spanning the geometries found in clinical practice. First, simulations with a high resolution 210 energy groups library were used to analyze the photon flux spectral distribution throughout this set of problems. These distributions were used to design an energy group structure consisting of three broad groups along with suitable weighting functions from which the three-group cross sections were derived. The accuracy of 2-D DANTSYS dose-rate calculations was benchmarked against parallel Monte Carlo simulations. Ray effects were remedied by using the DANTSYS internal first collision source algorithm. It is demonstrated that the 125I primary photon spectrum leads to inappropriate weighting functions. An accuracy of +/-5% is achieved in the four problem geometries considered using geometry-independent three-group libraries derived from either material-specific weighting functions or a single material-independent weighting function. Agreement between Monte Carlo and the three-group DANTSYS calculations, within three standard Monte Carlo deviations, is observed everywhere except for a limited region along the Z axis of rotational symmetry, where ray effects are difficult to mitigate. The three-group DANTSYS calculations are 10-13 times faster than ones with a 210-group cross section library for 125I dosimetry problems. Compared to 2-D EGS4 Monte Carlo calculations, the 3-group DANTSYS simulations are a 100-fold more efficient. Provided that these efficiency gains can be sustained in three-dimensional geometries, the results suggest that discrete ordinates simulations may have the potential to serve as an efficient and accurate dose-calculation algorithm for low-energy brachytherapy treatment planning.

Leptin in the ovine fetus correlates with fetal and placental size

OBJECTIVE

The purpose of this study was to detect the presence of leptin and its receptor in ovine fetal tissues and to examine the relationship between circulating leptin concentrations and fetal and placental weights on gestational day 138 (GD138) of ovine pregnancy (term, 145 days).

STUDY DESIGN

Pregnant sheep (n = 18) were instrumented on GD 110 to facilitate measurement and chronic reduction of uterine blood flow and produce intrauterine growth restriction. Four animals that served as controls were euthanized on GD 138 to obtain fetal tissues to determine the presence of ovine leptin and its receptor by reverse transcriptase-polymerase chain reaction. Seven instrumented animals were randomized into the control group, and 7 instrumented animals were randomized into the uterine blood flow restricted group (reduction equaled approximately 50% on GD 138). Maternal and fetal blood samples were obtained on day 138 to measure plasma leptin concentrations, and animals were euthanized for the determination of fetal morphometrics and placental weight.

RESULTS

Expression of RNA for ovine leptin and its receptor were observed in fetal liver, skeletal muscle, kidney, heart, and placenta. Fetal body weight, ponderal index, and placental weight were significantly decreased by approximately 40% in the blood flow restricted group as compared with controls. Fetal leptin concentrations were increased by 45% in the uteroplacental blood flow restricted group (P =.01). Maternal leptin concentrations were not significantly different between the 2 groups and did not correlate with fetal concentrations. Fetal leptin concentrations had an inverse relationship with uterine blood flow (r = -0.73; P =.004), fetal body weight (r = -0.78; P =.002), and placental weight (r = -0.68; P =.01).

CONCLUSION

Ovine fetal tissues express RNA for leptin and its receptor. Circulating leptin concentrations in the ovine intrauterine growth restriction fetus were significantly elevated on gestational day 138 compared with controls. Fetal leptin concentrations were inversely related to uterine blood flow and fetal and placental weight. These findings suggest that fetal leptin may be involved in an adaptive response to intrauterine growth restriction.

Sensory impairments and subjective well-being among aged African American persons

The limited number of studies concerning the prevalence of hearing loss and vision impairment and their causes, and the lack of strategies to prevent or treat the deleterious effects of hearing loss and vision impairment, point to a significant gap in the knowledge base concerning aged minority populations. This cross-sectional study evaluated the relationship between vision and hearing impairment and psychological well-being among a sample of 988 elderly African American persons. Fair or poor vision or hearing was reported for 36.5% and 26% of our sample, respectively. Reported prevalence rates for these impairments are considerably higher than rates previously documented in comparable studies of elderly people conducted in general (i.e., predominantly White) populations. Eighty-four percent of our study participants attempted to improve their vision through the use of eyeglasses. By contrast, only 4.3% of individuals in the study who described their hearing as poor reported using hearing aids. Using multivariate analysis and other related variables that have previously been identified as common predictors of psychological well-being, the findings of this study suggest that poor vision is independently associated with a lower level of psychological well-being among aged African Americans even after adjusting for sociodemographic characteristics, functional limitations, perceived health status, and cognition. Poor hearing was also found to be associated with a lower level of psychological well-being; however, this relationship was not independent but was mediated by the effect of hearing on functional status. These data indicate considerable potential for improved psychological well-being for African American elderly people through visual and audiological rehabilitation.

Teleophthalmology: rationale, current issues, future directions

Relatively little information exists concerning the delivery of ophthalmic services via telemedicine, yet ophthalmology is particularly amenable to the utilization of such applications. This paper discusses the technological issues pertinent to the research, development, and assessment of teleophthalmology delivery systems and begins to define the parameters that will determine the sustainability of teleophthalmology. A prototype urban teleophthalmology delivery system is presented in the context of improving access to eye care for an underserved inner-city population. Potential enhancements to the prototype telephthalmology system are discussed.

Hemodynamic response to tibolone in reproductive and nonreproductive tissues in the sheep

OBJECTIVE

We sought to determine the hemodynamic effects of tibolone in reproductive and nonreproductive tissues in the nonpregnant ovariectomized sheep.

STUDY DESIGN

Six ewes were chronically instrumented for measurement of mean arterial pressure, heart rate, cardiac output, and coronary and uterine blood flow. A dose response curve was generated for intravenous tibolone (1.25, 2.5, and 5 mg) and compared with intravenous 17beta-estradiol (1 microg/kg body weight). To determine whether tibolone-related cardiovascular responses were estrogen receptor mediated and produced by nitric oxide, animals were treated on separate days with either estrogen receptor antagonist ICI 182,780 or the nitric oxide synthase inhibitor, L -nitroarginine methyl ester.

RESULTS

Tibolone significantly increased coronary blood flow in a dose-related fashion by 5% +/- 3%, 9% +/- 2%, and 11% +/- 2% for the 1.25, 2.5, and 5 mg doses, respectively. Uterine blood flow was also increased significantly in a dose-dependent manner by 98 +/- 15, 216 +/- 59, and 303 +/- 56 mL/min, for the 1.25, 2.5, and 5 mg doses, respectively. L -Nitroarginine methyl ester attenuated tibolone-induced increases in uterine blood flow by 84% +/- 4% and abolished the increase in coronary blood flow. ICI 182,780 inhibited all tibolone-induced cardiovascular responses.

CONCLUSION

Tibolone significantly increases coronary and uterine blood flow in ovariectomized ewes. The coronary and uterine vascular responses are mediated via an estrogen receptor-dependent mechanism and are produced mainly by nitric oxide.

Dosimetric modeling of the microselectron high-dose rate 192Ir source by the multigroup discrete ordinates method

The DANTSYS multigroup discrete ordinates computer code is applied to quantitatively estimate the absorbed dose rate distributions in the vicinity of a microSelectron 192Ir high-dose-rate (HDR) source in two-dimensional cylindrical R-Z geometry. The source is modeled in a cylindrical water phantom of diameter 20 cm and height 20 cm. The results are also used for evaluation of the Task Group 43 (TG-43) dosimetric quantities. The DANTSYS accuracy is estimated by direct comparisons with corresponding Monte Carlo results. Our 210-group photon cross section library developed previously, together with angular quadratures consisting of 36 (S16) to 210 (S40) directions and associated weights per octant, are used in the DANTSYS simulations. Strong ray effects are observed but are significantly mitigated through the use of DANTSYS's stochastic ray-tracing first collision source algorithm. The DANTSYS simulations closely approximate Monte Carlo estimates of both direct dose calculations and TG-43 dosimetric quantities. The discrepancies with S20 angular quadrature (55 directions and weights per octant) or higher are shown to be less than +/- 5% (about 2.5 standard deviations of Monte Carlo calculations) everywhere except for limited regions along the Z axis of rotational symmetry, where technical limitations in the DANTSYS first collision source implementation makes adequate suppression of ray effects difficult to achieve. The efficiency of DANTSYS simulations is compared with that of the EGS4 Monte Carlo code. It is demonstrated that even with the 210-group cross section library, DANTSYS achieves two-fold efficiency gains using the the S20 quadrature set. The potential of discrete ordinates method for further efficiency improvements is also discussed.

Premarin-induced increases in coronary and uterine blood flow in nonpregnant sheep

OBJECTIVE

Menopause is associated with an increased incidence of cardiovascular disease among women, and estrogen replacement therapy is thought to reduce the risk of coronary artery disease. The mechanism by which this occurs is unclear, but coronary arterial endothelial and vascular smooth muscle cells have been shown to contain estrogen receptors, and their stimulation appears to increase nitric oxide synthesis. One conjugated estrogen preparation (Premarin) is widely used in postmenopausal hormone replacement therapy, but little is known about its effects on cardiovascular hemodynamics.

STUDY DESIGN

This study was designed to determine whether Premarin, like 17beta-estradiol, has significant effects on cardiac output and coronary and uterine blood flows at doses used clinically (0.625, 1.25, and 2.5 mg). Nonpregnant oophorectomized sheep were implanted with instruments to measure cardiac output, left coronary (circumflex) artery blood flow, uterine blood flow, heart rate, and systemic arterial blood pressure. After recovery from surgery, the animals received intravenous bolus injections of either 17beta-estradiol (1.0 microg/kg), Premarin (0.625, 1.25, or 2. 5 mg), or vehicle on different days.

RESULTS

The 1.0-microg/kg dose of 17beta-estradiol significantly increased coronary blood flow by 15% +/- 2% from baseline (mean +/- SEM). Premarin also increased coronary blood flow significantly at the 1.25- and 2.5-mg dose levels by 12% +/- 3% and 14% +/- 4%, respectively. As expected 17beta-estradiol increased uterine blood flow from a baseline of 15 +/- 3 mL/min to 169 +/- 19 mL/min. Premarin treatment was associated with a significant increase in uterine blood flow, which increased from an average baseline of 14 +/- 4 mL/min to 46 +/- 10 mL/min, 95 +/- 18 mL/min, and 135 +/- 20 mL/min at the three doses tested (0. 625, 1.25, and 2.5 mg, respectively). 17beta-Estradiol also increased cardiac output by 12% +/- 3%. Premarin increased cardiac output 2% +/- 3%, 9% +/- 4%, and 11% +/- 3%, with only the highest dose producing a significant change. 17beta-Estradiol also increased heart rate by 12% +/- 1%, whereas Premarin at doses of 0.625, 1.25, and 2.5 mg increased it by 4% +/- 3%, 7% +/- 4%, and 10% +/- 2%, respectively (increase significant only at the highest dose). Neither 17beta-estradiol nor Premarin altered either stroke volume or systemic arterial pressure.

CONCLUSION

Premarin, like 17beta-estradiol, has significant systemic, coronary, and uterine vascular effects. These vascular effects may help to explain in part why these compounds are cardioprotective.

The role of nitric oxide in mediating adenosine-induced increases in uterine blood flow in the oophorectomized nonpregnant sheep

OBJECTIVE

Adenosine administration to the uterine vasculature of the nonpregnant oophorectomized sheep results in dose-related increases in uterine blood flow. This study was designed to determine whether these adenosine-induced increases in uterine blood flow are mediated in part by nitric oxide release.

STUDY DESIGN

Five nonpregnant oophorectomized ewes had catheters placed in the femoral artery and vein and in the lateral branches of the right and left main uterine arteries. Adenosine dissolved in isotonic sodium chloride solution was infused into the uterine artery at sequentially increasing doses (1, 3, 10, 30, 100, and 300 microg/min), and a dose-response curve was constructed. After determination of control responses to adenosine a 10-mg/kg dose of the nitric oxide synthase inhibitor N omega-nitro-L -arginine methyl ester was administered into the femoral vein; the dose-response curves to adenosine were then determined again. Responses after N omega-nitro-L -arginine methyl ester administration were compared with those obtained before nitric oxide blockade.

RESULTS

Adenosine increased uterine blood flow in a dose-related fashion, from a baseline of 11 +/- 2 mL/min to 140 +/- 19 mL/min. No further increase was seen with adenosine doses >300 microg/min. There were no significant alterations in systemic arterial pressure or heart rate in response to uterine infusion of adenosine. N omega-nitro-L -arginine methyl ester administration increased baseline blood pressure 24% +/- 4% and decreased heart rate 13% +/- 4%. Responses to adenosine after N omega-nitro-L -arginine methyl ester administration were significantly reduced, from a maximum at the highest dose of 140 +/- 19 mL/min to 95 +/- 13 mL/min (P <.001).

CONCLUSION

A significant portion of adenosine-induced vasodilation in the uterine vasculature appears to be mediated by the release of nitric oxide.

Effects of chronic reduction in uterine blood flow on fetal and placental growth in the sheep

Pregnancy is associated with a significant increase in uteroplacental blood flow (UBF), which is responsible for delivering adequate nutrients and oxygen for fetal and placental growth. The present study was designed to determine the effects of vascular insufficiency on fetal and placental growth. Thirty-nine late-term pregnant ewes were instrumented to investigate the effects of chronic UBF reduction. Animals were split into three groups based on uterine blood flow, and all animals were killed on gestational day 138. UBF, which began at 851 +/- 74 ml/min (n = 39), increased in controls (C) to 1,409 +/- 98 ml/min (day 138 of gestation) and in the moderately restricted (R(M)) group to 986 +/- 69 ml/min. In the severely restricted (R(S)) group, UBF was only 779 +/- 79 ml/min on gestational day 138. This reduction in UBF significantly affected fetal body weight with R(M) fetuses weighing 3,685 +/- 178 g and R(S) fetuses weighing 2,920 +/- 164 g compared with C fetal weights of 4,318 +/- 208 g. Fetal brain weight was not affected, whereas ponderal index was significantly reduced in R(M) (2.94 +/- 0.09) and R(S) fetuses (2.49 +/- 0.08) compared with the value of the C fetuses (3.31 +/- 0.08). Placental weight was also significantly reduced in the R(M) group, being 302 +/- 24 g, whereas the R(S) group placenta weighed 274 +/- 61 g compared with the C values of 414 +/- 57 g. Fetal heart, liver, lung, and thymus were all significantly smaller in the R(S) group. Thus the present study shows a clear relationship between the level of UBF and both fetal and placental size. Furthermore, the observation that fetal brain weight was not affected, whereas fetal body weight was significantly reduced suggests that this experimental preparation may provide a useful model in which to study asymmetric fetal growth restriction.

Coronary and uterine vascular responses to raloxifene in the sheep

OBJECTIVE

We sought to determine whether raloxifene increases coronary and uterine blood flow in ovariectomized ewes.

STUDY DESIGN

Twelve ewes were chronically instrumented for measurement of mean arterial pressure, heart rate, cardiac output, coronary blood flow, and uterine blood flow. Sheep received 17beta-estradiol, Estrace, raloxifene, or KY Jelly vehicle on separate days.

RESULTS

17beta-Estradiol increased uterine blood flow from 21 +/- 3 to 254 +/- 36 mL/min and coronary blood flow by 21% +/- 2% within 2 hours. Estrace increased uterine blood flow from 30 +/- 7 to 260 +/- 62 mL/min and coronary blood flow by 8% +/- 4% within 3 hours. Raloxifene increased uterine blood flow from 20 +/- 3 mL/min to 220 +/- 53 mL/min by 6 hours and coronary blood flow by 22% +/- 5% within 24 hours. To determine whether hemodynamic responses were mediated by nitric oxide, L -nitroarginine methyl ester was administered and produced an approximate 50% decrease in uterine blood flow for all 3 compounds. L -Nitroarginine methyl ester attenuated increases in coronary blood flow induced by 17beta-estradiol, Estrace, and raloxifene.

CONCLUSION

Raloxifene has significant coronary and uterine vascular effects in the ovariectomized ewe. The coronary and uterine responses are partially mediated by nitric oxide.

Focus groups: a qualitative method complementing quantitative research for studying culturally diverse groups

CONTEXT

Focus groups are becoming an important method for conducting qualitative research in health care. This strategy enables information to be gathered on the perceptions, beliefs, and values of a group's participants and is particularly well suited to addressing cultural characteristics that impact on a population's health status. As nations become more culturally diverse, qualitative research will likely play a growing role in helping health professions educators develop appropriate educational programs and in helping researchers better understand the needs of minorities and other vulnerable populations who are experiencing disparities in health care.

OBJECTIVES

The purposes of this paper are to introduce the usefulness of a qualitative research strategy as an adjunct to quantitative survey research, and to describe briefly how researchers and educators at the Charles R. Drew University of Medicine and Science (Drew) have utilized this strategy when conducting combined qualitative and quantitative research.

DISCUSSION

Focus group research has been successfully used to develop culturally adapted surveys, to develop educational programs, and to conduct needs assessments at Drew, which serves a culturally diverse urban population.

Optic nerve edema as a consequence of respiratory disease

The authors describe a patient with bilateral papilledema, visual field abnormalities, poorly reactive pupils, meningeal enhancement on cranial MRI, and diffuse brain parenchymal hypervascularity. The opening pressure at the time of lumbar puncture was normal, and results of other CSF studies were normal. All abnormalities resolved with home oxygen therapy.

Ophthalmoplegic migraine with unusual features

We report the details of a patient with an unusual form of ophthalmoplegic migraine resulting in permanent vertical misalignment of the affected eye. The presentation, history, and ophthalmologic examination are reported as well as disease course and follow-up complications. We review the literature on ophthalmoplegic migraine with discussion regarding typical presentation, methods of diagnosis, and other diseases which may cause diagnostic confusion. In light of current case reports on ophthalmoplegic migraine, this is the first documented example with a permanent deficit.

A population-based survey of hospitalized work-related ocular injury: diagnoses, cause of injury, resource utilization, and hospitalization outcome

Occupational injury is a major source of ocular trauma and is often preventable. A statewide population-based survey of severe work-related ocular injury was generated by using the California Hospital discharge database to identify hospitalized ocular injury and workers compensation as principal payor to identify work-relatedness. Information concerning diagnoses, procedures, causes of injury, length of hospital stay, total hospital charges and disposition at hospital discharge were obtained for injuries occurring during the calendar year 1988. A total of 455 admissions for work-related ocular trauma were identified. The most common work-related ocular trauma diagnoses associated with hospitalizations were open globe injury (46%), adnexal wounds (20%), orbital fractures (11%), and traumatic hyphema (11%). The most common causes of work-related ocular trauma were foreign-body or projectile objects (19%), transport vehicles (18%), cutting or piercing objects (17%), and assaults (9%). Approximately 8% reported other than routine disposition at time of hospital discharge, including long-term nursing or rehabilitation services and death. Mean hospital stay when ocular trauma was the principal admitting diagnosis was 3.7 days. Results differed significantly for admissions reporting ocular trauma as the principal admitting diagnosis compared to admissions that did not. Hospitalized work-related ocular trauma is represented by a wide spectrum of injuries with substantial morbidity and economic costs. Projected to the United States population, these data indicate annual hospital charges excluding professional fees of $14.6 million when work-related ocular trauma is the principal admitting diagnosis and $40 million for admissions where ocular trauma is either a principal or secondary diagnosis.

Evaluation and classification of pediatric ocular trauma

PURPOSE

To offer to the pediatric emergency physician consistent and unambiguous terms for the description of pediatric ocular trauma, based upon an adapted version of a standardized classification system. To show the potential effect of this reclassification system in a tertiary care emergency department.

METHODS

The authors reviewed a new classification system of ocular trauma and adapted it for use by pediatric emergency physicians. In addition, a retrospective analysis of the records of pediatric patients presenting over a 2-year period to a tertiary emergency department with ocular complaints was performed. The diagnoses related to ocular trauma were reclassified according to the new classification system.

RESULTS

Over a 2-year period, 117 pediatric patients were evaluated for ophthalmic complaints. Sixty-seven (57%) of these cases involved an ocular contusion or ruptured globe; however, six disparate diagnoses were given. The cases were reclassified into an adapted, unambiguous, classification system. In some cases, the reclassification altered the indication for immediate ophthalmologic referral.

CONCLUSION

There is currently no standardized system of terminology to describe pediatric ocular trauma. This may lead to confusion in communication among the pediatric emergency physician, the pediatrician, and the ophthalmologist. Consistent, unambiguous, terminology will assist in this communication, facilitate the writing of peer-reviewed articles and case reports, and increase the level of accurate documentation in the medical record.

Eyelid kinematics following blepharoplasty

PURPOSE

This study characterizes the effects of blepharoplasty on blink dynamics in subjects with dermatochalasis. The authors evaluate the hypothesis that orbicularis oculi removal and the consequent alterations in blink are potentially harmful consequences of blepharoplasty.

METHODS

Sixteen patients were studied, before and after laser blepharoplasty, by a modified scleral search coil technique. Changes in lid position during blinks were recorded before surgery as well as 2 months, and 1 year postoperatively. Off-line analyses assessed blink down-phase amplitude, peak velocity, duration, and main sequence (peak velocity versus amplitude) relationships.

RESULTS

Despite muscle resection, there was no significant compromise of mean blink down-phase amplitude, peak velocity, or main sequence following blepharoplasty. Mean blink duration was likewise unchanged at either follow-up session from the preoperative state. Our data show that upper lid blepharoplasty does not cause any lasting decrement in lid function in blinking.

CONCLUSIONS

Blepharoplasty includes resection of a portion of the orbicularis oculi. It appears unlikely that the purposeful resection of preseptal portion of the orbicularis oculi that accompanies blepharoplasty is responsible for any functional complications such as dry eye.

Corneal topographic changes after extraocular muscle surgery

PURPOSE

Changes in refractive error have been reported after strabismus surgery. The influence of extraocular muscle tension on corneal topography is thought to be an important mechanism contributing to this alteration. This study investigates topographic changes after strabismus surgery in human beings.

METHODS

The corneal topography of 63 eyes of 43 patients who underwent either strabismus or optic nerve sheath fenestration (ONSF) surgery was measured before and after operation. The ONSF surgery involved removing and reattaching the medial rectus muscle, thus acting as a control for the strabismus procedures. Corneal power was measured centrally and at 1.5 and 3.0 mm in 8 meridians. Analysis of variance was performed to compare the difference in preoperative and post-operative corneal power for all procedures and comparing recessions, resections, combined recession and resection, and ONSF as grouped procedures.

RESULTS

All groups showed a significant change in preoperative to postoperative corneal power (P< .01). A significant change was seen between all grouped procedures except when the resection was compared with ONSF and compared with recession.

CONCLUSIONS

Change in the tension of 1 muscle does not produce a change in the adjacent quadrant as much as it produces a significant change in the entire corneal surface, which illustrates the interaction and interdependence all corneal positions have with respect to each other.

Efficacy of gold weight implants in facial nerve palsy: quantitative alterations in blinking

Deficient eyelid closure is a major visual threat to patients with unresolved facial nerve palsy. Gold weight implants assisted eyelid closure in patients with paresis of the orbicularis oculi, ameliorating patient complaints of dry eye, excessive tearing, and corneal epithelial breakdown. We used dynamic measures to assess the efficacy of upper eyelid gold weight implantation surgery for facial nerve palsy. The search coil technique was used to record spontaneous blinks bilaterally in six patients, before and after unilateral gold weight implantations into the upper eyelid in severe facial nerve palsy. In uncomplicated facial nerve palsy, the amplitude of blink down-phases for the paretic eyelid was 28.6 +/- 5.7% of the amplitude of the contralateral, normal eyelid. Following corrective surgery, closure of the paretic eyelid improved to 42.6 +/- 7.5% (P < 0.05). There was not a commensurate increase in the peak velocity of blink down-phases, suggesting that gold weight effects are mediated by a passive improvement in blink dynamics.

Demographic and clinical characteristics of patients with diabetes presenting to an urban public hospital ophthalmology clinic

OBJECTIVE

This study aims to describe the clinical and sociodemographic characteristics of patients with diabetes who are newly presenting to an inner city public hospital eye clinic. This study also aims to determine the prevalence and severity of ocular morbidity in this population at time presentation and to assess the adequacy of the ophthalmic surveillance to which this population was exposed before presentation.

DESIGN

A clinic-based, cross-sectional study.

PARTICIPANTS

A total of 118 consecutive patients with diabetes participated.

METHOD

During a 2-month interval, all patients with diabetes newly presenting to the Los Angeles County King-Drew Medical Center eye clinic were recruited who were at risk for diabetic eye complications according to American Diabetes Association criteria. Each patient underwent a standardized interviewer-administered questionnaire and a comprehensive ophthalmic examination.

RESULTS

Of the 118 patients, 65 (55%) were Hispanic and 51 (43%) were African American. Forty-six percent had a grade school education or less, 91% were unemployed, and 64% had no health insurance. Type two diabetes was predominant (91%), including 24 (22%) of new onset. Thirty-six patients with diabetes (31%) reported duration of diabetes greater than 10 years at time of presentation. At time of presentation, 62% had clinically apparent ophthalmic disease, whereas 40% had advanced ocular disease, including 6.8% of the sample that were legally blind. Sixty-nine patients (58.5%) reported never having had a dilated fundus examination, whereas 31 (63%) of the 49 patients reporting a previous dilated examination were last examined more than 2 years before presentation. Timing of ophthalmic examination was classified as appropriate for 38 patients (32%), marginal for 20 patients (17%), and inappropriate for 60 patients (51%).

CONCLUSION

In the setting of an inner city county hospital eye clinic, where the patient population is predominately minority and of low socioeconomic status, ophthalmic surveillance of high-risk patients with diabetes is inadequate and advanced disease often is present at initial presentation. Strategies must be developed to increase the routine use of eye services within this population.

Correlates of recency of eye examination among elderly African-Americans

This study uses a theoretical model of health services utilization to assess the effects of predisposing, enabling, and need-for-care characteristics on recency of eye examinations among a sample of 998 elderly African-American persons. More than 64% of participants reported that they had had eye examinations within the last 12 months. Multiple logistics regression analysis explains 13.3% of the variance of eye examinations. This data indicates that recency of eye examination is related to health locus of control, private insurance, Medicare, insulin-dependent diabetes, and presence of eye disease. No significant relationship between recency of eye examination and self-rated health status, social support, vision impairment, and non-insulin-dependent diabetes were detected. The lack of association between non-insulin-dependent diabetes and the recency of eye examination suggests that the amount of preventive care in place may not be adequate. This data shows that the unique contributions of need characteristics account for a major variance of recency of eye examination. However, enabling characteristics play a significant role in sending the participants of this study to eye-specialists, even after need-for-care factors are held constant.

Pseudotumor of the orbit in early childhood

Orbital pseudotumor, also known as idiopathic orbital inflammation, is defined as a nonspecific, nonneoplastic inflammatory process of the orbit without identifiable local or systemic causes. The disorder, first described by Birch-Hirschfield in 1905, is more prevalent in the adult population than in the pediatric population. In our study we discuss two cases of pseudotumor of the orbit in children less than 18 months old. This report will highlight the evaluation and management of pediatric orbital pseudotumor and the importance of its inclusion in the differential diagnosis of orbital disorders in young children.

Emergency department utilization, hospital admissions, and physician visits among elderly African American persons

This study uses a theoretical model of health services utilization to examine (a) emergency department utilization, (b) hospital admissions, and (c) office-based physician visits among a sample of 998 low-income elderly African American persons. Poisson Regression analysis was used to estimate the parameters specified in the Andersen behavioral model. Some of the more interesting results include the following: (a) a greater frequency of emergency room visits among respondents with a lower level of accessibility to physician services, (b) a lack of a significant relationship between some chronic illnesses such as diabetes and heart problems and the frequency of office-based physician visits, (c) a greater number of hospital admissions among insured persons, and (d) a significant impact of the health locus of control indexes on all three types of health care utilization. The results of this study challenge the assumption that hospital and emergency use are the results of nondiscretionary behavior.

Effects of continuous infusion of endothelin-1 in pregnant sheep

Plasma concentration of endothelin-1, a potent vasoconstrictor produced by the vascular endothelium, has been observed to be significantly increased in a number of pathophysiological states, including preeclampsia. In the present study we have evaluated the effects of elevated plasma endothelin-1 in pregnant sheep by continuous exogenous endothelin-1 administration. Nine pregnant ewes (110+/-5 days' gestation) were instrumented for measurements of maternal mean arterial pressure, renal blood flow, and uterine blood flow. After recovery, endothelin-1 was infused intravenously for 4 hours at a dose that was adjusted to raise mean arterial pressure by approximately 20 mm Hg by the end of the first hour (range 5 to 20 ng/kg per minute). Mean arterial pressure, renal blood flow, uterine blood flow, urinary protein excretion, hematocrit, and plasma endothelin-1 concentration were measured hourly, and renal and uterine vascular resistances were calculated. Endothelin-1 produced significant increases (% change from baseline at t=4 hours) in mean arterial pressure (45+/-8%), renal vascular resistance (353+/-66 %), and uterine vascular resistance (59+/-21%). Endothelin-1 also increased microvascular permeability both systemically and within the kidney, as suggested by marked increases in hematocrit (0.27+/-0.01 to 0.32+/-0.01) and urinary protein concentration (0.95+/-0.1 to 7.9+/-3.2 mg/mL per mg creatinine). There was a highly significant correlation (P<.0001) between plasma endothelin-1 and mean arterial pressure, renal vascular resistance, uterine vascular resistance, hematocrit, and urinary protein content in all sheep studied. In addition, plasma endothelin-1 corresponded well with the time course of the changes in cardiovascular parameters and urinary protein excretion observed. These results provide evidence to suggest that elevation of circulating endothelin-1 in pregnant sheep can produce cardiovascular and hemodynamic changes that in many ways resemble the human disease preeclampsia. This supports the hypothesis that endothelial cell damage and/or dysfunction that is associated with increased production of endothelin-1 could directly contribute to the progression of preeclampsia.

Large recession nystagmus surgery in albinos: effect on acuity

PURPOSE

To evaluate the effect of large muscle recessions on visual acuity in albinos with nystagmus.

METHODS

This is a retrospective, unmasked, chart review of 12 patients with ocular or oculocutaneous albinism demonstrating nystagmus who underwent four horizontal rectus muscle retroequatorial recessions. Pre- and postoperative visual acuity were measured.

RESULTS

Best corrected visual acuity improved postoperatively by two or more Snellen lines in 7 of 12 patients (58%). Subjective improvement of vision and nystagmus was noted by patients and examiners. Follow up was performed between 3 and 41 months; 25% of patients required reoperation for ocular alignment.

CONCLUSION

Large four-muscle horizontal rectus recessions may improve uniocular and binocular visual acuities in albinos with nystagmus as measured by Snellen acuity. Patients may note a qualitative decrease in the severity of their nystagmus.

Estrogen-induced increases in coronary blood flow are antagonized by inhibitors of nitric oxide synthesis

OBJECTIVE

Estrogen receptors have been found in coronary arterial endothelial and vascular smooth muscle cells. Therefore the present study was designed to determine if estradiol-17 beta can increase coronary blood flow and if so whether the changes are mediated by nitric oxide.

STUDY DESIGN

Five oophorectomized non-pregnant sheep were chronically instrumented to measure blood pressure, heart rate, cardiac output, left circumflex coronary blood flow and central venous pressure. Animals received estradiol-17 beta (1.0 micrograms/kg) and cardiovascular responses were followed for 135 min.

RESULTS

Estradiol-17 beta (1.0 micrograms/kg) increased left circumflex (coronary) blood flow 28 +/- 3%, cardiac output 15 +/- 1% and heart rate by 13 +/- 3%. Coronary vascular resistance decreased 23 +/- 5%, systemic vascular resistance decreased by 12 +/- 2% while blood pressure did not change significantly. Administration of the nitric oxide synthetase inhibitor L-nitroarginine methylester (L-NAME), had no effect on basal coronary blood flow but completely reversed estradiol-17 beta induced increases in coronary blood flow.

CONCLUSION

These results demonstrate that estrogen increases coronary blood flow in the non-pregnant sheep and that L-NAME, an inhibitor of nitric oxide, is able to reverse the estrogen induced flow changes.

Maladaptive neural compensatory mechanisms in Bell's palsy-induced blepharospasm

We described four patients with Bell's palsy and blepharospasm and evaluated potential mechanisms that may be responsible for an apparent association between the two disorders. Eyelid movements in spontaneous blinks were studied by the search coil technique in patients with this novel disorder. Kinematic analyses documented bilateral eyelid spasm subsequent to unilateral Bell's palsy. The temporal interval between the onset of palsy and onset of blepharospasm was highly variable (weeks to > 20 years). Changes in the relationship between spontaneous blink peak velocity and amplitude, the main sequence, shared features previously found in uncomplicated Bell's palsy and blepharospasm patients. Furthermore, as in patients with typical Bell's palsy and idiopathic blepharospasm, both normal blinks and spasms were conjugate in spite of interocular differences in blink amplitude/peak velocity. We suggest that there is a correlation between the eyelid palsy and subsequent blepharospasm, and have designated this potentially new disease entity as Bell's palsy-induced blepharospasm. We propose a two-stage model for Bell's palsy-induced blepharospasm in which blink adaptive systems may produce the maladaptive consequence of eyelid spasms.

Absence of oculomotor and trochlear motoneurons leads to altered extraocular muscle development in the Wnt-1 null mutant mouse

Wnt-1 null mutant mice lack midbrain somatic motor nuclei. Primordial migration and spatial patterning of the extraocular muscles, however, was preserved, but myogenesis was disrupted in aneural muscles. Some muscles normally innervated by oculomotor and trochlear nuclei received aberrant innervation, which proved sufficient to maintain prenatal stages of myogenesis. The absence of motoneurons followed by innervation from inappropriate motoneuron pools is a viable candidate mechanism in ocular motility disorders, including Duane retraction syndrome and congenital fibrosis of extraocular muscle.

The role of blink adaptation in the pathophysiology of benign essential blepharospasm

OBJECTIVE

To investigate eyelid movements in patients with benign essential blepharospasm (BEB), with an emphasis on the characterization of the kinematics of normal and spastic blinks, assessment of interocular differences, and further delineation of the role of adaptive blink mechanisms in eyelid movement disorders.

PATIENTS AND METHODS

The electromagnetic search coil technique was used to record the metrics of blinks bilaterally in 5 patients with untreated BEB. Eyelid kinematics and the main-sequence (peak velocity vs amplitude) relationships were analyzed.

RESULTS

Patients with BEB exhibited a decrease in blink amplitude and peak velocity. Moreover, the main-sequence slope was decreased bilaterally. Spasms were bilateral and relatively conjugate. There was no change in the coordination of normal blinking across the 2 eyelids.

CONCLUSIONS

These data demonstrate the operation of the adaptive regulation of blinking in an eyelid movement disorder. The findings suggest that the adaptive regulation of blink is a bilateral event. Blink-adaptive control systems can act on the blink reflex excitability and main-sequence relationships, changing these either together or independently. The hyperexcitable blink reflex of BEB is met by what is believed to be an adaptive decrease in the main-sequence slope that would decrease the strength of debilitating spasms. Collectively, these data extend the knowledge of the pathophysiology of BEB and, perhaps more important, establish the role of blink system plasticity in eyelid movement disorders.

Age-related changes in human blinks. Passive and active changes in eyelid kinematics

PURPOSE

The authors analyzed eyelid kinematics in normal aging subjects to test the hypothesis that eyelid movements exhibit age-related changes and that blink disorders prevalent among the elderly, in turn, represent an outcome of normal aging processes.

METHODS

The electromagnetic search coil technique was used to study blinks in normal human subjects for each decade from 40 to 89 years. Blink metrics (amplitude, peak velocity, and duration), main sequence relationships, and conjugacy were assessed.

RESULTS

Mean amplitude and peak velocity of blinks decreased with age for spontaneous blinks and, to a lesser extent, for voluntary blinks. Some but not all, of this decline could be attributed to a peripheral phenomenon, narrowed palpebral fissure width. The spontaneous blink down phase main sequence slope also declined with age. By contrast, blink rate and the coordination of movements of the two eyelids--blink conjugacy--exhibited no change.

CONCLUSIONS

These data demonstrate that disorders of blink systems typically seen in persons 50 years of age or older occur on a background of normal age-dependent changes in eyelid kinematics. Alterations in main sequence slope imply the operation of central adaptive systems during aging. Reduction in main sequence slope is interpreted as a reduction in aggregate orbicularis oculi motoneuron activity. Such a central neurologic adjustment in the motor output of blink systems may serve to compensate for an age-related increase in blink reflex excitability. Compensatory reduction in the main sequence relationship may offset a potentially hyperexcitable blink reflex, thereby reducing the likelihood of disorders such as blepharospasm. The authors conclude that although there are changes in the kinematics of blinking with age, such changes do not necessarily predispose an aging population to eyelid motility disorders.